CONTRACT NUMBER - AAIR3-CT94/2392

Participants:

P01 Faculty of Forestry, University of Joensuu, Joensuu, Finland

P02 Department of Forestry, The University of Aberdeen, Aberdeen, UK

P03 Centro Nacional de Informacao Geografica, Lisbon, Portugal

P04 The Forestry Authority, Northern Research Station, UK

P05 Macaulay Land Use Research Institute, Aberdeen, UK

P06 Instituto Florestal, Ministerio da Agricultura, Lisbon, Portugal

P07 Faculty of Forestry, The Swedish University of Agricultural Sciences, Umeå, Sweden

P08 School of Engineering, University College, Galway, Ireland

Period of report: Period 2 July - December 1995 SUMMARY

WIND, FIRE AND SNOW: INTEGRATING TREE, SITE AND STAND PROPERTIES WITH GEOGRAPHICAL INFORMATION SYSTEMS AND REGIONAL ENVIRONMENTAL MODELS TO EVALUATE OPTIONS FOR FOREST MANAGEMENT

Participants

P01 Faculty of Forestry, University of Joensuu, Joensuu, Finland P02 Department of Forestry, The University of Aberdeen, Aberdeen, UK P03 Centro Nacional de Informacao Geografica, Lisbon, Portugal P04 The Forestry Authority, Northern Research Station, UK P05 Macaulay Land Use Research Institute, Aberdeen, UK P06 Instituto Florestal, Ministerio da Agricultura, Lisbon, Portugal P07 Faculty of Forestry, The Swedish University of Agricultural Sciences, Umeå, Sweden P08 School of Engineering, University College, Galway, Ireland Scientific objectives This project aims at producing generic models which use the factors common to wind, snow and fire damage; to underpin, those models with an understanding of the forces and site factors acting on single trees or the fuel hazard risks associated with site factors to produce risk assessments to forestry to minor or catastrophic damage; to test these models as a way to derive long term strategies of silvicultural methods for managing forests against wind, snow and fire damage, that optimize wood production while appraised of the risk of forest damage. This project utilizes methodology where models for estimating the breakage and overturning due to wind and snow load and models to estimate fuel are integrated with the data bases for properties of climate and vegetation conntrolling the snow, wind and fire damages to forests in order to optimize wood production considering the risks to forests. The progress within the period of report Task 1. The planning report was completed during the previous six months and has been undergoing continual update throughout the current six month period. Initial framework output from Task 6 has been added to the Task 1 documentation and will act as a focus for developing working links between data and models in a technical as well as a conceptual sense via cooperation between participants. The metadata form developed for Tasks 4 and 5 will also facilitate the validation of links and the handling of scale issues (Sub-task 1.2) which will feed back into Task 1. In addition, there is continuous revision of the issues associated with each task. Task 1 update documents have had issues deleted which have been addressed, and new issues added. Particularly vital in the exchange of this information and the facilitation of input to Task 1 has been the world wide web discussed further under Task 8. The updated d ocuments for the Task 1 planning report are being placed on the ftp site at MLURI, so that all participants have timely access to the updated versions. Task 2. The objective of this task is to determine the main factors which control snow, wind and fire damage. These factors are crucial in establishing when and where damage will occur and which silvicultural practices reduce or increase the risk. Within this Task following measurements were made: tree pullings and tree swaying measurements, measurements of strength properties of wood. Furthermore, pure spectral data set was prepared, biometric data was collected, and critical tree characteristics which control snow damage were determined. Some initial results are now available for the tree pulling experiments of 74 trees. Linked with this work is the database of tree pulling (based on 1300 trees), already prepared. Regressions have been calculated for combinations of these with the aim of determining the parameters for the empirical model of tree breakage and overturning (Task 3.1). Critica l to this work is the study of strength properties of wood from populations of trees that have broken, overturned and remained undamaged. Most of the field sampling has been completed and the laboratory work is well under way. Measurements of tree swaying are continuing but no results are yet available. Preparation of the pure spectral data set is also going well. Early results are promising highlighting the value of using a spectral linear mixture for assessing some fuel loading. Task 3. This Task is developing in accordance to the existing plan. During this second six months period models predicting snow and wind damage have been developed under Sub-task 3.1, 3.2 and 3.3. A database on snow and wind damage have been made available. Computer based mathematical models , capable of calculating the wind speeds required to break or overturn trees based on a knowledge of the tree species, tree height, tree stem diameter, inter-tree spacing and soil type, are available (Sub-task 3.1). Furthermore, a test version of the mechanistic wind and snow damage model is available, i.e. HWIND-model, for Scots pine, Norway spruce and birch sp for determining the windspeed and snow load required to damage single trees along the stand edge and within the stand (Sub-task 3.3). Furthermore, an allometric model to predict individual pine trees (Pinus pinaster) Leaf Area (LA) was deve loped from data gathered by destructive sampling on 31 trees. This model uses as independent variables the tree total height (H) and the diameter at the base of the live crown (DBC), and it has a regional applicability. The field work necessary to develop a model to estimate stand LAI optically, based on canopy light trasmitance measurements, was initiated during the months of July and August. Task 4. Progress is beginning to be made on this task, although obviously initial attention on this contract has been devoted to Tasks 1-3 and certain parts of Task 4 are dependent on the successful conclusion of sub-tasks within Tasks 2 and 3. Initial efforts have been made in identifying suitable data sets for analysis, testing methodologies for measuring stand variability, investigating the importance of variability in stand growth models and calculating the effect of stand position on the wind loading on individual trees. This task involves an integrated approach to investigating the effects