S \r.\L i:K PORTS 01- DEPARTMENT OF AGRICULTURE, 1949 
The highly successful results of this program have prompted Fed- 
eral and private Land-managing agencies to adopt this met hod of bark 
beetle control in treating Beveral hundred thousand acres of ponder- 
oea pine timberlands in northeastern California and eastern Oregon. 
Its use has brought tremendous savings to Landowners as compared 
with those obtained by previous methods, which dest royed beet le popu- 
lations only after damage and lo~~ to timber had occurred. 
[uteres! in preventing Losses caused by bark beetles in stands of 
ponderosa pint' has also been stimulated among Lumber companies in 
the northern Rocky Mountain-. One Large company practices a light 
selection cutting in all its Lumbering operations. From 30 to 50 
cent of the stand volume is removed, chiefly in t rees most Likely to he 
killed by heel les within the next 20 year-. Other Large com panic- are 
planning to do Likewise. Two permanent demonstration areas have 
been established in western Montana on public and private land-. 
where each t ree has been marked to indicate it- SUSCept ibility to attack 
by hark hectic-. These area- are heine; u-ed to demonstrate marking 
principle.- a.- an aid to company foresters in adapting the practi< 
their needs. 
Mountain Home Owners of Southern California Combal 
Hark Beetles 
In 1947 Ips and D> ndroctonus beetles invaded areas in the mountains 
of southern California where millions of dollars have been invested 
in resorts and summer-home developments. Hundreds of property 
owner- promptly organized to combat the epidemic During the win- 
ter and spring of 1947— lb private, county. State, and Federal agencies 
pooled (heir resources to carry out an eradication campaign under 
Bureau supervision in the area around the town of Julian in San Diego 
County. About i2.-_'o< > infested pine trees were treated, mostly by fell- 
ing and burning. This first effort brought about a reduction oi 60 to 
75 percent in the number of t ree- killed during the L9 I s season. Work 
was next concent rated on the surviving infest at ion. which overwintered 
in t ree- attacked in the fall of L948. Both burning and toxic oil treat- 
ment- were u-ed. All indicat ions in tin 1 spring <d* L9 19 were that this 
outbreak had been brought to an end. The project has also demon- 
strated the value of coopcrat ive community effort in dealing with hark 
heel le prohleins in areas where many -mad owner-hips are involvt 
■ I. 
ipa Infestations Affected l>y Climate 
'Hie frequent flare-up of Ips infestations in and around timber 
cuttings by small nulls since L945 has emphasized the need for better 
understanding of the ecological factors governing the abundance of 
these hark hectic-. Recent studies throughout the pine type- of Cali- 
fornia have brought to light much new information on thi- problem. 
I )uritiL r t he L948 season t here was a genera] subsidence of outbreaks 
in many areas, whereas the reverse was true in the season of L9 17. The 
climate during these 2 years showed striking differences. In WHI, 
when [pi populations were increasing, precipitation was well below 
normal, ~<>d most u re wa- below normal during most ^( the growing 
