CASCADE

Cascade Simulation Model (CASCADE)

CASCADE is a simple rule-based simulation model that can be used to generate landscape pattern dynamics in response to forest cutting and subsequent regrowth. Forest regrowth is indexed as time since disturbance. The model operates in a simple, gridded landscape. The user specifies a cutting rate (rotation length), minimum stand age eligible for harvest, adjacency constraints on cutting and either an aggregated or dispersed distribution of cuts. As input, the model requires a map indicating the initial stand age and another map that defines "Potential Harvest Units" (PHUs) for the study area. The shape, size and position of the PHUs are defined by a forest engineer, based on regulatory, engineering and other logistical constraints on log removal, road placement and environmental protection. Topography and the position of the perennial stream network are the primary basis for defining these constraints. A "regions" map can be used to subdivide the study area and different management rules can be specified for each region. At each time step, the model outputs a new stand age map for the entire study area. These maps can be analyzed using FRAGSTATS. The model is written in C and operates in a UNIX environment. CASCADE requires arc/info SVF files as inputs, and outputs SVF files at each timestep. Additional information on the model is provided in the citations below. CASCADE builds on earlier modeling work by Franklin and Forman (1987. Land. Ecol. 1:5-18) and Li et al. (1993. Land. Ecol. 8:63-75).

Source code is available.

For additional information, contact Dave Wallin.

Citations:

Wallin, D.O., F.J. Swanson, B. Marks, J. Kertis and J. Cissel. 1996. Comparison of managed and pre-settlement landscape dynamics in forests of the Pacific Northwest, U.S.A.. Forest Ecology and Management 85:291-309. (Pub No: 2198).

Wallin, D.O., F.J. Swanson and B. Marks. 1994. Landscape pattern response to changes in the pattern-generation rules: land-use legacies in forestry. Ecological Applications 4(3):569-580 (Pub No: 1579).