METHODS AND PRACTICE 151 



The above figures show that with the thickest possible 

 planting, and subsequent crowding, the number of stems 

 per acre is reduced by the fiftieth year to 4G0 in 

 the case of Scots pine, to 600 in the case of beech, 

 and 700 with spruce. Any plantation in Britain under 

 average management would not fall far short of these 

 figures at fifty years, although planting of pure beech 

 woods is not common enough to make a reliable compari- 

 son. But taking mixed woods instead of pure, it is clear 

 that the low yields of mature timber from British woods 

 cannot be altogether due to thin planting, although it is 

 sometimes assumed that such is the case. 



It is true that many continental foresters plant, or 

 produce by sowing, ten to twenty times the above 

 numbers of trees per acre at the outset, and from 

 a purely sylvicultural point of view they are probably 

 right. The greater the number of trees planted or 

 sown per acre, the greater will be the number of in- 

 dividuals present which show an exceptional vigour of 

 growth, a greater power of resisting unfavourable climatic 

 influences, or of accommodating themselves to a particular 

 soil or situation. With thick cropping, the process of 

 natural selection comes more naturally into play, and the 

 resulting crop is likely to be better and finer in every 

 way. 



But from an economic point of view the question of 

 thick planting is closely bound up with two factors, 

 expense and early yield from thinnings. With sowing, or 

 the planting of two-year seedlings from a seed bed, the 

 cost of stocking ground with 5000 to 10,000 plants per 

 acre need not be greater than the planting of 2000 or 8000 

 four-year plants by slitting or pitting. On many soils, 

 however, the use of seedlings does not lead to successful 

 results, owing to ground game, weeds, rubbish, etc., or 

 if these are kept down by trapping and cleaning, to 



