Responses of plant and animal habitat diversity to forest management and climate change: a modeling approach

We are modifying the gap model, ZELIG, to simulatechanges in the diversity of plant and animal speciesfollowing various silvicultural treatments and climatechange scenarios. This report summarizes our progressduring the first year of this study. Specifically, modelmodifications, model verification, and a demonstrationproject exercising the utility of the model to evaluatetradeoffs of alternative silvicultural prescriptions aredocumented. Modifications implemented included areformulation of the height-diameter allometry,
consideration of snag and log dynamics, and addition of aforest management module that can simulate any number ofsilvicultural prescriptions. Results of the verificationeffort using the most recent version of ZELIG (PNW.OSU.2)indicated the model predicts with some reasonabilitytemporal dynamics of Douglas-fir stands at 500-1100 melevation. Potential modifications to improve modelperformance were identified. Although results arepreliminary, the demonstration exercise offered insight intothe costs and benefits, with respect to timber productionand diversity of bird habitat, associated with varyinglevels of structural retention following timber harvest.Future efforts of this modeling project are outlined.