MANUAL Part II Visual Assessment of Crown Condition - ICP Forests

II. CROWN CONDITION ASSESSMENTS 1 

UNITED NATIONS ECONOMIC COMMISSION FOR EUROPE 

CONVENTION ON LONG-RANGE TRANSBOUNDARY AIR POLLUTION 

International Co-operative Programme on 

Assessment and Monitoring of Air Pollution Effects on Forests 

MANUAL 

on 

methods and criteria for harmonized sampling, assessment, 

monitoring and analysis of the effects of air pollution on forests 

Part II 

Visual Assessment of 

Crown Condition 

updated: 06/2006 

new forms to be applied from 2007 onwards 

updated 06/2006

2 II. CROWN CONDITION ASSESSMENTS 

updated 06/2006


Contents 

1. INTRODUCTION ...................................................................................................................................................7 

2. FREQUENCY OF ASSESSMENT........................................................................................................................7 

3. SELECTION OF SAMPLE PLOTS AND TREES..............................................................................................8 

4. CROWN TO BE ASSESSED .................................................................................................................................9 

5. DIRECTION OF ASSESSMENT ........................................................................................................................11 

6. REFERENCE TREE.............................................................................................................................................11 

6.1 DOCUMENTATION AND PHOTOGRAPHS ..............................................................................................................12 

7. PARAMETERS TO BE ASSESSED ...................................................................................................................12 

8. GUIDELINES FOR FIELDWORK ....................................................................................................................12 

9. QUALITY CONTROL AND QUALITY ASSURANCE...................................................................................13 

9.1 SELECTION OF SURVEY TEAMS (LEVEL I AND LEVEL II) ....................................................................................13 

9.2 TRAINING ..........................................................................................................................................................13 

9.3 DATA PLAUSIBILITY...........................................................................................................................................14 

9.4 INTERNATIONAL QUALITY CONTROL ................................................................................................................14 

10. DATA REPORTING AND SUBMISSION .......................................................................................................15 

ANNEX 1: ASSESSMENT OF GENERAL PLOT AND TREE PARAMETERS, FOLIAGE, 

REPRODUCTIVE STRUCTURES AND EPICORMICS.....................................................................................17 

A1.1 COUNTRY (MANDATORY LEVEL I AND LEVEL II)...........................................................................................17 

A1.2 OBSERVATION PLOT NUMBER (MANDATORY LEVEL I AND LEVEL II).............................................................17 

A1.3 DATE OF OBSERVATION, DATE OF ASSESSMENT, ............................................................................................17 

DATE OF ANALYSIS (MANDATORY LEVEL I AND LEVEL II) ......................................................................................17 

A1.4 LATITUDE/ LONGITUDE COORDINATES (MANDATORY LEVEL I AND LEVEL II) ...............................................17 

A1.5 AVAILABILITY OF WATER TO PRINCIPAL SPECIES (ESTIMATE) (MANDATORY LEVEL I)...................................17 

A1.6 HUMUS TYPE (MANDATORY LEVEL I) ............................................................................................................18 

A1.7 ALTITUDE (MANDATORY LEVEL I AND LEVEL II) ..........................................................................................18 

A1.8 ORIENTATION (MANDATORY LEVEL I)...........................................................................................................18 

A1.9 MEAN AGE OF DOMINANT STOREY (YEARS) (MANDATORY LEVEL I)..............................................................18 

A1.10 SOIL UNIT (MANDATORY LEVEL I) ...............................................................................................................18 

A1.11 SAMPLE TREE NUMBER (MANDATORY LEVEL I AND LEVEL II).....................................................................18 

A1.12 SPECIES (REFERENCE FLORA EUROPAEA) (MANDATORY LEVEL I AND LEVEL II)........................................19 

A1.13 REMOVALS AND MORTALITY (MANDATORY LEVEL II).................................................................................20 

A1.14 SOCIAL CLASS (MANDATORY LEVEL II) .......................................................................................................21 

A1.15 CROWN SHADING (MANDATORY LEVEL II) ..................................................................................................21 

A1.16 VISIBILITY (MANDATORY LEVEL II).............................................................................................................22 

A1.17 DEFOLIATION (MANDATORY LEVEL I AND LEVEL II)...................................................................................22 

A1.18 DISCOLOURATION (OPTIONAL LEVEL I AND LEVEL II).................................................................................23 

A1.19 FOLIAGE TRANSPARENCY (OPTIONAL LEVEL II) ..........................................................................................23 

A1.20 FLOWERING (OPTIONAL LEVEL II) ...............................................................................................................25 

A1.21 FRUITING (OPTIONAL LEVEL I AND LEVEL II) ..............................................................................................26 

A1.22 SECONDARY SHOOTS AND EPICORMICS (OPTIONAL LEVEL II) ......................................................................26 

A1.23 CROWN FORM/MORPHOLOGY (INCL. ROLOFF) (OPTIONAL LEVEL II) ............................................................27 

ANNEX 2: ASSESSMENT OF DAMAGE CAUSES.............................................................................................29 

A2.1 INTRODUCTION ...............................................................................................................................................30 

A2.2 DEFINITIONS ...................................................................................................................................................30 

A2.3 SELECTION OF SAMPLE TREES .........................................................................................................................30 

A2.4 FREQUENCY AND TIMING................................................................................................................................30 

A2.5 PARAMETERS TO BE ASSESSED........................................................................................................................30 

A2.5.1 Symptom description ..............................................................................................................................31 

A2.5.1.1 Affected part of the tree and location in crown ...................................................................................31 

A2.5.1.2 Symptoms and their specification ........................................................................................................32 

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A2.5.1.3 Age of the damage............................................................................................................................... 35 

The age of the damage shall be reported using the following classes: ............................................................. 35 

A2.5.2 Causal agents / factors .......................................................................................................................... 35 

A2.5.2.1 Scientific name of cause (mandatory Level I and Level II)................................................................. 41 

A2.5.3 Quantification........................................................................................................................................ 42 

A2.5.3.1 Extent .................................................................................................................................................. 42 

Examples:.......................................................................................................................................................... 42 

A2.5.3.2 Extent classes (mandatory Level I and Level II)................................................................................. 43 

Specifications:................................................................................................................................................... 43 

A2.6 QUALITY ASSURANCE AND QUALITY CONTROL.............................................................................................. 44 

A2.7 REPORTING .................................................................................................................................................... 44 

A2.8 REFERENCES .................................................................................................................................................. 44 

ANNEX 3: FORMS .................................................................................................................................................. 46 

ANNEX 3: FORMS .................................................................................................................................................. 46 

A3.1 FORMS FOR ANNUAL REPORT OF NATIONAL CROWN CONDITION DATA........................................................... 47 

A3.3 FORMS FOR LEVEL II DATA ............................................................................................................................ 58 

ANNEX 4: DESIGN OF INTERNATIONAL CROSS-CALIBRATION COURSES ........................................ 63 

A4.1 THE CONCEPT OF THE ICC SYSTEM ................................................................................................................ 64 

A4.2 BASIC DESIGN ELEMENTS............................................................................................................................... 64 

A4.2.1 Plot and tree selection ........................................................................................................................... 64 

A4.2.2 Invitation and participation ................................................................................................................... 64 

A4.3 IMPLEMENTATION OF THE ICCS ..................................................................................................................... 65 

A4.3.1 Field work, use of home references ....................................................................................................... 65 

A4.3.2 Codes ..................................................................................................................................................... 65 

A4.3.2.1 Participant code.................................................................................................................................. 65 

A4.3.2.2 Plot code ............................................................................................................................................. 65 

A4.3.3 Data to be recorded ............................................................................................................................... 65 

A4.4 DATA SUBMISSION ......................................................................................................................................... 66 

A4.5 REFERENCES .................................................................................................................................................. 68 

Elaborated by: 

Expert Panel on Crown Condition 

Johannes EICHHORN, Andras SZEPESI, Marco FERRETTI, Dave DURRANT, Peter ROSKAMS 

updated 06/2006


0. Amendment history 

(amendments in comparison with version of 2004) 

ANNEX 1: 

1. Annex 1, A1.1: Country code list amended. 

2. Annex 1, A1.6: The humus type is no longer defined in this section but a link is set to 

the respective section in part IIIa of the ICP Forests Manual on Sampling and Analyses of 

Soil. 

3. Annex 1, A1.9: The mean age of dominant storey: definition of class 7 is defined 

correctly (> 120 years instead of > 121 years). 

4. Annex 1, A1.10: The soil unit is no longer defined in this section but a link is set to the 

respective section in part IIIa of the ICP Forests Manual on Sampling and Analyses of 

Soil. 

5. Annex 1, A1.12: The species list is amended by tree species (codes 91, 92, 93). 

6. Annex 1, A1.18: Discolouration (“old definition”) is no longer mandatory but optional 

on Level I and Level II. The text is re-phrased with a link to ANNEX 2 (“new 

definition”). The table for coding discolouration is completed by code 4 (dead trees). 

7. Annex 1, A1.21: Fruiting now is optional also on Level I (not assessed on Level I 

before). In the text the importance of this information especially for beech is underlined. 

ANNEX 2: ASSESSMENT of damage causes 

8. Introduction: re-phrased in order to improve the description which damage symptom to 

assess in which way. 

9. A2.5 Parameters to be assessed: Adaptations according to the revised submission forms. 

10. A2.5.1 Symptom description: re-phrased in order to improve the description which 

damage symptom to assess in which way. 

11. A2.5.1.2 Symptoms and their specifications: in point a. the usage of “National lists” is 

specified. 

12. A2.5.1.2: under Specifications “b. Avoiding duplication of crown condition assessment 

is” is revised 

13. A2.5.1.3 Age of the damage is a new parameter (optional on Level I and Level II) 

14. A2.5.2 Causal agents / factors: 3 rd paragraph: A procedure is described how to amend 

the list of causal agents for species which are not already included but were investigated. 

15. Table A2-6: Eriophyes ilicis was moved to code 800 (other) with code 87001 in the 

newly introduced class 870 “mites” 

16. Table A2-7: added “Lophodermella sulcigena” under 301 under other Lophodermium 

(genus affected: Pinus sp.); included Armillaria spec. in code for scientific name of cause 

(Annex 3 in internet presentation; see below). 

17. Table A2-8: included under physical factors “rock fall” with code 434. 

18. Table A2-9: added code 581 and 582; old “systematically wrong code number” remain in 

action 

19. Table A2-11: added “Clematis sp” as 81005 and “Mites” as 870. 

20. A2.5.2.1: The list of codes for scientific name of cause (table A2-12) is skipped from the 

manual; a link now is set to “http://www.icp-forests.org/WGbiotic.htm >> click on 

annex 3” 

FORMS for submitting data from the NFCs to the data centres 

21. The forms were revised in a way that there are 3 forms for Level I and 3 forms for 

Level II, respectively: 

The first form for a reduced plot file (PLO and PLT, respectively), 

the second from for the submission of crown/tree related parameters (in general 1 

observation for each tree, TRE and TRC, respectively) and 

the third form for submission of damage assessment data (0 to n observations for each 

tree, TRF and TRD, respectively). 

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22. The parameters which have to be submitted with the particular forms may change over 

time. Therefore, with the update from June 2006 the NFCs are asked to start each data 

file with a comment line. This line is starting with an exclamation mark followed by the 

names of the parameters, each separated by a comma. For each data file a proposal is 

given at the top of the respective form. 

23. Forms A1, A2, A3, B1, B2, B3, and C remain unchanged! 

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1. Introduction 

The assessment of crown condition is central to the ICP Forests operated under the UNECE 

since 1985. The assessment methods developed in the mid-1980s for Level I formed the basis of 

the assessments in the Level II plots. These were described in the earlier manual on the ‘Visual 

Assessment of Crown Condition’ and the ‘Submanual on Visual Assessment of Crown 

Condition on Intensive Monitoring Plots’. Within Europe, the combination of almost 6000 plots 

on a systematic 16x16 km grid (Level I) and almost 900 intensive monitoring plots (Level II) 

provides a unique and unrivalled data set. Scientific analyses of these data increasingly point to 

the need for a harmonised approach to data gathering, reporting and analysis. This re-design of 

the manual allows a harmonised, yet more flexible approach to crown condition monitoring, 

while retaining continuity and allowing better, more transparent quality assurance. All of the 

parameters described here have been tested in one or more countries in Europe or North America 

during the last 15 years. However, the value of the parameters will continue be monitored by an 

Expert Panel and any necessary adjustments will be recommended to the Task Force of the ICP 

Forests in future years. 

A number of new measures, additional to the existing Level I set of parameters, are proposed in 

this manual, mainly aiming at a more precise description of observed damages. An important 

addition is the requirement for the submission of quality control data. Such information is 

essential for the determination of confidence limits for the data, an important step is the 

identification of changes through time and in cause-effect studies. Without such confidence 

limits, the reliable identification of temporal or spatial variation in crown condition will be 

extremely difficult. 

This manual is a synthesis of earlier Expert Panel meetings, manuals, assessment 

recommendations, pilot studies and the recommendation of the 17 th Task Force where the Expert 

Panel was asked to ‘organise the planned workshop on data evaluation’ and ‘to present a revised 

submanual to the Task Force in 2003’. 

Objectives 

The major aim of Level I is to provide a periodic overview on the spatial and temporal variation 

in forest condition in relation to anthropogenic and natural stress factors in a European and 

national large-scale systematic network; 

whereas the Level II Intensive Monitoring Programme attempts to contribute to a better 

understanding of the relationships between the condition of forest ecosystems and stress factors, 

in particular air pollution, through intensive monitoring in a number of selected permanent 

observation plots spread across Europe; 

2. Frequency of assessment 

Crown condition assessments are mandatory for both levels at least once a year. The time of the 

assessment should be between the end of the first flush of foliage (when the leaves and needles 

are fully developed) and the beginning of autumnal senescence. For most species, the most 

suitable time for the assessment is mid- to late summer. The assessments should be done during 

the same period each year (2 to 3 weeks) and within this time window if possible under similar 

weather conditions. 

In regions with regular damage caused by summer drought, monitoring may be shifted to early 

summer. However, care should be taken to ensure that any effects are not under-estimated. 