of variability by using existing data sets, making new measurements and developing mathematical models. Task 5. Sub-tasks 5.1, 5.2 and 5.3, were all active during the reporting period. Sub-task 5.4 had started in August. Initial efforts are being made, by all participants, in the compilation and construction of the geographic database for all sites (Portugal, Finland and UK). Sub-task 5.3 has been completed, although the report, which documents the nature and location of Pan-European data sets, will be used throughout the project so that further information concerning relevant data sets can be added as it becomes available. Metadata forms were be developed as part of Sub-task 5.2 and are now available to participants to ensure the compilation of comprehensive geographic data bases required for the project. All Participants are working and progress is being made in each Sub-task. There were no deliverables or milestones to be achieved by any participant in Task 5 during this period. A meeting co ncerning snow damages was organised to identify the most appropriate means of developing a model to calculate hazard maps of snow incidence for the United Kingdom (Sub-task 5.1). Task 6. The development of a framework to integrate models and data has begun. This framework addresses the issues of scale and spatio-temporal variability to ensure the valid application of tree models to larger areas. Summary diagrams have been produced which describe, in representative terms, the basic components which comprise each task. These diagrams are currently being used to investigate in detail the nature of the links between developmental data, models, test data and potential input data in relation to the components identified. The schematic Task 6 summary component diagram which has emerged as a result of this will be modified as links become more clear and concrete, to integrate the components into a system which will be designed strategically to address the main aim of the project which is to identify the silvicultural practices which may be applied to prevent or ameliorate the problem of damage. Task 7. This task was not active during the second reporting period. Task 8. This task has been started at the beginning of the project, because the information dissemination of the project has been considered to be important already at very early stage of the project. The e-mailing list is operational, and is for the exclusive use of the project participants. It is designed to make communications between participants, especially for project­wide information dissemination efficient and rapid. A World Wide Web homepage has been established for information dissemination outside the project. CHAPTER 1 INTRODUCTION Scientific objectives of the project This project aims at producing generic models which use the factors common to wind, snow and fire damage; to underpin, those models with an understanding of the forces and site factors acting on single trees or the fuel hazard risks associated with site factors to produce risk assessments to forestry to minor or catastrophic damage; to test these models as a way to derive long term strategies of silvicultural methods for managing forests against wind, snow and fire damage, that optimize wood production while appraised of the risk of forest damage. This project utilizes methodology where models for estimating the breakage and overturning due to wind and snow load and models to estimate fuel are integrated with the data bases for properties of climate and vegetation conntrolling the snow, wind and fire damages to forests in order to optimize wood production considering the risks to forests. Scientific objectives during the period under report Task 1. Most of the work associated with the Task 1 planning stage was completed in the first six months of the project. Further development of the planning report will be pursued using Task 6 as a focus. As individual tasks evolve and the development of the work becomes clearer, Task 1 will be updated to reflect the increasing detail of plans and the solution of issues. Scale issues cannot be addressed until other parts of the project are better developed. The links identified in Task 6 will determine the details of the scale issues. Task 2. The objective of this task is to determine the main factors which control snow, wind and fire damage. These factors are crucial in establishing when and where damage will occur and which silvicultural practices reduce or increase the risk. The overall aim is to determine values for the critical parameters required to support the development of the models in the subsequent tasks. Task 3. This task aims at developing wind and snow assessment models and Leaf Area Index estimations for Europe. In this initial phase of Project work is performed with different approaches, depending on the existing material in the involved countries. Thus a whole set of different models will be developed: logistic risk models using single tree data, empirical models of breakage and overturning of a single tree by wind, mechanistic wind and snow damage model (HWIND) using single tree data, and a model for prediction of Leaf Area Index for (Pinus pinaster). Task 4. The purpose of Task 4 is to determine how the relationships and models developed in Task 3 can be applied at the stand level. One of the greatest difficulties in modelling wind, snow or fire risk is that the mean conditions within a stand are almost certainly not the critical conditions but rather it is the extreme conditions which will determine the stand vulnerability. Unfortunately, it is usually much easier to obtain measurements of the mean conditions within a stand and to model the vulnerability of these 'mean' trees. Attempting to model the range of vulnerability within a stand could involve making calculations for every tree within the stand, even assuming that such data are available in the first place. Obviously such an approach is impractical because we cannot attempt to model the vulnerability of every tree within European forests and another approach is required. The approach being taken is to determine just how much variability actually exists within the stands of plantation forests and then to model the impact of such variability on the calculated risk. From such information it should be possible to obtain relationships which can be applied to the calculation of risk for the 'mean' tree within a stand in order to provide a measure of the spread in vulnerability due to variations in ground conditions, tree size and tree position. These relationships will be dependent on species and silvicultural treatment and, therefore, this