You should be increasingly aware that change is a fundamental property of all forest ecosystems. Attributes including : structure ; plant, animal, and microbial composition and abundance ; patterns of nutrient distribution and cycling ; and productivity, vary over time, and across space. A thorough understanding of forest change, or dynamics, is an essential skill of forest ecologists, wildlife biologists and resource managers.
Temporal change is often very slow. Our understanding of it is based on long term data records and inference from chronosequences (spatially separated sites of different age). Prediction of future trends can obviously only be accurate if the information used to develop them still applies, i.e. the conditions that caused change in the past are constant. Factors which cause a forest to change that might not be constant include : climate ; disturbance regime ; nutrient and water availability ; and management practices.
Forest simulation model are used to “project” future structure and composition of a forest at an accelerated rate (minutes vs centuries), and to test predictions regarding future trends. These models are tools and are only as useful as the field data used to develop them (e.g. tree growth rates, competitive relationships, site requirements, etc.). Because these models allow the conditions that cause forest change to be altered, we can make comparisons between different environmental regimes.
