STREET AND HIGHWAY PLANTING. Hi 



As to cultivating it is the general practice to keep the soil free from 

 weeds and grass about the base of the trees-. In most cases an effort 

 is made, with varying success, to keep the soil stirred about the base of 

 the trunk. This insures a dry mulch, and hence a preservation of water 

 and an aeration of the soil, which is greatly to the advantage of the tree. 



As has been stated before, in the consideration of the nursery stock, 

 the training and pruning of the tree must begin in its earliest infancy. 

 Since our street is laid out on formal geometrical lines, and its purposes 

 are so strongly utilitarian, some concession must be made to service in 

 the training of a tree. The chief work in the nursery is to insure one 

 single straight leader. There may be strong lateral branches, but 

 there must be one still more vigorous central leader. 



As it is the Californian practice to plant trees from eighteen inches 

 to three feet high directly in position, all further training must be done 

 upon the street. Hence we can see the necessity of the firm, strong 

 stake advocated before. As young trees of this size do well, there is no 

 reason to discourage this practice. The only disadvantage is that in 

 having trees spread over the city, some may escape notice. The tree 

 comes from the nursery to the street with a single leader .and many 

 lateral branches. One by one these lateral branches are removed, 

 throwing the strength into the main leader. This leader must be 

 watched that it keeps an upright position. Eventually, the lateral 

 branches will have been removed far enough up the trunk, and there 

 they can be allowed to develop. 



For most trees it is best to have but a single leader throughout the 

 entire development. There are many exceptions, of course. But the 

 greatest generalization is a single erect leader, with a few good lateral 

 branches, which must branch in turn, and so on. In watching the 

 growth of the tree certain primary lateral branches will be found 

 stronger than others. Of these, certain ones will be more desirable. 

 The less desirable ones with the weaker branches should be thinned 

 out, and the lateral branches treated in a similar fashion for their sec- 

 ondary branches, until we have a symmetrical head. To determine 

 what branches should be left, and which removed, one must study the 

 natural habit of the tree and determine what procedure of pruning 

 will give a least artificial appearance, unless a frankly artificial system 

 of pruning is followed. 



Certain other methods of pruning have come to notice. For example, 

 it has been observed at Los Angeles and at Riverside that Acacia melan- 

 oxylon, if left to grow untouched, will produce a rather irregular 

 pyramidal crown. If, however, the top is severely cut out when the tree 

 is four or five years old, the resulting crown is more rounded and satis- 

 factory. So far, all the trees so treated are but seven or eight years 

 old, and the mature habit is as yet undetermined. In any event, the 



