UBC Theses and Dissertations
Development of regeneration standards for sustainable forest management Farnden, Craig
Linking regeneration activities to desired future forest conditions is a critical component of sustainable forest management. In much of North America, regeneration standards are an important administrative tool for ensuring this goal, but the links to predicted future outcomes are often weak. There is a need for developing regeneration standards that are solidly based on defensible predictions of future stand attributes and are indicators of a wide range of forest values. This dissertation describes the application of an analysis framework wherein many variations of simulated juvenile stand stem maps are used as the basis for regeneration standards development. The simulated stem maps were generated at the scale of operational cutting units using newly developed software routines. Spatial variation was emphasized at the scale of 5 to 200 m, reflecting underlying terrain and ecosystem patterns. The simulated stands were projected into the future using existing growth models, and sampled using simulated regeneration surveys. Simplified models to mimic predictions of selected stand attributes from the growth models were developed using survey summary data as predictor variables. The analysis system was applied to test relationships between various measures of stocking and yield for conifer monocultures. For the predictive relationships, curve shape and dispersion were found to be highly variable based on various stocking measurement parameters. Stocking was found to imperfectly account for spatial variation in the regenerating stand, and stocking thresholds for achieving a specific relative yield were found to vary by species and the top height at which relative yield was assessed. A second analysis developed simplified models to evaluate the contribution of regenerated stands to landscape level species composition in a vertically stratified, spruce-aspen (Picea glauca and Populus tremuloides) forest type. Various field assessment methods and model formulations were contrasted. Site index was found to have a major impact on absolute yield and on the curve shape for relationships between stocking and species composition. This dissertation provides a greater understanding of how to develop, interpret and apply regeneration standards. Relating standards and assessment methods to forest-level management goals provides a key link that is often missing in stand-level regeneration assessments.
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Attribution-NonCommercial-NoDerivatives 4.0 International