148 TENDING OF YOUNG HIGH FOREST, ETC. 



reason, pure Scots Pine planted at 3 feet apart, and pure Oak 

 at 2 feet 6 inches is far preferable to 4 feet planting ; so also 

 Spruce planted at 3 feet and Silver Fir at 2 feet 6 inches 

 will give better results than if planted at 4 feet apart. 



Until the principal height growth is attained thinnings 

 should toe slight, and the trees should be close enough 

 together to cause all side branches to die and fall off, and 

 thus clean timber will be produced. 



Light-demanding trees will usually require thinning in 

 the pole forest stage about every 5 to 7 years, and shade- 

 bearing trees every 8 to 12 years. 



After the trees are about 45 to 55 years old, very little 

 thinning is necessary in conifer crops unless partial clear- 

 ances are desired or natural regeneration cuttings are 

 required. 



On good soil, or in sheltered positions, or on cool aspects, 

 or at low altitudes thinnings must be begun earlier, and must 

 be more frequent, and may be somewhat heavier than when 

 the reverse is the case. 



On poor soil, or on hot aspects unless moisture is plentiful, 

 or at high elevations, or in exposed places, forest growth is 

 slower than when the reverse is the case, and therefore a 

 greater number of trees per acre should be found of any 

 given age, if a similar density of canopy is to be produced. 

 In the Black Forest 5 per cent more Beech were found on 

 southern than on northern aspects. In exposed places, the 

 edges of the wood should be thinned heavily from the 

 beginning, so as to encourage the growth of side branches 

 and to get bushy trees which will form a good wind-break. 

 Austrian Pine are often planted for this. 



Now, whereas it is obvious that some thinning is neces- 

 sary, any severe interruption of the canopy in the early 

 stages of a rotation should always be avoided, except in rare 

 instances. 



A great mistake is often made by starting to thin woods 

 too early; some people are frightened when they see the 

 branches interlacing, but the lower branches should inter- 

 lace ; the sooner they do the better, and under proper 



