1916] The Ottawa Naturalist. 163 



About 3,000 species and varieties of trees and shrubs may be 

 grown at Ottawa. 



For street planting, the Sugar Maple, (Acer saccharum), 

 and the American Elm (Ulmus aniericana), are two of the best 

 trees. The maple has not the graceful outlines of the elm, 

 but as a shade tree is very desirable. It grows rapidly, does 

 not split or break easily, and the foliage is handsome in summer 

 and very attractive in autumn. It is not, as a rule, much 

 affected by insects or disease. 



The American elm is particularly suitable for wide streets 

 and in front of public buildings, and has an advantage over 

 the Sugar Maple in that it can be pruned up quite high, with- 

 out inaking the tree less attractive, but rather improving its 

 appearance ; whereas in the case of the Sugar Maple it inakes 

 the tree much less attractive if it is pruned very high. The 

 elm is, however, more subject to injurious insects than the 

 maple, and the fall web worm often renders the tree very un- 

 sightly. 



Among the trees which might be used as a street tree 

 more than it is, is the Red Oak (Quercus rubra). This is a 

 rapid growing tree, not a slow grower, as many suppose. The 

 glossy foliage is quite attractive in summer, and it takes on 

 very pleasing shades in autumn. The foliage remains on the 

 trees longer than that the Sugar Maple and much longer than 

 that the elm. 



Some of the best ornamental trees are among the native 

 evergreens. The White Pine (Pimis Strohus), is the most de- 

 sirable pine for ornamental purposes. It is more graceful than 

 most other pines, and the foliage is a pleasing shade of green. 

 The Yellow or Bull Pine (Pinus Ponderosa), of British Col- 

 umbia, is a very stately species, succeeding well at Ottawa. 



Douglas Fir (Pseudotsuga Douglasn), the big tree of Bri- 

 tish Coluinbia, after twenty-five years' growth at Ottawa, pro- 

 mises to continue to do well, and is a very attractive tree. 



Englemann's Spruce (Picea Englemanm) , a native of the 

 Canadian Rocky Mountains and Selkirk Mountains, is a beauti- 

 ful tree, and has thriven well at Ottawa. While not as blue in 

 colour as the Blue Spruce (Picea pungens), it has softer foliage 

 and is of a different shape. Those who have grown the Blue 

 Spruce longest find that when the tree gets to be twenty-five 

 or thirty, or perhaps more, years of age, the branches die at 

 the bottom, even when the tree itself is in the open. This is 

 due to the fact that the growth is stronger part way up than 

 it is at the base, and the branches at the base eventually die. 

 The Englemann's Spruce, on the other hand, remains broadest 

 at the base. 



