TREES AS GOOD CITIZENS 
In scjme streets the entire sidewalk surface is needed 
for traffic, and this makes it impossible to sacrifice the 
space that is required. In a case of this kind, a sidewalk 
grating may be employed, permitting pedestrians to use 
the sidewalk up to the very base of the tree and still 
providing breathing room for the tree itself. This grating 
is level with the surface of the sidewalk, and the ground 
underneath slopes away from the tree, forming a pit or 
basin, which collects water, and is therefore useful in 
supplying moisture to the roots. The grating is so set 
as to be easily removed for cleaning the space underneath. 
In dense traffic the grating is essential, but where it is 
possible to provide a space free from paving, without the 
use of the grating, this should be done in the interest of 
the tree’s best development. 
Irrigation and drainage are essential to the life of the 
tree. The ideal means of providing water is by having the 
tree so placed that the soil surrounding the hoots may be 
loosened from time to time, in order that surface watering 
may penetrate the earth and reach the roots in abundant 
supply. This is possible where trees are planted in space 
free from paving, such as a strip of gravel or grass be¬ 
tween sidewalk and curb. If a grating is used, it should 
be taken up occasionally and the soil underneath made 
loose by cultivating. One of the most important features 
of the grating is that it allows this cultivation, in addition 
to preventing the traffic from packing the surface, as would 
occur if foot-traffic were allowed to use the space immedi¬ 
ately surrounding a tree without the protection afforded 
by the grating. 
If the natural drainage fails to prevent water from 
collecting at the roots, artificial drainage may be supplied 
by using tile drains, 3 or 4 feet below the surface, 
to carry surplus water to the nearest sewer. This is 
