CHAP, ix.] Tending of Woods 195 



of the crop in question as to species of tree, age and mode of 

 formation of crop, condition previous to, and at time of, thin- 

 ning, nature of soil and situation, &c. But Weise 1 seems 

 perfectly correct in making the broad generalization that 



' When a crop is too thick, increment in height and in girth both suffer 

 to an extent not compensated by the outturn jnelded from the greater 

 number of stems ; when it is too thin, however, the crop remains back- 

 ward in growth in height.' 



Experiments made in order to endeavour to formulate a 

 natural law regarding the effect of slight, of moderate, and 

 of heavy thinnings on increment in height, girth, form-factor, 

 and total yield of timber per unit of area, have hitherto failed 

 to yield any practical result. On the whole they simply lead one 

 in a general way back to appreciate the wisdom and the prac- 

 tical value of the rule, founded on experience, that * thinnings 

 should be begun early^ carried out moderately, and repeated 

 frequently' This does not militate against the correctness of 

 the theory and the practice of partial clearance, after once the 

 chief growth in height is completed, for the purpose of stimu- 

 lating the trees to rapid increment in girth and to improvement 

 in the shape of the bole. 



And, practically, the same conclusion must be come to when 

 the matter is viewed from the financial standpoint. Although 

 increased returns from material thinned out and profitably 

 disposed of regarding them not only as items reducing the 

 capital represented by the growing stock, but also as sums 

 which, for correct reckoning, must be taken as growing in value 

 at compound interest till the whole mature crop is harvested 

 would point to the desirability of heavy thinnings, and would 

 perhaps yield fair results where the market for small timber is 

 favourable, yet the future well-being of the ultimate crop is 

 undoubtedly the main object to be kept in view. And here, 

 again, experience has shown that considerations affecting both 

 the productive capacity of the soil, and the normal development 



1 See Chronik, 1881, p. 25. 

 O 2 