task represents a key point at which the influence of different silviculture can be assessed. Task 5. Within Sub-task 5.1 has been worked on the development and applicability of a method for calculating the effect to topography and surface roughness on windspeed. The objective of Sub-task 5.2 is the compilation of a geographic database, aquisition and image pre-processing. The aim is the construction of a database for U.K, Finland, and Portugal for modelling and test the risks models. The work that is outcome in this sub-task is the progress achived during the buiding up of geographic database from the site scale to regional level to more than 4 studies areas (country scale). Furthermore, metadata forms to be used in the compilation of this data will be developed. Sub-task 5.3 aims at identifying and listing the data available which may be relevant to the modelling of abiotic forest damage, specifically by means of wind, snow and fire within the geographic range for which damage may be modelled. Constructing the models, deriving suitable data and assessing the validity of such modelling at different scales or resolutions is the key outcome of this project. Sub-task 5.4 started in August, and it is in an exploratory stage, working with a new umixing software. Task 6. The development of a framework for the integration of components has begun. The technical report, progress reports and proposal were used to put together summary diagrams with more detailed information supplemented by email to participants to development a components diagram indicating information flow to and from models and sub-systems. Task 7. This task was not active during the second reporting period. Task 8. Dissemination and documentation of the project achievements has been continued. More detailed discussion of the work and achievements is given below Task by Task. Sub-tasks active during the period under report were marked with **. Being done in the year Task 1: Project Planning Sub-task 1.1: Planning Design ** 1 Sub-task 1.2: Scale ** 1 Task 2: Quantification of Component Factors Controlling Snow, Wind and Fire Damage Sub-task 2.1: Wood Property Factors Controlling Wind Damage ** 1, 2, 3 Sub-task 2.2: Wood Property Factors Controlling Snow Damage ** 2, 3 Sub-task 2.3: Tree and Soil Factors Controlling Wind Damage ** 1, 2, 3 Sub-task 2.4: Vegetation Characteristics Controlling Fire Damage ** 1, 2 Task 3: Tree-level Models to Predict Circumstances for Damage Sub-task 3.1: Empirical models of breakage and overturning of single tree by wind ** 1,2 Sub-task 3.2: Empirical models of breakage of single tree by snow ** 1,2 Sub-task 3.3: Mechanistic model for wind and snow damage of single tree ** 1, 2 Sub-task 3.4: Leaf area index (LAI) estimation ** 1, 2, 3 Task 4: Defining stand-level Variability to Permit Application of Tree-level Models Sub-task 4.1: Wind Flow across and within Stands Using Airflow Models ** 1, 2 Sub-task 4.2: Variation in Measured Tree Characteristics within Stands Using Various Methods Including Remote Sensing ** 1, 2 Sub-task 4.3: Plot-level Mixture Modelling ** 1,2,3 Sub-task 4.4: Preparation of Knowledge Base for Fuel Hazard Mapping ** 1, 2, 3 Task 5: Regional-level Snow, Wind and Fire Risk Models Sub-task 5.1: Climatology of Wind and Snow in Relation to Topographic Variability and Temporal Incidence ** 1,2 Sub-task 5.2: Construction of Geographical Database and Use of Image Processing ** 1,2 Sub-task 5.3: Explore Relevance of Pan-European Datasets of Eurostat and CORINE ** 1 Sub-task 5.4: Regional Classification of Fuel Types Using Mixture Models and Functional Vegetation Classification ** 1,2,3 Sub-task 5.5: Knowledge Base System Construction for Fuel Hazard Mapping 2,3 Sub-task 5.6: Fire Risk Model Construction 3 Task 6: Integrating Components from Tree/Stand Regional-level to Produce an Unified Risk Model Sub-task 6.1: Integrating the Component Models ** 1,2,3 Sub-task 6.2: Scale Issues and Error Propagation 2,3 Task 7: Testing Models against Independent Data and Outlining Implications for Silvicultural Strategies Sub-task: 7.1: Model Testing by Application of Change Detection System to Finnish Test Area. Detecting Wind Damages on Stand Level by Landsat TM Images 2,3 Sub-task: 7.2: Model Testing Through Portuguese Forest Service 3 Sub-task: 7.3: Model Testing through Forestry Commission Windthrow Monitoring Areas and Forest Districts 2,3 Task 8. Final Products, Documentation and Identification of New Opportunities Sub-task 8.1: Dissemination of Project Information and Results ** 3 Sub-task 8.2: Documentation of Project Achievements ** 3 CHAPTER 2 MATERIALS AND METHODS Task 1: Project planning All participants have a copy of the Task 1 documentation, and this document is undergoing continual update as issues are identified and resolved with Task 6 acting as a focus. Task 2: Quantification of component factors controlling snow, wind and fire damage Within this task were made following measurements: tree pullings and tree swaying measurements, measurements of strength properties of wood. Furthermore, pure spectral data set was prepared, biometric data was collected, and critical tree characteristics which control snow damage were determined. Task 3: Tree - level models to predict circumstances for damage Sub-task 3.1. Computer based mathematical models are being developed capable of calculating the wind speeds required to break or overturn trees based on a knowledge of the tree species, tree height, tree stem diameter, inter-tree spacing and soil type. The models use the fundamental information on wood properties and resistance to overturning being obtained in sub tasks 2.1, 2.2 and 2.3. Initially model development is carried out using Mathcad 6.0 for ease of construction and is then converted into a Turbo Pascal programme for integration with the GIS and for use by other participants. The model takes the tree characteristics and calculates the aerodynamic roughness and zero plane displacement of the forest. From this information the drag of the forest can be calculated which represents a force due to the wind on each tree. This force can then be converted into a bending moment which the tree must be able to resist to avoid breaking or overturning. The wind speed at which the applied bending moment is greater than the resistive moment offered by the soil and roots is the critical wind speed for overturning. The wind speed at which this bending moment induces stresses in the stem greater than the Modulus of Rupture of the wood is the critical wind speed for breakage. Sub-task 3.2. To apply logistic statistical analysis technique permanent sample plots (25 000) within the existing