TELSA: the Tool for Exploratory Landscape Scenario Analyses

The Tool for Exploratory Landscape Scenario Analyses (TELSA) is a spatially explicit model of vegetation succession, natural disturbances, and forest management activities. TELSA is a strategic planning tool designed to suppo rt adaptive management by projecting the consequences of alternative scenar ios at the scale of landscape units (i.e. 10 000-200 000 ha) over time fram es of decades to centuries. Scenario combine user-specified assumptions abo ut natural disturbances and management activities, and can include 'no acti on' or historic disturbance scenarios. The simulation model is at the core of a set of tools that also includes a geographic information system, datab ases, and several user interfaces for scenario definition, data analysis, s patial analysis and the display of results. Spatial characteristics of land scapes, such as fragmentation, patch-size distribution and connectivity are largely determined by management actions and their interaction with natura l disturbances. The TELSA toolbox includes a tool for the automated design of management units (i.e. harvest cutblocks), based on user-defined criteri a and scenario objectives. TELSA easily evaluates strategic alternatives re garding the size range of management units, their spatial aggregation, the use of adjacency constraints, and the application of different silvicultura l systems. TELSA represents vegetation succession as changes in species com position and structural stages of stands, thus projecting landscape conditi ons in a format that is relevant for the analysis of wildlife habitat and m any other resource indicators. Succession pathway diagrams define the trans ition times between successional classes and, for each class, the probabili ties and impacts of disturbance by insects, fire or other agents. These dia grams also define the impacts of management actions on stand structure and vegetation composition. Diagrams can be defined for forests and other veget ation types such as shrub and rangelands. Wildfires and other natural distu rbance events that affect vegetation dynamics are inherently unpredictable. The model can use multiple stochastic simulations of each scenario to prov ide estimates of the mean, range and variability of selected performance in dicators. (C) 2000 Elsevier Science B.V. All rights reserved.