Trends in forestry modelling

Different types of models have been developed and applied to address various problems and issues in forestry. This paper reviews modelling trends in four areas, namely, forest management planning and decision-making, forest dynamics and growth projection, forest landscape and spatial models and participatory forest management models. The first type includes decision models generally structured as optimization models applied to forest planning. These models evolved from single objective to multiple objectives with spatial dimensions, including visualization. The second type includes forest dynamics models designed to examine the growth response of trees using process-based empirical or conceptual models. Demands for 'close to nature' forest management created new challenges for modellers to provide models with expanded capabilities to deal with tree growth, succession, and competition in stands with many species and wide range of tree sizes. The third type takes advantage of increased computational and graphic capabilities to model landscapes and display them as 'virtual' realities. These models combine spatial models such as geographical information systems (GIS), visualization tools and analytical models to form an integrated decision support system. The fourth type includes participatory models designed to accommodate multiple stakeholders in addressing collaborative forest management. These models are particularly adaptable to community-based forest management. Finally, the uses of models as 'learning' tools and as 'problem structuring' tools are also described.