Weather associated with the start of mountain pine beetle outbreaks

Extreme weather conditions associated with mountain pine beetle outbreaks were evaluated by graphical techniques for six locations throughout British Columbia. Three major associations of extreme weather patterns with lodgepole pine growth and mountain pine beetle outbreaks were identified. (i) Weather effects prior to, or early in, the growing season can reduce growth without releasing the beetle population. (ii) Weather conducive to beetle establishment and early brood development can occur too late in the season to have a noticeable effect on tree growth and therefore will not be recorded in the annual growth rings. (iii) Warm, dry periods during the summer are associated with tree growth reduction and the beginnings of outbreaks. In each of these three cases, extreme low precipitation levels were involved. Average precipitation in some months did not compensate for the effects of unfavourable extremes in other months on tree growth.

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Growth characteristics of lodgepole pine associated with the start of mountain pine beetle outbreaks

Canadian Journal of Forest Research ◽

10.1139/x83-020 ◽

1983 ◽

Vol 13 (1) ◽

pp. 137-144 ◽

Cited By ~ 11

Author(s):

D. M. Shrimpton ◽

A. J. Thomson

Keyword(s):

Tree Growth ◽

Mountain Pine Beetle ◽

Cost Effective ◽

Annual Increment ◽

Growth Ratio ◽

Stand Growth ◽

Mountain Pine ◽

Periodic Growth ◽

Pine Beetle ◽

Mean Annual Increment

The dynamics of tree and stand growth were studied in six small but expanding mountain pine beetle outbreaks in British Columbia. Stands had exceeded a previously reported hazard threshold of age 80 years by 26 years, and a second frequently used hazard threshold of 20.5 cm mean dbh was exceeded by 37 years. However, stands had exceeded maturity, as defined by the intersection of current annual increment (CAI) and mean annual increment (MAI), by an average of only 17 years. In all cases, the beginnings of the outbreaks were coincident with a period of reduced tree growth. This reduced tree growth was difficult to detect at breast height, with a consequent failure of the periodic growth ratio to indicate susceptibility. Although the stands were past the point of maturity, the dominant and codominant trees continued to add significant wood volume, which could make surveillance for incipient outbreaks and subsequent control actions cost effective.

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Biology of the Mountain Pine Beetle, Dendroctonus monticolae Hopkins, in the East Kootenay Region of British Columbia.: III. Interaction between the Beetle and its Host, with Emphasis on Brood Mortality and Survival

The Canadian Entomologist ◽

10.4039/ent95225-3 ◽

1963 ◽

Vol 95 (3) ◽

pp. 225-238 ◽

Cited By ~ 76

Author(s):

R. W. Reid

Keyword(s):

Mountain Pine Beetle ◽

Weather Conditions ◽

Tree Diameter ◽

Brood Survival ◽

Lethal Temperatures ◽

Mountain Pine ◽

Subcortical Region ◽

Pine Beetle ◽

The Relationship ◽

Lower Stem

AbstractStudies were made on the distribution and survival of the mountain pine beetle over the lower stem of lodgepole pine. The relationship between density of attack and subsequent total length of egg galleries was examined as was the relationship between number of exit holes and number of emerging beetles. The influence on brood survival of tree diameter, density of egg galleries, moisture content of the outer sapwood, lethal temperatures, resinosis in the subcortical region, predators, and parasites is described. Survival is compared between broods established during different flights in the same year. The optimum weather conditions for brood survival are discussed.

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