8 ILLINOIS AUDUBON BULLETIN 
‘‘improvements”’ as streets, walks, 
water, sewers, game fields, and 
swimming pools. Intangibles, such 
as trees, often take a back seat. 
The urban forester must ‘‘sel 
“his tree program to the community 
which makes public education an 
essential part of his job. If the for- 
ester can instill an appreciation for 
trees and how they contribute to 
our cities, most financial obstacles 
can be overcome. 
(2? 
Solutions to Problems 
Most of the urban forester’s 
problems can be solved if a tree 
program is sensitive to (1) the bio- 
logical needs of trees planted on 
city parks and boulevards; (2) the 
present and future environments 
where trees are established; and (3) 
the needs of people. 
By recognizing the biological 
needs of trees, only those species 
that thrive under specific growing 
conditions will be established. This 
insures optimum growth for these 
trees. In addition, it eliminates sec- 
ondary pathogens that will not in- 
fect a tree unless it is under initial 
stress. 
The forester must be familiar 
with the various insects and dis- 
eases that infect trees. One must 
also know the best techniques for 
combating these pathogens. An 
example is treatment of Dutch elm 
disease. One of the best methods of 
containing this disease is early de- 
tection and rapid removal of in- 
fected trees. Root barriers between 
elms must be established to pre- 
vent the disease from spreading 
through the root system. 
One must know the life cycle of 
the fungus and know the principle 
vectors that spread the infection. 
Armed with this knowledge, the 
best method can be derived to 
check the spread of the pathogen. 
Solution to sidewalk-tree con- 
flict is to curve walkway 
around the tree. This mini- 
mizes need for root cutting and 
provides relief from tradition- 
ally arrow-straight sidewalk. 
