Forest Investment Account (FIA) - Forest Science Program
FIA Project G106003

    GYMP: Expansion of the Tree and Stand Simulator for complex stands
Project lead: James Goudie (Ministry of Forests and Range)
Author: Goudie, James W.
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Previous Work
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. Yield tables generated by TASS provide 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 to manage and rapidly manipulate a large database of TASS tables to meet the needs of yield analysts and silviculturists.

In a previous FIA-FSP project (Y083088), we initiated TASS III, which improved predictions for two-species and multi-cohort stands, and contained the structure for accommodating complex treatments in those stand types.

Proposed Work
In this three-year project, we are further developing TASS III for complex stands. This development will be directed toward priorities identified by GYMP and FSP-TPAC for modelling the growth and yield of complex stands, and modelling wood quality attributes.

In this project, we are:
Expanding the suite of species and mixtures modelled by TASS III.
Improving the accuracy of predictions, speed and general model performance of TASS III.
Expanding the reporting capabilities (see methods)
Enhancing the graphic outputs of TASS III in response to client feedback.
Enhancing the capability and user interface of TASS III by increasing the number and complexity of partial cutting and thinning treatments that users can specify.
Upgrade the database and other components of TIPSY
Upgrading components of the SYLVER system (e.g., sawmill simulator, financial analysis package) that facilitates the simulation and analysis of product yield.
Linking TASS III functions to climate change variables and effects.
Conducting workshop and training sessions to obtain client feedback on model capabilities, interface structure, and relevance to client needs.
Contributing to related projects that will link TASS to inventory attributes.

Calibration of TASS III requires both individual-tree measurements and plot-level statistics. Plot-level statistics and some individual-tree measurements are obtained from permanent sample plots, but several functions rely on detailed measurements from destructive sampling of individual trees. Some functional relationships in TASS III, particularly those related to wood quality and carbon balance, require measurements acquired in sampling techniques adopted in the last decade. To date, this type of information has been acquired for second-growth coastal Douglas-fir, coastal western hemlock, interior Douglas-fir, and lodgepole pine. Interior spruce sampling will be completed by 2010 as part of another FSP research project. Within this GYMP project, we will extend this level of sampling to other key commercial species. A lesser level of calibration can be achieved without the most detailed information, and we will continue to expand the suite of species and mixtures calibrated at that level.
Contact: Jim Goudie, (250) 387-6535,


Executive Summary (0.3Mb)

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Updated August 19, 2010 

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