Street Trees. 



319 



many times these injuries cannot be out- 

 grown. In some cities, ordinances provide 

 penalties for the hitching of horses to trees on 

 the highway, and such ordinances should be 

 enforced. When teamsters are heavily fined 

 for committing such trespasses on shade trees, 

 they will use sufficient care to lessen the num- 

 ber of injuries. In one town, the police ar- 

 rested and caused to be fined some two hun- 

 dred offenders for tying horses to trees, before 

 drivers became aware of the fact that the 

 laws could be enforced. Each community 

 must expect a certain amount of accidental 

 injury from this source; but no community 

 should permit the custom to prevail of making 

 a hitching post of a tree standing in front of 

 a residence. 



Trees that show injury from the above 

 causes, and especially those that have 

 areas of the trunk devoid of bark, should be 

 given attention without delay (see Fig. 240), 

 the ragged edges of the bark being cut to 

 a smooth edge and the entire area covered 

 with paint or tar to protect the wood during 

 the process of healing. Trees in a condition 

 similar to that shown in Fig. 239, should 

 be removed, as it is impossible to save or 

 restore them. 



(7.) Starving of root systems. 



The root systems of trees may be starved 

 in two ways: first, by being confined in a ster- 

 ile clay soil, and second, by receiving too large 

 or too small water supply. 



The trees on city streets suffer most often 

 because of a naturally poor soil and a lack of 

 sufficient water supply. City streets that are 

 macadamized, paved, or concreted, present a 

 surface layer that shuts off almost completely 

 the natural means by which water may reach 

 the roots, and directs all of the surface drain- 

 age into catch-basins and sewers. Thus, trees 

 on such streets are subjected to the extreme of 

 adverse conditions, and their natural vitality 

 and soil adaptation must be such that they 

 can withstand the abnormal strain on their 



Fig. 238. — The preservation 

 by means of cement filling 

 of a tree whose trunk has 

 been split from the effects 

 of freezing. 



