78 TENDING OF WOODS 



extremes, inclining to density in youth and openness towards 

 maturity. 



No regard should be paid to the distance apart of the stems. 

 It is at the crown that the woodman looks when making 

 a thinning, and so long as the crowns are kept so close that 

 there is a complete cover over the ground at all ages, it 

 matters not whether the stems are regularly or irregularly 

 spaced. The following figures given in Schlich's Manual of 

 Forestry, volume I, third edition, act as a guide as to what 

 number of stems may stand on an acre at various ages on 

 average soils if the production of high-class timber is aimed 

 at, and if the woods have been well managed from the start, 

 but these numbers are far in excess of what will usually be 

 found in existing British woods, owing to over-thinning in the 

 past. On first-class soils the number of trees will be smaller, 

 and on poor soils larger. 



Number of trees per acre. 



Age of Wood. Spruce. Beech. Oak. Scotch pine and Larch. 



40 i loo 950 850 750 



50 700 600 550 500 



60 500 420 370 400 



70 400 320 270 300 



80 300 250 220 250 



90 260 200 1 80 200 



IOO 22O 1 80 140 170 



IIO 200 170 120 ISO 



120 190 160 loo 140 



As a general rule conifers can stand closer than broad- 

 leaved trees, and shade-bearers than light-demanders. Species 

 like oak and Scotch pine, which tend to the formation of side 

 branches, should be kept closer when young than species with- 

 out this tendency. 



A thinning is called light when only dead and suppressed 

 trees are cut out ; moderate when some dominated trees are 

 also cut ; heavy when some of the dominating trees are 

 removed. 



