PLANTING OF WATER CATCHMENT AREAS 115 
found. This total absence of pine seedlings is due to the 
abundance of red deer, which are even more destructive 
than sheep to young trees. It is probable that deer have 
contributed to the lowering of the timber-line in Scotland. 
In determining the height to which plantations may be 
carried, the altitude, exposure to wind, and soil must all be 
taken into consideration. Where there are great masses of 
high mountains, the timber-line is raised a great deal, and 
trees may be successfully planted up to high elevations. 
This is well seen in the Highlands of Central Scotland, 
where several peaks exceed 4000 feet. In Rothiemurchus 
Forest, in Strathspey, which les in a basin enclosed and 
protected from wind by the Cairngorm Mountains, native 
Scots pine creeps up the hills to a height of 2000 feet. 
On the Ardverikie estate in Inverness-shire there are planta- 
tions of Scots pine and larch, on the hills beside Loch 
Earba, doing well between 1500 and 1700 feet. The 
highest wood in England occurs in the Pennine range. 
This is a plantation of 300 acres, at Ashgill, lying to the 
north-east of Cross Fell, the highest peak of the Pennines 
(2930 feet), by which it is sheltered from the prevailing 
wind. The elevation of the plantation varies from 1250 
feet along the bed of the South Tyne to 2000 feet, the 
highest point of a shelter belt that was planted in advance 
of the main crop. The greater part lies between 1500 and 
1800 feet, sloping gradually towards the north-west. The 
soil is glacial clay resting on limestone, the surface being 
covered with a foot or two of peat. The trees, which were 
50 years old in 1906, consist mainly of European spruce, 
forming a thick even crop, and attaining 36 to 45 feet in 
height at 1700 feet, and 60 to 75 feet at 1250 feet 
elevation. The volume per acre was 3500 cubic feet at 
the higher altitude, and 4500 cubic feet on the side of the 
River South Tyne. Mingled with the common species there 
were some American white spruce, which had succeeded 
well on the exposed margins at high elevations. This 
remarkable plantation is described fully by Mr. A. C. 
Forbes in Trans. Roy. Scot. Arbor. Soc. xx. 153 (1907), who 
