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. 
