Forest Investment Account (FIA) - Forest Science Program
FIA Project G106074

    GYMP: Development of the PrognosisBC model for the complex stands in southern and central interior of BC
Project lead: Catherine Bealle Statland (Ministry of Forests and Range)
Author: Bealle Statland, Catherine A.
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
The Prognosis suite of models, now called the Forest Vegetation Simulator (FVS) in the United States, was originally developed to assist in projecting the complex stands found in the northern Rocky Mountain region of the United States. The growth and yield component of this suite of models forecasts future stand conditions based on the expected growth and mortality of individual trees within a stand. The considerable work already completed on FVS, and the similarity of the stand conditions in the northern Rocky Mountain region of the United States to those found in southeastern British Columbia, prompted the Ministry of Forests to begin a project to adapt the northern Idaho variant of FVS for use in British Columbia (PrognosisBC). PrognosisBC has been calibrated for use in a number of Biogeoclimatic Ecosystem Classification (BEC) variants in the southern and central interior of the province, in particular, variants in the Interior Douglas Fir (IDF), Interior Cedar Hemlock (ICH) and the Montane Spruce (MS) zones.
The strengths of PrognosisBC include its ability to simulate almost any form of harvesting and to simulate the impacts of a host of forest health issues (e.g., root disease). Some of the forest health extensions are not yet calibrated for BC. The strength of the model is that it utilizes the architecture of the base FVS model and consequently it can be readily adapted to use extensions available in FVS if these are properly calibrated for BC.

In the past 5 years, a number of FSP-funded projects have been successfully completed developing PrognosisBC for use in the complex stands of the southern and central interior. These include projects to:
1) calibrate the growth and mortality components for mixed species stands in different subzones (Zumrawi et al, 2002 and Zumrawi et al 2005, Temesgen et al 2000);
2) develop a natural regeneration prediction system following partial harvesting (Hassani et al 2004)
3) develop a user-friendly graphical user interface (Robinson, 2005);
4) provide hands-on training workshops for model users; and
5) develop natural regeneration prediction models for MPB-attacked stands (ongoing).
Both version 2.0 and 3.0 of the model are supported by the BC Ministry of Forests and Range and are available for download from the Ministry’s growth and yield website.

Future development of PrognosisBC will build on the work completed in the last 5 years. The following research and development components are proposed for the next three years:
? review the growth and mortality components of Version 3.0 based on the results of the validation completed in 2006;
? complete model calibration for the SBS and SBPS BEC zones;
? amalgamate Versions 2 and 3 of the model to address gaps in it’s capability to predict natural regeneration following partial harvesting;
? develop snag and coarse woody debris and decay components to generate carbon reports for live and dead biomass in the short term and to facilitate future linkages to fuel and fire models in the long term;
? investigate the possibilities of incorporating climate change effects into the model’s predictions; and
? validate the model’s performance in each of these areas.

Repeated measurements from permanent sample plots (PSPs) in IDFdk were used to validate the PrognosisBC model performance (Zumrawi et al 2006). Overall, the model performance was found to be within acceptable limits. The model accurately simulated future individual tree dbh. Future individual tree heights were also predicted within acceptable limits; however, the model was highly variable and seemed to underestimate height growth of large trees. Also, the validation revealed that the random error component for the small tree height increment models behaved in erratically and need to be examined. Under this proposal both the large tree and small tree height increment models will be refitted and new model forms will be evaluated and where appropriate implemented. PSP data will be used to model large tree height increment models and temporary sample plot data collected for a number of projects in late 1990’s will be used to model the small tree height increment models.

Zumrawi et al (2005) developed large-tree radial increment models and height growth models for small trees (less than 7.5 cm dbh), for the major coniferous species in the SBSdw1 and SBSdw2 BEC subzones. However, because of data limitations, the model components were not fully calibrated in these subzones. PSP data with repeated measurements were lacking in the in SBPS and consequently no modeling was attempted. FSP project Y073022 will provide juvenile growth data from aspen-pine trials in the SBSdw1, SBSdw2 and SBPSxc subzones. Temporary sample plot data will be collected in 2008 and 2009 to calibrate the large tree components.

This project will link and parameterize an existing snag and coarse woody debris (CWD) simulation model to the PrognosisBC growth and yield model. Including a snag model adds further functionality to the model and extends the range of decisions that can be supported. This extension will support the capability to generate carbon reports for live and dead biomass in the short term and to facilitate future linkages to fuel and fire models in the long term.

Currently, PrognosisBC, like other variants of FVS, assumes that site factors will remain constant during the simulation period. This assumption is untenable as components of site quality are changing due to global warming. This includes changes in temperature, moisture, and atmospheric gas concentrations. Under this proposal, the project team will examine possible options and changes to the growth, mortality, and regeneration establishment components of the model to properly respond to climate change. The proponent participated in a workshop organized by the US Forest Service in 2007, the purpose of which was to define one or more approaches (or frameworks) for building a climate-driven version of the FVS (ESSA Technologies Ltd., 2007). Options including, the use of physiological models to provide a climate-based site productivity input to PrognosisBC and the use of long term climate data to refit growth and mortality models, will be investigate under this proposal.

ESSA Technologies Ltd. 2007. Development of a Climate–Driven Forest Vegetation Simulator: the Priest River Experimental Forest Workshop Results. Review DRAFT for Participants Report. Prepared by ESSA Technologies Ltd., for Rocky Mountain Research Station, USDA Forest Service, Moscow, Idaho and the Forest Management Service Center, USDA Forest Service, Fort Collins, CO. 14 p.
Temsegen, H.. and V. Lemay, 2000. Re-fitting the mortality model of PrognosisBC for both conifers and hardwoods in the Nelson and Kamloops forest regions. Report to the Ministry of Forests. 23 pp.
Zumrawi A., P. Marshall, V. LeMay, S.O. Akindele, and P. Parysow. 2006. Development of the PrognosisBC Growth and Yield Simulator in the Southern and Central BC: Model Validation. Two unpublished reports to the BC Forest Science Program (Project No: Y061132). 32 pp plus Appendices.
Zumrawi, A., V. LeMay, P. Marshall, B. Hassani and D. Robinson. 2005. Implementing a
PrognosisBC Regeneration Sub-model for Complex Stands of Southeastern and Central British Columbia. Unpublished report to the BC Forest Science Program (Project No: Y051355). 31 pp plus Appendices
Zumrawi, A., A. Stage and B. Snowdon. 2002. Stand level scaling of a single tree distance independent diameter growth model: Interim calibration of Prognosis in the South-eastern interior of British Columbia. IN: Nicholas L Crookston, and Robert N. Havis, Compilers. Proceedings of “Second Forest Vegetation Simulator (FVS) Conference”, February 12-14, 2002, Fort Collins, CO. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Ogden, UT. Proceedings RMRS-P-25. pp. 151-157:
Related projects:  FSP_G117074
Contact: Catherine Bealle Statland, (250) 387-5447,


Executive Summary (69Kb)

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Updated May 02, 2011 

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