A tree hollow dynamics simulation model

This paper describes a deterministic computer model for simulating forest d ynamics. The model predicts the long-term dynamics of hollow-bearing trees which occur in a single-species (monotypic) forest stand under an array of different timber harvesting regimes over a time scale of centuries. It is a pplied to a number of different timber harvesting scenarios in the mountain ash (Eucalyptus regnans F. Muell.) forests of Victoria, south-eastern Aust ralia. Computer experiments give results that have far-reaching implication s for forest management and could not have easily been predicted without a model. These include: (1) when the harvest rotation time is 100 years or le ss, a supply of trees with hollows cannot be ensured by only retaining tree s which already have hollows: and (2) when some retained trees are lost thr ough logging-related mortality, the effect on the number of trees with holl ows is exaggerated. For instance, if half of the retained trees are lost vi a logging-related mortality, it is not sufficient to double the number of t rees retained in order to maintain the same number of hollow-bearing trees. HOLSIM is a planning tool for forest and wildlife managers. it will assist them in forecasting long-term stand conditions that result from particular forest management regimes. The ability to make predictions over several har vesting cycles is extremely important for examining the effects of harvesti ng strategies on the dynamics and structure of forest ecosystems, determini ng if given management strategies will meet particular targets, anticipatin g the impacts of forestry operations on hollow-dependent fauna, and helping to better integrate biodiversity conservation within wood production fores ts. (C) 1999 Elsevier Science B.V. All rights reserved.