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 trees 10, others 14, others 18 Spanish chestnut, 2, 5, 6 Scots elm, _U. montana_, 16, 25, 32 English elm, _U. campestris_, 0, 10, 0 Red-wood willow, 8, 14, 0 Laburnum, 3, 5, 0 Wild cherry, _Prunus cerasus_, 16, 24, 0 Black Italian poplar, 9, 0, 0 Scots fir, 20, 30, 40 Pinaster, 0, 10, 0 White larch, free of rot, 5, 12, 18 _Of Foreign Growth._