180 FORESTS, WOODS, AND TREES 
approaching normal tree-growth. As is well known, the 
smoke of southern Lancashire and of the West Riding of 
Yorkshire affect to some extent the whole of the north of 
England. The bad effect of smoke on trees must be taken 
into account in all afforestation schemes of areas in or near 
these manufacturing districts. See our notes on effect of 
smoke, pp. 45 and 57, and J. A. Wheldon and W. G. Travis 
in Journ. Linnean Soc. (Botany), vol. xiii. pp. 89-95 (1915). 
Rivington catchment area of 10,000 acres, owned by 
Liverpool Corporation, with 1500 acres of plantations, is 
fully described on p. 94. 
Barrow in Furness obtains its water supply from two 
catchment areas, as follows: 
1. Poaka Beck and Pennington reservoirs, at 505 feet 
elevation, have a gathering ground extending up to 1000 
feet elevation; and Harlock reservoir at 610 feet elevation 
has a gathering ground ascending to 1025 feet elevation. 
The total area is 1980 acres, of which only about 135 acres 
are owned by the Corporation, and of this 92 acres are 
water. There are a few plantations on the gathering 
grounds (not on the Corporation land), most of which is 
moorland covered with heather and bracken. The planta- 
tions appear to have been much neglected, though there are 
some fair-sized trees among them. The average annual 
rainfall is 53 inches. 
2. The watershed of the river Duddon, above the intake, 
74+ miles from its source, is 12,000 acres, of which the 
Corporation own only about 100 acres, and of this 85 acres 
are water. There are on the lower levels of the gathering 
ground several woods and plantations with fair-sized trees 
in them which appear to thrive well. The upper levels 
consist of fell and moorland, used for sheep grazing. The 
average annual rainfall is 90 inches. About 43 miles 
above the intake, Seathwaite Tarn, the level of which was 
raised 20 feet by a concrete wall, has now an overflow level 
of 1230 feet, and forms a large compensation reservoir. 
The highest point of the watershed draining into it is 
