Keywords
regeneration, growth and yield models, decision support systems, ecosystem management, forest management
Start Date
1-7-2006 12:00 AM
Abstract
NED-2 is a goal-driven system designed to help manage timber, wildlife, visual, and ecological goals for a forested ecosystem. The basic approach of the decision process modeled by NED-2 is to develop alternative management plans for the stands in a management unit, to simulate these plans over time, and then to analyze the results of the simulation to see how well the management goals are achieved by the alternative plans. The basic simulation tool used in the system is the USDA Forest Service Forest Vegetation Simulator (FVS.) FVS provides a regeneration component, but a need was recognized for making available alternative regeneration models. The first effort in this direction was to integrate a competitive model developed by David Loftis and implemented as a program called REGEN. This model uses pre-disturbance inventories of existing regeneration sources and information about new seedling establishment, particularly light-seeded species from the seedbank or from trees in areas adjacent to a stand. The stochastic model uses a knowledge base that allows ranking the competitive abilities of different species, taking into account the origin of the regeneration source—new seedling, stump-spout, or different sizes of pre-existing seedlings. Different knowledge bases can be developed for different forest types and regions. This model must be interleaved with FVS when the user desires to use the REGEN model. Individual NED-2 software agents control the FVS and REGEN systems. This paper describes how these agents communicate using a blackboard architecture to synchronize the operations of these two models. The task is made more complicated because regeneration on one stand can affect the results on regeneration on an adjacent stand at a later time.
Interleaving Growth and Regeneration Models in the NED-2 Decision Support System for Forest Ecosystems.
NED-2 is a goal-driven system designed to help manage timber, wildlife, visual, and ecological goals for a forested ecosystem. The basic approach of the decision process modeled by NED-2 is to develop alternative management plans for the stands in a management unit, to simulate these plans over time, and then to analyze the results of the simulation to see how well the management goals are achieved by the alternative plans. The basic simulation tool used in the system is the USDA Forest Service Forest Vegetation Simulator (FVS.) FVS provides a regeneration component, but a need was recognized for making available alternative regeneration models. The first effort in this direction was to integrate a competitive model developed by David Loftis and implemented as a program called REGEN. This model uses pre-disturbance inventories of existing regeneration sources and information about new seedling establishment, particularly light-seeded species from the seedbank or from trees in areas adjacent to a stand. The stochastic model uses a knowledge base that allows ranking the competitive abilities of different species, taking into account the origin of the regeneration source—new seedling, stump-spout, or different sizes of pre-existing seedlings. Different knowledge bases can be developed for different forest types and regions. This model must be interleaved with FVS when the user desires to use the REGEN model. Individual NED-2 software agents control the FVS and REGEN systems. This paper describes how these agents communicate using a blackboard architecture to synchronize the operations of these two models. The task is made more complicated because regeneration on one stand can affect the results on regeneration on an adjacent stand at a later time.
