PRACTICAL INFERENCES. 123 



to the special nature of the tree, of course conduces to the 

 formation and proper development of leaves. Trees, from 

 their root-range being wider than that possessed by herba- 

 ceous plants, can collect food over a larger area, and thus 

 can extract nourishment from a comparatively poor soil 

 which would starve other plants with less capacity for food 

 collection and less duration of working life. The larger 

 the leaf- surface, and the more fully and thoroughly it can 

 be exposed to light, the greater the quantity of timber and 

 the sounder its quality. It may be requisite for certain 

 purposes to have straight unbranched spars, and, in such 

 cases, leaf- action is impeded and side-growth is arrested by 

 thick plantations and neglect of thinning ; but the actual 

 amount of timber is necessarily less in such trees than in 

 others of the same age allowed to develop freely on all 

 sides. Coppice wood is also grown for a special purpose, 

 which practically justifies that mutilation which, like most 

 pruning operations, is of course at variance with natural 

 growth. In the annual growth of timber it may readily be 

 seen that the greatest activity of growth, i.e., formation of 

 new tissues, takes place in the first few weeks after vegeta- 

 tion commences. After that, the period of maturation or 

 consolidation commences. A moist, warm, growing period 

 is, therefore, most propitious. The process of maturation 

 requires for its fulfilment greater heat, less moisture, and 

 more intense light, and in proportion to the degree in 

 which these requirements are satisfied, are the amount and 

 quality of the timber. Should a wet, sunless autumn be 

 succeeded by an early frost, when maturation is imperfect 

 or incomplete, the results to the young growth, that is, to 

 the crop of timber for the year, are correspondingly disas- 

 trous. The effect of mineral manures, especially potash, 