Swedish National Forest Inventory (NFI) data base have been used. Permanent sample plots are used so that the progression of damage can be monitored. Data will be separated according to species, site type, and management treatment. Data inputs used from the Swedish National Forest Inventory (NFI) are tree species, various tree and stand characteristics (i.e. height, diameters at stump height, breast height, and at 5m, stand density, standing volume). The NFI data base used for the development of logistic models developed under sub-task 2.2 have been continuously utilized by the inclusion of site and stand characteristics for different counties of Sweden. The database on snow and wind damage including tree, site and stand characteristics from the county of Västerbotten is avai lable at our ftp-site (see sub-task 2.2). Sub-task 3.3. A preliminary mechanistic model for wind damage of Scots pine under normal Finnish conditions has already been constructed, dealing with stand edge adjacent to clear cuts. The model has now been extended to deal also with within the stand conditions and has been applied to spruce and birch by modifying the controlling parameters. The snow damage risk of trees was modelled in terms of maximum snowload as the product of the projected area of the crown and a snow load, corresponding to snowfall accumulated in the crown. The HWIND-model attempts to fully describe the mechanistic behaviour of trees under wind and snow loading. The empirical (see Sub-task 3.1 and 3.2) and mechanistic approaches developed will be compared in order to improve the methods for estimating critical windspeed and snow loading. The model will be tested agains data from Sub-task 2.3 (tree pullings, and wind speed and tree swaying measurements 1995-1996). Sub-task 3.4. The aim of this Sub-task is the development of practical, easy to implement mathematical models to predict pine stands LAI by field measurements. Stand LAI is estimated by ceptometer measurements of the canopy transmitance applying the Beer-Lambert´s equation. In order to generalize LAI estimations to the study and regional areas, these data will work as ground-true data for satellite imagery calibration, in sub-task 5.4. The methodology followed entails three main steps: Development/Selection of allometric models to estimate pine trees Leaf Area (LA) using easily measurable tree dendrometric variables; Estimation of LAI per plot; LAI estimation by canopy transmitance measurements. An allometric regional model to estimate the pine trees LA was developed at the end of this research project first year. The needed field work for steps 2 and 3 was initiated during the months of July and August. The material used in this Sub-task includes a four wheel drive vehicle, topographic maps, infrared false-color aerial photography 1:15000 (1990), Trimble GPS professional receiver, ceptometer, digital scale, hipsometers, calipers, metric tapes and a Bitterlich telerelascope. Task 4: Defining stand-level variability to permit application of tree-level models Sub-task 4.1. Stand growth models using both tree and stand characteristics developed by Soederberg and Ekoe are available from the University of Umea and can be used to determine how much variation in tree characteristics exists within stands and how this changes with species and climatic conditions. The effect of position within the stand on the wind loading experienced by a tree is being explored by models of tree loading developed by the University of Joensuu in Finland and models of airflow across forest edges being developed by the Forestry Commission. The results of these models will be compared against measurements of wind speeds and wind loading back from forest edges from field and wind tunnel experiments. Sub-task 4.2. This Sub-task involves the use of existing data, measurement of stand variability and modelling of the effect of variability. A great deal of existing data exist from the wind damage monitoring areas within the United Kingdom and the extensive sample plots maintained in Sweden. Suitable aerial photographs of monitoring sites within the United Kingdom along with ground control points obtained with a GPS system have been selected and sent to Finland for analysis of the stand variability. New measurement techniques are becoming available which allow rapid assessment of tree characteristics within a stand. The combination of GPS system and Criterion laser relascope for rapidly measuring tree dbh and position within a stand are being explored by Aberdeen University and the Forestry Commission. Sub-task 4.3. CNIG, Portugal have carried out some initial analysis of the spectral data obtained in sub-task 2.4 which is designed to allow remote sensing of regional fuel loading. The analysis has shown some variability in the measurements and highlighted the noisy nature of data from the spectroradiometer. This has lead to a redesign of the measurement protocol and recognition of the need to apply smoothing techniques to the data. Further data collection will take place in spring/summer 1996. Sub-task 4.4. CNIG and MLURI are developing a knowledge based method for determining the fuel conditions within a stand based on site conditions. Task 5: Regional-level snow, wind and fire risk models Sub-task 5.1. Methods are to be compared for treating topographic effects on wind speed. Results from the various modelling approaches will be compared to existing field measurements to assess which method is suitable for recommendation for wider use in the project. A meeting concerning snow damages was organised to identify the most appropriate means of developing a model to calculate hazard maps of snow incidence for the United Kingdom This model will be used in the derivation of snow damage risk maps. The risk levels are defined by the tree models which predict the load, and therefore the amount of snow required to break or over-turn a tree. The discussions aimed to define a set of strategies and foci for further investigation. Sub-task 5.2. For the UK test sites the construction of datasets for windthrow monitoring areas has continued. Data is being assembled within a GIS representing the necessary locational, site, and tree data required to run the damage probability models. These datasets will then be used for validation of generic models. Furthermore, for the Finnish test sites, the compilation of the geographic database has been continued. The geographical information of the test areas has been stored in the geographic database. The field measurements of occurred wind damages in the test areas has been completed during November 1995. Wind damages occurred