The Tree and Stand Simulator (TASS II) is a biologically-oriented model that simulates the growth of crowns and stems of individual trees in a 3-D growing space. Since the early 1980s, TASS-generated yield tables have provided most of the growth and yield projections used in BC for Timber Supply Analysis and the evaluation of silviculture options. The Table Interpolation Program for Stand Yield (TIPSY) was developed in the early 1990s to manage and rapidly manipulate a large database of TASS tables to meet the needs of yield analysts and silviculturists (Mitchell et al. 2004). However, the potential of TASS II and TIPSY to address complex stands is limited to certain applications (e.g., variable retention (VR) in even-aged stands; Di Lucca et al. 2004). This proposed project will integrate and calibrate new and revised modules (already developed) into a new version (TASS III) designed specifically for the complex structures found in uneven-aged and mixed-species stands, and the complex treatments now being designed and implemented in BC. Newly developed modules to be revised and fully integrated include: 1. Revised computer architecture for the TASS 3-D canopy grid that accommodates multi-layered structures. The development and implementation of this architecture removed the limitation of a single canopy layer and permitted simulation of multiple canopy layers. 2. A raster-based light model, tRAYci. tRAYci (Brunner 1998, Gersonde et al. 2004) is already integrated as a reporting tool capable of characterizing the light environment at any point in the stand. Light maps from TASS II/tRAYci have been used to facilitate the design of field installations and predictions of wildlife habitat (Goudie et al. in press). 3. Table Interpolation Program for Stand Yield (TIPSY) The user input interface from TIPSY will be integrated into the application. Tabular output information from TASS III will captured, displayed and managed. Clients are already familiar with the control mechanisms of TIPSY since it is already used to access managed stand yield information from a database output from TASS. 4. VISTAS (Visual Interpretation of Silvicultural Treatments and stand Structures) is a Windows? application that creates a 3D visual representation of a stand of trees from tree data. It can create images from real or simulated data. The user can manipulate the image to expose the stand structure allowing them to see the forest despite the trees. VISTASS helps users implement complex silvicultural treatments. It will be integrated with the user input program and TASS to create a linked suite of models. We expect to deliver the following new features: ? Improved and expanded biological fidelity; ? Realistic and accurate predictions for complex stand structures (e.g., multi-species, multi-cohort, spatially heterogeneous), and complex treatments (e.g., Variable Retention , partial cutting, clearcutting-with-reserves) ; ? Capacity to assess light levels (e.g., light maps before and after partial cutting); ? User friendly and familiar front end similar to TIPSY interface; ? Visual display of thinning/partial harvesting with the capacity to view the trees from different positions above or within the stand, and zoom in on features of interest.
Group, Stand Development Modelling, Cameron, Ian R.; Goudie, James W.. 2008. TASS III: Simulating the management, growth and yield of complex stands. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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