206 ox THINNING PLANTATIONS 



rrom observing the sickly aspect of a very extensive planta- 

 tion after being thinned, and being called upon to assign a cause 

 for it, which I was at the time unable to do, I turned my atten- 

 tion exclusively to the subject, and, after much labour, concluded 

 I had solved the problem. The plantation consisted principally 

 of Scots pine, with a mixture of larch and sjDruce and some 

 hardwoods. 



All species of trees did not present the same sickly appear- 

 ance, nor did the same species on all soils. 



The Scots pine was of all others the most sickly, especially 

 upon the hard gravelly soils, and the larch least affected of any. 

 Of all forest trees the Scots pine is tlie most impatient of any 

 artificial interference, and suffers more from thinning tlian any 

 other species. In this case, after thinning the trees lost their 

 natural dark-green colour, and assumed a faint light-green. The 

 leaves became shorter, and presented a clustered appearance. 

 Some foresters, on giving their opinion upon it, said it required 

 more thinning ; that the crop was too great for the poor gravelly 

 soil to bear. Some thought it blighted by some atmospherical 

 influence, and others said it had attained maturity, and ought to 

 be cut down. 



After w^eighing all arguments, and duly examining the whole 

 case, I came to the conclusion that the thinning, and thinning 

 alone, had done the mischief From a very wonderful provision 

 in nature, the branches of a tree are so spread out as to shade 

 the surface of the ground underneath which the delicate tender 

 roots are spread, and thus keep them uniformly cool, and never 

 at any time scorched or unduly heated by tlie direct rays of the 

 sun. A plantation, therefore, like tliat under consideration, 

 which had grown i;p till about forty years old without ever 

 receiving a regular thinning, may well be understood to have so 

 far adapted itself to its circumstances as to be seriously and 

 injuriously affected by any change such as thinning. The trees 

 — inchiding stem, branch, and root — were what may be termed 

 acclimatised, or rather habituated, and therefore thinning pro- 

 duced a change upon them equivalent to removal to a different 

 soil and climate. 



There is much said about acclimatising of plants, which aj>plies 

 only to that part above ground, but there is little or nothing 

 said about the roots of the j^lants, although the latter are equally 

 as important as the former. 



Now, if a pine or fir plantation such as this, grown upon a 

 dry gravelly soil, with the roots extended and ramified all over, 

 and within an incii of the surface of the ground, is it either 

 unreasonable, strange, or unlikely, that, when a sudden opening 

 is made by cutting one or more trees, and letting in a stream of 

 sunny rays to heat or scorch the delicate, tender, sensitive roots, so 



