180 FOKESTS, WOODS, AND TREES 



approaching normal tree-growth. As is well known, the 

 smoke of southern Lancashire and of the West Eiding 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. xliii. pp. 89-95 (1915). 



Rivington catchment area of 10,000 acres, owned by 

 Liverpool Corporation, with 1300 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 6 1 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, 

 7^ 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 4 J 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 



