94 FORESTS, WOODS, AND TREES 
plantations made by the Corporation indicate that Douglas 
fir ought to bulk largely in the afforestation of mountain 
valleys. Various plots of Douglas fir showed the following 
growth: At 860 feet altitude, an average tree, 26 years 
planted, was 64 feet high by 2 feet 8 inches in girth; at 
850 feet elevation, an average tree, 29 years planted, was 
50 feet high by 3 feet 4 inches; at 840 feet elevation, 
two trees, 19 years planted, were 43 feet by 2 feet and 52 
feet by 2 feet 9 inches. At the high elevation of 1200 
feet, growth of Douglas fir was much checked by exposure 
to wind, the height, 20 years after planting, being about 
25 feet. Sitka spruce has unluckily not been planted as 
yet in quantity at Lake Vyrnwy; but there are three trees 
of this species growing near the embankment at 850 feet 
elevation, which show remarkable vigour of growth. Planted 
35 years ago, they are 70 feet in height, and average 5 feet 
8 inches in girth. Near them are numerous self-sown 
seedlings, 4 to 12 inches high, which show that natural 
regeneration of this valuable tree may be looked for, provided 
that rabbits are excluded. Sitka spruce should be largely 
used in wettish places, and at high elevations, Japanese 
larch, 9 years planted, is about 22 feet high, and flourishes 
here. Scots pine, planted in 1899, averages only 15 feet 
high, and is of little value for the production of timber in 
comparison with larch, Douglas fir, and Sitka spruce. 
These three species are unquestionably the most profitable 
for the afforestation of large areas of mountain land. 
The Rivington catchment area, 10,000 acres in extent, 
was purchased by the Liverpool Corporation in 1902. It 
is situated on millstone grit, between 450 and 1498 feet 
elevation, and consists mainly of moorland and hill grazing. 
The population surrounding the area had been increasing 
rapidly, and was tending also to increase upon the watershed 
itself, so that it was becoming extremely difficult to prevent 
the streams from being polluted, especially by the farming 
operations of numerous small holders on the estate. To 
deal with this danger effectually the Corporation became 
owners of the property; and since then have got rid of a 
