The late Duke of Athol planted large districts with this tree, and thereby converted the heathy wastes into valuable forests; but this was not the whole of the improvement he thus created. The Larch being a deciduous tree, sheds upon the earth so great a shower of decayed spines every succeeding autumn, that the annual addition which is made to the soil cannot be less than from a third of an inch to half an inch, according to the magnitude of the trees. This we have had opportunities of proving by our remarks made on the surfaces of newly cleaned pleasure walks. The result of planting a moor with Larches then, is, that when the trees have grown so much as to exclude the air and moisture from the surface, the heath is soon exterminated; and the soil gradually increasing by the decomposition of the leaflets annually thrown down by the Larches, grass begins to grow as the trees rise in elevation, so as to allow greater freedom for the circulation of the air below,-and thus, land which was not worth one shilling an acre becomes most valuable pasture; and we can say that our own experience amply bears out the fact. The Duke of Athol found that the value of the pasture in oak copses was worth five or six shillings (sterling) per acre for eight years only in twenty-four, when the copse is cut down again. Under a Scotch fir plantation it is not worth sixpence more per acre than it was before it was planted; under Beech and Spruce, it is worth less than it was before, But under Larch, where the ground was not worth one shilling per acre, before it was planted, the pasture becomes worth from eight to ten shillings per acre, after the first thirty years, when all the thinnings have been completed, and the trees left for naval purposes, at the rate of four hundred to the acre, and twelve feet apart.
The Larch is a very quick grower. Between 1740 and 1744, eleven trees were planted at Blair, the girths of which, at growths from seventy-three to seventy-six years, ranged from eight feet two inches to ten feet. This lot was calculated to average one hundred feet each, in the whole one thousand two hundred feet. The total measurement of this lot of twenty-two trees, therefore, is two thousand six hundred and forty-five feet, which, at the moderate value of two shillings per foot, would give the sum of £264 10s. ($1174) for twenty-two Larch trees, of something under eighty years' old. We find by the Duke of Athol's tables of measurement, that trees planted by him in 1743 were nine feet three inches in circumference, when measured at four feet from the ground, in 1795.