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3. Selection of sample plots and trees 

Level I 

Within the transnational survey (Level I) sample plots and trees Kraft classes 1-3 (1 = dominant; 

2 = codominant, 3 = subdominant; see Fig. A1-1 in Annex 1) should be selected according to a 

statistically sound procedure which includes the random principle. An example is the 4-point 

cross cluster, with 4 subplots oriented along the main compass directions at a distance of 25 m 

from the grid point. On each subplot the 6 trees nearest to the subplot centre are selected as 

sample trees, resulting into 24 sample trees per plot (see Fig. 1). Other procedures are possible; 

however, regarding Level I a minimum of 10 sample trees shall be assessed at each sample plot. 

Figure 1: Illustration of 4-point cluster with 6-tree sample and sample tree replacement 

Level II 

The different aims of Level I and Level II programme may influence plot and tree selection as 

trees will be observed in more detail over a longer period of time. For intensive monitoring plots 

– (Level II) – a significantly larger number of sample trees may be selected in order to describe 

the health status of the stand more completely. 

Preferably all trees Kraft classes 1-3 in the plot area should be sampled. The minimum 

requirement is 10 trees selected according to the method described for Level I. However a higher 

number of sample trees is highly advisable in order to keep a minimum of 10 identical trees over 

a long assessment period. If, during plot installation, a subplot was defined, then the assessments 

described in this chapter refer to all trees in the subplot. When the selection of sample trees 

follows different procedures (e.g. in very dense stands where crown assessment is impossible 

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within the plot or subplot boundaries), the procedure should be described and reported to the 

Programme Coordinating Centre. 

Selected trees on both levels should be identifiable (preferably permanently numbered) for reassessment 

during the subsequent inventories. 

Trees used for other surveys (e.g. foliage analysis, tree-ring analysis) located outside the (sub-) 

plot should also be assessed in order to correlate their crown condition with corresponding data. 

In principle, these trees are also permanently and uniquely numbered. These trees should be 

assessed annually together with the trees at the (sub-) plot. 

Trees with >50% mechanical damage in the crown should be excluded when setting up a plot. 

The foliage of suppressed trees in high forest stands is mainly influenced by the overstorey. The 

inclusion of these trees in assessments is therefore optional and will depend on the aims of the 

national programme and the nature of the forest ecosystem. 

In coppice stands, macchia and other forest types where individual stools have many stems, the 

tree may be considered as a single unit consisting of multiple stems. 

It is strongly advisable to map the layout of the plot. If possible, coordinates of the plot centre 

(Level I) or corners (Level II) should be tied into the national coordinate system for the country 

or GPS coordinate, facilitating the use of GIS in the analytical stage. 

The tree sample on both Levels includes all tree species, provided the trees have a minimum 

height of 60 cm. 

Trees removed within management operations or thrown by wind must be replaced by newly 

selected trees at Level I and Level II in order to ensure the minimum number of trees to assess. 

These newly selected trees must be labelled by new numbers which have never before been 

assigned to any tree at the respective plot. If the stand is clear-cut, the sample point ceases to 

exist until a new stand has been established. 

A periodic revision of the grid for adaptation to changes of forest area should be conducted. 

In younger, dense stands, where individual crowns are not assessable, sample trees are selected 

according to a defined process. This process is repeated until sufficient trees with assessable 

crowns have been found. Regeneration should be assessed as part of the ground vegetation 

assessments in the plots. Details are specified in part VIII of this manual. 

4. Crown to be assessed 

The estimation of crown condition strongly depends on the definition of the assessable crown. 

The crown present at the moment of the assessment is to be considered, regardless of the 

potential or theoretical crown which may have existed in previous years. The influence of any 

present or absent (removed) trees on the crown of the sample tree must be taken into account 

when determining its condition. In cases where the sample tree crown is influenced by 

competition, the assessable crown includes only those parts that are not influenced by other 

crowns i.e. shading. Parts of the crown directly influenced by interactions between crowns or 

competition are excluded (see Fig. 2, classification see Annex 1). 

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Figure 2: Assessable crown (indicated by light shading) in freely grown trees and trees within stands. 

Areas of foliage to be excluded are indicated by darker shading. (Based on original diagrams by D´Eon et 

al. 1994). 

The assessable crown of a freely developed tree is defined as the whole living crown from the 

lowest substantial living branch upwards. The following parts of such a crown must be excluded 

from the assessment: 

• Epicormic shoots below the crown 

• Gaps in the crown where it is assumed that no branches ever existed 

For the classification of epicormics see Annex 1. 

The assessable crown includes recently died branches, but excludes snags that have been dead 

for many years (i.e. which have already lost their side-shoots), as shown in Fig. 3. Snags 

represent the historic mortality of parts of the crown and have no influence on the current 

condition of the tree. They are therefore excluded from the assessment. Dieback of shoots and 

branches represents an active process in the crown and is therefore included. 

The determination of the assessable crown varies between countries, it is therefore essential that 

it is documented in the photoguides and manuals used. 

In coppice (and macchia) stands it may be necessary to consider the assessable crown as a single 

unit consisting of crown parts from different stems. 

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Figure 3: Outlines of the assessable crown (freely grown trees) showing which areas of dieback to 

include and exclude. Dead branches that exist only as snags (e.g. on the left-hand side of C) are excluded 

from the assessable crown. Recent dieback, as indicated by the presence of lower order branches, is 

included (e.g. left-hand side of D). (Based on original diagrams by D’Eon et al. 1994). 

5. Direction of assessment 

Trees should be assessed from as many directions as possible, at least from two sides, and 

normally from a distance of about one tree length. In dense stands this may become difficult, but 

at least parts of the crown can be observed from several directions. The visibility of each crown 

should be noted on Level II plots using four classes as defined in Annex 1. 

• On slopes, monitoring from a position upslope or to the sides is preferable, as defoliation will 

be underestimated if crowns are monitored from downslope only. 

• If trees are observed from fixed points, then the point of observation in relation to the sample 

tree should be recorded in the national database. With such a system, it is particularly 

important to document any changes in the observation point. 

• The observers should always try to avoid looking into the sun. 

6. Reference tree 

The concept of the reference tree is one of the most controversial issues in the monitoring 

programme, yet it is critical to the assessments. Two different types of reference trees are 

recognised: local reference trees and absolute reference trees. Use of absolute reference trees 

leads to higher defoliation estimates than the application of local reference trees, but the results 

are more amenable to temporal and spatial analyses. Most countries have adopted local reference 

trees as standards. 

This local reference takes into account the build-up and the development stage of the tree. 

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A local reference tree or a conceptual (imaginary) tree is defined here as the best tree with full 

foliage that could grow at a particular site, taking into account factors such as altitude, latitude, 

tree age, site conditions and social status. It has 0% defoliation. This tree should represent the 

typical crown morphology and age of trees in the plot. Absolute reference trees are the best 

possible trees of a genotype or species, regardless of site conditions, tree age, etc. A number of 

photo guides exist which provide guidelines on absolute reference trees in different parts of 

Europe. 

6.1 Documentation and photographs 

It is necessary to document details of both absolute reference trees (if not available in a manual) 

and the local reference tree with photographs backed up with information on the tree (see form 

PHOT for minimum requirements). 

It is advisable to photograph a selection of the trees in different defoliation classes in each area in 

each year. These should be accompanied by complete assessments of the trees using the relevant 

forms (PHOT) and should be permanently stored at the appropriate National Focal Centres. 

7. Parameters to be assessed 

To enable comparison between and within assessments made at Level I and Level II plots, 

methods for the estimation of defoliation and discoloration remain unchanged. A number of 

additional assessments were specified in the previous edition of the Manual (1996) for Level II 

and amended in this edition (2004), so that the actual status of individual trees can be better 

described. A large number of different parameters are currently being used throughout Europe 

and North America. 

Detailed descriptions of the parameters to be assessed within ICP Forests can be found in 

Annexes 1 and 2. 

The parameters described in this submanual are assessed by ground survey. For the assessment 

of parameters on tree parts 5 or more meters above ground, the use of binoculars is mandatory. 

The use of photo guides with typical photos of trees with different defoliation is strongly 

recommended. Some parameters may require closer observation (e.g. some forms of needle 

discoloration and foliage deformation). Closer (in-hand) examination is also usually required for 

full diagnostic assessments. Usually, a closer investigation becomes possible only every two 

years when the leaves for foliar analysis are picked. While every attempt should be made to 

provide as detailed and accurate information as possible, observers should always bear in mind 

that it is better to have no data than to have incorrect data. 

8. Guidelines for fieldwork 

Defoliation is generally estimated in 5% classes relative to a tree with full foliage (classification 

see Annex 1). The reference tree can be either a healthy tree in the vicinity (of the same crown 

type), a photograph locally applicable, representing a tree with full foliage or a conceptual 

(imaginary) tree. If different classification schemes are used, the class intervals, i.e. the 

respective defoliation percentages, must be specified. 

Observers should have a satisfactory view of the tree from several observation points. On level 

ground, the optimal view is given at a distance of one tree length. On slopes, trees should be 

observed at a distance of about one tree length above the tree or at least on the same level. 

It is recommended that assessments should be done by two trained observers. When the 

estimates produced of the two observers differ, both should change their observation position. 

Assessments should be done in full daylight, but it has to be recognised that the assessment, 

particularly of crown discolouration, may be affected by the quality of the light and the time of 

day. 

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The spatial and temporal comparison and as a norm for the valuator, the knowledge of optimal / 

ideal foliated trees of a species, independent of the location/stand is very useful. In this respect, 

photo guides are a very helpful tool. It is strongly recommended to support all teams of an 

inventory with such photo guides. 

Observers should be provided with locally applicable, standard photographs of trees of each 

species and of different crown types with which to compare the trees to be assessed. Examples of 

various defoliation classes can also be provided if this is considered desirable. 

9. Quality control and quality assurance 

Experience from Level I and Level II has indicated the importance of adequate quality assurance. 

This is especially so for Level II given the complexity of the data. Four main areas are important 

1. selection of field teams 

2. training of field teams 

3. plausibility of data 

4. international quality control 

9.1 Selection of survey teams (Level I and Level II) 

Ideally field crews should consist of two professionals, at least one a diploma-level/graduate 

forester as the responsible crew leader. 

The number of field crews per country should be optimized in order to facilitate training and 

harmonization. The number must take into account work loads and inaccurate assessments due to 

too long survey periods. Frequent changes of staff should be avoided. 

Each team or team member has his own ID coordinated by the NFC. All training and field 

assessment data must contain the surveyors’ IDs and date of assessment. 

9.2 Training 

National Level 

Prior to the beginning of the annual field season, survey crews should undergo a period of 

concentrated theoretical and practical training in measurement and assessment procedures and in 

filling out the various forms. As far as possible, the field crews should be experienced in 

phytopathology. 

All countries should have a designated person who is considered as a national expert on tree 

condition assessments and who is responsible either for undertaking the assessments or for 

training teams to make the assessments. It is recommended that the person is familiar with 

assessments at an international level and should if possible be a member of the National 

Reference Team. 

Training should be given in the use of the ICP Forests or national manuals. The latter should be 

updated (at least for those parameters that are used at an international level) in line with 

recommendations in the ICP Forests manual. 

Whenever local reference trees are used it is strongly suggested that photographs of them are 

also available. 

Photographs should be used as a part of the training exercise both to determine variation between 

surveyors and field scores and variation over time by using the same (or a sub set) every year. 

Results of national training courses should be available for audit/analysis. At least one person 

from a National Reference Team should be available to take part in International Cross- 

Comparison Courses (see Annex 4). 

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9.3 Data plausibility 

It is strongly recommended that plausibility checks are included in hand-held data gathering 

devices (if used) and/or in the early stages of data evaluation. Plausibility checks should also be 

integrated into any national data analysis system and NFC’s are responsible for the quality of 

national data reported. 

Field checks 

Aims: 

1. improve data completeness 

2. improve consistency between teams 

3. improve data consistency regarding Level II combined indices 

4. document variability 

5. provide information to improve training 

An independent check survey should re-measure a proportion (e.g. 5-10%) of the sample plots 

assessed by each survey crew and this should be done very close to the actual survey date to 

avoid differences due to crown development. In case of significant discrepancies, adjustments or 

clarification of instructions and their application must be arranged immediately to avoid serious 

systematic errors. 

National Focal Centres should compare the control data with the original observations and take 

action as appropriate. A summary of the data comparisons, together with details of any action 

taken, should be documented for potential evaluations. 

9.4 International Quality Control 

ICCs are field exercises aimed to 

(i) document the relative position of individual National Reference Teams (NRTs) 

within the international context, 

(ii) monitor the consistency of NRTs’ position through time, 

(iii) improve the traceability of the data by establishing a direct connection with the data 

collected at national level. This will also help to explain anomalous year-by-year 

fluctuations, and 

(iv) explore the relationships between the performance of the various NRTs and the major 

site and stand characteristics 

by using field estimates and photo methods. 

Detailed methodology see Annex 4. 

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10. Data reporting and submission 

Each National Focal Centre must submit an information describing deviations from UNECE 

recommended procedures or changes of assessment methods. 

Periodical quality control evaluations may be requested by the Programme Coordinating Centre 

to be part of integrated evaluations. 

References to any publications arising from the work on the Level I/ II plots should be notified 

so that they can be listed on the ICP Forests web site. 

Assessment data in electronic format (including mandatory and all optional parameters assessed 

by the relevant country) must be submitted to the responsible centre by the cut-off date 

requested. For the format see Annex 3. 

Data submission deadlines for the different Levels and data types have to be observed. 

