About the project

Introduction

Objectives

Project Workplan

Expected Results

Conclusion

Literature cited

ITM Consortium

Coordinator

Partner Organizations

Participating Enterprises

Quality Assurance Panel

Consortium Structure

Meetings

Kick-Off

1. Milestone meeting (Lisbon)

Introduction

European forest management has traditionally relied on yield tables to estimate yields for forest management decisions. The main assumptions concerning yield tables are that the forest stands they describe are pure and even-aged. In Europe there is a strong movement toward uneven-aged forest management based on the general understanding that uneven-aged mixed species stands increase or at least maintain soil fertility, increase biodiversity and improve stand resilience reducing there susceptibility to physical and/or biotic disturbances. The shift from even-aged forest management renders existing yield tables increasingly unreliable. One possibility to forecast yields for uneven-aged mixed-species stands is to develop stand growth models that operate at the individual tree level. Such individual tree growth models have been developed mainly to study stand development in uneven-aged mixed-species stands. Much research has been carried out to develop theories on projecting tree growth with the intention of replacing yield tables. However forest companies still hesitate to implement such models for practical forest management purposes because of their complexity and because the problem solving potential has not been properly marketed. Although tree growth models have reached a certain level of developmental maturity, there are still some theoretical areas requiring more research. However, with the majority of model development complete, the time is near for modelers to focus on identifying user related needs and testing the models ability to meet user needs. Members of our consortium have developed six different individual tree growth models representing the theory which will be applied within this project for a number of selected topics within Europe. The existing models are: MOSES (Hasenauer 1994, Hasenauer 1999a), PROGNAUS (Monserud and Sterba 1996, Hasenauer and Monserud 1996, Hasenauer 1999b, Monserud and Sterba 1999, Hasenauer 1999a), SILVA (Pretzsch 1992, Pretzsch 1993, Kahn 1994, Pretzsch and Kahn 1995, Pretzsch und Kahn 1996), BWIN (Nagl 1995, Nagl 1997, Nagl 1999), a preliminary approach for estimating cork production with CORKFITS (Amaro 1997), and STAND (Nyyssönene and Mielikäinen 1978, Pukkala and Miina 1997).

Objectives

Several areas of growth modeling are identified for our research. In using the knowledge gained within the research component, we will demonstrate that individual tree growth models are a viable alternative to existing yield tables. Thus the main tasks of our project can be summarized chronologically:

1. Develop a preliminary framework to define modeling terminology and to identify and categorize individual tree growth models with a European focus. The purpose is to simplify, clarify and harmonize the theory, technical aspects and terminology dealing with individual tree growth modeling. Considerations include: purpose of model development, internal structure and components, data requirements, user interface, forest applications, limitations, strengths and weaknesses.

2. The research component within ITM addresses four areas of growth modeling which are either weak or have not been extensively researched:

1. regeneration establishment an development,

2. economics,

3. decision support and

4. extending models outside their normal calibration range.

Because there is a great difference in modeling experience between partners in the consortium, the objectives of the research workpackages are twofold. For those who have developed models, research to address weak points within their models. For the new modelers, it is an excellent forum for knowledge transfer. Essentially they get access to first hand information from a number of experienced modelers. The important task of the research component is the development of documented and programmed algorithms which can be immediately implemented into existing tree growth models.

3. Every model was explicitly designed according to the interest of the developer and his/her scientific background. Hence they have a different level of maturity to solve our nine specified European problems. These nine topics have been selected by the participating companies and state agencies of our consortium and can be summarized as follows:

1. Regeneration establishment and development in uneven-aged mixed-species stands.

2. Timber harvesting scenarios in uneven-aged mixed species stands to enhance sustainable income.

3. Extend and incorporate tree growth models in an information system to optimize stand treatments.

4. The applicability of tree growth models beyond their calibration area and their potential to replace the yield tables.

5. To assist forest policy decision and instruct private enterprises on appropriate treatment strategies.

6. The use of tree growth models as part of a decision support system to assess and optimize biodiversity, scenic beauty, alternative harvesting options within stands, recreational aspects, stand risk analyses.

7. Optimizing cork production in southern Europe.

8. Assessing the conversion of even-aged pure secondary coniferous stands into uneven-aged mixed species stands.

9. Development of growth models for coppice forests in Greece.

The first two steps are the research part because for a successful demonstration of our nine defined topics the existing models have to be analyzed, improved and/or further developed so that a successful software implementation and demonstration can be performed. Following this, a series of demonstration runs and packages will be developed according to nine identified topics. This demonstration packages can be used to inform and encourage the forest industry, state agencies and the public to use individual tree growth models. This step allows the user to see the advantages in using tree growth modeling technology but also to identify the constraints and/or possible limitations.

Project Workplan

Our project has put together a group of European experts in this field who have either developed their own tree growth model or have a unique practical application which can be solved by using individual tree growth models. The demonstration workpackages are a unique part of the project. Thus, the intention is to allow each modeler to maintain independence and the ability to continue the application of the model as he/she chooses. We wish to avoid the development of one "super model" because in the long run we believe that this would destroy the regional aspects within tree modeling, flexibility, model diversity, innovation and the competition among model developers which is extremely important for enhancing the technology.

