TREE PLANTING ON STREETS AND HIGHWAYS. 205 



a proper aeration of the roots. This can be remedied to some small extent by the 

 openings left in the flagging at the base of the trunk. But this affords only a partial 

 remedy at the best, and so we cannot expect that a city tree on a closely paved 

 street and sidewalk will develop the same thrifty growth and appearance as if it 

 stood on a village street where the ground around it was exposed to air and sunlight. 



People who believe in the efficacy of fertilizers in promoting tree growth are apt 

 to consider the planting of paved streets a doubtful undertaking because there is 

 no opportunity to enrich or cultivate the ground. But such discouragement does 

 not seem to be based on sufficient reasons. Fertilizing material is beneficial to sur- 

 face crops, but it can exert but little influence on roots that pentrate deeply in the 

 earth, and which must draw their sustenance from the lower strata found there, 

 good or bad as the case may be. 



In many city streets the ground presents unnatural and unfavorable conditions. 

 The surface has been cut down extensively by grading or blasting, which leaves 

 exposed only the sterile earth of the lower strata; or a depression has been filled, 

 in which case the planting must be done on " made ground " composed of ashes, 

 street litter, old tinware, and all the other kinds of rubbish which are dumped in 

 such places by the street cleaning bureau. Such conditions, however, should not be 

 considered as a deterrent in planting; but they demand a more thoughtful study of 

 the situation, with some additional effort in providing larger holes and an ample 

 supply of fertile soil. 



While smoke and dust undoubtedly are injurious to some species, leakage from 

 gas mains has caused by far the greatest destruction of trees in city and village 

 streets. No matter how hardy the species, how well it is planted, or how carefully 

 it is fostered, if the ground becomes saturated with illuminating gas the tree is 

 doomed. It may be assumed that a gas company will, in its own interest, endeavor 

 to prevent any leakage in its mains. But the work of finding and stopping a small 

 leak may cost more than the loss of the gas ; and it is the small leak, when near a 

 tree, that does the mischief. 



A frequent source of injury is the unnecessary mutilation of the larger roots by 

 laborers employed in digging the ditches for gas or water mains. In most cases this 

 can be avoided by the exercise of some care and a slight expenditure of time, which 

 should be insisted upon by the city authorities. 



Let every citizen who finds enjoyment in well-shaded streets make an effort to 

 procure the passage of a city ordinance placing the entire control of the trees of his 

 town in the hands of a tree-planting society, or the park department, or some special 

 commission, and use his influence, also, to see that ample funds are annually appro- 

 priated by the municipal or village government to carry on the work. 