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Annex 1: Assessment of general plot and tree parameters, foliage, 

reproductive structures and epicormics 

A1.1 Country (mandatory Level I and Level II) 

1 France 11 Spain 55 Norway 65 Belarus 75 Iceland 

2 Belgium 12 Luxembourg 56 Lithuania 66 Cyprus 76 Holy See (Vatican City 

State) 

3 Netherlands 13 Sweden 57 Croatia 67 Serbia and 77 San Marino 

Montenegro 

4 Germany 14 Austria 58 Czech 

Republic 

68 Andorra 78 Former Yugoslavian 

Republic of Macedonia 

5 Italy 15 Finland 59 Estonia 69 Malta 79 Bosnia and Herzegovina 

6 United 50 Switzerland 60 Slovenia 70 Monaco 

Kingdom 

7 Ireland 51 Hungary 61 Republic of 71 Albania 95 Canares 

Moldova 

8 Denmark 52 Romania 62 Russian 72 Turkey 96 Azores 

Federation 

9 Greece 53 Poland 63 Bulgaria 73 Liechtenstein 

10 Portugal 54 Slovak 

Republic 

64 Latvia 74 Ukraine 

A1.2 Observation plot number (mandatory Level I and Level II) 

The observation plot number corresponds to a unique number given to the permanent plot during 

the selection or installation. 

A1.3 Date of observation, date of assessment, 

date of analysis (mandatory Level I and Level II) 

Dates shall be completed in the following order (day, month and year): 

Day Month Year 

08 09 94 

A1.4 Latitude/ longitude coordinates (mandatory Level I and Level II) 

Fill in the full six figure latitude and longitude coordinates of the centre of the observation plot, e.g: 

+/- Degress Minutes Seconds 

— latitude 

+ 5 0 2 0 2 7 

— longitude 

- 0 1 1 5 3 2 

the first box is used to indicate a + or - coordinate 

A1.5 Availability of water to principal species (estimate) (mandatory Level I) 

1: Insufficient 

2: Sufficient 

3: Excessive 

updated 06/2006


A1.6 Humus type (mandatory Level I) 

The classification of the humus type is described in Annex 3, Explanatory item (6) of part IIIa 

(Sampling and Analyses of Soil) of the ICP Forests manual on methods and criteria for 

harmonized sampling, assessment, monitoring and analysis of the effects of air pollution on 

forests 

A1.7 Altitude (mandatory Level I and Level II) 

1: ≤ 50 m 14: 651— 700 m 27: 1301— 1350 m 40: 1951— 2000 m 

2: 51— 100 m 15: 701— 750 m 28: 1351— 1400 m 41: 2001— 2050 m 

3: 101— 150 m 16: 751— 800 m 29: 1401— 1450 m 42: 2051— 2100 m 

4: 151— 200 m 17: 801— 850 m 30: 1451— 1500 m 43: 2101— 2150 m 

5: 201— 250 m 18: 851— 900 m 31: 1501— 1550 m 44: 2151— 2200 m 

6: 251— 300 m 19: 901— 950 m 32: 1551— 1600 m 45: 2201— 2250 m 

7: 301— 350 m 20: 951— 1000 m 33: 1601— 1650 m 46: 2251— 2300 m 

8: 351— 400 m 21: 1001— 1050 m 34: 1651— 1700 m 47: 2301— 2350 m 

9: 401— 450 m 22: 1051— 1100 m 35: 1701— 1750 m 48: 2351— 2400 m 

10: 451— 500 m 23: 1101— 1150 m 36: 1751— 1800 m 49: 2401— 2450 m 

11: 501— 550 m 24: 1151— 1200 m 37: 1801— 1850 m 50: 2451— 2500 m 

12: 551— 600 m 25: 1201— 1250 m 38: 1851— 1900 m 51: > 2500 m 

13: 601— 650 m 26: 1251— 1300 m 39: 1901— 1950 m 

A1.8 Orientation (mandatory Level I) 

1: N 4: SE 7: W 

2: NE 5: S 8: NW 

3: E 6: SW 9: flat 

A1.9 Mean age of dominant storey (years) (mandatory Level I) 

1: ≤ 20 4: 61-80 7: > 120 

2: 21-40 5: 81-100 8: Irregular stands 

3: 41-60 6: 101-120 

A1.10 Soil unit (mandatory Level I) 

The classification of the soil unit is described in Annex 3, Explanatory item (10) of part IIIa 

(Sampling and Analyses of Soil) of the ICP Forests manual on methods and criteria for 

harmonized sampling, assessment, monitoring and analysis of the effects of air pollution on 

forests 

A1.11 Sample tree number (mandatory Level I and Level II) 

The tree number is the number which has been assigned to the tree during the installation of the 

plot. 

Note: a copy of the numbers of sample trees that were assessed the year before and which must 

be included in the assessment in the current year should be provided to the surveyors each year. 

Further information should not be supplied as repeated assessments of, for example, species, will 

act as a control on the quality of the observations. 

updated 06/2006


A1.12 Species (Reference Flora Europaea) (mandatory Level I and Level II) 

Broadleaves (* = species to be used for the foliage inventory) 

001: Acer campestre* 

002: Acer monspessulanum* 

003: Acer opalus 

004: Acer platanoides 

005: Acer pseudoplatanus* 

006: Alnus cordata* 

007: Alnus glutinosa* 

008: Alnus incana 

009: Alnus viridis 

010: Betula pendula* 

011: Betula pubescens* 

012: Buxus sempervirens 

013: Carpinus betulus* 

014: Carpinus orientalis 

015: Castanea sativa (C. vesca)* 

016: Corylus avellana* 

017: Eucalyptus sp.* 

018: Fagus moesiaca* 

019: Fagus orientalis 

020: Fagus sylvatica* 

021: Fraxinus angustifolia spp. oxycarpa (F. oxyphylla)* 

022: Fraxinus excelsior* 

023: Fraxinus ornus* 

024: Ilex aquifolium 

025: Juglans nigra 

026: Juglans regia 

027: Malus domestica 

028: Olea europaea* 

029: Ostrya carpinifolia* 

030: Platanus orientalis 

031: Populus alba 

032: Populus canescens 

033: Populus hybrides* 

034: Populus nigra* 

035: Populus tremula* 

036: Prunus avium* 

037: Prunus dulcis (Amygdalus communis) 

038: Prunus padus 

039: Prunus serotina 

040: Pyrus coomunis 

041: Quercus cerris* 

042: Quercus coccifera (Q. calliprinos)* 

043: Quercus faginea* 

044: Quercus frainetto (Q. conferta)* 

045: Quercus fruticosa (Q. lusitanica) 

046: Quercus ilex* 

047: Quercus macrolepis (Q. aegilops) 

048: Quercus petraea* 

049: Quercus pubescens* 

050: Quercus pyrenaica (Q. toza)* 

051: Quercus robur (Q. pedunculata)* 

052: Quercus rotundifolia* 

053: Quercus rubra* 

054: Quercus suber* 

055: Quercus trojana 

056: Robinia pseudoacacia* 

057: Salix alba 

058: Salix caprea 

059: Salix cinerea 

060: Salix eleagnos 

061: Salix fragilis 

062: Salix sp. 

063: Sorbus aria 

064: Sorbus aucuparia 

065: Sorbus domestica 

066: Sorbus torminalis 

067: Tamarix africana 

068: Tilia cordata 

069: Tilia platyphyllos 

070: Ulmus glabra (U. scabra, U. scaba, U. montana) 

071: Ulmus laevis (U. effusa) 

072: Ulmus minor (U. campestris, U. carpinifolia) 

073: Arbutus unedo) 

074: Arbutus andrachne 

075: Ceratonia siliqua 

076: Cercis siliquastrum 

077: Erica arborea 

078: Erica scoparia 

079: Erica manipuliflora 

080: Laurus nobilis 

081: Myrtus communis 

082: Phillyrea latifolia 

083: Phyllyrea angustifolia 

084: Pistacia lentiscus 

085: Pistacia terebinthus 

086: Rhamnus oleoides 

087: Rhamnus alaternus 

088: Betula tortuosa 

090: Crataegus monogyna 

091: Ilex canariensis 

092: Laurus azorica 

093: Myrica faya 

099: Other broadleaves 

Conifers (* = species to be used for the foliage inventory) 

100: Abies alba* 

101: Abies borisii-regis* 

102: Abies cephalonica* 

103: Abies grandis 

104: Abies nordmanniana 

105: Abies pinsapo 

106: Abies procera 

107: Cedrus atlantica 

108: Cedrus deodara 

109: Cupressus lusitanica 

110: Cupressus sempervirens 

111: Juniperus communis 

112: Juniperus oxycedrus* 

113: Juniperus phoenicea 

114: Juniperus sabina 

115: Juniperus thurifera* 

116: Larix decidua* 

117: Larix kaempferi (L.leptolepis) 

118: Picea abies (P. excelsa)* 

119: Picea omorika 

120: Picea sichensis* 

121: Pinus brutia* 

122: Pinus canariensis 

123: Pinus cembra 

124: Pinus contorta* 

125: Pinus halepensis* 

126: Pinus heldreichii 

127: Pinus leucodermis 

128: Pinus mugo (P. montana) 

129: Pinus nigra* 

130: Pinus pinaster* 

131: Pinus pinea* 

132: Pinus radiata (P.insignis)* 

133: Pinus strobus 

134: Pinus sylvestris* 

135: Pinus uncinata* 

136: Pseudotsuga menziesii* 

137: Taxus baccata 

138: Thuya sp. 

139: Tsuga sp. 

140: Chamaecyparis lawsonia 

199: Other conifers 

updated 06/2006


A1.13 Removals and mortality (mandatory Level II) 

Definition 

Removals are trees which for some reason are not included in the sample of assessment trees. 

Mortality refers to assessment trees which have died. A tree is defined as dead if all conductive 

tissues in the stem(s) have died. 

Trees may have to be withdrawn or eliminated from sampling for several reasons. It is important 

to record this information so that the causes of changes in the numbers of assessment trees in 

each plot can be assessed. In particular, such information is critical if overestimation of mortality 

rates is to be avoided. 

If a tree has died the cause must be determined (if possible). Standing dead trees (classes 30–32) 

of Kraft classes 1–3 should remain in the sample and should be assessed as dead trees as long as 

they are standing (until they are removed or have fallen down). 

Note: This practice differs between countries, with some countries removing standing dead trees 

from the inventory after the initial report of mortality. It is strongly recommended that any 

standing dead trees in the plots are included in the assessments, regardless of the year of death. 

Methods 

The following classification must be used: 

Code 0: tree alive and measurable (new, note this is different than a missing value) 

01 tree alive, in current and previous inventory (formerly blanc) 

02 new alive tree (ingrowth) 

03 alive tree (present but not assessed in previous inventory) 

Tree has been cut and removed, only its stump has been left 

11 planned utilization, e.g. thinning 

12 utilization for biotic reasons, e.g. insect damage 

13 utilization for abiotic reasons, e.g. windthrow 

14 cut, reason unknown 

18 reason for disappearance unknown 

Tree is still standing and alive, but crown condition parameters are no longer assessed 

21 lop-sided or hanging tree 

22 heavy crown break (over 50% of the crown) or broken stem 

23 tree is no longer in Kraft classes 1, 2 or 3 (not applicable to the first inventory in a plot) 

29 other reasons (specify) 

Standing dead tree 

31 biotic reasons, e.g. bark beetle attack 

32 abiotic reasons, e.g. drought, lightning 

38 unknown cause of death 

Trees that have fallen (living or dead) 

41 abiotic reasons (e.g. storm) 

42 biotic reasons (e.g. beavers) 

48 unknown cause 

Note: Class 22 is only applicable in those countries that do not record trees with more than 50% 

crown damage. 

Note: Class 23 is only applicable to those countries that restrict sampling to Kraft classes 1, 2 

and 3. 

Note: Mortality and the number of dead trees present in a plot are two different issues. Annual 

mortality can be calculated from the number of living trees that are dead the following year. The 

total number of dead trees in a plot at any one time provides no information on mortality rates, 

but provides information on the condition of a stand in the year of assessment. 

updated 06/2006


Note: If trees in the plot have not been mapped, there may be some difficulty in identifying the 

fate of individual trees that have disappeared between surveys. 

A1.14 Social class (mandatory Level II) 

Definition 

Social status is a measure of the height of a tree relative to the surrounding trees. Information on 

social status is useful as an aid to interpreting crown condition and increment data for the 

individual trees. For example, dominant trees may be more susceptible to stress than codominant 

trees. 

Methods 

Four classes are recognized: 

1. dominant (including free-standing): Trees with upper crown standing above the 

general level of the canopy; 

2. codominant: Trees with crowns forming the general level of the canopy; 

3. subdominant: Trees extending into the canopy and receiving some light from above, 

but shorter than 1 or 2; 

4. suppressed: Trees with crowns below the general level of the canopy, receiving no 

direct light from above. 

Note: The assessment of the social class of a tree is in some cases difficult. Suppressed trees 

should not be equated with dying trees as, in a mixed-age stand, they represent future generations 

of trees. Classification on steep slopes presents a problem as even relatively short trees may 

receive direct light from above. In such cases, classification should be based on the relative 

heights of the trees. 

Figure A1-1: Illustration of social status classes (crown canopy classes) after Kraft 

(1 = dominant, 2 = codominant, 3 = subdominant, 4 = suppressed, 5 = dying) 

A1.15 Crown shading (mandatory Level II) 

Definition 

Crown shading is an estimate of the openness of the tree’s situation. 

Open-grown trees usually have much larger crowns than ones in closed canopies. In addition, the 

absence of any competition may change the susceptibility of a tree to particular stresses. A 

change in the degree of shading may have significant effects on crown condition. Consequently, 

this assessment should refer to the degree of shading at the time of assessment. This may change 

updated 06/2006


from one year to the next through, for example, thinning operations or storm damage. 

Consequently, it should be recorded annually. 

Methods 

Crown shading is assessed on a six-point scale as follows: 

1 crown significantly affected (shading or physical interactions) on one side 

2 crown significantly affected (shading or physical interactions) on two sides 

3 crown significantly affected (shading or physical interactions) on three sides 

4 crown significantly affected (shading or physical interactions) on four sides 

5 crown open-grown or with no evidence of shading effects 

6 suppressed trees 

A1.16 Visibility (mandatory Level II) 

Definition 

The visibility of a crown is the degree to which different parts of the assessable crown can be 

viewed from the ground. 

Crowns with poor visibility are not removed from the sample, but information about the 

visibility of individual tree crowns is useful to help with the interpretation of the data from those 

trees. Such trees remain in the sample as the use of an objective sampling design means that their 

exclusion could lead to bias in the results. Some parameters, e.g. stem and branch damage may 

be assessable on such trees. 

