Canadian Forest Service Publications
Data and model validation methods used in developing the STIM growth model. 1993. Bonnor, G.M.; De Jong, R.J.; Boudewyn, P.A.; Flewelling, J.W. Pages 122-128 in J.K. Vanclay, J.P. Skovsgaard, and G.Z. Gertner, Editors. Growth and yield estimation from successive forest inventories, Proceedings: IUFRO conference. June 14-17, 1993, Copenhagen. Danish Forest and Landscape Research Institute, Lyngby.
Issued by: Pacific Forestry Centre
Catalog ID: 3357
To produce the STIM (Stand and Tree Integrated Model) growth model, data from approximately 1400 permanent sample plots were obtained from eight forestry agencies in the Pacific Northwest. A major portion of the model development time was spent in data and model validation.
Data validation procedures included:
- screening tree and plot data to identify anomalies and missing data;
- plotting variables to identify outliers and artificially generated data;
- comparing growth rates and other derived variables to assess trends;
- discarding plots with deficient data.
Model validation procedures included:
- assessing the quality of individual growth predicting equations using various statistical analyses;
- checking individual model prediction runs against real-life data;
- comparing stand projections with the sum of tree projections;
- analysing yield curves to assess long-term trends.