164 THE DEVELOPMENT OF BRITISH FORESTRY 



Stage at which the branches begin to interlace and 

 become suppressed. In well-grown crops a complete 

 canopy should be present when the trees are not more 

 than ten feet in height, otherwise coarse timber will be 

 produced. A full canopy before that height is reached 

 can only be obtained by thick cropping, and it will 

 usually be found that the advantage of too great density 

 at first is not sufficiently great to repay the expense, 

 Avhile certain disadvantages may occur. 



The formation of a full canopy when the trees are not 

 more than ten feet in height prevents the formation of 

 large branches on the lower parts of the stem completely, 

 whatever the species may be. In a general way very 

 clean timber is produced when the branches are killed 

 off when not more than half an inch in diameter; 

 moderately clean timber when they are killed off at 

 anything under an inch, and with complete soil-shading 

 before the first ten feet of stem is formed, the latter size 

 is not likely to be reached. 



The density required for a full canopy at that height 

 depends upon the habit or character of the species. Ash 

 or sycamore, which grow rapidly in height as compared 

 with their branch development, must be planted at one 

 to two feet apart to produce a canopy at the height 

 named. Scots pine, larch, spruce, etc., and the majority 

 of conifers, owing to their more formal and pyramidal 

 habit, close up when planted at four feet apart without 

 difficulty by the time they have reached a height of ten 

 to tAvelve feet. Continental foresters, producing Avoods 

 from sowing or natural regeneration, are accustomed to 

 crops of 20,000 to 50,000 or more plants per acre 

 during the first ten to twenty years, and under these 

 conditions a canopy is formed when the trees are two or 

 three feet in height. This has the advantage of giving 

 natural selection every chance, and of checking all surface 



