receive due attention. The timber in the northern portion of the reserve is of slower growth, and in general reaches a smaller development at maturity.
(2) Immature Stands.—The immature stands, originating after fires, as already stated, constitute three-quarters of the forest growth on the east slope. These stands are practically always lodgepole pine. Only under exceptional circumstances has a reproduction of spruce followed the fire; on the prairie border poplar usually results.
This predominance of lodgepole pine over spruce in the reproduction following a fire is due largely to the difference in fruiting character of the two species. The cones of lodgepole pine remain on the tree for many years, opening slowly to discharge the seeds, while those of spruce open at maturity and shed the seeds within a short time. In addition, lodgepole pine seeds retain their germinating power for a longer period. A ground fire, therefore, which destroys the spruce seed, merely serves to release the accumulated seed supply present on the pine trees, since the heat opens the cones. Also, spruce trees are more readily killed by fire than lodgepole pine, and so their chances of escape to function as seed trees are less. In general, spruce reproduction follows only in the case of very light burning, and where neighbouring seed trees are left; the light burning does not destroy the litter and humus and lay bare the mineral soil, and pine does not germinate as well as spruce with such seed bed conditions.
The second growth stands of lodgepole pine are characterized by their great density, and by their evenness of age, each dating from a particular fire. Owing to the severity of the fires, a bare seed bed is prepared on which the stored-up crop of seeds rapidly falls. The result is a direct stocking up with altogether too dense a growth of seedlings. The young trees hinder the development of one another, so that a longer time is needed to reach merchantable size.
Lesser This is a newly-created reserve, of some 5,000 square
Slave Lake miles, situated mostly south of Lesser Slave lake. In
Reserve* general, it presents a rough broken topography, with large, poorly-drained areas aggregating over one-quarter of the whole.
The reserve embraces a variety of forest types, of which the lodgepole pine type is the most important from the standpoint of area. Although it covers over a million acres of the valley slopes of the Swan hills, the bulk of the forest is of a dense spindly growth, which will never reach more than pulpwood size.
Almost as large an area is represented in the poplar type, mostly as a result of fires. In this type aspen predominates, with a mixture
*The following description is based on Bulletin 29, Forestry Branch.