134 SHADE-TREES IN TOWNS AND CITIES 



catalpa, and willow are either too soft or brittle to depend 

 on without special care. The elm, hickory, and oak have 

 strong, flexible woods and are, therefore, safer than any 

 others. The red oak is weaker than the other oaks. The 

 sycamore and beech have a tough cross-grained wood and 

 are, therefore, fairly strong. The linden has a soft wood, 

 while the ash and gum, though strong and flexible, are apt 

 to split. 



"3. Look out for a limb that shows fungous growths. 

 Every fungus sends out a lot of fibers into the main body of 

 the limb which draw out its sap. The interior of the branch 

 then loses all strength and becomes like powder. Outside 

 appearances sometimes do not show the interior condition, 

 but one can be sure that every time he sees a fungus prop- 

 ping out, there is trouble behind it, and the limb is not alto- 

 gether safe. 



"4. When a limb is full of holes or knots, it generally 

 indicates that borers have been working all kinds of gal- 

 leries through it, making it unsafe. The silver maple and 

 sycamore maple are especially full of borers, which in many 

 cases work on the under side of the branch, so that the man 

 in the tree looking down cannot see its dangerous con- 

 dition. 



"5. A dead limb with bark falling off indicates that it 

 died at least three months before and is, therefore, less safe 

 than one with its bark tightly adhering to it. 



"6. Branches are more apt to snap on a frosty day when 

 they are covered with an icy coating than on a warm, sum- 

 mer day. 



"7. A rainy or drizzly day causes the branches of a tree 

 to be slippery, and greater precautions are then necessary. 



"8. Always use the pole-saw and pole-shear on the tips 



