Susceptibility of lodgepole pine to infestation by mountain pine beetles following partial cutting of stands

1988 ◽  
Vol 18 (6) ◽  
pp. 688-695 ◽  
Author(s):  
Gene D. Amman ◽  
Mark D. McGregor ◽  
Richard F. Schmitz ◽  
Robert D. Oakes

Thinning stands of lodgepole pine (Pinuscontorta Douglas var. latifolia Engelmann) is thought to increase vigor and thereby reduce susceptibility to mountain pine beetle (Dendroctonusponderosae Hopkins). Partial cut stands of lodgepole in the Kootenai and Lolo National forests, Montana, U.S.A., provided opportunity (i) to determine growth response of 76- to 102-year-old lodgepole pines following thinning and (ii) to test the hypothesis that vigor of residual trees infested and uninfested by beetles does not differ. Lodgepole pine stands receiving different partial cutting prescriptions were sampled. Characteristics measured for trees within the sample were diameter at breast height, grams of stem wood per square metre of foliage, periodic growth ratio, and leaf area. Trees in most treatments showed decreased growth the 1st year following thinning. The 1st year was followed by increased growth during the next 4 years. Of the tree characteristics measured, only dbh was significantly different on both forests between live trees and trees killed by the mountain pine beetle; the latter were larger (P < 0.001). The low amount of mountain pine beetle infestation in all stands in the presence of poor growth response and vigor of residual trees suggests that factors other than tree vigor will regulate mountain pine beetle infestations in recently thinned lodgepole pine stands. We hypothesize change in stand microclimate is the principal factor.

1987 ◽  
Vol 17 (10) ◽  
pp. 1234-1239 ◽  
Author(s):  
Mark D. McGregor ◽  
Gene D. Amman ◽  
Richard F. Schmitz ◽  
Robert D. Oakes

Partial cutting prescriptions were applied in the fall of 1978 through the early winter of 1980 to lodgepole pine stands (Pinuscontorta Douglas var. latifolia Engelmann) threatened by mountain pine beetle (Dendroctonusponderosae Hopkins) in the Kootenai and Lolo National Forests in western Montana, U.S.A. Partial cutting prescriptions consisted of removing from separate stands all trees 17.8, 25,4, and 30.5 cm and larger diameter at breast height (dbh), and prescriptions leaving 18.4, 23.0, and 27.6 m2 basal area per hectare. In thinned stands, the first 5 years' results following cutting showed greatly reduced tree losses to mountain pine beetle when compared with untreated stands (P < 0.01) on both forests. There were no significant differences in tree losses among partial cut treatments (P > 0.05). Post treatment mortality of lodgepole pine 12.7 cm and larger dbh to mountain pine beetle averaged 4.0 to 38.6% on the Kootenai and 6.0 to 17.1% on the Lolo in treated stands, compared with averages of 93.8 and 73.1% in untreated stands. Partial cutting appears to be useful for reducing lodgepole losses to mountain pine beetle.


2020 ◽  
Vol 472 ◽  
pp. 118257
Author(s):  
Jennifer G. Klutsch ◽  
Gail Classens ◽  
Caroline Whitehouse ◽  
James F. Cahill ◽  
Nadir Erbilgin

1989 ◽  
Vol 19 (1) ◽  
pp. 65-68 ◽  
Author(s):  
B. S. Lindgren ◽  
J. H. Borden ◽  
G. H. Cushon ◽  
L. J. Chong ◽  
C. J. Higgins

The effect of the aggregation-inhibiting pheromone verbenone on mountain pine beetle attacks in lodgepole pine stands was assessed by affixing verbenone release devices on trees on a 10 × 10 m grid. In one experiment, aggregation to trees baited with an attractive combination of trans-verbenol, exo-brevicomin, and myrcene was reduced in verbenone-treated blocks compared with control blocks (attractive baits only). The mean number of trees with mass attacks (≥31.3 attacks/m2), mean percentage of available trees mass attacked, and mean total number of trees infested were reduced by 74.3, 66.7, and 58.5%, respectively. The ratio of 1987 attacks to 1986 attacks was reduced from 14.0 to 2.6. In a second experiment, using no attractive baits, verbenone caused similar but nonsignificant reductions. The mean number of trees with mass attacks, mean percentage of available trees mass attacked, and mean total number of trees infested were reduced by 75.2, 53.5, and 62.1%, respectively. The 1987 to 1986 attack ratio was reduced from 13.2 in control blocks to 0.2 in the verbenone-treated blocks, and the percentage of trees that were infested but not mass attacked was significantly increased, from 45.7% in the control blocks to 63.2% in the verbenone-treated blocks. We conclude that verbenone shows promise as a management tool for controlling the mountain pine beetle.


