OBSERVATIONS ON TIMBER.
The quantity of measurable wood of the various timber trees which a certain extent of adapted ground will carry, when come to full maturity, or when they may be most profitably felled, and the quantity that may be thinned out during the maturing, with the time requisite to bring to value, with the relative selling price per foot, and also whether the greatest quantity of timber can be grown of one kind or mixed, are questions of more importance than might be judged, from the attention paid to the subject. Of our common timber trees, Scots fir, silver fir, and spruce, larch, pinaster, black Italian poplar, Salix alba, commonly called Huntingdon willow, red-wood willow, beech, Spanish chestnut, ash, plane, elm, birch, oak, are here ranked nearly in the order of quantity of measure which adapted ground in this country will produce or support; that is, that an acre of close Scots fir trees, of whatever age, will admeasure more timber than an acre covered with any other tree of the same size; and a close acre of oaks less. A little further south, in the temperate zone, the large-leaved deciduous trees, particularly the{123}elms, acquire thicker and longer stem, in closer order, in a given time. In this country, in rich warm situations, this is visible in some degree, both as regards quantity of timber and quickness of growth, compared with pines. It would be difficult to state the comparative quickness of growth of the various timber trees, as so much depends on soil, situation, and treatment; it also varies considerably at different stages of their growth. It is well known, that in proper soil, black Italian poplar, Salix alba, and red wood willow, exceed all others.
As, for naval use, it is not the quickness of growth and bulk of the timber altogether, but of the matured timber alone, which is of consequence—we give a view of the number of growths or annual circles of sap-wood (the useless part), which the main stems of several kinds of trees presented. Most of those we examined had a greater number of sap-layers near the top than at a few feet above ground, and the vigorous branches had generally more than the stem immediately adjacent to them; the branches with least vigour had fewest sap circles.{124}
Of Home Growth.Common oak, some trees10, others14, others18Spanish chestnut,2,5,6Scots elm,U. montana,16,25,32English elm,U. campestris,0,10,0Red-wood willow,8,14,0Laburnum,3,5,0Wild cherry,Prunus cerasus,16,24,0Black Italian poplar,9,0,0Scots fir,20,30,40Pinaster,0,10,0White larch, free of rot,5,12,18Of Foreign Growth.Memel fir,0,43,0Red Canadian pine,0,100,0Yellow Canadian pine,38,44,0
The process of maturing in several did not proceed regularly, some of the rings being reddened on one side and remaining white on the other: this did not seem to be influenced by position to south or north. In the larch, particularly in those trees{125}where the rot is incipient, this maturing is very irregular, in the view of the cross section dashing out into angles and irregularities, and being darker red than in the healthy plants: in those where rot had made considerable progress, the red-wood was within a circle or two of the bark. This approach of red-wood to the outside is so regularly connected with rot, that we needed no other indication of the roots being unfit for knees, and therefore not worth grubbing, than merely a slight notch by two cuts of a hatchet.
Those kinds of timber whose matured wood assumes a brown or reddish colour, are generally much less susceptible of change, either by simple putrefaction or by attack of fungi, or gnawing of insects, than those whose matured wood remains of a whitish colour. In many of the latter, there does not even appear to be any particular change of constitution, or greater capability of resisting corruption or insects, between the alburnum and mature wood, although the difference between the two is generally perceptible when the cross section is drying, and immediate, as in the brown or red; there being no gradual change or softening in either between the mature and immature. Although the change in those which become brown and red does not much affect{126}the hardness or strength of the timber (mature and immature being nearly equal in these when dried before corruption injures the latter), yet it materially influences its nature or quality. We have taken down Laburnum trees in the round natural form from the roofing of an old building, from which nearly the whole yellow or sap-wood was eaten away by insects, although they had not made the least impression upon the brown28.{127}
Whether timber be more lasting when cut at one time of the season than at another, is not yet determined. The matured wood does not seem to be much affected by the season, continuing nearly equally moist throughout the year; life or action in it, though not quite, being nearly extinct, and little or no circulation remaining; yet the matured wood of the stool of the pine throws out a little resin when the tree is cut down in summer,—perhaps only a mechanical effect of heat and drying. Steeping in water for a considerable time is of far more importance to the duration of timber than any thing depending on the time of the season when it is cut down; steeping causes some acetous{128}change in the timber (easily recognisable by the sense of smelling when any section of it is made), which, judging from the effect the acetous change has to preserve other vegetable matter from putrefaction, is probably of considerable use in preserving the timber from decay, either by rot or worming. The time of cutting, although of considerable importance to the quality and durability of the sap-wood, appears to be of little or none to the matured.
The age at which timber may be cut down being uncertain, the height to which it should be trained up of clear stem is not very determinable,—say that the trees are to be allowed to stand till nearly full grown,—as long as the timber continues to retain its strength and toughness when growing in proper soil, that is for hard-wood trees 100 years and upwards, and for pines from two to three hundred. On crowns of eminences and exposed bluffs, particularly when the latitude or altitude is rather high, the soil inferior, or the climate arid, from 15 to 30 feet of clear hole may be as much as can judiciously be attempted; upon plains under common circumstances, from 30 to 50 feet is an attainable stem; in sheltered dales and valleys, they may be trained clean, and without branch, from 50 to 70 feet in altitude; and in cases where soil, situation,{129}and climate, are all propitious, and it is desired that nature’s fullest, grandest, development should be displayed, from 70 to 150 feet, clear of branch, maybe gained. Lewis and Clarke describe a spruce, in a sheltered dell on the river Columbia, which they measured, lying upon the ground, 312 feet long from root to top. We have little belonging to earth more sublime, or which bears home to man a deeper sense of his bodily insignificance, and puny transient being, than an ancient majestic forest, whose luxuriant foliage on high, seems of itself almost a firmament of verdure, supported on lofty moss-covered columns, and unnumbered branched arches,—a scene equally sublime, whether we view it under the coloured and flickering lights and shadows of the summer eve and morning, resounding to the song of the wild life which harbours there,—or under the scattered beams streaming downward at high noontide when all is still,—or in winter storms, when the wild jarring commotion, the frightful rending and lashing of the straining branches, like the arms of primeval giants, contending in their might, bear accompaniment to the loud roar and bellow of the tempest, forming a drone and chaunter to which demons might dance.