372 



FORESTRY AND IRRIGATION. 



September, 



to the lack of light. This is a very 

 marked characteristic of the White 

 Pine, as its branches often die to the 

 height of thirty feet, which is also true 

 of all light-demanding species of con- 

 ifers. Sometimes the dead limbs drop 

 quickly to the ground ; in others they 

 remain for 3'ears, eventually producing 

 knots. If the lower branches do not 

 drop off naturally, they are usually re- 



GOOD PRUNING ; BRANCHES CUT OFF EVEN 

 WITH THE BOIvE. 



moved by artificial means, and to this 

 process is applied the term pruning. 



The pruning of live branches is done 

 to increase the value of the timber, stim- 

 ulate the expansion of the crown of the 

 tree, and also to free the young growth 

 from the too dense shade of the over- 

 hanging trees. 



Pruning to free the undergrowth from 



a too dense cover is usually done in 

 woods consisting of timber of different 

 ages. In many cases one may find a 

 stand where a valuable, slow-growing 

 species is liable to be shaded out by a 

 poor, faster growing one. In this case it 

 is preferable to prune the undergrowth 

 rather than remove it altogether. We 

 often notice trees which have been sub- 

 ject to unfavorable conditions showing 

 signs of failing strength in their crowns. 

 To remedy this, usually a good part of 

 the lower limbs should be removed. 

 This allows the tree to use all its nour- 

 ishment to strengthen the crown, and 

 in many cases this extra stimulus en- 

 ables it to pass the danger point. 



It is very seldom a tree is injured by 

 the removal of dead branches. On the 

 other hand, it may greatly reduce the 

 danger from rot, as the tree soon covers 

 over the opening with new layers of 

 wood. 



But a different state of affairs is met 

 with in the pruning of green branches. 

 Here the wound caused by the removal 

 of the limb often becomes the point 

 where fungi enter. The White Pine 

 has, however, peculiar methods for over- 

 coming this evil effect. Shortly after 

 the limb is removed the wound is cov- 

 ered by a gummy sap, which protects 

 the cut from disease until it is able to 

 heal over, so that in a few years after 

 careful trimming we have practically a 

 clean bole. Pruning, however, in a 

 crowded stand, where the limbs die 

 naturally to a considerable height, 

 should be confined to the dead branches 

 exclusively. 



For a farmer the easiest implement 

 to prune with is a good, sharp axe; if 

 wielded with accuracy, it is as good as a 

 saw, as it leaves a smooth surface 

 wound. Besides, pruning with an axe 

 can be done more rapidl3\ It must, 

 however, be carefully handled, as reck- 

 less cutting is apt to do considerable 

 damage to the bark. It is a waste 

 both of time and energy to prune a tree 

 above a height of eight feet, which is 

 about as high as an average man can 

 reach with an ax and cut carefully. 

 The branches should not be pruned in 

 such a manner that short stumps are 

 left sticking out from the stem, but 



