60 



STREET AND HIGHWAY PLANTING. 



attention to the shaping is the next item. The irregularity in the rate 

 of growth can be regulated to a reasonable degree by attention to the 

 watering with extra waterings for backward trees, and even a mulch 

 of street sweepings or rich manure in extreme cases. For those trees 

 which show a leader inclined to grow in an oblique or horizontal 

 position, the old practice of tying the limb to an upright pole is the 

 best method. Any suckers or shoots from the butt should be cut off 

 promptly, for if encouraged or let alone the tree will show a tendency 

 to assume a scrubby bush-like form, so that considerable effort will be 

 required to bring it back to good shape. 



Figure 31. 



Quercus calif ornica (Fig. 31), often called l( Kellogg 's oak," is 

 another native species which is commonly found through certain parts 

 of the northwest. It is a deciduous species of marked beauty. At 

 present the nursery supply of this species would be very limited in 

 most regions. Now that native species are receiving the attention 

 which they deserve this matter will have to be remedied. 



The valley oak (Quercus lobata) (Fig. 32) is another native species 

 worthy of a place. In many places it is badly infested by certain gall- 

 producing insects and by growths of various mosses, which render the 

 tree unsightly. In those parts of the State where it is one of the 

 dominant features of the landscape its use is to be recommended. 



The tanbark oak (Quercus densiflora) (Fig. 33), which is not a true 

 oak though closely related, is a tree which is a dominating species in 