Method 

The following codes should be used for the assessable crown: 

1 Whole crown is visible 

2 Crown only partially visible 

3 Crown only visible with backlighting (i.e. in outline) 

4 Crown not visible 

Note: Class 3 is distinguished from Class 4, as some parameters can still be assessed when only 

back-lighting is present. 

A1.17 Defoliation (mandatory Level I and Level II) 

Definition 

Defoliation is defined as needle/leaf loss in the assessable crown as compared to a reference tree. 

Defoliation is assessed regardless of the cause of foliage loss (i.e. for example it includes damage 

by insects). Defoliation may also include thin crowns caused by a lack of foliage, as this may be 

indistinguishable from true defoliation. 

This is one of the standard assessments made in Level I. Considerable problems exist with its 

definition, such that complete harmonization of its definition and method of assessment between 

countries is impossible. For example, the role of flowering is handled differently between 

countries. 

Methods 

Defoliation is assessed in 5% steps. These classes are 0, 5 (>0-5%), 10 (>5-10%) and so on. A 

tree with between >95% and 100% defoliation, which is still alive, is scored as 99. The score 100 

is reserved for dead trees (EC Regulation). Trees should be reported in these 5% classes and not 

in aggregated groupings. 

Hint: If the above-ground parts of a tree die (e.g. after a forest fire), the tree is classified as dead. 

The above-ground parts of the tree are considered dead if the phloem and xylem is dead. Note 

that dormant buds may continue to flush for one or more seasons on cut logs, indicating that the 

tissues may remain alive for some time after some people might consider them as dead. 

Regrowth from the roots is excluded until the shoots attain the requirements for inclusion in the 

assessments. Although biologically inappropriate, for practical reasons regrowth from the base of 

the trees should be classified as new stems with new crowns. 

updated 06/2006


A1.18 Discolouration (optional Level I and Level II) 

Definition 

Originally the assessment of discolouration was defined on national level only. 

A European wide adopted assessment of discolouration is now described in the section on 

damage assessment (ANNEX 2). Countries which are willing to continue the assessment of 

discolouration according to the classes given below are invited to report the results on an 

optional basis. 

Class Discolouration Percentage of needles/leaves discoloured 

0 none 0 - 10% 

1 slight >10 - 25% 

2 moderate >25 - 60% 

3 severe >60% 

4 dead dead 

A1.19 Foliage transparency (optional Level II) 

Definition 

Foliage transparency is defined as the amount of skylight visible through the live, normally 

foliated portion of the crown or branch. 

Each tree species has a normal range of foliage transparency. Changes in foliage transparency 

occur as a result of current damage, frequently referred to as defoliation, or from reduced foliage 

resulting from stresses during preceding years. 

Methods 

Estimate foliage transparency in 5% classes based on the live, normally foliated portion of the 

crown and branches using the transparency diagram in Fig. A1-2. Dead branches, crown dieback 

and missing branches where foliage is expected to be missing are deleted from the estimate (Fig. 

A1-3). 

Large uniform crowns are scored as if the whole crown should be foliated. When defoliation is 

severe, branches alone will screen the light, but the surveyors should exclude the branches from 

the foliage and rate the area as if light was penetrating. For example, an almost completely 

defoliated dense spruce may have less than 20% light coming through the crown, but it will be 

scored as highly transparent because of the missing foliage. Old trees, and some broad-leaved 

species, have crown characteristics with densely foliated branches which are spaced far apart in 

the crown. These spaces between branches should not be included in the foliage transparency 

score. When foliage transparency in one part of the crown differs from another part, the average 

foliage transparency is estimated and recorded. 

Foliage transparency should be assessed in the same way as defoliation, i.e. by two observers 

and from different positions. 

Hint: The easiest way to assess foliage transparency is first to mentally draw a two-dimensional 

crown outline. Then block the foliated area into the crown outline. Lastly, estimate the 

transparency of this foliated area. 

updated 06/2006


0 5 10 

40 30 20 

50 60 70 

99 90 80 

Figure A1-2: Guide to estimating transparency (derived from Tallent-Halsell 1994). 

updated 06/2006


Figure A1-3: Crown outline to be taken into account when estimating foliage transparency. Note the 

areas to be excluded from the estimates. This is a free standing tree, therefore the assessable crown covers 

a rather large area (derived from Tallent-Hassel 1994). 

A1.20 Flowering (optional Level II) 

Definition 

This score is defined as the estimation of (current) flowering in the crown. 

Flowering is important for two reasons. Firstly, it can affect the defoliation score in the assessable 

part of the crown, both in the year of flowering and subsequently. Secondly, flowering in 

the whole crown is of interest because of the effects that it has on the carbon balance of the tree – 

energy used for flowering cannot be used for increment. 

Methods 

Two assessments are made: of the assessable part of the crown and of the whole crown. Scoring 

is: 

1 Absent or scarce. The flowers are not seen in a cursory examination. 

2 Common. Flowering effect is clearly visible. 

3 Abundant. Flowering dominates the appearance of the tree. 

Hint: in some species, such as Pinus and Larix, the flowers will probably have been dropped by 

the time of assessment. Scoring is based on the gaps along the shoots where the flowers formerly 

were. 

updated 06/2006


Hint: Some species produce large amounts of green tissues associated with the flowers (e.g. 

Carpinus betulus and Fraxinus excelsior). These tissues contain chlorophyll and contribute to the 

carbon budget of the tree. It is recommended that such tissues are included with the foliage mass 

when assessing defoliation. As fruiting in such species remains relatively constant from year to 

year, annual changes in fruiting will not significantly affect the defoliation estimates. 

A1.21 Fruiting (optional Level I and Level II) 

Definition 

This score is defined as the estimation of fruiting in the crown. Only fruits produced in the year 

of assessment are included. 

Information on fruiting is useful to have because of its effect on the carbon economy of the tree. 

As with flowering, fruiting diverts energy away from other parts of the tree. As with flowering, it 

may also have an effect on the future branch structure of the tree. 

Especially on beech this parameter may provide very valuable information and its submission is 

very much encouraged. 

Methods 

As with flowering, two assessments are made: of the assessable part of the crown and of the 

whole crown. Scoring is: 

1 Absent or scarce. The fruits are not seen in a cursory examination. 

2 Common. Fruiting is clearly visible. 

3 Abundant. Fruiting dominates the appearance of the tree. 

Note 

Quantitative estimates of both flowering and fruiting can be obtained by the use of litter traps. 

However, such data cannot be readily related to individual trees. 

A1.22 Secondary shoots and epicormics (optional Level II) 

Definition 

Secondary shoots and epicormics are used synonymously and are defined as shoots that have 

developed from dormant buds on the stem or on branches. 

In some species, the development of secondary shoots is the normal part of crown formation. For 

example, in Picea abies, secondary shoots develop along the main branches to replace older 

shoots that have lost their needles. In other species, particularly broadleaves, the development of 

epicormic shoots in the crown and on the stem may reflect increased levels of light penetration 

through the foliage of the outer crown. 

Scoring of the presence of shoots reveals whether the tree is responding to loss of foliage and 

thus the regenerative capacity of the tree. For example, a heavily defoliated Picea abies that has 

no secondary shoots is indicative of a tree under extreme stress. 

updated 06/2006


Methods 

Separate assessments are made of the frequency (3 classes) of epicormics in the assessable 

crown and on the stem. The assessment must include all epicormics, not only the ones of the 

current year. Scoring is in three classes: 

1 None or rare 

2 Medium: light development or only present in parts of the crown or stem 

3 Abundant: present throughout the majority of the crown or all over the stem 

A1.23 Crown form/morphology (incl. Roloff) (optional Level II) 

Definition 

Crown form is defined as the appearance of the crown. It may be influenced by crown shape 

and/or by branch habit. 

Crown form provides supplementary information about the condition of a tree. In many cases, 

crown form changes through time. The premature development of such changes often indicates 

the action of one or more types of stress. However, the separation of stress- and geneticallyinduced 

changes is often difficult. 

Crown form classifications have been so far been developed for Picea spp., Fagus sylvatica and 

Pinus sylvestris. Note: the use of the Roloff classification system for species other than Fagus 

sylvatica must be undertaken with special care and is not recommended. 

Methods 

Picea (Fig. A1-4) 

11 comb 

12 brush 

13 plate 

14 mix 

Fagus sylvatica (Fig. A1-5) 

21 trees with vigorous growth both of apical and side shoots 

22 reduced apical shoot growth, side shoots are still formed but at lower frequency (mainly 

consisting of short shoots) 

23 strongly reduced apical shoot growth, no new lateral branches are formed. Shoot 

appearance is “claw-like” 

24 development of 23, with loss of side shoots 

29 other 

Pinus 

31 pine, vigorous apical dominance with tree growing strongly upwards 

32 pine, reduced or no apical dominance with crown showing signs of widening 

33 pine, as 32, but lower branches being lost through suppression 

34 platform developing, with dominant growth direction no longer upwards, 

but crown still with some depth 

35 platform fully developed, no vertical growth 

39 other (specify) 

updated 06/2006


11 

12 

13 

Figure A1-4: Crown form in Picea spp. 11: Comb; 12: Brush; 13: Plate. 

Figure A1-5: Crown form in Fagus sylvatica. 21: Vigorous growth of apical and side shoots; 

22: Reduced apical growth; 23: Development of „claws“; 24: Disintegration of crown. 

updated 06/2006


Annex 2: Assessment of damage causes 

Elaborated by: 

ad hoc Working Group Biotic Damage 

Peter ROSKAMS 

updated 06/2006


A2.1 Introduction 

The causes of damage to a tree and their influence on crown condition are central to the study of 

cause-effect mechanisms. Without this information, data on defoliation and other crown 

parameters are extremely difficult to interpret. Data on leafloss and discoloration caused by the 

actions of defoliating insects or other factors will also provide valuable information for 

interpreting e.g. litterfall measurements and phenological observations. 

The main objective of assessing damage causes in the framework of this programme is to 

provide information about their impact on crown condition. Therefore this assessment should 

focus on the main damage factors influencing crown condition. Any part of a tree may show 

symptoms caused by the actions of insects, fungi, weather conditions or other factors. They may 

consist of defoliation, discoloration, deformations, wounds etc. and their impact may vary from 

completely harmless to lethal to the tree. 

Long-term monitoring may also provide baseline data on the distribution, occurrence and 

harmfulness of biotic agents / damage factors in Europe. These data may also contribute to other 

aspects relevant for forest policy like sustainable forest management. 

A2.2 Definitions 

Damage is defined as an alteration or a disturbance to a part of the tree which may have an 

adverse effect on the ability to fulfill its functions. 

Symptom: Any condition of a tree resulting from the action of a damaging agent that indicates its 

occurrence (e.g. defoliation, discoloration, necrosis) 

Sign: Evidence of a damaging factor other than that expressed by the tree (e.g. fungal fruiting 

bodies, nests of caterpillars) 

Discolouration: any deviation from the usual colour of the living foliage for the assessed tree 

species. 

Dieback: branch mortality which begins at the terminal portion of a branch and proceeds towards 

the trunk and/or the base of the live crown. 

A2.3 Selection of sample trees 

Level I + Level II: assessment of damage causes is mandatory for all trees of the crown condition 

sample. 

A2.4 Frequency and timing 

Level I + Level II: assessment of damage causes should be carried out during normal crown 

condition assessment in summer. 

At Level II plots where the complete programme is carried out, the so-called ‘key-plots’, an 

additional visit for damage assessment is strongly recommended if important damage is observed 

outside the period of crown condition assessment. The observations of the staff responsible for 

deposition sampling or phenological observations may act as an early warning system. This 

additional visit should be made at the time when the main damage cause is supposed to be at its 

maximum (e.g. spring for defoliators). 

A2.5 Parameters to be assessed 

The assessment of damage causes consists of 3 major parts: 

- symptom description 

- determination of the cause 

- quantification of symptoms (extent) 

updated 06/2006


The following table gives an overview of mandatory (M) and optional (O) parameters at Level I 

and Level II plots. 

Level I Level II 

Symptom Specification of affected part M M 

description 

Symptom M M 

Specification of symptom O M 

Location in crown O M 

Cause M M 

Extent M M 

In case that more than one damaging agents/factors are found on the same tree they should be 

reported using additional lines in the submission forms (more than one line per tree). 

In the event of several symptoms on a tree caused by the same, identified agent/factor, only 

the main symptom shall be reported in the submission forms. 

If a damage of a tree is observed and the cause is unknown, the symptoms and the extent should 

be reported nevertheless (regarding defoliation see “specifications”, point b, page 34). However 

in the field “cause” the code 999 should be entered (see Chapt. A2.5.2). 

A2.5.1 Symptom description 

“Describe what you see” could be a summary of the aims of the symptom description: it 

indicates which part of the tree is affected and the type of symptom it shows. It is an essential 

step for diagnosis of the causal agent and for the study of cause-effect mechanisms. However 

this does not mean that every symptom observed has to be reported. The symptom description 

should focus on important factors for which an actual or future impact on may influence crown 

condition. See also National lists (page 34). 

The symptom description does not deal with quantification: it indicates only the presence of 

symptoms. For quantification see A2.5.3. 

In principle the symptom description is restricted to causal agents or factors which may influence 

crown condition (defoliation, discoloration). However this does not mean that the symptom 

description is restricted to symptoms observed on the foliage: damage to the branches or the stem 

(e.g. bark beetle attack) often results in defoliation but its contribution in the defoliation score 

may be very difficult to assess. Therefore the symptom description should cover all affected 

parts of the tree. 

As regards the crown the total crown (which may be different from the assessable crown) 

should be taken into account. This is important because symptoms that may be recognized 

outside the assessable crown may indicate the start of a process which may affect the assessable 

crown at a later stage (e.g. Peridermium pini infection in Pinus). 

A2.5.1.1 Affected part of the tree and location in crown 

Three main categories are distinguished for indicating the affected part of the tree: (a) 

leaves/needles; (b) branches, shoots & buds; (c) stem & collar. For each affected part further 

specification is required, which is important for diagnostic purposes. For this more detailed 

description, the categories used in other parts of the crown manual are applied. A separate code 

allows for reporting also the location in the crown. This may provide further valuable 

information for the diagnosis. 

