Mortality, structure, and regeneration in whitebark pine stands impacted by mountain pine beetle in the southern Sierra Nevada

2016 ◽  
Vol 46 (4) ◽  
pp. 572-581 ◽  
Author(s):  
Marc D. Meyer ◽  
Beverly Bulaon ◽  
Martin MacKenzie ◽  
Hugh D. Safford
Keyword(s):  
Sierra Nevada ◽  
Mountain Pine Beetle ◽  
Large Diameter ◽  
Whitebark Pine ◽  
Tree Diameter ◽  
The Past ◽  
Mountain Pine ◽  
Pine Regeneration ◽  
Pine Beetle ◽  
Pine Stands

Whitebark pine (Pinus albicaulis Engelm.) is vulnerable to mountain pine beetle (Dendroctonus ponderosae Hopkins) attack throughout western North America, but beetle outbreaks in the southwestern portion of the range (i.e., Sierra Nevada) have been spatially limited until recently. We examined patterns of mortality, structure, and regeneration in whitebark pine stands impacted by mountain pine beetle in the southern Sierra Nevada. Mortality was greatest in medium to large diameter (>10–20 cm dbh) trees, resulting in declines in mean and maximum tree diameter and tree size class diversity following an outbreak. Severity of beetle attack was positively related to mean tree diameter and density. Density of young (<3 years old) whitebark pine seedling clusters was positively related to severity of beetle attack on mature stands. All sites showed a stable production of whitebark pine regeneration within at least the past 30–40 years, with a pulse of new seedlings in the past 3 years in beetle-impacted stands. Our results show that mountain pine beetle outbreaks in the southern Sierra Nevada result in substantial changes in whitebark pine stand structure and suggest low resistance but high resilience to initial attack, especially in the absence of white pine blister rust.

scholarly journals Whitebark and Foxtail Pine in Yosemite, Sequoia, and Kings Canyon National Parks: Initial Assessment of Stand Structure and Condition

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 35 ◽  
Author(s):  
Jonathan C.B. Nesmith ◽  
Micah Wright ◽  
Erik S. Jules ◽  
Shawn T. McKinney
Keyword(s):  
Sierra Nevada ◽  
National Parks ◽  
Mountain Pine Beetle ◽  
Whitebark Pine ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Blister Rust ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Foxtail Pine

The Inventory & Monitoring Division of the U.S. National Park Service conducts long-term monitoring to provide park managers information on the status and trends in biological and environmental attributes including white pines. White pines are foundational species in many subalpine ecosystems and are currently experiencing population declines. Here we present results on the status of whitebark and foxtail pine in the southern Sierra Nevada of California, an area understudied relative to other parts of their ranges. We selected random plot locations in Yosemite, Sequoia, and Kings Canyon national parks using an equal probability spatially-balanced approach. Tree- and plot-level data were collected on forest structure, composition, demography, cone production, crown mortality, and incidence of white pine blister rust and mountain pine beetle. We measured 7899 whitebark pine, 1112 foxtail pine, and 6085 other trees from 2012–2017. All factors for both species were spatially highly variable. Whitebark pine occurred in nearly-pure krummholz stands at or near treeline and as a minor component of mixed species forests. Ovulate cones were observed on 25% of whitebark pine and 69% of foxtail pine. Whitebark pine seedlings were recorded in 58% of plots, and foxtail pine seedlings in only 21% of plots. Crown mortality (8% in whitebark, 6% in foxtail) was low and significantly higher in 2017 compared to previous years. Less than 1% of whitebark and zero foxtail pine were infected with white pine blister rust and <1% of whitebark and foxtail pine displayed symptoms of mountain pine beetle attack. High elevation white pines in the southern Sierra Nevada are healthy compared to other portions of their range where population declines are significant and well documented. However, increasing white pine blister rust and mountain pine beetle occurrence, coupled with climate change projections, portend future declines for these species, underscoring the need for broad-scale collaborative monitoring.

