302 ENGLISH ESTATE FORESTRY 



is desired, and the practice of sticking it in everywhere is not 

 a more judicious proceeding than that of many other practices 

 in British forestry. So long as the roots are in the surface 

 soil and the latter fairly suitable, they will grow, but when 

 they descend to lower depths they suffer and quickly become 

 diseased. 



Another indirect cause of disease is the practice of plant- 

 ing larch pure or unmixed. Pure crops of larch do succeed 

 in some instances, we admit, but we rarely get such good 

 specimens as when they are scattered about among hardwoods. 

 The reason for this is, we believe, in part the same as that 

 given for its better growth on a bare surface, viz. the greater 

 chance its surface roots have of developing and obtaining a 

 proper supply of food. When mixed sparingly with deep- 

 rooting or compact-rooting trees, the larch roots can spread 

 without meeting with much opposition, while their more rapid 

 stem-growth gives them a lead over the other species from 

 the first. 



But, when planted pure, it is a case, as with all pure 

 plantations, of the survival of the fittest, and only a small 

 proportion of those planted manage to get the lead and keep 

 it. The fact may be noticed in many larch plantations, 

 more or less diseased, that a tree here and there will show a 

 cleaner growth and greater freedom from disease than the 

 average ; and these are they that have secured a more rapid 

 hold of the ground than their neighbours, and have kept the 

 advantage thus early gained. The weaker individuals are 

 consequently kept back, and fall a more easy prey to disease, 

 although on the most suitable soils it often happens that 

 disease is comparatively rare throughout, however thick the 

 trees may stand. 



It is very probable that the above are the most likely 

 reasons for the greater freedom from disease and more 

 vigorous growth of larch, when sprinkled with such hard- 

 woods as oak or beech. But the better shading of the 

 ground, and the moister condition of the surface soil with 

 a hardwood humus layer, may also conduce to healthier 

 growth, especially on rather dry soils, and in such cases the 

 additional moisture may be the more potent factor in pro- 

 moting the health of the trees. 



