16 The Colorado Experiment Station. 
this orchard was 18 years. The owner stated that he had observed 
a Eawver tree about three years previous to this time which turned 
brown on one side but recovered so that it grew healthily the 
following year. Some of these burned trees put forth a few new 
leaves which had a whitish yellow color and soon died. We 
visited this orchard again on November 3, when we found a number 
of the trees evidently dead, and again on December 3, 1909, when 
with the help of the owner we dug out a number of the roots and 
again sought to ascertain the depth of the water table. We fol¬ 
lowed the roots from the trunk of the tree as far as possible. In 
one case this proved to be 21 feet at which point we lost it because 
it had turned abruptly toward the surface and had been cut off by 
the plow. The root had become so small at this point and other 
roots were so numerous that we could not identify it with certainty. 
We attempted to follow other roots but we found it very difficult 
to do, owing to the presence of such a number of other roots and 
the smallness of the extreme ends. The greatest depth attained 
by those that we followed was two feet below the surface. All of 
the little roots that we encountered in this attempt seemed to be 
perfectly healthy even to the minute fibrous roots. Th greatest 
distance that we followed any root was 23 feet. There were only 
a very few fibrous roots as deep as 30 inches, almost all of them 
being within 24 inches of the surface. These roots which we dug 
out belonged to the trees which had been badly burned. Not only 
were the roots of the trees apparently healthy but the crowns and 
larger roots near the trunk were also apparently perfect. The 
owner suggested that we dig up one of these trees but as the root 
system seemed to be in such good condition I suggested that it 
would be better to let it and the rest of them stand till the next 
spring, 1910, and see whether they would recover or not. The 
trees were left standing, but they did not recover—they had already 
been killed. 
Wishing to dispel, if possible, all doubts in regard to the 
part played by the ground water in the death of these trees, we 
dug another hole near one of the trees just described. The or¬ 
chard had received a heavy irrigation on September 25, and the 
next few days following. The ditch, 120 feet east of where we 
dug this second hole, had stood full of water for three or more 
weeks in September. It had overflowed and formed a small pond 
at the edge of the orchard. The soil at the place where we dug 
this hole was sandy and we encountered the water plane at five and 
one-half feet, or two and three-quarters feet below the deepest roots 
that we observed. On May 14, 1910, four days after the orchard 
had been irrigated, I found the leaves on some trees burning. There 
seemed to be so good as no recovery from the injury of 1909. On 
June 11 the condition of this orchard was very bad indeed, and 
