The Pioche record. [volume] (Pioche, Nev.) 1908-1925, 1920-03-05
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N S& chief of the bureau of en-
6@J tomology. United States de-
partment of agriculture
The report says of western field work
IAN 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 field data have been
standardized.
"A special study was completed on
the INTERROGATION of forest fires and
insects on an area of about 1000 acres
in southern Oregon. This area has been
under observation since l914. and the
fire had burned over ahont 500 acres
In 1918. The records show that previ-
Gus to the fire the insects had killed
$4,000 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
thu hrvr Oh lvHn hov
1000 per cent. but 1t was found that
the infestatiOn in the surrounding
areas decreased. 1t 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.
.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 100000 board feet of pine
timber. In 1915. 1.615.0OO board feet
were killed; 1888, 900 feet in 1916. and
60S.0OO 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 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 End other disturbing factors.
This relps explain why these beetle
epidemics rise and fall within lin
tied period Of years. and Il explains
how the western forests of yellow
Z pine are naturally protected from total
destruction. These facts are especially
significant in connection with the an
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 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 approximate,
36 square miles. II was shown Tim,
there Is large percentage Of mortal
ity between the young and maturec
stages In the developing broods, bu,
that normally IN average Of about IL
beetles to the square foot OF bark de
veloped to the adult, or reproductiv,
stage, which would be $4,000 beetles