Forest Investment Account (FIA) - Forest Science Program
FIA Project G095003

    GYMP: Expansion of the Tree and Stand Simulator for complex stands
Project lead: Goudie, James (Ministry of Forests and Range)
Contributing Authors: Goudie, James W.; Simpson, David G.; Di Lucca, C. Mario; Grout, Shelley E.; Polsson, Ken R.; Allen, Kristine; Dobozi, Attila
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.

A three-year FIA-FSP project (Y083088), now in its final year, will see TASS II upgraded to TASS III, which will improve predictions for two-species and multi-cohort stands, as well as accommodate complex treatments in those stand types. At the end of the FIA-FSP project, we will have the first approximation TASS III calibrated for pure and mixed stands of Douglas-fir and western hemlock on the BC coast, and Douglas-fir and lodgepole pine in the interior.

Proposed Work
In this new three-year project, we propose further development of TASS III for application to other 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 of wood quality attributes.

In the proposed project, we will:
Expand the suite of species and mixtures modelled by TASS III.
Improve the accuracy of predictions, speed and general model performance of TASS III.
Expand the reporting capabilities include summaries such as snag retention, coarse woody debris, carbon sequestration, light values at specific sensor locations and light values on a horizontal and/or vertical grid.
Enhance graphic outputs of TASS III in response to client feedback.
Enhance 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
Upgrade components of the SYLVER system (e.g., sawmill simulator, financial analysis package) that facilitates the simulation and analysis of product yield.
Link TASS III functions to climate change variables and effects.
Conduct workshops and training sessions to obtain client feedback on model capabilities, interface structure, and relevance to client needs.
Contribute 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 an approved FSP research project. Within the proposed GYMP project, we will extend this level of sampling to western redcedar and other key commercial species, potentially amabilis fir, subalpine fir and Engelmann spruce.


Executive summary (0.2Mb)
Stand Yield Prediction for a changing Climate (0.5Mb)
TASS III Graphical User Interface - version 1 documentation (1.8Mb)

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Updated August 16, 2010 

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