Mountain pine beetles (MPB) are a major destructive force of western forests. This study would say the destruction of these beetles is equal to if not greater than wildfires. The story of MPBs could be made into a film noir. It has sex, murder, fights, incest, parasitism, infidelity, necrophilous (eating the dead), cannibalism, and predation. The metropolis of organisms living with the bark beetles includes mites, nematodes fungi, yeasts, and bacteria and other organisms that help the beetles kill trees. Chemicals, electrocution, heating, burning, tree-cutting, and numerous other methods have failed to control the beetles. Mountain pine beetles organize their attacks through smell, touch, sound, sight, and taste. People study them, try to control them, are amazed by their vast destruction and as such, this has been a story in the making for over 115 years in the Black Hills. Scientists have put together this story in a new publication.
In the Black Hills 39 plots with a variety of tree densities were established for various studies. In 1985, mountain pine beetles began attacking some of the plots and major tree mortality commenced in several of them in 1987. Trees on most of the plots experienced extreme MPB pressure and of these, the only ones to have surviving trees had densities less 80 square feet of basal area per acre.
Mountain pine beetles, their associated organisms, the forest conditions, climate, geographical setting, and all of their interactions contribute to a very complex and destructive forest disturbance that is poorly understood.
115 years of direct control of MPBs has failed to alter their destruction.
Stands and landscapes within the Black Hills with tree densities ranging from 40 to 80 square feet of basal area per acre showed considerable resistance to MPBs.
This publication chronicles the understanding, controlling, and impacts of mountain pine beetles (MPB) central to the Black Hills of South Dakota and Wyoming from the time they were described by Hopkins in 1902, through the presentation of data from work started by Schmid and Mata in 1985. The plots established by these two men from 1985 through 1994 were subjected to the most intense MPB stress to occur since 1900 in the Black Hills.
The differentiation of western bark beetle species is discussed and how the final species designations of MPBs and western pine beetles (WPB) came about. The life cycle of MPBs is described and how it was used to develop direct control strategies. Bark beetles carry from tree to tree with them a suite of mites, fungi, nematodes, bacteria, and other organisms that can be both antagonistic and beneficial to the bark beetle and several of these contribute to the death of the tree. The direct control efforts of peeling, burning, harvesting, and spraying trees with chemicals to kill WPBs and MPBs are described.
Both Crater Lake and the Back Hills experiences to directly control MPBs are discussed. Millions of dollars were spent to directly control both species of bark beetles were futile and indirect methods of tree and stand treatments were tried. In the Black Hills, Schmid and Mata established 46 MPB study plots, of which 39 were useable, beginning in 1985 with tree densities ranging from 44 feet2 of basal area per acre to 199 feet2 per acre. MPB-caused tree mortality commenced on some of the plots in 1985 and maximum tree densities occurring on the plots ranged from 75 feet2 of basal area per acre to 217 feet2.
During this time MPB populations within the Hills expanded and the fate of the trees on each plot is shown. Plots with densities over 150 feet2 of basal area per acre experienced major mortality as early as 1987 and all of the plots with densities of 90 feet2 of basal area per acre or greater experienced major mortality by 2010. Stands and landscapes within the Black Hills with tree densities ranging from 40 to 80 feet2 of basal area per acre showed considerable resistance to MPBs.
Most likely these outcomes were related to the disruption of pheromone plumes facilitated by the open canopy conditions. However, there were exceptions to these findings currently and historically and they are discussed.
This publication strives to synthesize a large portion of the information produced in the last 115 years on MPBs and provide this context for informing, planning, and executing forest treatments to produce MPB resilient forests. In addition, it tells an intriguing and fascinating story about bark beetles and the people who tried to understand and control them.
Amman, Gene D.; Cole, Walter E. 1983. Mountain pine beetle dynamics in lodgepole pine forests. Part II: Population dynamics. Gen. Tech. Rep. INT-145. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 59 p.
Miller, J. M.; Keen, F. P. 1960. Biology and control of the Western pine beetle (Dendroctonus brevicomis): a summary of the first fifty years of research. Misc. Publ. 800. Washington, DC: U.S. Department of Agriculture, Forest Service. 381 p.