TREES FOR WATER CATCHMENT AREAS 127 
stem, attaining 30 to 70 feet in height, but slow in growth. 
It is extremely hardy, suffering little from snow, and occurs 
at high elevations on the poorest soil. Both these forms 
of Pinus montana grow better in wild, wet, undrained bog 
than any other species; but in such circumstances their 
growth is very slow. At Knockboy, Connemara, 490 acres 
of peat, at no great elevation, but fully exposed to the west 
wind, were planted in 1891-1894 with over two million 
trees, comprising 16 broad-leaved species and ten conifers. 
Practically none of these survive, except two species—Pinus 
montana, which has thriven over the whole area, but had 
attained only 6 feet in height in 1915, and maritime pine, 
of which there were a few groups about 20 feet high. 
Neither form can ever be expected to attain a useful 
size or be grown commercially in this country. It is 
possible, however, that Pinus montana may be of considerable 
value in the heather zone on exposed sites, in mixture 
with Sitka spruce, Corsican pine, or silver fir. It would 
greatly improve the peaty soil by its decaying leaves, 
producing good humus, which would favour the growth of 
the other species. Its dense foliage, persisting on the 
branches five to ten years, also protects the soil. It has 
been tried of late years on high moorland at Corrour in 
Inverness-shire; and reference may be made to articles by 
Sir John Stirling Maxwell in Zrans. Roy. Scot. Arbor. Soc. 
mG (90/), xxi. 1-15 (1908), xxi. 157 (1910), and 
xxviii. 77 (1914). See also Quarterly Journal of Forestry, 
x. 126 (1916). Pinus montana may also be used in 
mixture with other trees in shelter belts on wet peaty soils. 
Pinus Insignis, a native of Monterey in California, 
makes remarkably fast growth in the milder parts of 
England, Wales, Ireland, and south-west Scotland. This 
vigour, often an increase of three feet in height annually, is 
kept up on the poorest soils, provided the situation is a 
mild one near the sea-coast. In inland places the young 
shoots are often injured by frost; and in exposed cold 
situations trees may be killed outright during exceptionally 