2021 ◽  
Vol 97 (01) ◽  
pp. 65-77
Author(s):  
W. Richard Dempster ◽  
Sharon Meredith

Changes in the structure and dynamics of lodgepole pine stands following the 2006 outbreak of mountain pine beetle in western Alberta were investigated by monitoring attacked permanent sample plots over the following decade and projecting future stand development with locally validated growth models. Results suggest that a wide range in growth and yield of attacked stands is likely, with projected impacts varying from minor and inconsequential modifications to full stand replacement. Severely disturbed stands are unlikely to naturally regenerate to pine. The degree to which timber production is naturally restored in such stands will depend to a large extent on the amount and composition of non-pine advance growth and regeneration. Variation in attack severity and tree species composition will, in the absence of clearcutting following disturbance, result in increased diversity in stand and forest structure. Recommendations are made for scheduling salvage and restoration operations to ameliorate losses in timber supply.


2008 ◽  
Vol 38 (11) ◽  
pp. 2826-2836 ◽  
Author(s):  
Gordon D. Nigh ◽  
Joseph A. Antos ◽  
Roberta Parish

Insect outbreaks, such as the current mountain pine beetle ( Dendroctonus ponderosae Hopkins) outbreak in lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests in British Columbia, are major disturbances in many forests. After an insect outbreak, the advance regeneration typically forms a new canopy, which may be adequate for timber objectives in some stands. Our purpose was to quantify and then model the abundance and spatial distribution of advance regeneration (trees <10.0 m tall). We sampled understory and overstory trees in 28 lodgepole pine stands in south-central British Columbia at two spatial scales: 0.1 ha plots and 25 m2 subplots. We developed models predicting advance regeneration abundance and spatial distribution. Density of advance regeneration averaged 2689 trees/ha (range 120 to 23 000 trees/ha), most of which were <1 m tall. Although advance regeneration was clumped, 75% of the subplots contained at least one individual. Models indicated negative relationships of advance regeneration abundance to overstory basal area and density. Over half the stands had enough advance regeneration to form new stands of adequate density, indicating that use of advance regeneration is a viable option in this mountain pine beetle outbreak and probably other insect disturbances.


1983 ◽  
Vol 13 (1) ◽  
pp. 137-144 ◽  
Author(s):  
D. M. Shrimpton ◽  
A. J. Thomson

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.


Forests ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
José Negrón

Research Highlights: The biology of mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, in Colorado’s lodgepole pine forests exhibits similarities and differences to other parts of its range. Brood emergence was not influenced by stand density nor related to tree diameter. The probability of individual tree attack is influenced by stocking and tree size. Findings have implications for understanding MPB as a disturbance agent and for developing management strategies. Background and Objectives: MPB causes extensive tree mortality of lodgepole pine, Pinus contorta Douglas ex Loudon, across the western US and Canada and is probably the most studied bark beetle in North America. However, most of the current knowledge on the biology and ecology of MPB in lodgepole pine comes from the Intermountain Region of the US and western Canada. Little information is available from Colorado. This is the first study addressing effects of stand stocking levels on the biology of MPB and quantifying phloem consumption. In addition, although data are available on the conditions that foster stand infestation, this is the first study estimating the probability of individual tree attack among stands of known different stocking. Materials and Methods: Studies were conducted in managed lodgepole pine stands in Colorado. Unbaited traps were used to monitor MPB flight across stands of different densities. Cages were used to monitor emergence and bark samples to determine attack densities, and phloem consumption in trees growing under different stocking. Beetle collections were used to determine emergence across the growing season. Tree mortality data from plots of different densities were used to examine the probability of individual tree infestation. Results: More beetles were caught flying through higher density stands. More attacks were observed in lower stocking stands but there were no differences in the number of insects emerging nor phloem consumption. There was no relationship between tree size and beetle emergence. Peak flight occurred in early to mid-August and only one peak of beetle emergence occurred. The probability of tree attack was influenced by stand stocking and tree diameter. Conclusions: In general, aspects of the biology of MPB in Colorado exhibit similarities and differences with other regions. The data suggest the need to more closely examine how MPB functions in stands of different stocking and how the distribution of tree sizes influence the probability of infestation and extent of mortality in stands. Biological characteristics of MPB in Colorado need further examination, particularly as climate change continues to manifest. Baseline information will be critical to refine management approaches, and extend the understanding of how MPB contributes to shape forest composition and structure in Colorado.


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