NOURISHMENT. 13 



Water. Street trees require more water than lawn trees because 

 their roots are apt to be restricted and because sun-heated pave- 

 ments and buildings increase transpiration. A good rule is to see 

 that the ground about a tree is soaked once a week. If rain fails 

 use the hose or a pail. Sprinkling, tho done frequently, is only a 

 little better than nothing. Too frequent soaking will exclude the 

 air and cause the roots to rot. When the ground has dried after 

 a wetting, rake the surface to check evaporation. If the ground 

 does not dry within an hour too much water has been applied. 



Food. In the forest, and in neglected places, nature provides 

 trees with food. Along the streets and on well-kept lawns it must 

 be furnished. If a tree shows thin foliage, slender branches or a 

 dead top starvation may be suspected. The best fertilizer is com- 

 posted (not fresh) manure. In the spring spread it 2 inches deep 

 over as much of the root extension as can be reached and fork it 

 into the soil; or, tho not so good, put it on December first and let 

 it lie over winter, when what remains can be raked off. On a paved 

 street the fertilizer must be placed in the opening at the tree base, 

 but whenever possible it should be spread away from the trunk and 

 beneath the foliage, where most of the feeding roots are found. If 

 manure is objectionable, apply each spring iVz pounds per 100 

 square feet of a commercial fertilizer composed as follows : 



For light soils. For heavy soils. 



Nitrate soda i part 2 parts 



Acid phosphate i " 3 " 



Muriate potash 1 i " i " 



Ground bone i " 2 " 



Distribute the fertilizer evenly and mix it with the soil ; be care- 

 ful not to use an excess else the tree roots may be burned. 



If it is desired simply to sustain an old tree without inducing 

 growth, use a small quantity of manure, or from i to i!/2 pounds per 

 100 square feet of a mixture containing i part nitrate soda, i part 

 bone meal, 5 parts acid phosphate. 



Pruning 



Trees need to be pruned only (i) when they are transplanted; 

 (2) when they interfere with other trees or structures; (3) when 

 they are weakened by decay or by overgrowth. Much of the prun- 

 ing done by so-called experts is useless or even harmful. Most trees 

 should be allowed to develop according to their natural habit. When 

 pruning is permissible the following rules apply. 



When transplanted, a tree must have its crown cut back to bal- 

 ance the inevitable loss of roots. See figure 3, and observe that 

 useless interior branches are removed entirely. 



Form. If a tree grows one sided, if its branches interfere with 

 a building, or with another tree, curtail or cut out entirely the aggres- 



ashes may be substituted at the rate of 10 pounds to 1 pound 

 of muriate potash. 



