132 TREES AS GOOD CITIZENS 



species. Trees which have roots near the surface require 

 more water than those with roots which penetrate more 

 deeply, and the trees of rapid growth demand more than 

 those which grow slowly. As a general rule, watering 

 should be done every week or ten days when copious 

 rains are lacking. Too frequent application of water is 

 as bad as not watering enough, since excessive supply 

 causes the earth at the roots to become soggy and sour. 

 During the first year from ten to fifteen gallons of water 

 should be applied each time. 



The water should be applied gradually and so 

 thoroughly that it will soak into the ground for at least 

 one and one-half feet. A gradual application is best for 

 the reason that it resembles Nature's methods. Heavier 

 application will wash the soil away from the roots near 

 the surface and cause the formation of a hard top crust 

 of earth. The water should be encouraged to filter 

 through the soil. This may be done by using moderately 

 light soil and keeping the top soil pulverized. A simple 

 method of applying water to a small number of trees is 

 to allow it to run slowly through a small opening near 

 the bottom of a barrel placed near the base of each tree. 

 Another method, which will be found simpler in watering 

 a large number of trees, is to make a basin of earth, 

 surrounding the base of each tree, and fill this with water. 

 In following either plan, it is desirable to smooth the 

 surface after the water has penetrated to prevent the 

 formation of a crust; and to cover the wet soil with dry, 

 fine soil or a mulch of leaves and straw, to conserve the 

 moisture by preventing evaporation. 



In some cities underground irrigation is provided by 

 means of tile drains, supplied with water from the city 

 mains. This is effectual and especially useful in streets 

 where the paving takes up the entire surface area. 



