TREES FOR WATER CATCHMENT AREAS 123 
CONIFERS 
Scots Pine.—As mentioned above, this is now the only 
native conifer used in planting. Wild forests of Scots pine 
exist in Inverness-shire and Perthshire, occupying the heaths, 
which are tracts of sandy or gravelly soil covered with a 
thin layer of peat and carrying a thick vegetation of 
heather. These forests and also plantations of Scots pine 
occasionally ascend up to 1800 feet elevation, but only in 
very sheltered localities, Originally planted in the south 
of England, Scots pine spreads itself naturally and freely 
over the heaths of the Bagshot Sands and Lower Greensand, 
and also sows itself on the heaths of East Anglia and 
North-east Yorkshire. Scots pine develops a deep tap-root, 
and in consequence should never be planted on shallow soil, 
on which its growth remains always stunted. At high 
elevations it is liable to snow-break. It is most suitable 
for pure sands, loamy sands and gravels of considerable 
depth, and should not be grown on rich soils, as it then 
produces wide-ringed soft timber of little value. It thrives 
on lowland peat, if this is drained; but on wild undrained 
peat soon ceases to grow, or remains a stunted, useless tree. 
As a main-crop tree it should be planted close and grown 
pure, and be thinned lightly only, as in this way the stems 
are readily cleaned, and the ground kept protected. Grown 
in mixture with other trees it is liable to be suppressed by 
faster-growing species, and such suppressed stems are of no 
value as thinnings; or if it holds its own, it retains its 
branches and produces coarse and knotty timber. Grown 
on sandy or gravelly soil at moderate elevations it pro- 
duces timber of excellent quality, the average yield in good 
situations being 70 cubic feet per annum. The follow- 
ing measurements were taken by Messrs. E. R. Burdon 
and A. P. Long: A plot of Scots pine, on good deep 
sandy loam at Woburn, 95 years old, with 176 trees to 
the acre averaging 88 feet high, contained 6391 cubic feet 
of timber (quarter girth measurement under bark), equiva- 
lent to an average annual increment of 67 cubic feet per 