Affected part 

Leaves/needles 

Specification of affected part 

(mandatory Level I and Level II) 

Current needle year 

Older needles 

Needles of all ages 

Broadleaves (incl. evergreen spec.) 

updated 06/2006 

Code 

11 

12 

13 

14 

Location in crown 

(optional Level I, 

mandatory Level II) 

Upper crown 

Lower crown 

Patches 

Total crown 

Code 

1 

2 

3 

4


Affected part 

Branches, 

shoots & buds 

Stem & collar 

Specification of affected part 


Current year shoots 

Twigs (diameter < 2 cm) 

Branches diameter 2 – < 10 cm 

Branches diameter ≥ 10 cm 

Varying size 

Top leader shoot 

Buds 

Crown stem: main trunk or bole within the crown 

Bole: trunk between the collar and the crown 

Roots (exposed) and collar (≤ 25 cm height) 

Whole trunk 

Code 

21 

22 

23 

24 

25 

26 

27 

31 

32 

33 

34 

Dead tree see below 04 

No symptoms on see below 00 

any part of tree 

No assessment see below 09 

Table A2-1: Affected parts of a tree and location in the crown. 

Location in crown 

(optional Level I, 

mandatory Level II) 

Upper crown 

Lower crown 

Patches 

Total crown 

Code 

1 

2 

3 

4 

Special cases: 

The following codes for special cases shall be reported in the column for ‘specification of 

affected part’ of the tree: 

a. Dead trees: 

Dead trees should be reported using code 04. The cause of death should be reported in the 

column for the causal agent / factor. 

b. No symptoms at all are observed on any part of the tree: 

In order to avoid that the observers have to report that there are no symptoms on the foliage, nor 

at the branches and the stem, this case should be reported using code 00. 

c. No assessment of damage causes was made 

Report code 09 in the column for specification of affected part. 

A2.5.1.2 Symptoms and their specification 

Symptoms are grouped into broad categories like wounds, deformations, necrosis etc. A separate 

code (specification of symptom) allows for a more detailed description. Nests of caterpillars, 

fungal fruit bodies etc. are not considered as symptoms but are defined as ‘signs’ of insects, 

fungi, ... Their presence provides valuable information for diagnostic purposes and should be 

reported. If signs of insects or fungi are observed it is important to report also the observed 

damage symptoms. 

An overview of symptoms, specifications and codes is given in Table A2-2. For the field teams 

this table provides a complete overview of the section on symptom description, including the 

codes for reporting. 

updated 06/2006


Affected part Symptom / sign Code Symptom/sign specification Code 


(optional Level I, mandatory Level II) 

Leaves/needles Partly or totally devoured/missing 01 holes or partly devoured/missing 31 

notches (leaf/needle margins affected) 32 

totally devoured/missing 33 

skeletonised 34 

mined 35 

Premature falling 36 

Light green to yellow discolouration 02 overall 37 

Red to brown discolouration (incl. necrosis) 03 flecking, spots 38 

Bronzing 04 marginal 39 

Other colour 05 banding 40 

interveinal 41 

tip, apical 42 

partial 43 

along veins 44 

microfilia (small leaves) 06 

other abnormal size 07 

Deformations 08 curling 45 

bending 46 

rolling 47 

stalk twisting 48 

folding 49 

Galls 50 

wilting 51 

other deformations 52 

other symptom 09 

Signs of insects 10 black coverage on leaves 53 

nest 54 

adults, larvae, nymph, pupae, egg masses 55 

Signs of fungi 11 white coverage on leaves 56 

fungal fruiting bodies 57 

Other signs 12 

Branches devoured / missing 01 

shoots& buds Broken 13 

Dead / dying 14 

Abortion / abscission 15 

Necrosis (necrotic parts) 16 

Wounds (debarking, cracks etc.) 17 debarking 58 

cracks 59 

other wounds 60 

Resin flow (conifers) 18 

Slime flux (broadleaves) 19 

Decay/rot 20 

Deformations 08 wilting 51 

bending, drooping, curving 61 

cankers 62 

tumors 63 

whitches broom 64 



Signs of insects 10 boring holes, boring dust 65 

nest 54 

white dots or covers 66 


Signs of fungi 11 fungal fruiting bodies 57 


Table A2-2: Symptoms/signs and specification of symptoms/signs; part I / II 

updated 06/2006


Affected part Symptom / sign Code Symptom/sign specification Code 


(optional Level I, mandatory Level II) 

Stem / collar Wounds (debarking, cracks etc.) 17 debarking 58 

cracks (frost cracks, …) 59 

other wounds 60 

Resin flow (conifers) 18 

Slime flux (broadleaves) 19 

Decay/rot 20 

Deformations 08 cankers 62 

tumors 63 

Longitudinal ridges (frost ribs, …) 68 


tilted 21 

fallen (with roots) 22 

broken 13 

Necrosis (necrotic parts) 16 


Signs of insects 10 boring holes, boring dust 65 

white dots or covers 66 


Signs of fungi 11 fungal fruiting bodies 57 

yellow to orange blisters 67 


Table A2-2: Symptoms/signs and specification of symptoms/signs; part II / II 

Important remarks: 

a. National lists 

Table A2-2 aims at giving an overview of the more important symptoms that may occur in trees. 

The symptom description is mandatory for foliage, branches and stem, but countries are free to 

select for each affected part the more important symptoms at national level. If a selection is made 

this should be reported to the international data centre. 

In order to reduce the time needed for the symptom description countries may wish to compose a 

national standard list with a complete symptom description for well-known and frequently 

occurring damage factors for their field teams. This way the surveyor will only have to fill in the 

name of the causal agent and the quantification of the damage. In the event of damage by a factor 

which is not on the standard list, the complete symptom description should be made. 

Reporting to the international data centre however should always include the complete symptom 

description. 

The categories ‘other’ (symptom, sign, colour etc.) should be specified in the remarks column. 

b. In the event of symptoms of ozone damage the guidelines of the ’Submanual on Ozone 

injury on European Forest Ecosystems’ (Part X of this manual) shall be applied. 

Specifications 

a. If damage symptoms on a tree are observed and the cause is unknown, the symptoms and the 

extent should be reported nevertheless. However in the field “cause” the code 999 should be 

entered (see Chapt. A2.5.2). 

b. Avoiding duplication of crown condition assessment: 

Crown condition assessment in the ICP Forests monitoring programme mainly deals with 

defoliation. This symptom is also very important for the assessment of damage causes. In this 

respect the following rules apply: 

• if defoliation of a tree is observed and the cause is unknown, defoliation should only be 

reported in the crown condition assessment, and should not be reported as a symptom in 

the damage causes section. However, other relevant symptoms observed on the same tree 

(e.g. dead branches) should be reported. 

updated 06/2006


• If defoliation can partly or totally be attributed to a certain, identified cause(s) (e.g. 

defoliators), defoliation should be reported in the damage causes section in addition (see 

2.5.2 and 2.5.3). 

c. Necrosis of leaves/needles and its pattern is an important symptom for diagnostic purposes. 

For the assessment of damage causes necrotic leaves or parts of leaves should be reported as 

‘red to brown discoloration, incl. necrosis’ (code 03) and should not be considered as 

defoliation. 

d. In the event of several symptoms on a tree caused by the same, identified agent/factor, only 

the main symptom shall be reported. 

e. Dead branches: Snags (dead branches which are dead for several years and without side 

shoots) and dead branches due to competition are excluded from the assessment of dead 

branches. 

In some tree species (e.g. spruce), small dead branches may be a ‘normal’ phenomenon. This 

should not be reported except when an abnormal percentage of dead branches is observed. 

A2.5.1.3 Age of the damage 

(optional Level I and Level II) 

Recording this parameter helps in detecting new epidemics. Moreover, some injuries, like 

harvesting scars remain visible for many years. 

The age of the damage shall be reported using the following classes: 

Code class damage age description 

1 Fresh damage that has begun after the last year’s inventory 

2 old damage that has begun earlier 

3 fresh and old both, fresh and old damage is visible 

A2.5.2 Causal agents / factors 


Determination of the causal agent that is responsible for the observed damage symptoms is 

crucial for the study of cause-effect mechanisms. The description of symptoms is an important 

step in the diagnostic process, but damage symptoms on their own do not always provide the 

explanation for the observed damage. In many cases further examination will be necessary to 

determine the causal agent. However there should be no destructive sampling within plot 

boundaries. 

Determination of causal agents should be carried out by trained observers and should be 

confirmed by an expert phytopathologist whenever possible. 

In case that more than one damaging agents are found on the same tree they should be reported 

using additional lines in the submission forms (more than one line per tree possible). 

In case that damage has to be reported caused by a damage factor for which no code is foreseen 

this should be reported to the PCC of ICP Forests. PCC will take care that a respective code will 

be defined by the EP and be provided to the NFCs. 

Causal agents are grouped into the following categories: 

updated 06/2006


Agent group 

Code 

Game and grazing 100 

Insects 200 

Fungi 300 

Abiotic agents 400 

Direct action of men 500 

Fire 600 

Atmospheric pollutants 700 

Other factors 800 

(Investigated but) 999 

unidentified 

Table A2-3: Main categories of causal agents / factors 

In each category a more detailed determination is possible according to a hierarchical coding 

system (see Tables A2-3 – A2-11). Report the damage cause as detailed as possible, if possible 

up to species level. E.g. a code 210 for insects is more helpful than a score 200, as in the first 

case it is specified that the causal agent is a defoliator. 

Agent group Code Class Code Type Code 

Game and grazing 100 Cervidae 110 Roe deer 111 

Red deer 112 

Reindeer 113 

Elk/Moose (Alces alces ) 114 

Other Cervidae 119 

Suidae 120 Wild boar 121 

Other Suidae 129 

Rodentia 130 Rabbit 131 

Hare 132 

Squirrel etc. 133 

Vole 134 

Beaver 135 

Other Rodentia 139 

Aves 140 Tetraonidae 141 

Corvidae 142 

Picidae 143 

Fringillidae 144 

Other Aves 149 

Domestic animals 150 Cattle 151 

Goats 152 

Sheeps 153 

Other domestic 159 

Other vertebrates 190 Bear 191 

Other vertebrate 199 

Table A2-4: Codes for agent group 100 (game and grazing) 

updated 06/2006


Agent 

group 

CONIFERS 

Code Class Code Main species Code Affected genus Symptoms 

200 

210 

Acantholyda sp. Pinus Shelter made of silky threads and frass, on the needles, 

Brachonyx pineti 

Pinus 

Fine spots d dwith b da central dhole ld in the dlneedles and presence 

of small holes in the sheaths 

Brachyderes suturalis 

Pinus 

Devoured needles forming a thick saw edge 

Diprion pini 

Gelechia senticetella 

Pinus 

Juniperus, Cupressus 

Summer defoliations. False caterpillars, greenish with 

brown - orange head. Eggs in the needle margins and 

pupas in the soil 

Silky threads in dry twigs 

Defoliators 

Lymantria dispar 

Lymantria monacha 

Bupalus piniarius 

Choristoneura 

murinana 

Cephalcia abietis 

Cephalcia lariciphila 

Dendrolimus pini 

Larix, Picea, Pinus 

Pinus 

Pinus 

Abies 

Picea 

Larix 

Pinus 

Devoured needles; caterpillars with long hairs, variable 

yellow to black coloured with characteristic double row of 

blue and red spots on the back 

Eggs disposed in cracks of the bark. Recently born 

caterpillars disposed in lines in the trunk. Summer 

defoliations. 

I N S E C T S 

Stem, branch 

& twig borers 

(incl. shoot 

miners) 

220 

Dioryctria sylvestrella 

Pinus 

Boring hole with resin crumb on the trunk along with 

sawdust and reddish excrement rests 

Hylobius abietis Pinus Shallow bites in thin twigs and young pines 

Ips acuminatus 

Pinus 

Star - shaped system of galleries under the bark . Trees 

damaged situated in sparce close groups. Death of trees in 

summer. 

Ips sexdentatus 

Pinus 

Star - shaped system of galleries under the bark . Trees 

damaged situated in close groups. Death of trees in 

summer. Adult is bigger than the adult Ips sexdentatus 

Ips typographus Picea Bark beetle, borer, killing red spruce, dangerous for whole 

forest 

Magdalis sp. 

Pinus 

Punctures in buds and young twigs. Dry and hollow young 

shoots 

Orthotomicus sp. 

Pinus 

Long star - shaped system of galleries under the bark 

Adults of very small size. 

Phaenops cyanea 

Pissodes castaneus 

Pityogenes 

chalcographus 

Pityokteines curvidens 

Retinia resinella 

Semanotus laurasi 

Tomicus destruens 

Pinus 

Pinus 

Picea, Larix, Abies, 

Pseudotsuga 

Abies 

Pinus 

Juniperus 

Pinus 

damage of larvae in part of stem with thick bark, galleries of 

older larvae with 'cloudy' boring dust; beetle dark blue with 

green glow 

Very small holes with resin drop resina in buds and shoots. 

Galleries under the bark and pupation chambers with thick 

wood chips. 

Thick and big resin crumb, hollow inside, along with 

excrements, in small branches and/or buds 

Galleries and pupation chambers in branches and twigs. 

Reddish small areas disperse in the crown. 

Dry and hollow apical twigs. Resin crumb in trunk with a 

hole for entering. Under bark galleries with shape of fish 

thorns. Death of the trees in spring. 

Bud boring 

insects 

230 

Rhyacionia buoliana Pinus Hollow buds and young shoots (bayonet shaped shoots), 

Rhyacionia duplana 

Pinus 

Hollow 

l 

buds 

ith 

and 

i 

young 

b 

shoots (bayonet shaped shoots), 

along without resin crumbs. 

Fruit boring 

insects 

240 

Dioryctria mendacella 

Pissodes validirostris 

Pinus 

Pinus 

Irregular shaped boring holes filled with resin in the fruit 

(pine cones). Presence of galleries with excrements and 

silky threads. 