during 1990-1995 has been measured at totally 20 stands in the test area. In addition, Portuguese test sites the compilation of the available information, including analogic forest and landuse maps, aerial photographs, satellite imagery, military analogic ma ps, digital terrain model, etc., is being made according to the planned since the last report. This information is being merged in a GIS, and co-registered. Simultaneous to the construction of the database was the prodution of the Metadata forms, modelled on a simplified version of the MLURI meta data model and the United States Federal Geographic Data Centre (FGDC) metadata standard (Federal Geographic Data Committee 1994). The forms were tested by data capture teams in MLURI and, on their experience, two experimental forms filled in to check consistency, suitability and clarity of options on the form. An explanatory sheet and detailed description of the criteria were included. Sub-task 5.3. Information about European and national scale data sets in existence was obtained by request from European and national agencies responsible for data collection and supply. Additional information about individual countries was obtained from the other project participants. The metadata-base will be populated, in part, by data collected in Sub-task 5.3. This involved cross-referencing with the metadata criteria on the forms developed in Sub-task 5.2. Any dataset which has to be created for the purpose of the project will be referenced in future versions of the data listing thus providing a source of information for assessing the data available for the modelling. Sub-task 5.4. This sub-task started in August of 1995. So far, we have tested a spectra unmixing software, IMPACT, developed by the University of Washington. The test has been performed with image endmembers and a Landsat TM scene. Currently an exploratory study for using reference endmembers is under way. Task 6: Integrating components from tree/stand regional-level to produce an unified risk model An iterative strategy of participant query with feedback to the framework development is being adopted (Sub-task 6.1). Information from participants concerning the details of the developmental data sets and model sensitivity tests will be used to characterise the data space for which a model is valid. For example if a geographical area under investigation complies with the circumstantial characterisation of a model for all but one parameter, and the model is not sensitive to this parameter, then it would be valid to apply the model to that area. Participant cooperation and communication is vital for success in this development of a robust and valid integration framework. A strategy of participant query is currently being developed so that interrogation will be clear, precise and structured to prevent misunderstandings and elicit the necessary information. This will require a degree of understanding of the issues by all participants, and the task summary diagrams are a first step to facilitating communication by providing an overview of components and links which can act as a common basis for focused discussion. These diagrams are a simple representation of the current state of the project, and the links represented may look different once the models and data sets are better developed and the details evolve. Task 7: Testing models against independent data and outlining implications for silvicultural strategies This task was not active during the second reporting period. Task 8. Final products, documentation and identification of new opportunities A listserver is used to manage e-mail connections between project participants. A File Transfer Protocol (ftp) is used to transfer project documents between participants. A World Wide Web homepage has been further developed for information dissemination outside the project. CHAPTER 3 RESULTS Task 1: Project planning The results of Task 1 come in the form of Planning document updates on the ftp site. Task 2: Quantification of component factors controlling snow, wind and fire damage Some initial results are now available for the tree pulling experiments providing a tree-pulling database with the relationship determined between critical turning moment (for uprooting and/or stem breakage) and tree characteristics (Norway spruce, Scots pine and birch species). Linked with this work is the database of tree pulling (based on 1300 trees), already prepared, that is being examined for relationships between tree characteristics and the bending moment required to break or overturn trees. Regressions have been calculated for combinations of these with the aim of determining the parameters for the empirical model of tree breakage and overturning (Task 3.1). Critical to this work is the study of strength properties of wood from populations of trees that have broken, overturned and remained undamaged. Most of the field sampling has been completed and the laboratory work is well underway. Measurements of tree swaying are contin uing but no results are yet available. Preparation of the pure spectral data set is also going well. Early results are promising highlighting the value of using a spectral linear mixture for assessing some fuel loading. Task 3: Tree-level models to predict circumstances for damage Sub-task 3.1. A Mathcad programme (ECRISK.MCD) capable of calculating the wind speed to break or overturn a tree has been written and is being tested to ensure that predictions are consistent with observations of the wind speeds required to cause damage. The model is being tested also for consistency against measured bending moments already obtained from field and wind tunnel. This allows fine tuning of model parameters. The model results show also that on good rooting soils, such as brown earths, the wind speeds required to break and overturn spruce are very similar which is consistent with the mix of damage that one observes on such sites. On poorly draining sites, such as peaty-gleys, the trees always overturn before they break. Furthermore, the Mathcad programme has been converted into two Turbo Pascal programmes. BREAK.PAS is a model designed to integrate with a GIS. It takes the .img fi les of tree and soil characteristics created by the GIS, calculates the wind speed required to damage the tree at each data point and creates a new .img file of critical wind speed which can be incorporated back into the GIS. Another Turbo Pascal model (TREESNAP.PAS) has been written which has the same basic structure as BREAK.PAS but which is designed as a stand alone programme in which the tree and soil characteristics are entered by the programme user. This