Care in Planting Trees 173 
roadside, paring off the sod, and, if need be, with sand 
added, or well decomposed humus from a swamp, furnish 
good material for filling in. Rotted sod may also be placed 
at the bottom of the hole to enrich the soil. 
Manure of any kind is much better kept away from roots; 
itIs apt to do more hart than-pood;-both mechanically and 
chemically, But W extra Gare teetewret,@ mulching oF top 
dressing to the depth of two or three inches with well-rotted 
manure, spent bark, leaves, or other litter is commendable, 
as it prevents evaporation from the soil more persistently 
than even cultivation. Stones may also be used for this 
purpose. If manure is to be placed in the hole to enrich 
the soil, and especially to increase its water capacity, make 
sure that it is well mixed with the soil and kept away from 
direct contact with the roots. 
Especially in planting street trees, the depth of the hole, 
and improvement of the soil is essential. A hole three 
feet deep, and an area of four square yards of prepared 
soil and an open space of at least one and a half yards un- 
paved and cultivated, are the proper conditions for city 
trees. 
Different species, we must repeat, make different demands 
on character and depth of soil (see Chapter IX), and hence 
more or less care in the preparation of the soil is required 
for different species. 
In actually setting the tree, the first care is not to set it 
‘too deep. Many trees are lost from this cause, suffocation 
resulting by removing the Tréspiratory organs of thé Toots 
donot Eke to have their roots deeply buried is natural, but 
is often not realized by the planter. Deep-rooted species 
also have some shallow specially designed_for respira- 
tion and these must be kept near the surface. The proper 
