Some Problems of Re-afforestation. 11 



three to five hundred of the best being retained to grow on. 

 Before the war these thinnings realised 20/. to 251. per acre. 

 At this stage the wood is underplanted with Douglas fir, 

 Sitka spruce, Abies grandis, Thuja gigantea, Western hemlock, 

 beech or some other species which will establish itself and 

 grow up under the mild shade of the larch. It is intended to 

 thin the larch again when about forty years old, leaving at that 

 time 100 to 200 trees per acre to grow into heavy timber. At 

 the end of the rotation (sixty to eighty years) both the larch 

 and underwood will be felled, or the underwood be left to grow 

 on till it also is mature. 1 



In regard to initial density of stocking that is, number of 

 trees planted per acre it may be said that in the period 

 immediately before the war there was a distinct reaction from 

 the very close planting (about 6,000 plants per acre) that was 

 strenuously advocated twenty years ago. As in so many cases 

 the question is largely one of circumstances. If one is dealing 

 with two-year-old seedlings, costing, say, 8s. per 1,000 when 

 planted, one can afford to make a more liberal use than if one 

 is employing four-year-old plants, possibly pitted, costing, it 

 may be, 21. or 3J. per 1,000 when in their final position. 



An extra thousand trees planted per acre will only affect the 

 very earliest thinnings, and if there is no local demand for 

 small stuff it may not pay to take it out. Of course one gets a 

 complete canopy a year or two earlier by close planting, but if 

 the planting of an extra thousand trees costs 11. per acre one 

 must receive 21. nett per acre more for the thinnings at the 

 eighteenth year if, apart from any problematical benefit to the 

 main crop, one is to secure 4 per cent, on the outlay. Whatever 

 the number of trees that may be planted on Scots pine land of 

 the best class there will only be room for some 1,400 by the 

 twentieth year. Planted 4 ft. by 4 ft. in triangles, 3,144 trees 

 are required to stock an acre, whereas, with interspaces 3 ft. 

 by 3 ft. the number is 5,590. In the former case 1,744 would 

 theoretically have come out as thinnings, in the latter case 

 4,190; but it may easily happen that the larger individual size 

 of the smaller number may make them the more valuable. 



Besides the local market, other factors that should influence 

 one's judgment in regard to density of stocking are (a) the 

 quality of the situation, (6) the rate of growth and character of 

 the particular species, (c) the presence or absence of rank 

 herbage. The poorer the soil the smaller is the average size of 

 each tree, and therefore the larger the number for which there 

 is room. Trees that grow rapidly in youth, like larch, Douglas 

 fir, poplars, &c., need not be so close planted as slower growing 



1 Journ. Board of Agr., Vol. xii., p. 722. 



