44 PURE AND MIXED WOODS 



thus improve their value causing them to form clean timber 

 and also to become more cylindrical. 



Underplanting should therefore be carried out in all woods of 

 light-demanders, as soon as the latter are no longer capable of 

 protecting the soil by themselves. Care should, however, be 

 taken to see that the existing crop is worth underplanting ; for 

 instance, open oak woods are seldom worth underplanting if this 

 has been left till they are sixty or seventy years old, as the oaks 

 are then too old to respond to the improved character of the 

 soil. Put shortly, only valuable species, sound and of good 

 shape, and young enough to respond to the treatment, should 

 be underplanted, as to underplant badly growing woods is a 

 waste of money and it is more profitable to cut them and to 

 replant the area. 



It must be remembered that we do not expect to obtain 

 fine timber from the underwood itself. A certain amount of 

 produce will be obtained from it, but we look chiefly to the 

 improved value of the overwood to repay us for the cost of 

 forming the underwood. The fairly heavy thinning made at 

 the time of underplanting will, however, often produce enough 

 to pay the cost of the operation, especially if the wood con- 

 tains larch which have been grown as nurses and which must 

 be removed for the benefit of the permanent species. One 

 case where underplanting is of special value is that of a larch 

 wood between fifteen and thirty years of age, where the trees 

 are badly attacked by the larch disease. In a wood of this 

 type the best thing to do is to make a heavy thinning, cutting 

 out all, or the larger portion, of the diseased stems, leaving 

 only the tallest and most healthy trees ; then the area is filled 

 up with whatever kind of shade-bearing species appears to be 

 most suitable. 



In an article which appears in the Board of Agriculture 

 Journal for March, 1906, it is stated that this system is carried 

 out with success on the Novar Estate in Scotland, the larch 

 being reduced to from 350 to 600 trees per acre, at about 



