Mountain pine beetle infestations have increased in second-growth ponderosa pine stands in the Garnet Mountains since 1971. The extremely dry 1973 season resulted in an increase of Ips engraver beetle activity that was responsible for over half of the tree mortality in 1973. Commercial thinning is recommended to alleviate the...
The mountain pine beetle reached epidemic levels in second-growth 80-yearold ponderosa pine stands on the Ninemile Ranger District in 1969. The
outbreak increased through 1971 and spread over 30,000 acres. Heavy
infestation occurred on about 2,600 acres within this area. A two-stage
survey was used during 1972 and 1973 to...
Mountain pine beetle infestations have continued at epidemic level in
lodgepole pine stands since 1969 in the West Gallatin River drainage.
This infestation has increased at about a 1.9:1 buildup ratio annually.
Since the outbreak began in 1969, surveys indicate that approximately 22,354 merchantable size trees have been killed with...
A mountain pine beetle infestation has been active in the St. Regis area since 1964. Heaviest tree mortality occurred during the period 1969-70. The infestation has continued to decline since 1970. Over 2 million board feet of lodgepole and ponderosa pine were killed during the outbreak. Overstocking resulted in slow...
The mountain pine beetle, Dendroetonus ponderosae Hopk., has been at epidemic levels in second-growth ponderosa pine stands in the Ninemile area of the Lolo National Forest and surrounding private lands since 1969. An impact survey, using two levels of photography and a small ground sample, was conducted to estimate a...
This report includes information obtained in both 1983 and 1984. Beginning in 1983, only four of the original six permanent plot locations in the State would be revisited. The two in the southwestern part of the State--Centennial Valley and Madison River--were not visited because of reduced beetle populations and 111.1...
For the fourth year since their establishment, the six permanent plot locations in Montana were revisited following beetle flight in 1982.Beetle populations remained low in five of the six areas. Only in the Murr Creek plots did newly attacked trees represent an epidemic beetle population. In the Centennial Valley location,...