10 BULLETIISr 816, U. S. DEPARTMENT OF AGRICULTURE. 



it is short lived in order to make room for a good one that will be 

 permanent does not appeal to the average citizen. Where trees 

 which have been planted by the property holder come under city 

 control a strong feeling of proprietorship still remains, which is 

 outraged by the suggestion of the removal of even poor trees. Where 

 all the work is under city control good work is often hampered by a 

 strong public sentiment against the removal of trees, even though they 

 are poor or crowding. 



Because of» this difficulty it is extremely important that young 

 trees be planted farther apart than at that time seems reasonable. 

 If they are planted as far apart as is pro23er for mature trees the 

 distance will be so great as to make planting seem a joke. If they 

 are planted half the distance apart they should be when mature, 

 good results would follow if the intermediate trees were removed 

 when they nearly touch those to be left. As the intermediate 

 trees would probably not be removed, or not until too late for the 

 good of the remaining ones, planting had better be sufficiently 

 far apart in the beginning to avoid the necessity of later removals. 

 In the beginning the trees wiU be too far apart and when mature 

 too close together, but it seems to be the alternative imposed by a 

 misguided public opinion. 



There is scarcely a community that would permit the removal of 

 interplanted trees from' a street of fine elms, oaks, or other worthy 

 varieties without a protest that would be the almost sure political 

 death of the administrative authorities responsible, no matter how 

 great the need or how much expert support they might have. If 

 short-lived intermediate trees were used they would not be likely to 

 be taken out before they died, and they probably would not die before 

 they had irreparably injured the permanent trees. The removal of 

 surplus or interj^lanted trees can be made with least shock to the 

 community by gradually narrowing the tree tops by severe pruning 

 from year to year on the sides next the permanent trees until finally 

 they are so narrow they may be removed and leave only small 

 openings between the permanent trees. Even this method wiU not 

 materially lessen the public protest at the final removal. 



A common practice is to set street trees 35 feet apart. If it were 

 practicable to remove one-half the trees at the proper time this would 

 be a good distance, but in the eastern half of the United States and 

 on the Pacific slope 50 feet apart is close enough for most varieties, 

 and for the larger growing trees 60 to 70 feet would be better. 



CONDITIONS FOR TREE GROWTH. 



In order to grow, trees must have a soil of suitable texture, in 

 proper mechanical condition, that contains sufficient available mineral 

 elements and plenty of organic matter, and, last but not least, a con- 

 stant supply of moisture and air. In addition to these there must 



