198 Choice of Plant Material 



wise being no more subject to insect pests than many other 

 species which are supposed to be immune, because the , 

 opportunity for extraordinary multiplication of its enemies 

 has not been given. 



General Considerations. In addition to economic tree- 

 planting for orchard and forestry purposes, which lie out- 

 side the scope of this book, there are three objects for which 

 trees are planted, namely, shade, ornament, and botanical 

 interest. The selection of plant material will in the first 

 place be influenced by the prominence which one or the 

 other of these objects may assume, and it will in addition 

 be circumscribed by the situation and space at command. 

 Different points of view will guide the selection for street 

 and avenue planting, for planting in yards and small places, 

 for planting on lawns in small or large parks, and for plant- 

 ing with special purposes in view, like the binding of shore 

 or dunes. 



In all cases, however, except where the botanical interest 

 — i.e., the collection of specimen trees — is uppermost, 

 the two paramount considerations are adaptation to cHmate 

 and adaptation to soil. 



While in street planting and in public parks, only trees 

 of proven adaptability should be used, in other cases experi- 

 ment is not excluded, although there should be at least a 

 reasonable expectation of success to warrant the choice, 

 which should be made with a knowledge of the points dis- 

 cussed in Chapter III, concerning the selection from local- 

 ities of the most unfaxorable climate in which the species is 

 at home, or at least from a locality which compares most 

 nearly to that to which the specimen is to be transferred. 



As regards adaptation to soil, we must emphasize again 

 that in most cases physical conditions, especially of water- 

 supply, are of more moment than chemical composition; 



