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86 PATTERSON v. M'CAUSLAND.
It has been often said, not only that the age of a tree may be
ascertained by the number of its concentrical layers; but that their
closeness or distance from each other indicates the slowness, or the
rapidity of their growth. The concentrical layers of the wood of
the live oak, (quercus wrens,} are very close, and it is very hard and
heavy. The concentrical layers of the wood of the white cedar,
(thuya occidentalism) which grows near the falls of the Potomac,
are also very close; as many as one hundred and seventeen have
been found in a log of little more than thirteen inches in diameter;
but the wood is very light, soft, and fine grained. Yet the close-
ness of the concentrical layers of the wood in these two species of
trees, differing so widely in all other respects, is said to shew the
extreme slowness of their growth, (o) The rapid growth of the
catalpa, and the loblolly pine, is said to be proved by the great
width of their concentrical layers, (p) But the wood of the locust,
(robinia pseudo acacia,) is finer in its grain than any of the oaks,
and much harder, when seasoned, than any of them, except the
live oak. The locust converts its sap into perfect wood every
third year; which is not done by oaks in less than every tenth or
fifteenth year; and at twenty-five years of age it yields twice the
mass of wood of any other tree, (q)
The eminent botanist who has given us the most full, accurate,
and instructive account of all our forest trees, appears to have
frequently adverted to this general opinion, that the concentrical
layers in the wood of such trees afforded evidence as well of their
progress in vegetation as of their age. In speaking of the white
cedar, (cupressus thyoides,) he says, that 'the concentrical circles
are always perfectly distinct, even in stocks of considerable size;
but their number and compactness prove that the tree arrives at its
full growth only after a long lapse of years. I have counted two
hundred and seventy-seven annual layers in a trunk twenty-one
inches in diameter, and five feet from the ground; and forty-seven
in a plant only eight inches thick at the surface, which proved it
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body below it, And though several years have elapsed, the latter has not been able
to overtake the former. The upper part of the tree, rooted in the air, vastly out-
grew the under rooted in the earth. Therefore it must have drawn either its whole
or chief sustenance from the atmosphere. Indeed between the bark and the wood
of most trees, and of the locust particularly, we find the chief channel of their juices;
and the communication of those juices was utterly cut off so that neither portion of
the tree could supply the other,'—Orator, by John Taylor, of Caroline, p, 85.
(o) 1 Mich. Am. Sylva, 59; 2 Mich. Am. Sylva, 859.—(p) I Mich, Am. Sylva,
330; 2 Mich. Am, Sylva, 289,—(q) 2 Mich. Am. Sylva, 11.
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