Forest Co-op MOSSY Project
The goal of this project is to use re-measured permanent sample plots to predict the changes in forest tree species composition and age structure that would occur as a result of growth and forest succession in the absence of stand replacing disturbance. Predicting stand level succession is an important part of forest management planning, particularly for wood supply and habitat supply analysis. This information was identified by Ontario’s forest managers as a high priority need as the only information available to them tends to be based on expert opinion.
The Forest Co-op MOSSY Project commenced in 2006. In 2009 work focused on adding Forest Co-op Growth and Yield Science Unit data plots, most of which had not been re-measured at the time of first analysis for this study. Twenty percent of the plots were randomly selected and set aside to evaluate predictions. The other eighty percent of the plots were assessed using regression analyses to determine which of the factors recorded in the re-measured plots and present in Ontario’s forest inventory can be used to predict the rate of change of stand species composition. The coefficients from the regression analyses were coded into the computer tool called Modeling Ontario’s Stand Succession and Yield (MOSSY). The data set aside for evaluation were then used to determine if the predictions made by MOSSY for changes to stand composition were reasonable. One of the tests used (equivalence testing) was inconclusive as the validation sample sizes by leading species were small. The other test indicated that the direction and amount of change predicted by MOSSY for tree species with larger sample sizes such as black spruce, white pine, balsam fir, jack pine, poplar, white birch and maple were reasonable. Tree species groups with smaller sample sizes such as red pine and white spruce showed differences in some cases between the actual and predicted tree species composition. Figure 1 illustrates sample predictions for two plots.
Work on evaluating the results from this project continues as this Annual Report is being written. It is planned that once the evaluation is completed, results from this project will be included in Ontario’s Modeling and Inventory Support Tool (MIST), an OMNR computer application used by all developing Forest Management Plans for Crown land in the province.