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A description of the Canada Land Capability Classification for forestry, and an analysis of data collected in the East Kootenay and Vanderhoof Districts of British Columbia were presented. A brief description of the climate, geology, physiography and soils in the East Kootenays was given. A description of the objectives of the land capability for forestry and a survey of the pertinent literature was included. The determination of Forest Land Productivity, and the accuracy of assigned productivity classes, were reviewed. It was found that the sources of error in productivity determinations included: (1) insufficient plots, (2) problems in defining 'normal' stocking, (3) extrapolation of MAI to a base of 100 years, (4) a strong tendency to select plots on northern aspects, and (5) the exclusion of plots on soils not representative of soil series descriptions. Two alternative methods for assigning productivity classes were discussed. They were point sampling and regression techniques. Both the point sampling and regression techniques gave results comparable to the conventional method, i.e. MAI determinations based on 1/5th acre plots, within prescribed constraints, and only in the interior of British Columbia. Results obtained from point samples on Vancouver Island were significantly different from those obtained on one-twentieth acre plots. The assignment of productivity subclasses was discussed. Here the only method presently feasible is a value judgement made by research workers. The results of the study revealed three areas where further research would result in a more accurate Forest Land Classification. These areas include: (1) the measurement of environmental factors which determine forest productivity, (2) the use of field and greenhouse experiments to establish methods for determining the relative effect of environmental influences in limiting tree growth, and (3) a more extensive study of the use of various sampling techniques to get a direct measure of productivity in terms of MAI.

Plant growth, production, competition and, to a limited degree, secondary succession have been simulated for a mixed species forest ecosystem operating on a big-game winter range. The simulation was based on empirically derived relationships. The major plant species investigated included Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir), Amelanchier alnifolia, Ceanothus sanguineus, Shepherdia canadensis, Prunus virginiana, Rosa nutkana, Symphoricarpos albus, Agropyron spicatum, Poa compressa and scabrella, Calamagrostis rubescens and Koeleria cristata. Distinction was not made among forb species. The simulation model predicts plant community development and production by species for a maximum period of 100 years following establishment, with up to 20 calculation intervals. Individual plants form the basic simulation unit. Variable data inputs include simulation period, calculation interval, species composition, density, inherent biological variability and site quality. Output is expressed in terms of wood production, weight of annual twig production of shrubs, current annual growth and carry-over of grasses, and current annual growth, of forbs. Designed to be used on the Wigwam big-game winter range in the East Kootenay district of British Columbia, the model provides a quantitative comparison of the land's capability to produce wood, browse, grasses and forbs. It also provides a basis for the solution of forestry-wildlife conflicts, such as assessment of the implications of management for wood production on ungulate food production, and formulation and testing of strategies designed to increase yields of wood, browse, grass and forbs.