11 



age annual net return per acre of $10.67, while eight groves of white 

 willow gave an average annual net return of $24.01. 



Of the hardy conifers the following are recommended for protect- 

 ive planting: Scotch pine, white spruce, Norway spruce, western 

 yellow pine, and European larch. Either of the spruces should be 

 mixed with one of the pines or larch. 



White elm, green ash, and hackberry are hardy deciduous trees, 

 but grow more slowly and afford poorer protection in winter. Cot- 

 tonwood and white willow do well even upon the upland if planted 

 in single rows. 



In selecting species for park, lawn, and roadside planting, after 

 hardiness, symmetry of form and gracefulness of foliage are the chief 

 considerations. Much depends upon the taste of the individual 

 planter, but the following species seem desirable for all situations 

 and in the order named : Colorado blue spruce, white spruce, bur oak, 

 white elm, green ash, hackberry, and boxelder. 

 Of the species not recommended 



Black locust is too early and too seriously affected by borers; 



Osage orange is not hardy; 



Silver maple is not sufficiently drought resistant ; 



Basswood has not been tried upon the upland, and does not 



appeal to the tree planter; 

 Butternut lacks good qualities; 



Diamond willow is a bushy shrub and grows slowly ; 

 Black spruce is too slow of growth ; 

 Red cedar grows slowly and suffers from the effects of the 



cedar apple fungus; 

 Lombardy, Carolina, Norway, Russian, and balsam poplars 



are inferior to the common cottonwood. 



White pine, jack pine, honey locust, and black cherry are not being 

 planted enough to recommend them on a basis of experience in grow- 

 ing. It is likely, however, that they would grow well if properly 

 planted and cared for. 



DISCUSSION OF THE SPECIES. 



These notes comprise a more detailed discussion of the merits of 

 each species. They are based upon general observations as well as 

 upon actual measurements of a number of planted groves. 



BROADLEAF TREES. 



Broadleaf trees as a class require from 6 to 10 times as much water 

 during the growing season as conifers. On bottomlands they grow 

 fast and some of them cottonwood and white willow are com- 

 mercially profitable. On the upland the broadleafed species either 

 fail or grow too slowly to be profitable except for protection. 



[Cir. 145] 