allows the model to be easily tested against the mechanistic model being developed in sub task 3.3. Sub-task 3.2. The logistic models developed under sub-task 2.2. have been further developed, not only for separate species, but also for different soil types and management treatments. This will be completed before month 21. A database on snow and wind damage was prepared by 1.5.95. The description of the dataset, stored and available at our project ftp adress. Sub-task 3.3. The test version of the mechanistic model (HWIND) for determining the windspeed and snow load required to damage single trees along the stand edge and within the stands has been derived. The HWIND-model can be run within Windows and in that case figures and tables drawn by specific graphical application (made by Visual Basic). HWIND can be used also without Windows (without graphical presentation, i.e. only tables available in that case). Hardware needed to run the model is PC-computer (programming made by C++). Sub-task 3.4. The model was used to estimate individual pine trees Leaf Area (LA) by field measurements is a generalization of the simple allometric model using as independent variables the tree total height and the diameter at the base of the live crown, as well as the stand basal area as a linear combination on the parameters and on the allometric constant. Task 4: Defining stand-level variability to permit application of tree-level models This task is still at an early stage and all progress to date has been devoted to determining the best approaches to tackling Sub-tasks 4.1-4.4, the identification of existing data sets and models, and the development of existing methodologies. However, previous wind tunnel measurements of the mean and extreme wind loading on trees are reproduced as a function of the distance from the forest edge and the stand density (Sub-task 4.1). Task 5: Regional-level snow, wind and fire risk models Sub-task 5.1. Recently the airflow model developed at the Riso Laboratory in Denmark, WaSP has been acquired and installed on a PC at NRS. The results of simulations of the airflow over the Kintyre peninsula have been compared against field measurements of wind speed and direction at 14 locations on the peninsula and the results from Flowstar, MS-Micro and DAMS. These initial results suggest very similar behaviour from all the models with good agreement on the tops of hills but overprediction of the wind speeds in valleys and on lee slopes. However, the WaSP model does appear to have an additional superimposed steady decline across the peninsula which is probably an overreaction to the sudden roughness change from ocean to land. Furthermore, the DAMS comparison is slightly artificial because DAMS is designed to integrate the effects of winds from all wind directions and the data tested were for a pure westerly airflow. An internal report on the setting up and operation of WaSP has been produced.We have also explored the relationship between mode/range variables of the extreme value distributions and windiness score using data from a number of Meteorological Office sites in Britain. The initial tests appear promising and offer the prospect of a rapid way of applying the extreme value distribution to a wide range of sites. The discussion in the snow damage meeting focused initially on the mechanisms by which damage occurred due to snow and wind, and some concern was also given to the silvicultural aspects of this damage. Discussion then moved to the climatological parameters which might be important, to identify which needed to be understood and modelled. This discussion also considered the extent of damage incidence both temporally and spatially and the issues associated with scale and variability of climate events with respect to the meteorological records. Sub-task 5.2. For the UK test site, aerial photography for each area was obtained during summer 1995, and GPS survey carried out to record precise locations of basal area plots, windthrown gaps and boundaries. The data from the GPS survey is being used to update estimates of location on the GIS. The aerial photographs are being interpreted for windthrown pockets and overlays produced will be digitised and added to the GIS datasets. Data layers for Cwm Berwyn have been assembled to allow development of the orthophoto analysis, and for collaborative work outwith the scope of this project with University of Salford, UK and the Australian National University. For the Finnish test site, the construction of geographic database of test areas, and the preprocessing of the satellite images for the change detection has been continued. Forest stand boundary layers have been stored in the geographic database. The wind damage measurements have been completed during November 1995 and the wind damage data have been stored in the geographic database and added to the existing data. The satellite images have been preprocessed for further use. The Portuguese the study area was expanded to the construction of the regional geographic data base. The elevation map sheets are now being assembled for the construction of the regional DTM (corresponds to about sixty 1:25000 contour maps). In addition, metadata form were produced to be used by the partners in data collection and digitisation for the development of comprehensive databases, to aid in the validation of links between project components, and to ensure that all relevant information was collected which would be required for input to models ensuring compatibility between data sets of scale and error issues. Sub-task 5.3. The results of the data investigations was a report documenting what data was available for where and from what organisation the data could be obtained. It also includes other information such as data format, coverage, scale and error. This information will feed into a task 6 component to assess data availability for areas where model output might be required. Sub-task 5.4. The results achieved so far showed that linear mixture modelling software works well when using image endmembers. Task 6: Integrating components from tree/stand regional-level to produce an unified risk model Apart from the task summary diagrams which indicate models and data and information flow between these components, there are as yet no results from this task. Task 7: Testing models against independent data and outlining implications for silvicultural strategies This task was not active during the second reporting period. Task 8. Final products, documentation and identification of new opportunities A number of papers has been published or submitted to scientific journals. Furthermore, some models