FUTAIE, OR FULL-GROWTH SYSTEM. 375 
like most fish and reptiles, has no natural limit of life or of 
growth, and that the only reason why our oaks and our pines do 
not reach the age of twenty centuries and the height of a hun- 
dred fathoms, is, that in the multitude of accidents to which 
they are exposed, the chances of their attaining to such a length 
of years and to such dimensions of growth are millions to one 
against them. But another explanation of this fact is possible. 
In trees affected by no discoverable external cause of death, 
decay begins at the topmost branches, which seem to wither and 
die for want of nutriment. The mysterious force by which the 
sap is carried from the roots to the utmost twigs, cannot be 
conceived to be unlimited in power, and it is probable that it 
differs in different species, so that while it may suflice to raise 
the fluid to the height of five hundred feet in the eucalyptus, 
it may not be able to carry it beyond one hundred and fifty in 
the oak. The limit may be different, too, in different trees of 
the same species, not from defective organization in those of 
inferior growth, but from more or less favorable conditions of 
soil, nourishment, and exposure. Whenever a tree attains to 
the limit beyond which its circulating fluids cannot rise, we may 
suppose that decay begins, and death follows from want of 
nutrition at the extremities, and from the same causes which 
bring about the same results in animals of limited size—such, 
for example, as the interruption of functions essential to life, in 
consequence of the clogging up of ducts by matter assimilable 
in the stage of growth, but no longer so when increment has 
ceased. 
In the natural woods we observe that, though, among the 
myriads of trees which grow upon a square mile, there are 
several vegetable giants, yet the great majority of them begin 
to decay long before they have attained their maximum of 
stature, and this seems to be still more emphatically true of the 
artificial forest. In France, according to Clavé, “oaks, in a 
suitable soil, may stand, without exhibiting any sign of decay, 
for two or three hundred years; the pines hardly exceed one 
hundred and twenty, and the soft or white woods [bozs blancs], 
