Feb. 19,1917 Arsenical Injury through the Bark of Fruit Trees 
307 
to the ground. Some lodges in cracks and other irregularities of the 
bark on the trunk; but this is not likely to cause injury, as it soon dries 
out. Around the crown, however, it accumulates to a much greater 
extent and is often kept moist by the soil for long periods of time. As 
the crown of the tree is covered by the rough or furrowed bark which 
theoretically offers only partial protection, it is highly important to 
determine its vulnerability by actual test. 
INJURY TO LARGE LIMBS WITH ROUGH BARK 
A few large limbs were found having longitudinal cracks in the bark 
of the kind just described. These limbs were treated with copper aceto 
arsenite or calcium arsenite under bandages such as were used for most 
of this investigation. Care was used to make no artificial wounds. The 
results are shown in Table VII. 
Table VII .—Results of treating large unwounded limbs of apple showing the first cracks 
of rough bark formation, on July 13, !Qi 2 t to show injury through rough bark 
No. 
Chemical (50 gm,). 
Diame¬ 
ter of 
treated 
limb. 
Natural cracks in bark, appar¬ 
ently recent. 
Inches. 
1 
Copper aceto ar¬ 
senite, Baker. 
3 % 
One short, deep, longitudinal* 
crack 5 inches long. 
2 
s'A 
Irregular # longitudinal crack 
about 3 inches long. 
3 
2X 
Deep longitudinal crack 6 inches 
long. 
4 
Calcium arsenite, 
Baker. 
2% 
Longitudinal crack 7 inches long. 
Lower portion recently formed. 
S 
4 
Six longitudinal cracks on under 
side of limb. Not all recent. 
6 
iX 
Irregular cracking on one side... 
Extent and character of injury. 
Limb completely girdled under 
bandage and for about 2 inches 
above. 
Limb girdled under bandage and 
for about 3 inches above and 
below. 
Limb girdled under bandage and 
about 3 inches above and below. 
Streak runs up 10 inches. 
Limb girdled under bandage and 
about 7 inches above and 3 inches 
below. 
Limb girdled under bandage. 
Wide streak runs up 2K feet and 
down to ground 2% feet. 
Limb girdled under bandage. 
Streak rims up 2 feet and down 
6 inches. 
It will be seen from this table that in every case the limb was severely 
injured. The absorption was rather slow and there was little tendency 
to form the dead, sunken streaks up and down the limbs so characteristic 
of injury through wounds. In this respect there was a close similarity 
to the crown injury under controversy in Colorado and elsewhere. 
Tenticel injury was out of the question in these cases, as the lenticels had 
become nonfunctional and indeed had practically disappeared from the 
larger limbs. 
INJURY TO TRUNKS 
A few trunks also were treated early in the course of this investigation. 
The method here was to apply the chemicals in funnels about the 
trunks as described on page 286. 
That the bark on the trunk fails to protect the tree from arsenical 
injury is shown by Table VIII. The absorption was evidently slow, 
