TREES FOR WATER CATCHMENT AREAS 139 
is planted for shelter in wet bleak situations in Caithness, 
Aberdeenshire, the Moorfoot Hills of Midlothian and the 
Peeblesshire Hills. In Loudon’s time it was planted in Con- 
naught, where it throve in elevated positions much exposed 
to the wind. It can be raised in the nursery quite cheaply 
from seed, its treatment differing in no way from the common 
spruce. It may be tried in difficult situations, as on exposed 
ridges or in wet peaty soil at high elevations, when it is 
desired to give shelter to adjoining plantations below. It will 
ascend 200 feet higher than the limit of the common spruce. 
European Larch.—This species, when grown in suitable 
conditions and kept free from disease by measures calculated 
to sustain its vigorous development, is one of the most 
profitable trees. It has the especial merit of yielding 
earlier returns than any other species, as its thinnings are 
saleable from the 15th to the 20th year onwards; and 
plantations are ready for felling at the end of forty to sixty 
years. Heartwood is formed very early ; and the timber is 
remarkably durable and generally useful, as for gates and 
fencing on estates, for pitwood, poles of all kinds, and in 
building where strength is required. Grown properly, the 
larch develops a clean cylindrical stem, the slender branches 
being killed off before they form large knots. The larch 
combines high quality of timber with rapid growth, but 
nevertheless cannot be considered a very reliable species, 
as most plantations contain a considerable percentage of 
diseased and crooked stems. Being very light-demanding, 
the trees, as they advance towards maturity, do not stand 
dense upon the ground; and the yield of timber per acre is 
much less than that of spruce and silver fir, even when a 
plantation is quite successful. As a main-crop tree larch is 
unfortunately very liable to be attacked by canker, a disease 
caused by the Peziza fungus, which often ruins whole 
plantations. 
Larch rarely remains healthy if grown on unsuitable 
soil or in low-lying situations liable to spring frost. On 
dry shallow soils, as on chalk, it does not thrive, and early 
