14 The Colorado Experiment Station. 
the scaffold limbs of the tree would not only keep rabbits from 
gnawing . but would also do much toward breaking the direct and 
reflected sun rays on the trunks. Wood veneering will answer the 
same purpose here as wire netting. Never use tar paper, as it not 
only concentrates the rays of the sun, but has an injurious effect 
upon the trunks, and in some cases the writer has seen death caused 
by its use. 
It seems that the darker the bark the more liable it is to in¬ 
juries from sun scald. Whitewashing the trunks of the trees is a 
very good practice and one that can be used on old trees as well as 
young. A very good whitewash is the California formula, which 
is as follows: 
Quicklime .30 pounds 
Tallow . 4 pounds 
Salt . 5 pounds 
Water..enough to make mixture flow well 
Prof. W. Paddock says that this makes a tenacious whitewash 
not easily washed off by rains or removed by other means. 
If whitewash is to be applied to the trunks of old trees in the 
winter time, it is a good thing first to remove all the old, rough 
bark. In this way many of the injurious insects that are hibernat¬ 
ing over winter under this bark will be killed. A rough rasp or file 
is a very good implement to use in removing the old bark. 
In peach orchard districts, where the temperature sometimes 
falls from 15 to 24 degrees below zero, there is more or less danger 
of damage being done to peach trees. Especially is this true when 
the trees are young and the temperature remains low for any length 
of time. It is sometimes very hard to tell whether considerable 
damage has been done to trees or not, until late winter, or some¬ 
times it is the first of May before one can be sure whether the trees 
have withstood the rigorous weather. Perhaps, for peaches, the 
most common injury is that of killing the fruit buds. But this is 
not to be dreaded as much as freezing at the crown or ground line, 
which causes the so-called “collar girdle.” Another form of freez¬ 
ing is that beginning at the terminals on the one-year wood and 
freezing back onto the older wood. This latter form is perhaps 
more common on older trees than young ones. 
Eor the reason that it is almost impossible to tell the extent of 
the damage done by freezing until earlv summer, it is often a good 
plan to delay pruning until about the first of May. It must be un¬ 
derstood that this is when the trees have undergone a severe win¬ 
ter. In other cases perhaps it is better to prune when a tree is dor¬ 
mant, although this is disputed by some of our best orchardists. At 
