174 THE GYPSY MOTH. 



care and therefore not being weakened by the almost univer- 

 sal decay, upheld their loads, survived the storm's fury and 

 were not seriously injured. 



It is far better never to prune at all than to prune in an 

 unscientific manner. Native forest and fruit trees never 

 pruned by the hand of man grow to maturity in better con- 

 dition than those in many orchards. In the forest, trees 

 are pruned by nature. As they grow upward, the dense 

 shade formed by their tops kills the lower branches by de- 

 priving them of the sunlight. These branches decaying drop 

 off or are torn away by the wind. Little or no damage to 

 the resinous coniferous trees results from this process. As 

 the branches usually break off close to the trunk, and the 

 wood is so filled with resin as to exclude water and parasitic 

 fungi, the wounds heal readily and the trunk remains per- 

 fect. More injury is likely to follow to deciduous trees 

 from this operation, especially when the branches are large, 

 yet wounds caused by broken branches are often healed. 

 The breaking is most likely to take place during the winter 

 storms, when there is less danger of injury to the trunk and 

 bark. Yet serious injury is often done and the weaker trees 

 are frequently killed or their shape is ruined by this process 

 of natural pruning. Such pruning as is required for the pur- 

 poses of the gypsy-moth work will assist in forming healthy 

 growth rather than retard it. 



That many apple trees are in ruins before they are fifty 

 years old is almost entirely due to neglect or the ruinous 

 policy pursued in their handling. Such trees well cared 

 for might continue to bear fruitfully for a century.* A 

 knowledge of vegetable physiology and the practical applica- 

 tion to tree culture of its laws is greatly needed by those 

 who have the care of trees. A knowledge of the causes of 

 diseases of trees and the means of their prevention is also 

 essential to the farmer, orchardist and forester. 



It is the function of roots to fix the plant in the soil and to 

 absorb from it water and the soluble organic and inorganic 

 crude material which is needed for growth and development. 

 It is now believed by botanists that this fluid, which we will 



* Apple trees in an orchard planted in Medford by Gov. John Brooks soon after 

 the Revolutionary War have borne fruit within a few years. 



