CABALA: a linked carbon, water and nitrogen model of forest growth for silvicultural decision support

Forest managers now operate in an information-rich but increasingly challenging environment in which the competing demands of environmental stewardship and sustainable management must counter-balance the demands of increased production and profitability. Management support tools, in particular, decision support systems are essential aids in this operating environment. A dynamic forest growth model, CArbon BALAnce (CABALA), that links carbon, water and nitrogen flows through the atmosphere, trees and soil including soil organic matter is presented here as a central part of a silvicultural decision support system. The strong linkage between stand biomass allocation and external environmental conditions make CABALA a model suitable for exploring stand management options and the effects of factors such as frost and drought on growth. The model performance is verified extensively using fertiliser, spacing and thinning trials. Predictions of nitrogen mineralisation, light interception, plant water stress, and biomass allocation as well as stand growth and stand leaf area index are tested with observed data.