are available for further testing, and project's web page has been updated frequently. CHAPTER 4 DISCUSSION Task 1: Project planning Task 1 project planning is ongoing and in particular the issues extant are being targeted using other tasks particularly Task 6. Task 2: Quantification of component factors controlling snow, wind and fire damage Work is progressing in Task 2 with useful results and datasets now available. Integration between the different parts of the work is progressing better than expected and new areas of exchanging data, and also wood and root samples, are being developed. Task 3: Tree-level models to predict circumstances for damage Sub-task 3.1. Initial comparison tests of the models being developed in sub tasks 3.1 and 3.3 were carried out during the visit by participants to Joensuu in August 1995. These revealed some differences in results and the reasons for these differences will be the subject of investigation during the next reporting period. As part of this response another model (EXPBREAK.MCD) is being developed in Mathcad which calculates the wind loading on the tree by assuming an exponential wind profile in the forest canopy. This is closer to the methodology adopted in sub task 3.3. This method will also allow the loading on individual trees to be calculated rather than only a mean loading based on an average tree. This will assist with the investigation of the implications of stand variability being carried out in Task 4. As a separate study a full dynamical tree model was developed as part of his Diplomarbei t at Gottingen University by Tobias Kerzenmacher in collaboration with participant 4 while he was working at the Forestry Commission from October 1994-October 1995. This model will be used to test the simplified models being used as part of this programme, in particular to determine the best ways of parameterising the dynamic response of trees to the wind. Sub-task 3.2. The data needed for the work is already available at this state of the work. The preliminary results obtained, show that characteristics of single trees are possible to use as measure of future risk of damage from snow and wind. During the period until month 21 risk assessment models for the whole country will be developed. Sub-task 3.3. The test version of the mechanistic wind and snow damage model, i.e. HWIND, has been derived. The next period will see progress across this sub-task, i.e. the mechanistic model for evaluating the wind and snow damage risk of various tree species will be tested against data from Sub-task 2.3. Sub-task 3.4. The developed model to estimate the LA of Pinus pinaster trees over a wide range of environmental conditions and tree ages has fairly good scores on goodness-of-fit and predictive ability statistics but is weaker on its multicollinearity diagnostic statistics. Nevertheless, models developed to more limited regions (local models) have proved to have better performances than this one. Therefore, the development of a local model for Viseu study area will be considered in the next field work campaign. The plot LAI estimations obtained so far are consistent with the values expected for Pinus pinaster plantations. However, the sampling of trees inside the plot makes the LA estimation a little unreliable since the independent variables are also themselves estimated from other tree and stand variables. This problem will be overcomed by measuring the needed variables for LA estimation in all trees of the plot. Task 4: Defining stand-level variability to permit application of tree-level models Identification of the existing data and available models in order to determine the best way to calculate relationships for wind-loading within stands continues (Sub-task 4.1) as well as the provision of test data (Sub-task 4.2). Task 5: Regional-level snow, wind and fire risk models Sub-task 5.1. Further refinement of the geographic predictors (windiness scores) is being attempted. Once this analysis is complete we will conduct a comparison of methods with windiness scores and airflow models in the challenging terrain of the West of Scotland - where we already have digital terrain and on site windspeed measurements; the latter have just been subject to a careful data-cleaning exercise and are ready to be used for initialising and comparison with model predictions. Sub-task 5.2. For the UK test site, further deployment of the GPS and acquisition of aerial photography is being planned for summer 1996. The potential to acquire a vector-based GIS to complement the existing raster-based system is being investigated. For the Finnish and Portuguese test sites, the aims identified, receptively for the period of report has been achieved and the compilation of geographic database of test areas for wind damage model testing has continued as planned. Furthermore, the metadata forms were kept simple for ease of use but are comprehensive enough to ensure that all relevant criteria are covered. Completion of these forms will save time in the future by minimising the possibility of important information being omitted during the collection process which might be difficult to recover later in the project. The forms constitute a summary of important metadata necessary for data use. Minor changes were made to the forms in response to comments from MLURI data capture personnel and project participants who have some experience in the area. Sub-task 5.3. The information contained in the report will be important for use in Task 6 to create a system framework which has valid links between models and data. There also exists the possibility of graphically incorporating this information into the system to allow easy identification of relevant data sets for particular model runs and to enhance its user-friendliness. The report revealed some major gaps in European coverage and the inadequacy of data sets currently available when compared to the metadata form resulting from Sub-task 5.1. A significant contribution of this project to the whole subject of European data collection, dissemination and use is that these issues are being addressed in the context of metadata provision. Sub-task 5.4. Some effort will be needed , in order to work with reference endmembers (that are an input to this sub-task from sub-task 2.4), when using the software selected. If not, another software should be found. Task 6: Integrating components from tree/stand regional-level to produce an unified risk model Sub-task 6.1. The successful integration of models and data into a working system which can provide a measure of damage risk and an understanding of the effects of silvicultural practices is of