78 The Colorado Experiment Station. 
sections which have been planted on ground rich in alkali, which 
are in good condition. Nearly every case cited in which an orchard 
is involved is one in illustration of this fact. Cases 5, 6, 7, 9, 11, 
12 and 21 were old orchards, from fourteen to twenty-eight years 
old, in which the trees had thriven till within a few weeks before 
their death. The soils in these orchards are not richer in alkalis 
now than they have been in years past, nor richer than the soils of 
many other orchards which are still in a flourishing condition. 
Water does not kill so quickly nor in this manner. 
The trouble in the cases of orchards is not at all related to 
the age of the trees, for trees of all ages have been killed. Older 
trees with large root systems seem to be more readily affected than 
younger trees but I have seen a nine and an eighteen-year-old tree 
standing within twenty-five feet of one anotner attacked and killed 
in practically the same time. 
This trouble has spread very rapidly since the summer of 
1909 when I first observed bad attacks in orchards. Orchards 
Nos. 1, 2, 3 and 4, mentioned in Bulletin 155, had been observed 
previous to that time, but during the past year, 1910, I have seen 
many orchards, distributed over a wide area, seriously injured. In 
former years I have seen no injury done in May or early June, 
but this year, 1911, the damage already wrought is large and the 
outlook is very ominous. 
Orchard lands are by no means the only lands in which this 
trouble occurs, other lands are as badly affected as are the orchard 
lands, but orchard lands are conspicuous because of dead or dying 
trees, or of vacancies caused by the removal of dead trees. Cases 
19, 20, 24, 25 and 26 are examples of ordinary cultivated lands. 
Apple trees have been mentioned so nearly to the exclusion of 
others that one might think that the apple is the only tree or plant 
that is killed. This is not the case. The following trees and other 
plants have been noted: the anole, pear, peach, plum, apricot, 
cherry, quince, maple, cottonwood, ash, currant, grape, corn, to¬ 
mato, bean, pumpkin, cantaloupe, pea, elm, willow, Lombardy 
poplar, Carolina poplar, sorghum, oats and barley. 
I have made no experiments in addition to those recorded on 
pp. 43 and 44 of Bulletin 155, to demonstrate the effect of nitre 
on apple trees. The results of those experiments were stated as 
follows: “The effects were in all respects similar to those produced 
in the affected orchards, the beginning and progress of the effects, 
the killing of the leaves, the throwing out a few whitish-yellow 
leaves, their speedy death and the annearance of the bark and wood 
after death, were identical. An application of large quantities of 
salt proved injurious but did not produce these effects.” The ex¬ 
periments, eight of them, were concordant and conclusive. 
4 
