FLOATLNG OF TIMBER. 353 



Another evil, sometimes of serious magnitude, wMcli attends 

 the operations of the lumberman, is the injury to the banks of 

 rivers from the practice of floating. I do not here allude to rafts, 

 which, being under the control of those who navigate them, may 



this theory can not be admitted upon the evidence in question. In fact, the 

 order of succession — for a rotation or alteration is neither proved nor prob- 

 able — may be made to move in opposite directions in different countries with 

 the same climate and at the same time. Thus in Denmark and in Holland the 

 spike-leaved firs have given place to the broad-leaved beech, while in Northern 

 Germany the process has been reversed, and evergreens have supplanted the 

 oaks and birches of deciduous foliage. The principal determining cause seems 

 to be the influence of light upon the germination of the seeds and the growth 

 of the young tree. In a forest of firs, for instance, the distribution of the 

 light and shade, to the influence of which seeds and shoots are exposed, is by 

 no means the same as in a wood of beeches or of oaks, and hence the growth 

 of different species will be stimulated in the two forests. 



"When ground is laid bare both of trees and of vegetable mould, and left to 

 the action of unaided and unobstructed nature, she first propagates trees 

 which germinate and grow only under the influence of a full supply of light 

 and air, and then, in succession, other species, according to their ability to 

 bear the shade and their demand for more abundant nutriment. In Northern 

 Europe the larch, the white birch, the aspen, first appear ; then follow the 

 maple, the alder, the ash, the fir ; then the oak and the linden ; and then the 

 beech. The trees called by these respective names in the United States are 

 not specifically the same as their European namesakes, nor are they always 

 even the equivalents of these latter, and therefore the order of succession in 

 America would not be precisely as indicated by the foregoing list, but so far 

 as is known, it very nearly corresponds to it. 



It is thought important to encourage the growth of the beech in Denmark 

 and Northern Germany, because it upon the whole yields better returns than 

 other trees, and does not exhaust, but on the contrary enriches, the soil ; for 

 by shedding its leaves it returns to it most of the nutriment it has drawn from 

 it, and at the same time furnishes a solvent which aids materially in the de- 

 composition of its mineral constituents. 



When the forest is left to itself, the order of succession is constant, and its 

 occasional inversion is always explicable by some human interference. It is 

 curious that the trees which require most light are content with the poorest 

 soils, and vice versa. The trees which first appear are also those which prop- 

 agate themselves farthest to the north. The birch, the larch, and the fir bear 

 a severer climate than the oak, the oak than the beech. " These parallelisms," 

 says Vaupell, "are very interesting, because, though they are entirely inde- 

 pendent of each other, they all prescribe the same order of succession." — 

 Bogens Indmndring, p. 42. See also Berg, Das Verdrangen der Lauhwdlder 

 im Nordlichen DeutscMand, 1844. Heter, Das Verhalten der Waldbdume 

 gegen Licht und Schatten, 1852. Staring, De Bodem van Nederland, 1856^ 

 L, pp. 130-200. Vaupell, De DansJce Skove, 1863. Knorr, Studien iiber 



