16 The Colorado Experiment Station. 
gone severe winters, it is often possible to find the sap wood dis¬ 
colored, generally due to freezing and in some cases traceable by 
the annual rings to the year of the injury. 
WINTER INJURY OE THE OLD TREES. 
One form of freezing found on the old, and sometimes young 
apple trees, is due to “freezing dry.” This is thought to result 
from perhaps two causes, one being lack of moisture in the soil, 
and the other a deeply frozen condition, stopping all root action. 
Transpiration, or the loss of water from the limbs and twigs of 
the tree, goes on in winter as well as in summei. Whenever either 
or both of the conditions mentioned above exist for any length or 
time, the results are detrimental to the tree and, if severe enough, 
may cause death. For this reason it is necessary to irrigate in late 
fall or early winter. As a rule, the first of November is a desirable 
time to do this, as it very seldom happens that the soil around the 
roots freezes enough to do any damage unless the trees are shallow 
rooted. In this case root freezing might prove to be detrimental. 
The above statements will hold tor the peach as well as for the 
apple. 
There is another form of winter injury to old apple trees that 
is often found and vfiffch in some cases, is hard to distinguish from 
injuries due to arsenical poisoning. The distinguishing features 
are that the injury for the most part is at the crown or ground line 
primarily and seldom runs down into the root system. The roots, 
of course, may be affected from this injury, but in such cases the 
injury would be secondary. The injury takes place in the form of 
?■ partial or complete girdling at the ground line. The bark peels 
off in rough pieces and generally m one spot only. It may extend 
up to the trunk of the tree for several inches. It depends upon the 
size of this affected spot whether the injury will prove fatal to the 
tree or not. In cases of arsenical poisoning the bark becomes cor ¬ 
roded to a mealy mass in which the tissues are broken down and 
may be scraped off from the wood, while with winter injury the 
bark remains intact and separates at the cambium. The writer has 
seen cases where fifteen year old Ben Davis trees were killed by 
this crown line injury. Attempts were made to save the trees by 
bridge grafting, but as stated before, the scions that had to be used 
were too long, and dried out before adhesion could take place. 
These trees were in such a position that undoubtedly more or less 
ice and snow remained around the bases of them for long periods 
of time. Although in some cases it would appear that ice around 
the base of a tree had no detrimental effect, it is not well to allow 
this, as one can never tell when the conditions are just right for 
damage to be done. In the fall irrigation it is well to keep the 
