The mapping of land capability for forestry is based on a national classification system comparable with the other Canada Land Inventory sectors. Land is rated according to seven classes depending on its capability to grow commercial timber in areas stocked with the optimum number and species of trees. This rating considers the land in its natural state, without improvements such as fertilization, drainage, or amelioration practices. With improved forest management, production may change and limitations may be overcome so that class changes may occur, however, significant changes will only be achieved through costly and continuing practices. The best lands for tree growth are Class 1, and Class 7 land cannot yield timber in commercial quantities, these represent the extremes, because of unsuitable climate, no Class 1 lands will be found in several regions of Canada and in certain regions, Class 2 areas will be too small to show at the chosen scales of mapping.

The capability mapping is accomplished through interpretation of air photographs and field surveys. The assignment of land units to a capability class is made on the basis of all known or inferred information about the unit, including subsoil, soil profile, depth, moisture, fertility, landform, climate, and vegetation. Associated with each capability class is a productivity range based on the mean annual increment of the best species or group of species adapted to the site at or near rotation age. Productivity classes are expressed in gross merchantable cubic foot volume to a minimum diameter of four inches. Thinnings, bark, and branch wood are not included. The productivity as expressed is that of "normal" i.e., fully stocked stands. It may be assumed that only good management would have produced stands of this nature. The following are not considered in the classification: location, access, distance to markets, size of units, ownership, present state, or special crops such as Christmas trees.

As shown in the symbols on the above map, the capability class is indicated by large arabic numerals. The smaller numerals following the capability class give the proportion of that class out of a total of ten. The capability subclass, shown as a capital letter, indicates the environmental limitations to tree growth. The letters under the capability class represent the native tree species that can be expected to yield the volume of timber associated with the capability class. These forestry maps represent the first comprehensive set of forest land capability maps for Canada. The maps are a valuable source of resource information for application in regional planning for the forestry sector as well as for multiple land-use planning.