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nurse tree should grow rapidly during the first few years to afford 
protection as soon as possible and either moderately or very slowly 
thereafter. Within the forest area rapidity of early growth is less 
important. As in the human family, the nurse loses its usefulness 
when its protégé becomes old enough to take care of itself. 
Nurse trees have always as their principal object a helpful effect 
upon those among which they are planted. They may produce the 
poorest quality of timber themselves, or may even never grow large 
enough to make timber of any kind, and yet be of the greatest value 
to the plantation. 
The Boxelder, one of our most useful species for Northwestern plant- 
ing, because shady and most readily grown, is short lived, makes a 
crooked stem, inferior in quality even for fuel, and is neither a strong 
nor durable wood, but many valuable species are the better for growing 
surrounded by Boxelders during their youth, and hence it deserves a 
place in every plantation in the Northwest. 
The nurse tree is of the greatest importance during the first ten to 
twenty years of the plantation’s history. It will frequently,in the first 
few years, seem to threaten to crowd out the trees which it is intended 
to benefit, but this is a danger more apparent than real, for if a grove 
be properly designed, the more permanent trees require just such 
erowding in order to insure their best development. If the nurse trees 
are permitted to remain in the plantation too long, or are allowed to 
encroach upon the main crop, they may become a positive detriment 
instead of a benefit. 
There are two groups of nurse trees—those with thin foliage, making 
a slight shade, which are principally useful in protecting the infancy 
of trees difficult to start, but of vigorous aftergrowth; and those havy- 
ing dense foliage, making a heavy shade which will prevent the 
growth of side branches on their charges by cutting off all the light 
except that directly overhead, and to serve as soil cover. In the first 
class are Aspen and Cottonwood; in the second, Boxelder, Silver Maple, 
Russian Mulberry, and Chinaberry. 
It will be readily understood that these two groups of species have 
a widely different effect, both upon the trees they are intended to bene- 
fit and upon the soil. The thin-foliaged kinds will not prevent weed 
growth, since their shade is so slight that almost all the grasses and 
weeds are but little affected by it, and they will thus be of slight bene- 
fit in shortening the period of cultivation. But they create a condition 
seemingly favorable, especially for the conifers, in the plains where the 
excess of bright sunshine is in striking contrast to the native environ- 
ment of most young evergreens. 
Within the White Pine region, when fire has destroyed the forest, 
it has been observed that the first trees to appear in the burned dis- 
trict are Poplars (Aspen) and Birches, and’ when these have attained 
a height of from 5 to 10 feet many young Pines and other evergreens 
