TENDING OF CROWDED WOODS. 211 



the three regions approximately indicated as below 1200, 

 12002400, and 24003600 feet, showed the following 

 proportion in the number of trees : 100, 126, 244. 

 This law could not be established above 3600 feet, be- 

 cause at that height regular woods disappeared. It was 

 further noticed, that the difference is more pronounced 

 in the case of shade-bearing species and during the 

 earlier part of life, than in the case of light- demanding 

 species and later on in life. 



/. Aspect and Slope. 



Aspect in itself causes only slight differences in the 

 growing space. Southern and western aspects, in the case 

 of Beech in the Black Forest, had up to 5 per cent, more 

 trees than northern and eastern aspects. Sloping ground 

 has probably the same number of trees as level ground, 

 other conditions being equal. 



g. Summary. 



It may be said that the average growing space per 

 tree is greater in old woods, in the case of light-demand- 

 ing species, on good soil, and in low elevation, than 

 under reverse conditions. 



In judging of the desirability and the degree of 

 thinning in any particular wood, the forester must 

 take into consideration 



(1.) The objects of management. 



(2.) The density of the crop. 



(3.) The age of the crop. 



(4.) The species. 



(5.) The character of the locality, its soil, climate, 



and the special external influences to 



which it is exposed. 



p 2 