Round and clean boring holes in the pine cones. Egg - 

layings are covered with a dark stopper and disposed in 

the pine cone scales 

Suking 

insects 

250 

Haematoloma 

dorsatum 

Leucaspis pini 

Matsucoccus sp. 

Pinus, Juniperus 

Pinus 

Pinus 

Eggs - laying in shape of a "spit" over grasses. Reddened 

needles. 

Adults with eliptic white bodies (like white scales stucked to 

the needles). 

Breakage and formation of scales in stems. Adults with 

eliptic sessile bodies under the bark. 

Mining 

insects 

260 

Epinotia subsequana 

Abies 

Brown and curved needle in part of its length, with a boring 

hole. 

Gallmakers 270 

Other insects 290 

Table A2-5: Codes for agent group 200 (insects): Conifers 

updated 06/2006


Agent 

group 

BROADLEAVES 

Code Class Code Main species Code Affected genus Symptoms 

200 

210 

Abraxas pantaria Fraxinus It attacks leaves during the summer. Caterpillars let 

themselves down from the crown by means of silky threads 

Agelastica alni Alnus Leaves are skeletonized and devoured irregularly. Eggs are 

yellow and the egg - laying is over the leaf. 

Altica quercetorum Quercus Leaves look brown due to the skeletonizing. 

Epirrita autumnata Betula leaves devoured 

Galerucela linneola Populus, Salix Leaves skeletonized with the veins intact and damages in 

buds. Eggs - layings in the back side of the leaf. 

Defoliators 

(incl. skeletonizers, 

leaf rollers etc.) 

Gonipterus scutellatus Eucalyptus Leaves devoured, with margins looking as narrow and deep 

saw teeth 

Leucoma salicis Populus, Salix, Betula White eggs - layings in trunks and branches. 

Lymantria dispar 

Archips xylosteana 

Quercus 

Quercus 

Attacks the current year leaves and in extreme cases also 

the older ones. Eggs - laying look like yellow mass and are 

Attacks di dthe i tip h of lt the dcurrent year f t shoots. k d thi Shelter k b is hmade 

with young leaves tied toghether by means of silk threads. 

Lymantria monacha 

Quercus, Fagus, Betula u.a. 

Melolontha spec. 

Operophthera brumata 

Quercus u.a. 

Quercus 

Operophthera fagata 

Fagus 

Thaumetopoea 

processionea 

Quercus 

Melasoma populi = 

Chrysomela populi 

Populus, Salix 

Leaves devoured starting from the margins and /or in holes. 

Orange eggs - laying over the leaf. Very typical larvae (easy 

to recognise) 

I N S E C T S 

Stem, branch 

& twig borers 

(incl. shoot 

miners) 

220 

Tortrix viridana Quercus Attacks the current year shoot tips. Makes a shelter with 

young leaves tied toghether by means of silky threads. 

Greenish caterpillar, they let themseves down by means of 

silky threads. 

Xanthogaleruca luteola Ulmus Leaves look brown due to skeletonizing. 

Agrilus grandiceps Quercus Death of thin twigs as it is a twig girdler - galleries . Circular 

exit holes 

Cerambyx sp. Quercus Big eliptic holes at the base of the trunk and thick branches 

through which sawdust flows. Big sized galleries 

Coroebus florentinus Quercus Death of small and median sized branches. Death of twigs 

due to twid girdling (galleries) Tha damage looks like red 

flashes distributed all along the crown 

Agrilus biguttatus 

Quercus 

Agrilus viridis 

Fagus 

Crematogaster 

scutellaris 

Quercus 

Great number of small holes in the cork. Ants. 

Cryptorrhynchus 

lapathi 


Circular holes in the trunk trough which small wood chips 

flow. Superficial girdling damages. 

Melanophila picta Populus Debarking and eliptic holes with a compact dark brown 

coloured detritus at the base of the trunk. 

Paranthrene 

tabaniformis 

Phoracantha 

semipunctata 


Eucalyptus 

Circular holes in the trunk through which flows round wood 

chips Rests of the chrysalis in the hole. Affects to young 

Eliptic holes in the trunk. Wide galleries under the bark. 

Platipus cylindrus Quercus Circular holes in the trunk through wich flows sawdust , 

which is acumulated at the base of the trunk. 

Sesia apiformis Populus, Salix Circular holes at the base of the trunk and chrysalid cocoons 

made of sawdust. Affects to trees of more than 10 - 15 

centimetres of dbh 

Bud boring 

insects 

230 

Fruit boring 

insects 

240 Curculio glandium Quercus Boring holes in the acorns 

Sucking 

insects 

250 

Ctenaritaina eucalypti Eucalyptus Small aphids over young shoots. Bent shoots and sap fluxes 

Kermes sp. Quercus Spherical bodies covered by a brilliant black reddish wax 

cover, situated in the stalks insertion areas of leaves, buds 

Mining 

insects 260 

Rhynchaenus fagi Fagus Many small holes in the leaf, it mines the leaf starting from 

the central vein to the margins 

Gallmakers 

270 

Cynips tozae Quercus Big spherical greyish - brown galls with a crown of teeth on 

the top, in small branches or twigs. 

Dryomyia lischtensteini Quercus Hemispheric or irregular shaped swellings at the back side 

Mikiola fagi Fagus Small f h pink l f galls with a shape like waters drops, on the leaf 

Other insects 290 

Table A2-6: Codes for agent group 200 (insects): Broadleaves 

updated 06/2006


CONIFERS 

Agent Code Class Code Main species Code Affected genus Symptoms 

300 Needle casts 301 Lophodermium pini = 

Pinus 

Long brilliant black carpophores located on the upper needle surface 

and needle- rust 

Leptostroma pinostri 

fungi 

Lophodermium sulcigena 

Pinus sp. 

Cyclaneusma minus = 

Naemacyclus minor 

Phaeocryptopus gaeumannii 

Pinus (Sylvestris, 

radiata) 

Pseudotsuga 

Formation of traverse reddish brown stripes (banding) and presence of elliptic 

carpophores (ligth brown or the same colour than the needle) 

Rhabdocline pseudotsugae 

Pseudotsuga 

F 

U 

N 

G 

I 

Stem and shoot 

rusts 

Dieback and 

canker fungi 

302 

309 

Blight 303 

Mycosphaerella laricina 

Larix 

Naemacyclus nivens Pinus Ligth coloured carpophores. When they come off, they leave holes in the 

needles. 

Thyriopsis halepensis Pinus Needles with circular black carpophores with brown centre. 

Mycospherella pini = 

Pinus (radiata, 

It is the so called "red banding" in needles 

Dothistroma septospora 

nigra, halepensis) 

Chrysomyxa abietis Picea yellow to orange-brown spots on needles which fall prematurely 

Melampsora pinitorqua Pinus Shoots are curved in shape of "C" or "S". To complete its biological cycle 

needs host trees pertaining to Populus and/or Pinus genus 

Cronartium ribicola 

Pinus strobus 

Coleosporium tussilaginis = 

Coleosporium senecionis 

Cronartium flaccidum = 

Peridermium pini 

Pinus "Blister rust" of the needles. Blisters are orange when full and white when 

empty. 

Pinus 

"Blister rust" of the bark. Girdling of the branches or trunk with abundant resin 

flows. Blisters are orange when full and white when empty. 

Gremmeniela abietina Pinus Death of branches and buds with black carpophores over the bark. When it 

ripens pink pendants with conidia go out. 

Cenangium ferruginosum Pinus Death of branches and buds. Black carpophores over the bark 

Shaeropsis sapinea = 

Diplodia pinea 

Pinus 

Side shoots are curved, presenting deformations, resin flows and black 

carpophores. 

Sirococcus conigenus Pinus (halepensis) Death of shoots and reddish brown hanging needles. 

Decay & root 

rot fungi 

304 

Fomes pini = Trametes pini Pinus Flat woody carpophores with "horse hoofs" shape, greyish brown 

Amillaria mellea many tree species White leather cover visible when debarking roots and root collar, goes up. 

Forms honey coloured mushrooms with foot, in small groups 

Other fungi 390 

Heterobasidion annosum 

Abies, Pinus, Picea, 

Larix, Pseudotsuga 

White leather cover but less dense than the one from Armillaria visible when 

debarking the root or root collar. Mushrooms are greyish brown with white 

margins and they are stuck to the root collar surface 

BROADLEAVES 

Agent Code Class Code Main species Code Affected genus Symptoms 

300 Leaf Spot fungi 305 Drepanopeziza punctiformis = 

Populus, Salix Small round spots, with brown margins and greyish white centre. 

marssonina brunea 

Rhytisma spp Salix, Acer Big black irregularly- shaped scabby spots 

Taphrina aurea Populus Yellowish swellings or bumps 

Mycosphaerella maculiformis Castanea Chestnut rust. Reddish brown dots distributed all along the leaf 

Septoria populi Populus Grey spots limited by a necrotic margin 

Harknessia eucalypti Eucalyptus Reddish brown irregular spots 

Mycosphaerella eucalypti Eucalyptus Red spots 

Anthracnose 306 Apiognomonia spp. Quercus, Juglans Affects to the veins 

Powdery 307 Uncinula spp. Populus, Salix, Greyish white powder over buds and/or leaves (oidium) 

mildew 

Microsphaera alphitoides Quercus White powder over the leaves (oidium) 

Wilt 308 Ophiostoma novo - ulmi Ulmus Shoots and buds wilt, when cutting the buds and thin branches you can see a 

necrotic ring which corresponds to the vascular collapsing 

Ceratocystis fagacearum 

Quercus 

Venturia populina = Pollaccia 

Populus 

leaves are brown coloured and curved by the stalk 

elegans 

Rust 302 Mellampsora allii - populina Populus Yellow to orange dots in the back side of the leaf 

F 

U 

N 

G 

I 

Blight 

Canker 

Decay & Root 

rot 

303 

309 

304 

Melampsoridium betulinum Betula rapidly multiplying small spots on leaves which fall prematurely 

Botryosphaeria stevensii = 

Diplodia mutila 

Quercus 

Dry and curved shoots (dieback) with necrosed bark and longitudinal cracks 

where the carpophores appear 

Hypoxilon mediterraneum Quercus The bark comes off, showing plates, in trunk and branches 

Fusicoccum quercus 

Quercus 

Dothichiza populea Populus Black carpophores in buds and branches bark 

Cryphonectria parasitica = 

Castanea Yellowish leather cover (triangle shaped) under the cracks of the bark 

Endothiella parasitica 

Pezicula cinnamomea 

Quercus 

Stereum rugosum 

Quercus, Fagus 

Cytospora crysosperma= 

Populus 

Orange carpophores over the bark 

valsa sordida 

Nectria spp. Quercus Red carpophores under the bark cracks 

Fomes fomentarius Fagus Flat woody carpophores with a "horse hoofs" shape. The upper part has a 

concentric flat area greyish brown coloured 

Ganoderma applanatum Fagus Flat woody carpophores with a "horse hoofs" shape. The upper part is 

covered by a reddish brown powder 

Ungulina marginata Fagus Flat woody carpophores with a "horse hoofs" shape. The upper part is 

reddish brown with yellowish margins and the bottom part is yellowish. 

Amillaria mellea 

Phytophthora spec. 

many tree species 

Alnus, Castanea, 

Quercus, Betula, 

Fagus 

Black spot with jagged margins under the bark and blackish flows 

Deformations 310 Taphrina kruchii Quercus Witches broom, with many buds presenting chlorotic and abnoramlly small 

sized leaves 

Other fungi 390 

Table A2-7: Codes for agent group 300 (fungi) 

updated 06/2006


Agent 

group 

CONIFERS/BROADLEAVES 

Code Class Code Type Code Specific factor Code Symptoms 

400 

Chemical factors 

410 Nutritional disordersnutrient 

deficiencies 

411 

Cu - deficiency 

41101 

A 

B 

I 

O 

T 

I 

C 

marine salt + 412 

surfactants 

Physical factors 420 Avalanche 421 

Drought 422 

Flooding /High 

water 

423 

Frost 424 

Hail 425 

Heat /Sun scald 426 

Ligthning 427 

Mud/ land slide 429 

Snow /Ice 430 

Wind/ Tornado 431 

Winter injury - 432 

winter desiccation 

Fe - deficiency 41102 

Mg - deficiency 41103 

Mn - deficiency 41104 

K - deficiency 41105 

N - deficiency 41106 

B-deficiency 41107 

Mn - toxicity 41108 

Other 41109 

Winter frost 42401 

Late frost 42402 

Shallow/ poor soil 433 

Rock fall 434 

Other abiotic factor 490 

Table A2-8: Codes for the agent group 400 (abiotic factors). 

Agent group Code Class Code Type Code Symptoms 

Direct action of 500 Imbedded 510 

men 

objects 

Improper 520 

planting 

technique 

Land use 

conversion 

530 

Silvicultural 

operations or 

forest 

harvesting 

Mechanical/ 

vehicle 

damage 

Road 

construction 

540 

550 

560 

Cuts 541 

Pruning 542 

Resin tapping 543 

Cork stripping 544 

Silvicultural operations in close trees and other 545 

silvicultural operations 

Soil 

compaction 

Improper use 

of chemicals 

570 

580 Pesticides 546, 581 

Other direct 

action of men 

590 

Deicing salt 547, 582 

Table A2-9: Codes for the agent group 500 (direct action of man). 

updated 06/2006


Agent group Code Class Code 

Atmospheric 700 

SO 2 701 

pollutants 

H 2 S 702 

O 3 703 

PAN 704 

F 705 

HF 706 

Other 790 

Table A2-10: Codes for the agent group 700 (atmospheric pollutants). 