Lodgepole pine regeneration in an old, self-perpetuating forest in south central Oregon

1989 ◽  
Vol 19 (9) ◽  
pp. 1096-1104 ◽  
Author(s):  
John D. Stuart ◽  
James K. Agee ◽  
Robert I. Gara
Keyword(s):  
Sierra Nevada ◽  
Mountain Pine Beetle ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
Disturbance Intensity ◽  
South Central ◽  
Mountain Pine ◽  
Pine Regeneration ◽  
Pine Beetle ◽  
Type Frequency

Historic regeneration patterns and regeneration requirements were investigated in an old, self-regenerating lodgepole pine (Pinusconforta Dougl. ssp. murrayana (Balf.) Critchfield) forest in south central Oregon. The forest was multiaged, with episodic regeneration pulses being correlated with mountain pine beetle (Dendroctonusponderosae Hopk.) outbreaks or fire. The magnitude of a regeneration pulse was a function of disturbance intensity. Tree ring indices show growth declines prior to mountain pine beetle outbreaks. Radial tree growth improved following disturbance. Differences in stand structure among climax lodgepole pine stands in the Rocky Mountains, Sierra Nevada, and south central Oregon were related to disturbance type, frequency, and intensity. Successful lodgepole pine reproduction was limited by soil moisture and partly by microclimate. Shading did not inhibit seedling establishment, but rather provided relief from excessive evapotranspiration, heat, and frost.

Patterns in whitebark pine regeneration and their relationships to biophysical site characteristics in southwest Montana, central Idaho, and Oregon, USA

2010 ◽  
Vol 40 (3) ◽  
pp. 476-487 ◽  
Author(s):  
Evan R. Larson ◽  
Kurt F. Kipfmueller
Keyword(s):  
Mountain Pine Beetle ◽  
Tree Mortality ◽  
Stand Age ◽  
Whitebark Pine ◽  
Seed Sources ◽  
Mountain Pine ◽  
Site Characteristics ◽  
Pine Regeneration ◽  
Pine Beetle ◽  
Nonparametric Correlation

Declines of whitebark pine ( Pinus albicaulis Engelm.) have occurred across much of the species’ range over the last 40 years due to mountain pine beetle outbreaks and white pine blister rust infection. Management efforts to stem these declines are increasing, yet the long-term success of whitebark pine depends on the species itself adapting to the modern environment. Natural regeneration will be a critical part of this process. We examined patterns in natural whitebark pine regeneration as related to the biophysical environment in sixty 0.1 ha plots in Montana, Idaho, and Oregon. Whitebark pine regeneration was present in 97% of our plots and varied widely in density from 0 to 17 000 seedlings/ha and 0 to 2680 saplings/ha. Using nonparametric correlation analysis and ordination techniques, we found whitebark pine regeneration abundance was unrelated to stand age but significantly related to several biophysical site characteristics, including positive relationships with elevation and canopy tree mortality caused by mountain pine beetle and negative relationships with moisture availability, temperature, and subalpine fir importance. Our findings indicate that whitebark pine is regenerating in many areas and that the widespread mortality from recent mountain pine beetle outbreaks may provide suitable settings for whitebark pine regeneration given sufficient seed sources.

scholarly journals Biological Aspects of Mountain Pine Beetle in Lodgepole Pine Stands of Different Densities in Colorado, USA

Forests ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
José Negrón
Keyword(s):  
Mountain Pine Beetle ◽  
Tree Mortality ◽  
Lodgepole Pine ◽  
Tree Size ◽  
Individual Tree ◽  
Tree Diameter ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Similarities And Differences ◽  
Pine Stands

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.

scholarly journals Landscape Topoedaphic Features Create Refugia from Drought and Insect Disturbance in a Lodgepole and Whitebark Pine Forest

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 715 ◽  
Author(s):  
Jennifer Cartwright
Keyword(s):  
Climate Change ◽  
Mountain Pine Beetle ◽  
Pine Forest ◽  
Boosted Regression Trees ◽  
Pine Forests ◽  
Whitebark Pine ◽  
Insect Outbreaks ◽  
Landscape Characteristics ◽  
Mountain Pine ◽  
Pine Beetle

Droughts and insect outbreaks are primary disturbance processes linking climate change to tree mortality in western North America. Refugia from these disturbances—locations where impacts are less severe relative to the surrounding landscape—may be priorities for conservation, restoration, and monitoring. In this study, hypotheses concerning physical and biological processes supporting refugia were investigated by modelling the landscape controls on disturbance refugia that were identified using remotely sensed vegetation indicators. Refugia were identified at 30-m resolution using anomalies of Landsat-derived Normalized Difference Moisture Index in lodgepole and whitebark pine forests in southern Oregon, USA, in 2001 (a single-year drought with no insect outbreak) and 2009 (during a multi-year drought and severe outbreak of mountain pine beetle). Landscape controls on refugia (topographic, soil, and forest characteristics) were modeled using boosted regression trees. Landscape characteristics better explained and predicted refugia locations in 2009, when forest impacts were greater, than in 2001. Refugia in lodgepole and whitebark pine forests were generally associated with topographically shaded slopes, convergent environments such as valleys, areas of relatively low soil bulk density, and in thinner forest stands. In whitebark pine forest, refugia were associated with riparian areas along headwater streams. Spatial patterns in evapotranspiration, snowmelt dynamics, soil water storage, and drought-tolerance and insect-resistance abilities may help create refugia from drought and mountain pine beetle. Identification of the landscape characteristics supporting refugia can help forest managers target conservation resources in an era of climate-change exacerbation of droughts and insect outbreaks.

