© 2000 Heron Publishing—Victoria, Canada
Process-based models for forest ecosystem management: current state of the art and challenges for practical
implementation
Annikki Mäkelä (1), Joe Landsberg (2, 3), Alan R. Ek (4), Thomas E. Burk (4), Michael Ter-Mikaelian (5), Göran I. Ågren (6), Chadwick D. Oliver (7) and Pasi Puttonen (1)
1. Department of Forest Ecology, P.O. Box 24 (Unioninkatu 40), FIN-00014 University of Helsinki, Finland / 2. Visiting Fellow, Australian National University, Department of Forestry, Canberra, Australia
/ 3. Landsberg Consulting, 22 Mirning Crescent, Aranda, Canberra ACT 2614, Australia / 4. Department of Forest Resources, University ofMinnesota, St Paul, MN 55108-6112, USA / 5. Ontario Forest Research Institute, Sault Ste. Marie, Ontario P6A 5N5, Canada / 6. Department of Ecology and Environmental Research, Swedish University of Agricultural Sciences, Uppsala, Sweden / 7. College of Forest Resources, University of Washington, Seattle, WA 98195, USA / Received December 20, 1999
Summary
Recent progress toward the application of process-based models in forestmanagement includes the development of evaluation
and parameter estimation methods suitable for models with causal structure, and the accumulation of data that can be used
in model evaluation. The current state of the art of process modeling is discussed in the context of forest ecosystem management.
We argue that the carbon balance approach is readily applicable for projecting forest yield and productivity, and review several
carbon balance models for estimating stand productivity and individual tree growth and competition. We propose that to develop
operational models, it is necessary to accept that all models may have both empirical and causal components at the system
level. We present examples of hybrid carbon balance models and consider issues that currently require incorporation of empirical
information at the system level. We review model calibration and validation methods that take account of the hybrid character
of models.
The operational implementation of process-based models to practical forest management is discussed. Methods of decision-making
in forest management are gradually moving toward a more general, analytical approach, and it seems likely that models that
include some process-oriented components will soon be used in forestry enterprises. This development is likely to run parallel
with the further development of ecophysiologically based models.
Keywords:
carbon allocation, carbon balance, competition, stand productivity, tree growth.