Agent group Code Class Code Species/Type Code Affected 

genus 

Other 800 Parasitic/Epiphytic/Cl 810 Viscum album 81001 Pinus 

imbing plants 

Symptoms 

Arceuthobium 81002 Juniperus 

oxycedri 

Hedera helix 81003 All sps 

Lonicera sp 81004 All sps 

Clematis sp 81005 All sps 

Bacteria 820 Bacillus vuilemini 82001 Pinus 

halepensis 

Swellings of different sizes in 

branches and branchlets 

Brenneria quercinea 82002 Quercus Slime flux in fruits 

Virus 830 

Nematodes 840 Bursaphelenchus 

xylophilus 

84001 Pinus fast reddening of the crown and 

sudden death of the tree 

Competition 850 

Lack of ligth 85001 

Physical interactions 85002 

Competition in 85003 

general (density) 

Other 85004 

Somatic mutations 860 

Mites 870 Eriophyes ilicis 87001 Quercus Areas with abundant 

reddish brown hair at the 

back side of the leaf 

Other (known cause 

but not included in 

the list) 

890 

Table A2-11: Codes for the agent group 800 (other) 

A2.5.2.1 Scientific name of cause (mandatory Level I and Level II) 

If the organism involved can be identified the scientific name must be reported, using the codes 

of 7 letters. As a general rule the codes consist of the first 4 letters of the Genus name, followed 

by the first 3 letters of the species name (e.g. Lophodermium seditiosum = LOPHSED). If the 

Genus name has only 3 letters, these are followed by the first 4 letters of the species name (e.g. 

Ips typographus = IPSTYPO). Codes for the most common damaging species are listed in the 

internet file http://www.icp-forests.org/WGbiotic.htm >> click on annex 3. This table also 

provides information on synonyms and tree species on which the damaging agents occur most 

frequently. 

updated 06/2006


The following sources of information provide information for the field observers to facilitate 

the diagnosis: 

• Tables A2-3 – A2-11 contain the coding system for damaging agents. Especially the 

sheets on insects and fungi provide information about specific symptoms caused by a 

selection of relevant organisms. 

• http://www.icp-forests.org/WGbiotic.htm >> click on Annex 3, provides codes for 

the scientific names of causal agents. 

• http://www.icp-forests.org/WGbiotic.htm >> click on Annex 4, provides examples, 

descriptions and photographs of damage caused by important categories of insects and 

fungi. 

• http://www.icp-forests.org/WGbiotic.htm >> click on Annex 5, provides a key with 

symptoms linked to frequently occurring damage causes. However keep in mind that 

these are possible damage causes, other factors may cause similar symptoms. 

Diagnosis should always be confirmed by an expert phytopathologist whenever 

possible. 

Important remark 

Tables A2-3 – A2-11 give an overview of some important damaging factors in Europe. At 

national level however, important factors may be missing, while others may be less important. 

Therefore countries may wish to compose their own national list of damaging agents/factors 

and classify these according to the groups and classes of the manual. Reporting to the 

international data centre should always be done according to the categories and codes of the 

manual. 

A2.5.3 Quantification 

For foliage and branches quantification of symptoms is referring to the assessable crown. 

A2.5.3.1 Extent 

The extent of the damage indicates the quantity (%) of the affected part of the tree due to the 

action of the causal agent or factor. Damage to the branches is expressed as a % of affected 

branches, damage to the stem as a % of the stem circumference. 

The extent of symptoms reflecting defoliation (e.g. leaf damage by defoliators) indicates the 

% of the leaf area which is lost due to the action of the agent/factor concerned. This means 

that the extent should take into account not only the % of affected leaves, but also the 

‘intensity’ of the damage on leaf level: physiologically it makes a difference for a tree if 30 % 

of its leaves show only some small holes or if 30 % of its leaves are totally devoured. 

The affected leaf area is expressed as a percentage of the actual foliage at the time of 

observation. 

Examples: 

• Crown condition assessment results in a total defoliation score of 40 % (including 

defoliation by identified causes like defoliators). 20 % of the leaves in the assessable 

crown are totally devoured by defoliators extent of defoliator damage = 20 % (class 

2 – see A2.5.3.2); 

• Crown condition assessment results in a total defoliation score of 40 % (including 

defoliation by identified causes like defoliators). 20 % of the leaves in the assessable 

crown are partly devoured by defoliators extent of defoliator damage is e.g. 10 % 

(in any case < 20 % since the affected leaves are only partially devoured). 

updated 06/2006


A2.5.3.2 Extent classes (mandatory Level I and Level II) 

The damage extent will be reported in the following classes: 

Class Code 

0 % 0 

1 – 10 % 1 

11 – 20 % 2 

21- 40 % 3 

41 – 60 % 4 

61 – 80 % 5 

81 – 99 % 6 

100 % 7 

Table A2-13: Damage extent classes. 

Countries using different classes (e.g. 5%) should report their results according to the classes 

as above. 

Specifications: 

a.) Damage to the stem is expressed as a percentage of the stem circumference according to 

the classes as above. 

b.) Signs of insects and fungi and the symptoms ‘tilted tree’ and ‘fallen tree’ should not be 

quantified. 

c.) When two or more similar symptoms caused by different agents/factors occur on the 

same part of the tree, it may be extremely difficult to assess the respective contributions of 

the agents/factors in the damage extent. In this case only the overall extent and the different 

factors involved should be reported. 

d.) Assessments in coppice (and macchia) stands: 

- QUANTIFICATION OF STEM DAMAGE PRESENT ON DIFFERENT SHOOTS: the damage is 

expressed as a percentage of the total stem circumference of coppice i.e. the sum of 

circumference of each shoot; 

- • STEM DAMAGE PRESENT ON DIFFERENT PARTS OF DIFFERENT SHOOTS (for 

example cankers present on crown stem in one shoot and on roots & collar in other 

shoots): for ‘specification of affected part’ use code 34 (whole trunk); for 

quantification see above; 

- ASSESSMENT OF A DEAD SHOOT(S) with the contemporary presence of other living 

shoots: by convention the dead shoot(s) shall be recorded as illustrated in the table 

below. Quantification of the symptom (dead branches of varying size) follows the 

general rule, thus is expressed as % of affected branches. 

updated 06/2006


N. tree Specification of affected part Symptom Location in crown 

1 25 14 4 

Coppice shall only be recorded as a dead tree (code 4) when all the shoots are dead. 

Note: The symptom description is related to the total crown and quantification is related to 

the assessable crown. Therefore it is possible that the presence of damage symptoms is 

indicated in the symptom description, but that the extent is 0 % if symptoms occurred outside 

the assessable crown. 

A2.6 Quality assurance and quality control 

- field crews should undergo a theoretical and practical training in diagnosing and 

quantifying the more important damage symptoms prior to the start of the annual field 

season; 

- Diagnosis should always be confirmed by an expert phytopathologist whenever possible. 

- If a field check by an expert phytopathologist is not possible photographs of the affected 

tree and/or samples of affected foliage, branches, fungal fruitbodies etc. may be of help 

for diagnosis. However damaging trees in the plots by destructive sampling is not 

allowed. Sampling of nearby trees outside the plot showing the same damage symptoms 

may be considered. However one should remember that similar damage symptoms may 

result from different causes. 

- Surveyors should be provided with forest pathology field guides to facilitate diagnosis 

(see 9. References) 

See also Crown Condition manual main text chapt. 9 for QA/QC guidelines. 

A2.7 Reporting 

Validated data are sent every year to the European database accompanied by a “Data 

accompanying report – questionnaire (DAR-Q), including details on the applied method and 

any deviation from the manual. It is recommended to include a chapter on damage causes in 

the yearly national report on forest condition. 

A2.8 References 

Abgrall, J. F., Soutrenon A., 1991. La forêt et ses ennemis. CEMAGREF, Grenoble. 

Blanchard, R.O., Tattar, T.A., 1981. Field and laboratory guide to tree pathology. Academic 

Press, New York. 

Butin, H., 1989. Krankheiten der Wald- und Parkbäume. Georg Thieme Verlag, Stuttgart - 

New York. 

Ferreira M. C., Ferreira G. W. S., 1990. Pragas das Resinosas. Guia de campo. Ministerio da 

Agricultura, Pescas e Alimentaçao, Lisboa. 

Ferreira M. C., Ferreira G. W. S., 1991. Pragas das Folhosas. Guia de campo. Ministerio da 

Agricultura, Pescas e Alimentaçao, Lisboa. 

Hartmann, G., Nienhaus, F., Butin, H., 1995. Farbatlas Waldschäden. Ulmer Verlag, Stuttgart. 

Johnson W. T., Lyon H. H., 1991. Insects that feed on trees and shrubs. Comstock Publishing 

Associates. Cornell University, Ithaca and London. 

Luciano, P., Roversi, P. F., 2001. Fillofagi delle querce in Italia. Industria Grafica Poddighe, 

Sassari. (English version also available) 

Munoz, C., Pérez, V., Cobos, P., Hernández, R. & Sánchen G., 2003. Sanidad forestal. Guía 

en imágenes de plagas, enfermedades y otros agentes presentes en los bosques. Mundi-Prensa, 

Madrid. 

updated 06/2006


Nienhaus F., Butin H., Bohmer B., 1996. Farbatlas Gehölzkrankeiten: Ziersträucher und 

Parkbäume. Eugen Ulmer, Stuttgart. 

Novak V., Hrozinka F., 1976. Atlas of insects harmful to forest trees. Volume I. Elsevier 

Scientific Publishing Company, Amsterdam. 

Patocka J., Kristin A., Kulfan J., Zach P., 1999. Die Eichenschädlinge und ihre Feinde. 

Institut fur Waldökologie der Slowakischen Akademie der Wissenschaften, Zvolen. 

Prota R., Luciano P., Floris I., 1992. La protezione delle foreste. Dai lepidoptteri defogliatori. 

Università degli studi di Sassari, Regione Autonoma della Sardegna. 

Romanyk, N., Cadahia, D. (coord.), 2001. Plagas de insectos en las masas forestales. 

Ediciones Mundi-Prensa. Sociedad Española de Ciencias Forestales, Madrid. 

Schwenke, W., 1972. Die Forstschädlinge Europas (vol. 1 - 5). Paul Parey Verlag, Hamburg – 

Berlin. 

Stergulc, F., Frigimelica, G., 1996. Insetti e Funghi Dannosi ai Boschi nel Friuli Venezia 

Giulia. Servizio Selvicoltura. Direzione Regionale delle Foreste e dei Parchi, Regione 

Autonoma Friuli – Venezia Giulia. 

Strouts R.G., Winter T.G., 1998. Diagnosis of ill-health in Trees. Forestry Commission, 272 

pp. 

Tomiczek, C. et al., 2000. Krankheiten und Schädlinge an Bäumen im Stadtbereich. 

Eigenverlag C. Tomiczek, Wien. 

updated 06/2006


Annex 3: Forms 

The parameters which have to be submitted with the particular forms may change over time. 

Therefore, with the update from June 2006 the NFCs are asked to start each data file (A3.2) 

with a header line. This line is starting with an exclamation mark followed by the names of 

the parameters, each separated by a comma. For each data file a proposal is given at the top of 

the form. 

updated 06/2006


A3.1 Forms for annual report of national crown condition data 

Convention on Long-Range Transboundary Air Pollution 

International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests and 

European Union Scheme on the Protection of Forests against Atmospheric Pollution 

Annual report on health status of main tree species on the basis of defoliation: 

Country (region): total area of country (1000 ha): total forest area (1000 ha): forest area surveyed (1000 ha): 

SURVEY 2006 

Institution (National Focal Centre): total coniferous area (1000 ha): 

CONIFERS 

total broadleaved area (1000 ha): 

Survey period: day/month - day/month/year 

(from - to) 

form A1 

Classification Percentage of trees defoliated 

trees up to 59 years old trees 60 years and older 

1 2 3 4 5 6 7(1-6) 8 9 10 11 12 13 

species: 

area of species: 

no. of sample trees: 

defoliation 

class 

0 not 

defoliated 0 - 10% 

1 slightly 

defoliated >10 - 25% 

2 moderately 


3 severely 

defoliated 

>60% -





Annual report on health status of main tree species on the basis of discolouration: 


SURVEY 2006 


CONIFERS 



(from - to) 

form A2 

discolouration 

class 

Classification Percentage of trees discoloured (yellowed) 


1 2 3 4 5 6 7(1-6) 8 9 10 11 12 13 14(8-13) 15(7+14) 

species: 



0 not 

discoloured 0 - 10% 

1 slightly 

discoloured >10 - 25% 

2 moderately 


3 severely 

discoloured >60% 

others total others 

total grand 

total 

percentage of 

needles disc. % % % % % % % % % % % % % % % 

4 dead 

total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 

Return to: PCC of ICP Forests, Bundesforschungsanstalt für Forst- und Holzwirtschaft, Leuschnerstr. 91, D-21031 Hamburg, Federal Republic of Germany, e-mail: luebker@holz.uni-hamburg.de 

updated 06/2006





Annual report on health status of main tree species on the basis of defoliation and discolouration (combined assessment): 


SURVEY 2006 


CONIFERS 



(from - to) 

form A3 

Classification Percentage of trees damaged (defoliation and yellowing combined) 


1 2 3 4 5 6 7(1-6) 8 9 10 11 12 13 14(8-13) 15(7+14) 

species: 



others total others 

total grand 

total 

combined damage class % % % % % % % % % % % % % % % 

0 not damaged 

1 slightly damaged 

2 moderately damaged 

3 severely damaged 

4 dead 

total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 


updated 06/2006







SURVEY 2006 


BROADLEAVES 



(from - to) 

form B1 

Classification Percentage of trees defoliated 


1 2 3 4 5 6 7(1-6) 8 9 10 11 12 13 

14(8-13) 15(7+14) 

species: others total others total grand 

total 



defoliation 

class 

0 not 

defoliated 0 - 10% 

1 slightly 


2 moderately 


3 severely 

defoliated 

>60% -





Annual report on health status of main tree species on the basis of discolouration: 


SURVEY 2006 


BROADLEAVES 



(from - to) 

form B2 

discolouration 

class 

Classification Percentage of trees discoloured (yellowed) 


1 2 3 4 5 6 7(1-6) 8 9 10 11 12 13 14(8-13) 15(7+14) 


total 



0 not 

discoloured 0 - 10% 

1 slightly 


2 moderately 


3 severely 

discoloured >60% 

percentage of 

needles disc. % % % % % % % % % % % % % % % 

4 dead 

total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 


updated 06/2006





Annual report on health status of main tree species on the basis of defoliation and discolouration (combined assessment): 


SURVEY 2006 


BROADLEAVES 



(from - to) 

form B3 

Classification Percentage of trees damaged (defoliation and yellowing combined) 


1 2 3 4 5 6 7(1-6) 8 9 10 11 12 13 14(8-13) 15(7+14) 


total 



combined damage class % % % % % % % % % % % % % % % 

0 not damaged 

1 slightly damaged 

2 moderately damaged 

3 severely damaged 

4 dead 

total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 


updated 06/2006






SURVEY 2006 

ALL SPECIES 

Country: 

form C 

All species 

no. of no. of % trees defoliated 

sample 

plots 

sample 

trees 

class 0 

not defoliated 

class 1 

slightly 

defoliated 

class 2 

moderately 

defoliated 

class 3 

severely 

defoliated 

class 4 

dead 

class 2 to 4 

moderately to 

dead 

class 1 to 4 

slightly to 

dead 


updated 06/2006


updated 06/2006


Annex 4: Design of International Cross-Calibration Courses 

Elaborated by 

Expert Panel on Crown Condition Assessments 

Marco FERRETTI, Volker MUES, in collaboration with: 

Dave DURRANT, Johannes EICHHORN, Martin LORENZ, and Andras SZEPESI 

updated 06/2006


A4.1 The concept of the ICC system 

Details concerning the “New Design of International Cross-Calibration Courses of ICP 

Forests and the EU Scheme”, hereafter referred to as International Cross-comparison Courses 

(ICCs), are described by Ferretti et al. (2002). 

