114 TREES IN WINTER 



CHAPTER VII 

 THE CARE OF TREES. 



There are many people who believe that a tree after being 

 properly planted requires no further treatment. While <many trees 

 growing wild have attained a perfect development^, it should be 

 remembered that these are the exceptions and that many of their 

 youthful companions either have died or have been seriously affected 

 in form and vitality. When trees become well established and are 

 allowed to develop under normal conditions they require very 

 little attention. On the other hand, yo^i'^g trees and trees growing 

 under abnormal or adverse conditions are less able to take care 

 of themselves. The growing of trees on narrow streets, where the 

 ground is almost completely covered with pavement and where 

 the trees are smothered with smoke and poisoned wdth coal gas, 

 is decidedly an abnormal condition and it is a wonder that there 

 are not more failures. 



IMPROVING SOIL CONDITIONS 



Tlie Need of Humus in the Soil — The failure of trees to de- 

 velop is more often due to an unfavorable physical condition of the 

 soil than to any other cause. When the physical condition is not 

 right the tree roots cannot develop properly and the tree cannot 

 get an adequate supply of water. Since plant food must be 

 dissolved in water before the tree can make use of it, a shortage 

 of water means a shortage of nutrition. Moreover, the soil must 

 be in a good, physical condition for the development of certain 

 useful micro-organisms and to facilitate favorable chemical action. 

 The constituent most necessary to keep the soil in a good mechanical 

 condition and the one most commonly deficient is humus, or 

 decayed vegetable matter. In nature this is supplied by the con- 

 tinual decay of leaves and other herbage on the surface. It is 

 not practicable in our streets and on our lawns to allow the leaves 

 to remain where they fall and the grass to develop and to con- 

 tribute vegetable matter when it dies. When lawns are made and 

 w^hen new streets are being planted it is a feasible thing to apply 

 a good dressing of vegetable matter in the form of stable manure 

 or other coarse material. The turning under of a good crop 

 of herbage is the easiest way to increase the humus content of 



