CHAPTER XLI.
ON THE KINDS OF TIMBER BEST ADAPTED FOR DIFFERENT SITUATIONS.
That the growth and quality of timber will be influenced by the nature of the soil is a matter so well understood that it would scarcely require to be treated of in this place, if we did not daily see examples of planting in which all laws of growth have been set at defiance; still, occasionally, experience has lent her aid and produced some satisfactory results; and, as an exemplification of our meaning, and as showing the influence of geological position upon planting, we would direct attention to the following section:—
ALICE HOLT FOREST.
4. Chalk. 3. Chalk Marl. 2. Upper G. S. 1. Gault Clay.
Here we have the oak—of both varieties known to planters, to be hereafter described—flourishing most luxuriantly on the stiff soil of the gault; the chalk-marl, upper green sand, and gault—the two latter only partially—being engaged in hop cultivation. The green sand surrounding the forest is mostly devoted to the growth of larch or spruce, the thinnings of which are used for hop-poles and the larger trees are left as timber-belts; whilst the beech will be found to favour the chalk. Hops and other cultivated plants flourish according to geological position.
That the geology of a district affects vegetation mainly, according to the mechanical and chemical structure of its individual rocks and the climate in which they are situate, is quite true; and yet the following table will show that different formations favour the growth of trees upon other conditions than those named.
Choosing figures to represent relative values, the annexed table is intended to show the amount of influence exercised by certain geological rocks in the growth of different fruit and forest trees met with in England.