304 PRUNING. 



growing tissue, but the wood in the centre of the wound will, in all 

 probability, begin to rot before it is covered over, and consequently the 

 timber of the trunk will be more or less injured. The second injurious 

 mode of lopping is, that of cutting off side branches at from six inches 

 to a foot, or even two feet, from the trunk, which is called 



Snag Lopping. By this mode there can be no efficient source of 

 returning sap, the wounds can never heal over, and are certain, in 

 connexion with the stumps on which they are made, to rot and 

 disfigure and deteriorate the timber much more than in the case of 

 close lopping. 



Lopping-in. The only mode of lopping large branches from the 

 sides of the trunks of trees, without injuring the timber in these 

 trunks, is to shorten them to a branch of sufficient size to heal the 

 wound at its base, or at all events to maintain the growth of the whole 

 of the part of the branch left, and prevent any decay from reaching 

 the trunk. Clean timber, that is, timber free from knots, will not be pro- 

 duced by this mode, but sound timber will be the result, which is much 

 more valuable than the apparently clean and sound timber that would 

 have been produced by close lopping, and letting the tree stand till the 

 wounds were covered with new wood and bark. If the branch, had not 

 been lopped, it would have continued to increase in diameter in as great 

 a ratio as the stem ; but when lopped so as to produce only as much 

 foliage as keeps the part left alive, such part will increase very little ; 

 and as the stem increases, the proportion which the diverging sound 

 knot bears to the straight timber of the stem will be less and less. 



Cutting down the stem or trunk of a tree to the ground is an 

 important operation, because in some cases, such as that of resinous 

 or needle-leaved trees, it kills the tree ; while in others, or what are 

 called trees that stole, which is a property of most broad-leaved trees, 

 it affords the means of renewing the tree. Thus coppice-woods, which 

 consist of trees and shrubs cut down periodically, have their stems 

 and branches repeatedly renewed from the same root or collar. Thorn 

 hedges are also frequently renewed by cutting down to the ground ; 

 but perhaps the most valuable application of the practice is to young 

 stunted forest trees when finally planted out. The slow growth of a 

 tree which is stunted appears to depend on the thinness of the albur- 

 num, and consequent smallness of its sap channels, the result of which 

 is, that the sap rises slowly and in smaller quantities than it otherwise 

 would do ; and hence, that a proportionately smaller quantity is 

 returned from the leaves through the bark. But by cutting over the 

 stem just above the collar, the whole force of the sap accumulated in 

 the roots will be employed in the development of some latent buds in 

 the collar, and one of the shoots produced by these buds being selected, 

 and the others slipped off, an erect stem will be produced of five or 

 six feet the first season, and the sap vessels in this shoot being large, 

 and abundantly supplied from the root, the plant will grow freely ever 

 afterwards. A tree may be renovated though not cut back to the 

 collar, and part of the old stem with its thin alburnum left. The 

 vigour of the new growth will give a thicker coating of alburnum ; 



