ON THINNINGS IN PLANTED SPRUCE. 133 



is the measure, one in three, the thinnest, and maybe the tallest, 

 or oftener the mean of three contiguous stems, so as to relieve the 

 best. At this rate, after fifteen or eighteen years there will only 

 remain some 440 to 480 of the original 1600 stems. But a 

 certain number of formerly dominant stems, notwithstanding the 

 two first thinnings, will, by the time of the third, have fallen to 

 the dominated state. Hence it will be wise to estimate afresh 

 the number of dominant stems before proceeding to the thii'd 

 thinning. Tf this new estimate should produce only 560 dominant 

 stems, the third thinning will be only at the rate of one in four, 

 so that about 400 stems may remain. In any case the thinnings 

 will have allowed the utilisation of all that there was to utilise. 

 The dominated stems do more good than hai-m, and they should 

 be kept so long as their leaders are not dry. Once the leader 

 is dry, they should be utilised. A spruce that has relapsed into 

 the dominated state does not live long, hence all broad-leaved 

 species that may be found in the crop are valuable, and should be 

 carefully preserved even if they have shot up above the spruces, 

 provided they are not too numerous. Such trees are the friend 

 of our friends the birds, the worms and slugs, and other things 

 that find no living in pure spruces. 



Suppose, again, a fine young crop of spruce poles forty years 

 old, unequal in size, and the biggest of them barely 8 inches 

 thick. There are about 400 stems per acre in the upper story 

 which sees the sky. It is too many. In thirty years' time one 

 half the number will be sufficient. At that time 200 stems, 

 seventy years old, per acre, should be 14 to 16 inches thick. 

 Three thinnings, at the rate of one in five, will halve the present 

 number in the thirty years' period. 



Always try to have some broad-leaved species in the lower 

 story, but especially, as the canopy is opened, introduce the silver 

 fir. A number about equal to that of the spruce removed will 

 ensure an excellent state of vegetation for the latter. If the 

 situation is not too warm, the firs will prosper rapidly twenty or 

 thirty years later, when the rest of the spruce are felled. Thus, 

 to perfect a spruce forest, plant it with silver fir. 



The statement that three thinnings are better than two is 

 hardly capable of proof, but it is the key to the situation. If 

 there is a case in which ciution is especially needed in opening 

 out a canopy, that case is the case of a tall spruce forest. The 

 prescription one in four, or one in three, is not in practice carried 