scholarly journals Verbenone and Green-Leaf Volatiles Reduce Whitebark Pine Mortality in a Northern Range-Expanding Mountain Pine Beetle Outbreak

2021 ◽  
Author(s):  
Etienne Cardinal ◽  
Brenda Shepherd ◽  
Jodie Krakowski ◽  
Carl James Schwarz ◽  
John Stirrett-Wood
Keyword(s):  
Mountain Pine Beetle ◽  
Green Leaf Volatiles ◽  
Green Leaf ◽  
Whitebark Pine ◽  
White Pine Blister Rust ◽  
Leaf Volatiles ◽  
Disease Resistant ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Pine Trees

This is the first study testing effectiveness of semiochemical treatments to protect individual trees from a range-expanding mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins) attack into newly exposed host populations of endangered whitebark pine (Pinus albicaulis Engelmann). We investigated the effectiveness of a combination of verbenone and Green-Leaf Volatiles (GLV) to protect rare and valuable disease-resistant trees during a MPB epidemic from 2015 to 2018 in Jasper National Park, Canada. Treatments reduced the proportion of trees attacked by MPB for all diameter classes, across all stands, from 46 to 60%. We also evaluated the effect of the exotic disease white pine blister rust (caused by the fungus Cronartium ribicola J.C. Fisch), the species’ other main regional threat. MPB were less likely to attack large, rust infected trees than healthy trees, emphasizing the value of the semiochemical treatment. Protecting large, cone-bearing disease-resistant whitebark pine trees is fundamental to whitebark pine recovery. Maintaining reproductive trees on the landscape increases the frequency and diversity of rust-resistant genotypes more effectively than just planting seedlings to replace MPB-killed trees, because this slow-growing species takes over 80 years to reproduce. Our study confirmed protecting large rust-resistant trees with verbenone and GLV is a proactive and effective treatment against MPB for whitebark pine in naïve populations.

scholarly journals Whitebark pine mortality related to white pine blister rust, mountain pine beetle outbreak, and water availability

Ecosphere ◽  
2016 ◽  
Vol 7 (12) ◽  
Author(s):  
Erin Shanahan ◽  
Kathryn M. Irvine ◽  
David Thoma ◽  
Siri Wilmoth ◽  
Andrew Ray ◽  
...  
Keyword(s):  
Water Availability ◽  
Mountain Pine Beetle ◽  
Whitebark Pine ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Blister Rust ◽  
Mountain Pine ◽  
Pine Beetle

Species, elevation, and diameter affect whitebark pine and lodgepole pine stored resources in the sapwood and phloem: implications for bark beetle outbreaks

2014 ◽  
Vol 44 (11) ◽  
pp. 1312-1319 ◽  
Author(s):  
Eleanor C. Lahr ◽  
Anna Sala
Keyword(s):  
Nutritional Quality ◽  
Pinus Contorta ◽  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Large Diameter ◽  
Small Diameter ◽  
Whitebark Pine ◽  
Mountain Pine ◽  
Pine Trees ◽  
Lodgepole Pines

Stored resources in trees reflect physiological and environmental variables and affect life history traits, including growth, reproduction, resistance to abiotic stress, and defense. However, less attention has been paid to the fact that stored resources also determine tissue nutritional quality and may have direct consequences for the success of herbivores and pathogens. Here, we investigated whether stored resources differed between two hosts of the mountain pine beetle (Dendroctonus ponderosae Hopkins, 1902): lodgepole pine (Pinus contorta Douglas ex. Loudon), a common host, and whitebark pine (Pinus albicaulis Engelmann), a more naïve host that grows at higher altitudes. Phloem and sapwood were sampled in small- and large-diameter trees at two elevations, and nitrogen, phosphorus, nonstructural carbohydrates, and lipids were measured. We found that concentrations of stored resources increased with elevation and tree diameter for both species and that whitebark pine had thicker phloem than lodgepole pine. Overall, stored resources were higher in whitebark pine such that small-diameter whitebark pine trees often had resource concentrations higher than large-diameter lodgepole pines. These results suggest that whitebark pine is of higher nutritional quality than lodgepole pine, which could have implications for the current expansion of mountain pine beetles into higher altitude and latitude forests in response to climate warming.

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