A4.2 Basic design elements 

The system of the International Cross-comparison Courses (ICCs) is installed to provide 

exercises with sufficient space and time replication for the most frequent tree species of the 

transnational surveys under realistic work condition. It incorporates formally photo QA 

exercises and its link with the traditional field exercises. 

For each of the most frequent tree species ICC sites are spread across Europe. These ICC sites 

are selected by the hosting countries to ensure the possibility of re-assessments of the same 

plots in a periodic system to provide data for the documentation of temporal consistency. The 

willingness of the host countries and of the forest owners to provide the ICC site must 

therefore be ensured. 

A4.2.1 Plot and tree selection 

For each ICC site, a number of visual assessment plots (hereafter referred to as visual plots), 

eventually supplemented by a special photo assessment plot (hereafter referred to as photoplot), 

are selected. Each ICC in principle is dealing assessments on two tree species, 3-4 plots 

per species are used as visual plots, each of them covering a wide range of defoliation values. 

According to available field conditions the host countries should select the plots varying 

according to only one or two environmental factors. The plots should be designed consistently 

with the actual Level I plots in the host country. This will help to provide realistic assessment 

conditions 

All plots should be located as close together as possible in order to prevent cost and time 

consuming travelling between the ICC plots. Each visual plot should consist of 24-30 trees of 

the same species. Trees within the visual plots should be selected according to the usual 

Level I tree selection criteria of the host country. When visual plots are unsuitable for the 

purposes of photo QA, an ad-hoc photo plot with 24-30 trees should be selected in the 

surroundings. 

The plots should be managed as permanent plots. Plot locations should be recorded and trees 

permanently numbered and/or geo-referenced to enable the re-assessment of the same trees. 

Photo-QA exercises can be carried out on the visual plots when the trees fulfil the selection 

criteria reported in the annex on photo QA. When the visual plots are not suited for the photo 

QA exercise, then there is the need to select ad-hoc photo-plots. The photos of the photo 

exercise should be assessed as long as possible after the field assessment of the respective 

trees. The photos can be mirrored to ensure that objective assessments are made and not the 

field assessments be remembered by the participants. Furthermore, photos from other ICCs on 

the respective tree species should be re-assessed in terms of the documentation of temporal 

consistency. 

A4.2.2 Invitation and participation 

The host countries decide in co-operation with the Programme Co-ordinating Centre (PCC) of 

ICP Forests about the dates of the ICCs at the end of the survey period (usually this period 

lasts from end of June to end of August). For the evergreen tree species in the Mediterranean 

region, an extension up to the end of September can be allowed. The host countries invite all 

other NFCs by end of March of the respective year to send their National Reference Teams 

(NRT) for participation in the ICCs. 

updated 06/2006


The participants of the ICCs should be the NRTs for the concerned species. The National 

Focal Centres decide about the participation. Ideally National Reference Teams should 

participate as it is important that the participants at the ICCs also participate in the national 

courses to get the linkage to the survey results. 

A4.3 Implementation of the ICCs 

A4.3.1 Field work, use of home references 

It is important that the participants work independently and that there is no mutual influence 

of their assessments. Each team should use its own method and reference standard. Positions 

for assessments should be marked in the field. After assessing from this position the 

participants may make a second assessment according to their national methods. 

The host country should present site and stand information (age, below/above average site, 

altitude, etc.). Usually, local reference trees will be not presented, unless a specific request 

will be made by the crews. 

Any discussions or exchange of information, especially concerning individual trees, between 

the teams should be avoided before and during the cross-calibration field work for the 

concerned species. However, the experience gained in the past suggests that a brief discussion 

about the most diverse assessments could help clarification. 

There is no evaluation/presentation of assessment results in the field before finishing the last 

plot of a given tree species. Nevertheless, e.g. presentations of national or regional evaluations 

could be a topic in the evening to introduce a discussion about special issues. 

A4.3.2 Codes 

A4.3.2.1 Participant code 

Participants of National and International Courses as well as field teams will receive a unique 

ID number that stays the same through time (Country, Region, Person // CCRRPPPPP). 

“Country” referes to the usual country code; “Region” (when applicable) refers to the code of 

a given region in a country. If it is not necessary to develop a code for “region” the digits for 

RR should be filled with “99”. “Person” is the code given by the NFC to every members of its 

NRT. NFCs are responsible for the distribution of codes to their staff. Code lists and their 

annual updates are submitted to PCC by the National Focal Centres by the end of September. 

A4.3.2.2 Plot code 

The host countries provide the plot IDs for the ICC test ranges according to the following 

method: the plot ID should be the plot number in case of Level I plots, otherwise “99” and an 

ICC plot specific ongoing number of 4 digits both divided by an underline. The test range 

specific ongoing number consists of the country code (first two digits) followed by a plot 

specific ongoing number. An example of four plot IDs is given below with the second plot 

being a real Level I plot with plot ID 194: 

99_5501, 194_5502, 99_5503, 99_5504 

A4.3.3 Data to be recorded 

The host countries are asked to provide the plot ID code and a detailed stand description for 

each ICC test site/plot including latitude, longitude, site type, altitude, exposition, canopy 

closure, tree species, tree heights, dbh, stand age and recent thinning. 

updated 06/2006


Data 

Provided 

by host 

Collected by 

participant 

Entry in the 

field form 

by 

participant 

Submitted 

to PCC by 

host 

General data 

Calendar date + + 

Participant code + + 

Plot data 

Plot ID + + + 

Latitude + + 

Longitude + + 

Altitude + + 

Aspect + + 

Canopy closure + + 

Tree species assemblage + + 

Tree height (dominant storey, average) + + 

DBH (dominant storey, average) + + 

Age (dominant storey, average) + + 

Tree data 

Species + + + + 

Number + + + + 

determine assessed part of crown 

e.g. using photographs + + + 

Defoliation (0,5,10,15 ... 95,99,100%) + + + 

Discolouration (0,1,2,3,4) + + + 

Specification of affected part (11, ..., 34), see + + + 

Symptom (01,..., 22) + + + 

Cause (codes see annex 2, e.g. 81001 + + + 

Scientific name of cause (codes see annex 6, e.g. 

LOPHSED) + + + 

Extent (0,1,2,3,4,5,6,7) + + + 

Table A4-1: Overview of the data and parameters to be provided, collected and reported. 

Ideally, all mandatory parameters of the Level I and II crown condition surveys should be 

covered by the ICCs. However, given the importance of defoliation and discolouration in the 

reporting of forest condition, these parameters have the highest priority. The mandatory 

damage parameters are to be assessed too. Additional parameters may be assessed after 

explicit requests of participating countries or in consequence of changes of the manual on a 

voluntary basis. Plot ID, date, and ICC participant code should be recorded by the participants 

once per plot. All these parameters and codes must be entered in the field form. The field 

forms should be supplied by the host countries. 

A4.4 Data submission 

If possible data should be digitised during the course. Thus, uncertainties could be clarified 

directly with the participants. 

The data can be handed over to PCC directly at the end of the courses or should be sent to 

PCC latest by the end of September of the respective year. Furthermore the host country 

provides a list with the participants and their codes used during the ICC which should be the 

same as given for the field survey. 

Excel Format: 

All results of one species (ICC test range) are listed in one file (filename containing species, 

year, host country, e.g. “ICCFagusSylvatica2003Germany.xls”, or short: 

“ICCFagSylv03GER.xls”). 

updated 06/2006


The file includes several sheets for the respective plots and parameters, the name of the sheet 

gives plot ID and parameter (e.g. 99_5501_defoliation, 194_5502_discolouration, …). 

Structure of table as follows 

Filename (e.g.ICC2003FagusSylvaticaGermany) 

Plot ID and parameter (e.g. 99_5508_defoliation) 

Tree 

No. 

NRT1 

(CCRRPPPPP, 

CCRRPPPP) 

NRT2 

(CCRRPPPPP 

, CCRRPPPP) 

NRT3 

(CCRRPPPPP 

, CCRRPPPP) 

... 

1 

2 

3 

6 

... 

24 

updated 06/2006


A4.5 References 

Bille-Hansen, J., Hansen, K., 2001: Relation between defoliation and litterfall in some Danish Picea 

abies and Fagus sylvatica stands. Scand. J. For. Res. 16: 127-137. 

Czaplewski, R.L., 1994: Variance approximations for assessments of classification accuracy. USDA 

Forest Service Research Paper RM-316, 29 p. 

Dimitri, L., Rajda, V., 1995: Elektrodiagnostik bei Bäumen als ein neues Verfahren zur Ermittlung ihrer 

Vitalität (The electro-diagnostic as a new method to determine the vitality of trees). Forstwiss. 

Cbl. 114: 348-361. 

Dobbertin, M., Landmann, G., Pierrat, J.C., Müller-Edzards, C., 1997: Quality of crown condition data. 

In: Müller-Edzards, C., De Vries, W., Erisman, J.W. (eds.): Ten years of monitoring forest 

condition in Europe. UN/ECE, EU, Brussels, Geneva, 7-22. 

Dobbertin, M., Mizoue, N., 2000: Mit dem Computerprogramm CROCO die Kronenverlichtung 

erfassen. Eidgenössische Forschungsanstalt WSL. Informationsblatt Forschungsbereich Wald 

2/2000: 5-6. 

Dufrêne, E., Bréda, N.,1995. Estimation of deciduous forests leaf area index using direct and indirect 

methods. Oecologia 104. 156-162. 

Ewald, J., Reuther, M., Nechwatal, J., Lang, K., 2000. Monitoring von Schäden in Waldökosystemen 

des bayerischen Alpenraumes. Bayerisches Staatsministerium für Landesentwicklung und 

Umweltfragen, Materialien 155. 235 p. 

Fabianek P., 1998. – Intercalibration courses on the crown condition assessment. Some comments to 

the current method. Unpublished manuscript distributed at the 1 st meeting of the Expert Panel 

on Crown Condition Assessment, Hann. Munden, Germany, July, 1-3, 1998. 

Ferretti M., 1998a - Intercalibration course: what strategy for the future? Unpublished manuscript 

distributed at the 1 st meeting of the Expert Panel on Crown Condition Assessment, Hann. 

Munden, Germany, July, 1-3, 1998. 

Ferretti M., 1998b – A proposal for the future international intercalibration courses (IICs). Unpublished 

manuscript distributed at the 1 st meeting of the Expert Panel on Crown Condition Assessment, 

Hann. Munden, Germany, July, 1-3, 1998. 

Ferretti M., Dobbertin M., Durrant D., Herkendell J., Landmann G., Nakos G., Neumann M., Sanchez- 

Pena G., 1999. Future International Intercalibration Courses (IICs) - Developing a Concept. 

Unpublished manuscript prepared for the ICP Forests Expert Panel on Crown Condition 

Assessment: 6 ps. 

Ferretti, M., Lorenz, M., 2001: Concept and guidelines for the international cross-calibration courses 

(ICCs). not published, 11 p. 

Hansen, K., 1998: Evaluation of the 4 th international ECE/EU intercalibration course for northern 

Europe. In: Hansen, K. (ed.): Monitoring forest damage in the nordic countries 1998. 

Proceedings from a combined SNS ad hoc group meeting on monitoring of forest damage and 

the 4 th internatinal ECE/EU intercalibration course of northern Europe, Denmark. Danish 

Forest and Landscape Research Institute, Hoersholm, 74-78. 

Hornvedt, R., 1997. Relationship between visually assessed crown density and measured foliage 

density, and between visually assessed crown colour and measured chlorophyll content in 

mature Norway spruce. Aktuelt fra Skogforsk (Ås) 10/97. 23-25. 

Innes, J.L., 1988. Forest health surveys: problems in assessing observer objectivity. Can. J. For. Res. 

18. 560-565. 

Innes, J.L., Landmann, G., Mettendorf, B., 1993: Consistency of observations of forest tree defoliation 

in three European countries. Environmental Monitoring and Assessment 25: 29-40. 

Jalkanen, R.E., Aalto, T.O., Innes, L.J., Kurkela, T.T., Townsend, I.K., 1994. Needle retention and 

needle loss of Scots pine in recent decades at Thetford and Alice Holt, England. Can. J. For. 

Res. 24: 863-867. 

Klap, J., Voshaar, J.O., de Vries, W., Erisman, J.W., 1997. Relationships between crown condition and 

stress factors. In: United Nations Economic commission for Europe, European Commission 

(eds.): Ten years of monitoring forest conditions in Europe. Brussels, Geneva. 277-307. 

Klap, J.M., Voshaar, J.H.O., de Vries, W., Erisman, J.W., 2000. Effects of environmental stress on 

forest crown condition in Europe. Part IV: statistical analysis of relationships. Water, Air, and 

Soil Pollution 119. 387-420. 

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MANUAL Part II Visual Assessment of Crown Condition - ICP Forests

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