2376

ARBORETUM AND FRIJTICETUM.

I'ART III.

general, if these be low ; and, where oak, chestnut, elm, and ash have producedwood perfectly sound, the larches in the same soil and situation have hadtheir trunks quite hollow a good way upwards.” ( Plant. Kal., p. 93.) AtRaith, at Leslie, and at other places in Fifeshire , the larch had, in 1812,attained a great size on rich banks and in warm situations; but, in nearly1000 trees which were cut down at that time, there was scarcely one in whichthe trunk was not beginning to decay at the heart. {Ibid., p. 59.) The fitnessof soil for larch, Matthew observes, “ seems to depend chiefly upon the abi-lity the soil possesses of affording an equable supply of moisture; that is,upon its mechanical division, or on its powers of absorption or retention ofmoisture ; and its chemical composition would seem only efficacious as con-ducive to this.” Throughout Scotland , he says, wherever he has observedthe decay of larch wood, it has resulted almost solely from unsuitableness ofsoil. “ We have witnessed,” he continues, “the tree as much diseased onour highest trap hills, 1000ft. in altitude, as on a similar soil at their base.”{Ibid., p. 78.) “ The larch,” Sir W. Jardine observes, “ is very soon lostwhen planted above a substratum of red sandstone. In the vale of theAnnan, wherever the sloping banks have a substratum of this rock, or onecomposed of a sort of red sandstone, shingle, or gravel, the outward decay ofthe tree is visible at from 15 to 25 years of age. The internal decay com-mences sooner, according to the depth of the upper soil, in the centre of thetrunk at the root, in the wood being of a darker colour, extending by degreesin circumference, and up the stem, until the lower part of it becomes entirelydeprived of vegetation, and assumes a tough and corky appearance. Thisextends to the whole plant, which gradually decays and dies. On the samesoil, the oak grows and thrives well.” {Sir IV. Jardine, in his notes to White’sNat. Hist, of Selborne.) Mr. Matthew divides soils and subsoils into twoclasses : the first, where larch will acquire a size of from 30 to 300 solid feet,and will generally be found free of rot; the second, where it reaches onlyfrom 6 to 20 solid feet, and, in most cases, becomes tainted with rot before it is80 years old. As this subject is of great importance to the planter of thelarch, and as Mr. Matthew is an author whose science and practical knowledgemay be relied on, we quote his observations on the subject at length : —

“ Class I. Soils and Subsoils proper for the Larch .— 1. Sound Rock, with acovering of firm loam, particularly when the rock is jagged or cleft, or muchbroken, and mixed with the earth. In such cases, a very slight covering oradmixture of earth will suffice. We would give the preference to primitiverock, especially micaceous schist and mountain limestone. Larch seldomsucceeds well on sandstone or on trap, except on steep slopes, where the rockis quite sound, and the soil firm. We have had no experience of larch,except very young, growing on chalk and its affinities. Primary strata aregenerally well adapted for larch, except where the surface has acquired acovering of peat moss, or received a flat diluvial bed of close wet till, or softmoorish sand, or occupies too elevated or exposed a situation; the two latterexceptions only preventing the growth, not inducing rot.

“ 2. Gravel , not too ferruginous, and in which water does not stagnate inwinter, even though nearly bare of vegetable mould, especially on steep slopes,and where the air is not too arid, is favourable to the growth of the larch.The tree seems to prefer the coarser gravel, though many of the stones exceeda solid yard in contents. The straths, or valleys, of our large rivers, in theirpassage through the alpine country, are generally occupied, for several hundredfeet of perpendicular altitude up the slope, by gravel ; which covers the pri-mitive strata to a considerable depth, especially in the eddies of the salientangles of the hill. Every description of tree grows more luxuriantly here thanin any other situation in the country. The causes of this are : 1. the openbottom allowing the roots to penetrate deeply, without being injured by stag-nant moisture; 2. the percolation of water down through the gravel from theneighbouring hill; 3. the dryness of the surface not producing cold by eva-poration, and the ground, on this account,soon heating in spring; 4. the moist