Date of this Version
The factors affecting the natural reforestation of a fire-denuded area may, in general, be said to be the same in Idaho and Oregon as in Maine or Minnesota. There may be and actually are differences in detail as to what species of herbaceous and shrubby plants may prepare the way for the more delicate seedlings of those trees native to the particular locality. But the principle prevails everywhere that certain plants or plant societies. are antecedent and probably essential to the appearance and permanent establishment of a forest. The first step in the reforestation of a fire-swept area is the restoration of the conditions necessary to insure the germination and vigorous early development of the tree seedlings. The presence of humus in the soil insures a certain degree of moisture conservation and the retention of certain ingredients of plant food so easily lost by drainage.
Experience and observation teach us that however hardy, however well equipped, may be such trees as those which come to occupy the most trying situations, they were doubtless so sensitive to environmental factors during their first years as to have perished but for the fact that there must have prevailed a proper and essential balance of physiologic factors. To establish this balance may have required but a year, or it may have taken a much longer time.
In this paper it is not our purpose to discourse on the laws which regulate natural reforestation in different sections of the continent; notwithstanding the fact that great practical benefit would very likely result from an extended and careful scientific study of the factors which determine such growth.