Expected Results

The mission of this project is to establish individual tree growth model as an alternative tool to existing yield tables and address the urgent need for an appropriate management tool for uneven-aged mixed species stands. In meeting our mission, the following achievements will be realized:

1. to develop processes for information transfer between scientists, model developers, model users and the forest industry. 2. to simplify the complex issues surrounding individual tree growth modeling. 3. to harmonize the individual tree growth modeling theory into an understandable form. 4. to produce methodology for categorizing individual tree growth models. 5. to produce standard set of criteria for evaluating individual tree growth model performance. 6. to research areas of growth modeling requiring more research. 7. to produce useful tools to assist and encourage the forest industry in adopting the use of individual tree growth models. 8. to enhance forest management by promoting new technologies. 9. to improve silvicultural treatment strategies and optimize timber production. 10. to get feedback from practical users and induce research efforts in improving existing systems. 11. provide information in the problem solving potential for a number of important application areas for tree growth models at a European scale.

Conclusion

The uniqueness and strength of ITM is based on allowing each partner, after the research component is completed, to proceed with the application using the model that is best suited to solve the particular problem, as it was intended by the model developer. This ensures also that those partners who have little experience in tree modeling will be able to continue their modeling efforts independently. All the models have distinct approaches and unique qualities which the consortium feels must be maintained. Therefore this parallel application approach in the demonstration portion, is essential for the mission of ITM. An important role in preparing this proposal are the results of concerted action AIR3-CT94-2149 Management of Mixed-species Forest: Silvicultural and Economics. Members of our consortium were actively involved in this project which has basically agreed that (1) an urgent need to have alternative management tools (tree growth models) available as an option to replace the commonly used yield tables; (2) such tree growth models are available and they have proven (from a scientific prospective) that they are capable to forecast forest dynamics including biodiversity, sustainability, etc. in pure as well as uneven-aged mixed species stands; (3) the differences between the model types developed but there is a large gap between technology used within practical forest management decision making and (4) joint efforts are needed which are specifically designed to introduce and simplify existing technology on a tree level so that we are able to bridge this gap between implementation and research results available. This link between tree modeling research and using tree growth models for silvicultural and forest management decisions as they are needed to ensure the sustainability within uneven-aged mixed species forests is addressed in ITM. The project will start in Fall 2000 and has a duration time of three years.

Literature cited

• Amaro, A.. 1997. Modelação de crescimento de povoamentos de Eucalyptus globulus Labill de 1ª rotação em portugal. Dissertação de doutoramento. IST. Lisboa.

• Hasenauer, H. 1994. Ein Einzelbaumwachstumssimulator für ungleichaltrige Fichten-Kiefern- und Buchen-Fichtenmischbestände. Forstl. Schriftenreihe, Univ. f. Bodenkultur, Wien. Österr. Ges. f. Waldökosystemforschung und experimentelle Baumforschung. ISBN3-900865-07-8. 152 pp.

• Hasenauer, H., and Monserud, R.A. 1996. A crown ratio model for Austrian forests. For. Ecol. and Manage.84: 49-60.

• Hasenauer, H. 1999a. Die simultanen Eigenschaften von Waldwachstumsmodellen. Verlag Paul Parey, Berlin. 131 pp.

• Hasenauer, H. 1999b. Höhenzuwachsmodelle für die wichtigsten Baumarten Österreichs. Forstw. Cbl. 118:14-23.

• Kahn, M. 1994. Modellierung der Höhenentwicklung ausgewählter Baumarten in Abhängigkeit vom Standort, Forstl. Forschungsber. München, Nr. 141, 221 pp.

• Monserud, R.A., and Sterba, H. 1996. A basal area increment model for individual trees growing in even- and uneven- aged forest stands in Austria. For. Ecol. and Manage. 80: 57-80.

• Monserud, R.A., and Sterba, H. 1999. Modeling individual tree mortality for Austrian forest species. For. Ecol. and Manage. 113: 109-123.

• Nagl, J. 1995. BWERT: Programm zur Bestandesbewertung und zur Prognose der Bestandesentwicklung. Deutscher Verband Forstlicher Forschungsanstalten -Sektion Ertragskunde- Joachimsthal 29. - 31. Mai 1995, 184-198.

• Nagl, J. 1997. BWIN Program for Standanalysis and Prognosis. User's Manual for Version 3.0, Niedersächsische Forstliche Versuchsanstalt Göttingen.

• Nagl, J. 1999. Konzeptuelle überlegungen zum schrittweisen Aufbau eines waldwachstumskundlichen Simulationssystems für Nordwestdeutschland. Schriften der Forstl. Fakultät, Univ. Göttingen & Niedersächsischen Forstl. Versuchsanstalt. Verlag J.D. Sauerländer, Frankfurt a. Main. 122 pp.

• Nyyssönen, A., and Mielikäinen, K. 1978. Estimation of stand increment. Acta For. Fenn. 163. 40 pp.

• Pretzsch, H., 1992. Konzeption und Konstruktion von Wuchsmodellen für Rein- und Mischbestände, Forstl. Forschungsber. München, Nr. 115, 358 pp.

• Pretzsch, H. 1993. Analyse und Reproduktion räumlicher Bestandesstrukturen. Versuche mit dem Strukturgenerator STRUGEN, Schriften aus der Forstlichen Fakultät der Universität Göttingen und der Nieders. Forstl. Versuchsanstalt, Band 114, Sauerländer's Verlag, 87 pp.

• Pretzsch, H., and Kahn, M. 1995. Modeling growth of Bavarian mixed stands in a changing environment. Proc. 20th IUFRO World Congress, Tampere Finland, Interdiv. Session. (in press).

• Pretzsch, H., and Kahn, M. 1996. Modeling growth of Bavarian mixed stands in a changing environment. In IUFRO XX World Congress report. Jyväslylä, Finland.

• Pukkala, T., and Miina, J. 1997. A method for stochastic multiobjective optimization of stand management. Forest Ecology and Management 98: 189-203.