SORTIE-ND model evaluation for management predictions in forests affected by mountain pine beetle
Evaluation of the Complex Stand Simulation Model SORTIE-ND for Timber Supply Review in Sub-Boreal Forests of Northern BC
Dave Coates, Rasmus Astrup, Erin Hall, Beth Henderson, FIA Forest Sciences funded project 2007-2010 (Y103187)
The overall objective of this project is to evaluate SORTIE-ND model performance in sub-boreal forests. More specifically, we are evaluating the suitability of the model to produce unbiased estimates of individual tree and stand growth in for use in management decisions and as a timber supply analysis tool in mountain pine beetle (MPB) disturbed forests. For a broader discussion of our approach to model testing and evaluation see Model Development, Testing and Validation. To move SORTIE-ND from a research model emphasis to a management model emphasis requires extensive testing of model predictions. For a model to be used in timber supply analysis it is important that the model is evaluated and that efforts are made to obtain unbiased model predictions.
The mountain pine beetle epidemic has resulted in structurally complex unsalvaged stands and salvaged stands with variable levels of retention. Currently, we have limited ability to predict growth and yield in these stand types. Adding SORTIE-ND to the Timber Supply Review suite of available models will enhance our ability to predict yield in complex-structured stands. This is especially important for predicting the growth and yield value of secondary structure for mid-term timber supply in pine-leading and other stand types damaged by the mountain pine beetle.
The Objectives of this Project are:
- To compare model predictions to independent observations of growth from permanent sample plots or other sources of long-term data. This will provide information on ranges of accuracy and precision of stand level predictions.
- To provide users with information on the model performance and model developers with knowledge on where to concentrate further model development.
- To have SORTIE-ND accepted as a model that can be used for planning silvicultural treatments including their impacts on Timber Supply Review. The emphasis will be using the model in complex-structured stands resulting from the MPB epidemic, especially for prediction of mid-term timber supply opportunities.
- To calibrate SORTIE-ND, if necessary, for use in the timber supply analysis.