EPICORMIC BRANCHES 149 



conditions they will kill each other off, and effect natural 

 pruning ; there should be no need for artificial aid in pruning. 



Any severe thinning in the early stages of a crop encour- 

 ages the expansion of the crown and growth of side 

 branches, to the detriment of the height growth ; though the 

 individual trees will increase their quarter-girth measurement 

 to a greater extent than if the canopy is close. Trees taper 

 unduly if too heavily thinned, especially during the pole 

 forest stage. 



On the other hand, trees left unthinned too long, will 

 probably lose even in height growth, for their vigour will be 

 slight, and they will be liable to be blown over by the wind. 



With some trees, especially Oak and Chestnut, an 

 unduly thick canopy will often cause, especially in the latter 

 half of a rotation, the flushing of latent buds along the stem, 

 and epicormic branches will be thrown out. The reason of 

 this is because the crown is too small, and the root system is 

 too vigorous in proportion, and hence the excess of soil 

 nutrients and water cause the flushing of latent buds. 



On the other hand, a similar result often follows where 

 stems grown in close canopy are suddenly exposed, especially 

 in the case of Oak. In this case it is due to the stimulating 

 action of sunlight on the trunks, the bark of which is com- 

 paratively thin and tender when grown in close high forest, 

 and also to a state of hypertrophy induced by an excess of 

 soil nutrients. Other evil effects which usually supervene if 

 a close-canopied young crop is suddenly thinned, may be 

 traced to exposure of the tender bark and buds to inimical 

 influences, such as frost, cold winds, and hot sun. Often, 

 early spring growth will be induced, and the young foliage 

 and shoots may be injured by a late spring frost. 



The thinning of pure Oak woods requires special care, 

 partly on account of the liability of these trees to throw out 

 epicormic branches, and partly because there is great diffi- 

 culty in growing trees with tall clean boles and crowns of a 

 moderate size. 



Up to the age of 30 to 35 years they must be grown very 

 close to stimulate height growth, and to kill off side branches ; 



