METHODS OF OBSERVATION ON WOODS 147 



ensure the purity of the water supply, have tried to obtain wooded 

 areas in which to form their reservoirs. Glasgow is supplied by 

 Loch Katrine, Manchester by Thirlmere, and Liverpool has 

 created an artificial lake in Montgomeryshire, Lake Vyrnwy. 

 This is five miles long, and drains some 18,000 acres. Portions of 

 this are being systematically planted with trees, primarily to 

 ensure the purity of the water supply, although it is hoped in the 

 future to get valuable timber from the plantations. 



The larger number of our existing woodlands are, however, 

 maintained for the sake of game, and there is no reason why 

 foresters should not manage woods so as to have covert for game 

 without reducing the yield of timber. This is especially easy 

 in the case of pheasants. The essential thing is to have an under- 

 wood worked as coppice, and an over-wood for the produce of 

 timber. The under- wood must be dense, therefore the trees 

 planted in the coppice must give a great deal of shade ; ash and 

 hazel are perhaps the best for this purpose. The under-wood 

 should be cut periodically, but how often depends on circum- 

 stances. As far as the trees of the over- wood are concerned, it 

 is better not to cut the coppice too frequently. In some cases 

 every ten years is the time fixed, but every twenty years would 

 be better ; for if the under-wood is cut more frequently the 

 trees forming the over-wood will make branches low down, and 

 the wood will be knotty. On the other hand, if the under-wood 

 is allowed to grow too old it becomes thin below, and, when 

 cut down, does not form vigorous young shoots, and is of course 

 useless as covert for game. The selection of the tree forming the 

 over-wood is a very important matter. It must not be a species 

 with thick foliage, but one with an open canopy, allowing plenty 

 of light to get through to the coppice. Ash, oak, larch, birch, 

 poplar are all suitable ; but beech, sycamore, elm would not 

 answer, for these trees have thick foliage and cast a deep shade. 



It would be interesting to make observations on the woods 

 within reach of a school, and to note which were shelter belts; 

 which served the double purpose of game preserves and produc- 

 tion of timber. In these latter, the trees forming the coppice 

 and those of the over-wood should be noted, especially the char- 

 acter of the foliage and the height above the ground of the lowest 



