Another method of summarizing forest information is by individual tree species, regardless of the forest type in which they occur. In these summaries, tree species distribution, as well as growing stock volumes and growth are measured from a sub-stand level, by species, independent of working group or forest type. For example, the Black Spruce component within the lowland conifer forest type is summarized along with the Black Spruce component of upland conifer, Mixedwood, and anywhere else it may occur.

Many species in Ontario occur in a wide variety of stands, in very small amounts. For example, within the AOU, White Pine can be found in concentrations of 1% or more on 3.4 million hectares of forest, but as a provincial forest type (Red and White Pine) is only found on 1.1 million hectares.