36 BOTANY. 
as Dry Ridge. He adds that the growth was slower, but that quite as 
many of the trees lived. We may in many respects consider this a crucial 
test. After three years’ growth, the following percentages were alive and 
thriving: 
Per cent. 
Silver-maple, one year old when planted...... See ee 
Box-elder, one year old when planted. ....:.... ...... 0.02 ceeeee 80 
Honey-locust, one year old when planted........... ecb awen 100 
Ailanthus, one year old when planted . ....-.................-. 100 
Statistics from New Mexico and Arizona are meagre in the extreme. 
There is no doubt, however, but that thousands of trees of the indigenous 
cottonwoods, and of box-elder, Ailanthus, and China-tree, could be grown 
along the irrigating ditches and in other moist places: enough to raise the 
farmer in a few years beyond any immediate want for his most needed 
woods, and to largely spare the drain on the pine forests that cover the 
remoter mountains. It is in the highest degree probable that some of the 
various Australian trees, now being so successfully cultivated in California, 
especially some of the Eucalyptus species, could be made to do well in the 
warmer valleys of New Mexico and the warmer ones in Arizona where water 
may be had. These trees, as rapid growers, and as making good lumber, 
are of great value. 
We must still regard the problem a mooted one as to whether or not 
forests actually increase the rainfall of any region. The probabilities, 
however, appear to be against the supposition that they do. There can be, 
I think, no reasonable doubt but that they aid in obtaining greater benefits 
from what does fall. I am aware of recent observations in France which 
would appear to make even this doubtful, but I think the facts are so well 
established here that they may be regarded as above suspicion. The 
paper by Mr. Muir, already quoted, gives a striking illustration of ‘this in 
the case of the Sequoia gigantea, and other instances not less apt might be 
furnished. Mr. Cooper, of Santa Barbara, has elaborated at some length a 
plan for obtaining larger results in agriculture from the same quantity of 
water by making the shade of the eucalyptus diminish the excessive evapo- 
ration of the water. The details of this will be considered elsewhere.* 
eer OURESS PASSA ee Meee | 
*It may be considered a question as to whether the water taken up by the roots would not equal 
or exceed that saved from evaporation, 
