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may be found growing in their shade. In the denser shade of mature 
Hemlock, for instance, comparatively few seedling Pines are found. 
The seed would germinate there, but the plants could not thrive in 
such dim light any more than they could in the full sunshine. 
Acting upon this observation, plantings were made the past season 
of Aspen and Birches at all our stations, having spaces at intervals of 
8 to 12 feet, in which various species of Pine, Spruce, and Fir will be 
planted when the nurse trees have from one to three years’ start. So 
far as known this is the first experiment of this kind that has been 
undertaken in the West. 
The Aspen (Populus tremuloides) should be a better tree for this 
purpose in the plains than either the Cottonwood (Populus deltoides) or 
the Birch (Betula lutea), because its shade is the least dense and its 
vigorous growth lasts a shorter period. The Birch, which in its native 
woods has a rather slender habit of growth, in the bright sunshine of 
the plains becomes stalky and densely leafed. This has been observed 
at the stations in South Dakota and Nebraska, and may result in a 
totally different effect upon the conifers to be set with it than has been 
observed in the natural forests. Indeed, it may be said in passing that 
the intense light of the plains region, no less than the widely differing 
soil and moisture conditions, is apt to have a pronounced effect upon 
the development of species native of cloudy, moist localities. 
Other light-foliaged trees that may serve equally well as nurses, 
especially in the Southwest, are the Black Locust, also called Yellow 
Locust (Robinia pseudacacia), and the Mesquit (Prosopis juliflora). 
These species have the advantage of being valuable timber trees. 
The Black Locust is like the Cottonwood in being a gross feeder, 
and this habit may prevent the use of either species as a nurse for 
conifers, which in several species are slow to become established. 
Like the Cottonwood, too, it is a thin-foliaged, light-demanding species. 
So far as known the Mesquit has never been tested in artificial groves. 
The use of quick-growing, densely shading nurse trees has been more 
thoroughly tested, and results have already been reached which fully 
warrant the practice. They are especially valuable where broad-leafed 
trees only are planted, and as the price of evergreens has hitherto pre- 
vented their extensive use in the plains, the employment of dense- 
shading nurse trees is worthy of somewhat extended discussion. 
A plantation of Green Ash or White Elm, two of the most widely 
successful species that can be grown in the plains, can best be estab- 
lished by covering one-half to three-fourths of the ground with Box- 
elder or Russian Mulberry, and setting in the desirable Ash and Elm 
at regular intervals. Planted by themselves, Ash and Elm will each 
make more vigorous growth than when surrounded by the other 
species, because they are both light-loving trees, and in the full sun- 
Shine they will throw out many branches, spreading their tiny crowns 