fundamental importance. Ensuring linkages will dictate the progress of other parts of the project. The intention is to produce a general framework with a more detailed plan of parts being developed as related tasks are completed. The completion of the models will determine the variables and links with data sets. As tasks are completed components can be slotted into the framework plan without the necessity for continual re-structuring. The diagrams will be used to explore detailed links and flag issues such as data compatibility and parameter input to the model and sensitivity testing. Task 7: Testing models against independent data and outlining implications for silvicultural strategies This task was not active during the second reporting period. Task 8. Final products, documentation and identification of new opportunities A number of papers has been published or submitted to scientific journals. Furthermore, some models are available for further testing, and project's web page has been updated frequently. The electronic transfer of data, models and documents has been very efficient way to manage the project, and it will be continued. CHAPTER 5 DISSEMINATION Meetings: Second Project Meeting was arranged on 10-13th, August 1995 in Tampere and Joensuu, in Finland. The timetable of the meeting is presented in appendix 1, list of participants and minutes are presented in the report of participant 4. Documentation: The results of each task are being made available on the World Wide Web site for dissemination. The updated Task 1 document pages and summary diagrams can be found on the ftp site in the directory air/task1/. They are stored in Word Perfect 5.2 and Word for Windows 2.0 format. A report has been produced as a result of the snow modelling workshop and has been distributed to both workshop and project participants. A subsequent workshop is planned to discuss the success of the adopted strategies to the modelling approach (Sub-task 5.1). The metadata form is currently available on the MLURI ftp site and it is planned that web pages will also be available shortly, which will allow participants to fill in the metadata form on-screen direct to the Macaulay Land Use Research Institute over the internet. The information added using the form will be stored automatically on the ftp site, and will thus be available for perusal by all participants (Sub-task 5.2). The report detailing information about Pan-European data sets will be available on the ftp site and accessible via the WWW pages (Sub-task 5.3). The summary diagrams are currently available on the ftp site and can be accessed by all participants there. They are also to be added to the Task 1 planning document. (Task 6) EDGE.XLS (Data on bending moment as function of distance from forest edge and stand density in Excel 5.0 format) has been placed on Edinburgh University ftp site (ftp.ed.ac.uk/pub/risk). A self extracting copy HWIND-model for Windows 3.1 is available on Joensuu University ftp-site (gis.joensuu.fi /hwind/windows/hwind05.exe). The first version of the stand alone empirical model (treesnap.exe) to calculate critical wind speeds for damage and base bending moments has been made available to participants on the Edinburgh University ftp site (ftp.ed.ac.uk/pub/risk) Growth models developed by Soederberg and Ekoe at Umea University, Sweden using single tree and stand characteristics made available to other participants. List of publications: There has been the following publications and scientific manuscripts published, in press, and in prep. within the second period of Project: Gardiner, B. A. and Stacey, G. R. (1995). Designing Forest Edges to Improve Wind Stability. Forestry Commission Technical Paper 16, Forestry Commission, Edinburgh. Gardiner, B. A., Stacey, G. R., Belcher, R. E. and Wood, C. J. (1995). Field and wind tunnel assessments of the implications of respacing and thinning for tree stability. Submitted to Forestry. Lundqvist, L. and Valinger, E. 1996. Stem diameter growth of Scots pine trees after increased mechanical load in the crown during dormancy and (or) growth. Annals of Botany (in press). Peltola, H. 1995a. Swaying of trees in response to wind and thinning in a stand of Scots pine. Manuscript accepted to Boundary-Layer Meteorology. 18 p. Peltola, H. 1995b. Model computations on the wind flow and turning moment by wind for Scots pine along the margins of clear-cut areas. Manuscript accepted to Forest Ecology and Management. 15p. Peltola, H., Kellomäki, S. and Väisänen, H. 1995a. Model computations on the impacts of the climatic change on soil frost and the risk of trees for windthrows. Unpublished manuscript. 11 p. Peltola, H., Kellomäki, S. and Väisänen, H. 1995b. HWIND: A mechanistic model for wind and snow damage of Scots pine, Norway spruce and birch sp. Model description 1 p. Valinger, E. and Pettersson, N. 1996. Wind and snow damage in a thinning and fertilization experiment in Picea abies in southern Sweden. Forestry (in press). Valinger, E., Lundqvist, L. and Sundberg, B. 1995. Mechanical bending stress applied during dormancy and (or) growth stimulates stem diameter growth of Scots pine seedlings. Canadian Journal of Forest Research 25, 886-890. Valinger, E., Lundqvist, L. and Sundberg, B. 1994. Mechanical stress during dormancy stimulates stem growth of Scots pine seedlings. Forest Ecology and Management 67, 299-303. Valinger, E., Lundqvist, L. and Brandel, G. 1994. Wind and snow damage in a thinning and fertilisation experiment in Pinus sylvestris. Scandinavian Journal of Forest Research 9, 129-134. Varjo, J. 1995b. Controlling continuously updated forest data by satellite remote sensing. International Journal of Remote Sensing. In print. CHAPTER 6 CONCLUSIONS Coordination and management of the project is crucial to the successful integration of components in Task 6. The Web pages, the ftp site and the mailing list have afforded efficient and timely communication and made coordination and management much easier, providing not only mass communication of inter-participant messages, but the exchange of images, documents, diagrams and forms which can be instantly updated with no time delay. The next period will see progress across a number of the Sub-tasks. Participant 05 will arrange Project Meeting 13-17th, March 1995 in Edinburgh, in Scotland. Coordination, management and communication of the project is crucial to the successful integration of components in Task 6. CHAPTER 7 ACTION No specific action are proposed, since the activities planned to be executed during the the next period January 1996 - June 1996 are well in line the experiences during the current period. Appendix 1