Palisadian. [volume] (Cliffside Park, N.J.) 1906-current, 1920-03-06

a
EG IT. to the annual report Of the
E1SI IN chief of the bureau of en-
E tomology, United States de-
partment of agriculture.
The report says of western field work:
"An especial investigation of the in
sect damage to crude spruce products
for airplane stock in the states of
Washington and Oregon showed that
the greater part If not all Of the dam
age could be prevented by proper
methods of logging and production.
with little or no additional cost.
EXHAUSTIVE studies of insect investi-
cation and control were continued in
the Sequoia and Yosemite national
parks. Much new information has been
gained, and the methods of gathering
and compiling feld data have been
standardized.
"A special study was completed on
the INTERPOLATION Of forest fires and
Insects on an area Of about 1000 acres
In southern Oregon. This area has been
under observation since 1914, and the
FIRE had burned over about 800 acres
In 1918. The records show that previ-
Gus to the fire the insects had killed
485, 900 board feet Of timber. The fire
killed 10000 feet, and subsequently
the slightly fire-injured as well as the
uninjured trees in the burned area
were killed by beetles, which were at
tracted from the surrounding areas.
1t was noticed that the infestation in
the burned area increased more than
1000 per cent, but it was found that
the infestation in the surrounding
areas decreased. It was also found that
the broods Of the beetles in the fire.
scorched trees failed to develop to
much beyond the original number that
attacked the trees. So the fire did not
contribute to an increase Of the beetles
In general area or to the starting
or extension of an epidemic of beetles.
This result is of extreme interest and
hardly to be expected.
1.-THE most careful study ever made
of the history of an epidemic infesta-
ton of tree-killing beetles was COM
pleted and report submitted during
the year. In the Rogue river area in
about $4,000 acres near Ashland, Ore,
the western pine beetle in 1914 caused
the death of $4,000 board feet Of pine
timber. In 1915, 1,615OOO board feet
were killed; 1,3S3,000 feet in 1916, and
$685. in 1917. A count of the young
and matured stages of the beetles that
developed in an average foot of bark,
and also of the number of exit holes
through which the beetles emerged to
attack other trees, showed that there
was a notable decrease in numbers
during the development of the broods
each year in the infested trees on ac-
count Of the increase of natural en-
emies and other disturbing factors.
This helps explain why these beetle
epdemics rise and fall within linn
tied period of years, and 1t explains
how the western forests of yellow
pine are naturally protected from total
destruction. These facts are especially
significant in connection with the ap-
plication of the percentage principle of
control, as by aiding the natural forces
crease and epidemic shows the impor-
lance of prompt recognition and
prompt treatment of a threatened out
break In order to prevent the great
loss of timber which would occur before
natural control became operative.
Another special study was made of
the number of all stages of the west
ern pine beetle in $50 square feet of
infested bark selected from 81 trees,
which represented an average infesta-
ton within an area of approximately
80 square miles. 1t was shown that
there is large percentage of mortal
ity between the young and matured
stages In the developing broods, but
that normally an average of about 40
beetles to the square foot of bark de-
veloped to the adult, or reproductive
stage, which would be $4,000 beetles