TEEES FOR WATEE CATCHMENT AEEAS 159 



As a main crop it is ripe for felling at 6 years old ; and 

 coppice of it is cut every 1 5 years. 



Chestnut has a very limited use in afforestation, as it 

 can only be grown commercially in favoured spots. It can 

 rarely be planted in the hills ; and is quite unsuitable for 

 low damp places or for situations that are exposed to wind. 



Chestnut bears shade when young ; but after 3 years 

 requires much light and space. It may, however, be grown 

 as a pure crop on suitable sites ; but the stems stand far apart, 

 scarcely exceeding 6 to 1 per acre on good soil at 6 years 

 old. It is suitable for mixture with ash or larch, if the soil 

 suits these species. In such mixtures, the chestnut can be 

 cut over and kept as coppice, amongst which the ash and 

 larch will grow well as standards. In other cases, the larch 

 may be removed as thinnings, and the chestnut allowed to 

 remain. In Quarterly Journal of Forestry, vi. 20 (1912), 

 there is a description of a very successful plantation of 

 larch and chestnut on heavy loam in Gloucestershire ; the 

 trees were planted 6 feet apart, the two species being in 

 alternate rows. 



Elm. — None of the species of elm as a rule form pure 

 woods, but are almost invariably in the wild state scattered 

 singly or in small groups in the broad-leaved forests. Of 

 the various species in this country, practically only the 

 wych elm is found naturally in woods. The other kinds 

 are seen in hedgerows, parks, or avenues ; and if, as is 

 probable, they also are native, the original forests in which 

 they grew have long since disappeared, giving place to farm 

 land. All the elms bear shade in youth, but later they re- 

 quire considerable light and space. They need a soil of 

 at least moderate fertility and depth, and there must be 

 sufficient moisture. Elms are quite unsuitable for very dry 

 soils, such as dry sand, stiff clay, or thin chalk. The 

 various elms have marked differences in their climatic re- 

 quirements, which will be pointed out in the following brief 

 account of each species. None, however, ascend to a great 

 elevation, and elms are not grown above the agrarian zone. 



