64 BRITISH FOREST TREES 



the utilisation and reproduction of the growing crop can 

 take place most advantageously and remuneratively. 



In general the growth of the Scots pine is most 

 vigorous throughout the thicket, and the pole-forest, and 

 until after it enters the tree-forest stage of growth, in the 

 latter two of which it also yields the largest returns from 

 thinnings. But the poorer the soil, the sooner the average 

 increment culminates and begins to diminish, the earlier 

 the growth in height declines, and the rounding off of the 

 crown begins. Along with the latter comes increased 

 demand for growing-space, trees die off, and weevils, beetles, 

 and caterpillars at once become attracted towards them 

 as breeding places, frequently combined with simultaneous 

 infection with fungoid disease, whilst the process of regular 

 and judicious thinning out is somewhat interfered with, as 

 the sickly and diseased stems must be removed first of all. 

 Owing to the greater amount of light playing over the soil, 

 this becomes covered with a growth of mosses, grasses, 

 whortleberries, or heather according to \ts quality, and soon 

 the canopy, from being at first merely interrupted, gradually 

 becomes completely broken, the annual increment sinks, 

 and the question of reproduction and clearance, or too 

 often merely its alternative, clearance and reproduction, 

 inevitably presents itself for consideration. 



The poorer classes of pine soil exhibit these changes in so 

 short a time that low periods of rotation are those most 

 advantageous both in regard to outturn and with respect to 

 the soil, but on the better classes the quantity of the out- 

 turn in timber, as well as its quality, points to the remunera- 

 tive advantage offered by a fall fixed at from eighty to one- 

 hundred and twenty years according to the circumstances of 

 each case. 



In comparison with spruce and silver fir, Scots pine 

 has a rapid growth in early youth and often succeeds in 



