22 ANNUAL REPORTS OF DEPARTMENT OF AGRICUI/TUBE. 1939 
- of deteri< lue to poor e and in] i rtain 
forms of insect activity. It is consi< ered that tl such 
i g :i breeding ground for endemic western pine beetle ba- 
it ions vi bich at t im< - develop ini I . ajging 
of trees infested with Di ndra - a combined control and 
salvage measure has been tried at various times during tJ e ecade 
by private I iml er-holdin j . Some control 
has been secured by the operat ions, but values of the Balvaged material 
were seriously affected by degrade due to rapid development of blue 
stain- in the logs following attacks by the beet les. 
Results of the salvage projects led to the theory that logging highly 
susceptible but living trees before they could be infested by D( ndroc- 
tonus beetles would be more effective both for control and sa] 
This method offers two decided advantages over logging only inf< 
tree-: (1) The lumber product would not be blue-stained, and (2) those 
trees in which beetle populations breed up would be removed, and an 
indirect control effect would be secured against further outbreak.-. 
In 1939 the California Forest and Range Experiment Station initiated 
logging of high-risk trees on it- experimental forest of L0,000 acres in 
the La— en National Forest. This operation was planned a- an ade- 
quate test of the foregoing theory. In the spring of L939 on,- of the 
larger lumber companies, acting on information supplied by the 
Bureau of Entomology and Plant Quarantine, followed .-nit. Plans 
of the company have been based on detailed information regarding 
those areas where high insect hazards exist and on estimates of the 
volume of high-risk trees that should be removed. 
Both these logging projects are being followed with detailed studies 
to check on their control efficiency. Plot^ have been established in 
both treated and untreated areas, which will be observed for a period 
of years to determine the effect of the logging upon subsequent beetle 
infestation. These plot studies will show what trees die. what rela- 
tive losses occur on treated and untreated areas, what types of trees 
should be removed, and what types of trees will be most likely to 
survive if left in the vv^vv^ stand. The operation of the private 
company will be more extensive than that on the experimental forest 
and will provide reliable cost data. Only the best of modern cater- 
pillar and truck logging equipment will be used, and experienced 
woods laborers will be employed. The company plans to follow log 
grades of high-risk material through the mill and will make a com- 
parison of the yield of values from this material with that from 
simihir stands logged by the usual methods of cutting. 
MOUNTAIN PINE Hi ET] E 
Present method- of reducing outbreak- <»f the mountain pine beetle 
in lodgepole pine involve the use of fire. This practice is in many 
instances destructive and entails considerable expense in combating 
those fires which inevitably get out of control. To avoid the da 
dated with the use oi >.« been necessary t<» conduct control 
projects m n seasoii of the year when -uch operations are most ex- 
pensive. To eliminate this objection to an otherwise satisfactory 
method of control, experiments have been conducted to develop a 
spia\ which, when applied to the bark of standing infested lodge- 
pole pine, would penetrate the bark and destroy the overwintering 
