132 ENGLISH ESTATE FORESTRY 



for a part of those present, owe their existence to their 

 individual exertions, or, as it is commonly called, "the 

 struggle for existence." 



But this struggle leaves its mark on a certain proportion 

 of those which have managed to secure sufficient space for 

 their existence, but insufficient for their normal development. 

 These middle-sized individuals, in the case of a wood left to 

 itself, constitute a considerable proportion of the crop, and, 

 when large timber is most in demand, lower its market value. 

 If all the strongest individuals in a group or wood could be 

 evenly and properly distributed over the entire area, the 

 proportion of large trees would be increased, and that of 

 medium individuals diminished, and the resulting crop would 

 be fairly satisfactory. But . when a crop is sown or planted 

 at a very early age it is impossible to foresee the future 

 development of individuals, and chance — that arch-enemy of 

 uniformity — often distributes them irregularly or in isolated 

 groups, which brings about irregular results and too large a 

 proportion of small and improperly developed trees. 



Herein lies the necessity for the interference of the 

 forester. He must take the place of nature and decide 

 the fate of individual trees, where there is any hesitation 

 in taking the lead on their part. Crown development of 

 crowded groups must be watched and encouraged by cautious 

 thinning, while extra large individuals should be kept in 

 confinement as much as possible. The aim should be 

 directed towards ensuring just that degree of crown de- 

 velopment which is necessary for maintaining the wood ring 

 at its proper breadth, and no more. What the proper 

 breadth is depends upon the species, soil, and situation. 

 In the case of conifers a small ring-breadth is an advantage, 

 as the timber made up of small rings is more durable and 

 close in the grain. With hardwoods, such as oak or ash, too 

 narrow a wood ring produces inferior timber, owing to the pre- 

 ponderance of spiral vessels in the wood. But the forester 

 need rarely trouble himself about ring-breadth or crown de- 

 velopment until height-growth culminates, which may be 

 about the fortieth year on good soil and a little later on bad. 



If careful thinning is not attended to at this stage, large 

 timber cannot be expected in any quantity, while, if thinning 



