4 8 
Colorado Experiment Station 
usually found in other dying trees. In cases where arsenic is known 
to have been the cause of injury one of its effects has been to check 
the growth of the affected parts, in fact to almost prohibit it. These 
tre t es are small for their age, and make but little annual growth. \ All 
of the observed difficulties may be caused by arsenic and we find 
no other causes to which we can with any degree of reasonableness 
attribute the difficulty. We therefore conclude that systemic arsen¬ 
ical poisoning is very probably the cause of the unhealthy condition 
of these trees and in some cases of their death. 
It is difficult to tell what part, if any, the lime may be playing 
in producing this specific trouble. I have stated that while it is well 
known that apple trees do well in limestone soils and that lime in the 
soil as carbonate of lime, this is the composition of our marls, is not 
per se injurious to the apple tree, yet the composition of the deposits 
formed by the bleeding described in Bulletin 131, and again in this, 
indicates strongly that lime, in some way, participates in producing 
it. Leaky spots in trees do not ordinarily, so far as my Observation goes, 
give rise to such incrustations or form stalactites as we find on these 
apple trees. I have been unable to find an analysis of the ash of the 
apple tree juice and I have been unable to collect the juice in order to 
make one myself. I have, then, no data pertaining to this subject 
to serve for comparisons and can only present the facts. 
In default of any knowledge concerning the composition of the 
juice of the apple tree, the best available subject from which to ob¬ 
tain some light would appear to be the ash of the wood on which there 
seems to be almost no data. I was able to find but one analysis of 
the ash of this wood and that is an old one, quoted by Adolph Mayer 
from the compilation of E. Wolf. This analysis shows the presence 
of over 36 per cent of silicic acid and can scarcely be considered as 
a typical ash. Dr. E. W. Allen was kind enough to call my atten¬ 
tion to the analyses of apple tree ashes published in the report of the 
Director of the New York Experiment Station for 1891, page 164. 
The trees subjected to investigation were young trees. The 
object in view was to determine the amount and character of the 
mineral constituents of plant food removed by nursery stock. The 
trees were probably not more than three or at most four years old. 
The trees discussed in this bulletin are of various ages, mostly from 
fourteen to eighteen years old. While I know nothing about the in¬ 
fluence of the age of the tree upon the amount of ash in the wood and 
its composition, I will use these analyses for comparison for I have 
no others. Again the influence of the soil is a question which must 
be passed over. Another unavoidable condition which may affect the 
results is the necessity which compelled me to use small limbs one 
and a half to two inches in diameter to represent the living trees 
whereas I cut off a limb fully five inches in diameter at the trunk 
of the tree to represent the dead one. These are all weaknesses in 
our data but these data are the only available ones. 
The soil in which two of the Colorado trees grew is represented 
by the analysis given under the caption “Analysis of a Marly 
