Project

Modelling trees and forests

Recently, we started with a new major effort to develop mechanistic tree and forest models.

Project description

We currently develop two different models. (1) The first is a rather detailed 3D tree growth model, which includes the 3D modular development of trees, L-system related growth rules, architectural-tree-model related growth rules, local growth responses to local light conditions, carbon balances, and carbon transport. We also modelled 3D canopy dynamics and related 3D dynamics in light levels. A first version is tested and a manuscript on the model and its potentials is in preparation. (2) A tree / forest model on water-light effects on tree growth and forest production. Water dynamics depend on the relationships between soil conductivity, water content, and water potential. Water transport depends on tree / forest dimensions, the water potential gradient, and the behaviour of stomata in relation to microclimatic conditions. A first tested version of the model is expected at start-2004. These models are based on the physical, physiological, morphological, and development principles of trees in general, and are thus applicable to any tree / forest in a light-limited or light-water limited situation, respectively. With these models we hope to explore the mechanisms of tree and forest growth patterns that fail explanation, to develop new hypotheses on tree and forest growth patterns, and to predict forest and tree growth under different scenarios of forest management or climatic change. The models will work in joint action with field studies to test hypotheses for both tropical and temperate forest sites.

Publications

MSc theses

  • Just a matter of scaling. The effects of tree size on production, allocation and shoot development in Fagus sylvatica L. ( Andries Polinder, completed 2007)
  • The pipe model theory tested for pines and oaks dry versus wet forests in the Wallis valley, Switzerland. (Simone de Brock, completed 2006)
  • Effects of water availability on hydraulic architecture of Quercus pubescens Willd. and Pinus sylvestris L. in the Wallis Valley, Switzerland. (Q. Chowdhury, completed 2006).
  • Developmental trajectories of pubescent oak (Quercus pubescens) and Scots pine (Pinus sylvestris) in drought-stressed environments in the Wallis Valley, Switzerland. (Alfred Chitiki, completed 2005).
  • Mechanical properties of tropical rain forest tree species and their consequences for crown development. (Arnold van Gelder, completed 2005)