scholarly journals A dendroecological assessment of whitebark pine in the Sawtooth–Salmon River region, Idaho

1996 ◽  
Vol 26 (12) ◽  
pp. 2123-2133 ◽  
Author(s):  
Dana L. Perkins ◽  
Thomas W. Swetnam

Whitebark pine (Pinusalbicaulis Engelm.) tree-ring chronologies of 700 to greater than 1000 years in length were developed for four sites in the Sawtooth–Salmon River region, central Idaho. These ring-width chronologies were used to (i) assess the dendrochronological characteristics of this species, (ii) detect annual mortality dates of whitebark pine attributed to a widespread mountain pine beetle (Dendroctonusponderosae Hopkins (Coleoptera: Scolytidae)) epidemic during the 1909–1940 period, and (iii) establish the response of whitebark pine ring-width growth to climate variables. Cross-dating of whitebark pine tree-ring patterns was verified. Ring-width indices had low mean sensitivity (0.123–0.174), typical of high-elevation conifers in western North America, and variable first-order autocorrelation (0.206–0.551). Mountain pine beetle caused mortality of dominant whitebark pine peaked in 1930 on all four sites. Response functions and correlation analyses with state divisional weather records indicate that above-average radial growth is positively correlated with winter and spring precipitation and inversely correlated with May temperature. These correlations appear to be a response to seasonal snowpack. Whitebark pine is a promising species for dendroclimatic studies.

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 715 ◽  
Author(s):  
Jennifer Cartwright

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.


Author(s):  
Etienne Cardinal ◽  
Brenda Shepherd ◽  
Jodie Krakowski ◽  
Carl James Schwarz ◽  
John Stirrett-Wood

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.


Ecosphere ◽  
2016 ◽  
Vol 7 (12) ◽  
Author(s):  
Erin Shanahan ◽  
Kathryn M. Irvine ◽  
David Thoma ◽  
Siri Wilmoth ◽  
Andrew Ray ◽  
...  

2020 ◽  
Vol 457 ◽  
pp. 117736
Author(s):  
Nickolas E. Kichas ◽  
Sharon M. Hood ◽  
Gregory T. Pederson ◽  
Richard G. Everett ◽  
David B. McWethy

2016 ◽  
Vol 26 (8) ◽  
pp. 2507-2524 ◽  
Author(s):  
Polly C. Buotte ◽  
Jeffrey A. Hicke ◽  
Haiganoush K. Preisler ◽  
John T. Abatzoglou ◽  
Kenneth F. Raffa ◽  
...  

2000 ◽  
Vol 30 (7) ◽  
pp. 1051-1059 ◽  
Author(s):  
Elizabeth M Campbell ◽  
Joseph A Antos

A major decline in the abundance of whitebark pine (Pinus albicaulis Engelm.) has recently occurred in the United States, primarily as a result of white pine blister rust (Cronartium ribicola J.C. Fisch. ex Raben.). However, no information on the status of whitebark pine in British Columbia, Canada, was available. We sampled 54 subalpine stands in British Columbia, examining all whitebark pine trees within plots for evidence of blister rust and mountain pine beetle (Dendroctonus ponderosae Hopk.) damage. About 21% of all whitebark pine stems were dead, and blister rust was the most important agent of mortality. Of all living trees sampled, 27% had obvious blister rust infection (cankers), but actual incidence was suspected of being as high as 44% (using all evidence of blister rust). Blister rust incidence and whitebark pine mortality were significantly related to differences in stand structure and the presence of Ribes spp., but relationships with local climate and site variables were absent or weak. The lack of strong relationships with climate suggests favourable conditions for the spread of the disease throughout most of British Columbia. Very little evidence of mountain pine beetle was found. Overall, the prospects for whitebark pine in British Columbia do not appear good; a large reduction in population levels seems imminent.


2016 ◽  
Vol 46 (4) ◽  
pp. 572-581 ◽  
Author(s):  
Marc D. Meyer ◽  
Beverly Bulaon ◽  
Martin MacKenzie ◽  
Hugh D. Safford

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.


2021 ◽  
Author(s):  
David Soderberg ◽  
Bethany Kyre ◽  
Pierliugi Bonello ◽  
Barbara Bentz

A key component in understanding plant-insect interactions is the nature of host defenses. Research on defense traits among Pinus species has focused on specialized metabolites and axial resin ducts, but the role of lignin in defense within diverse systems is unclear. We investigated lignin levels in the outer bark and phloem of P. longaeva , P. balfouriana , and P. flexilis ; high elevation species in the western United States known to differ in susceptibility to mountain pine beetle ( Dendroctonus ponderosae ; MPB). Relative to P. flexilis , P. longaeva and P. balfouriana are attacked by MPB less frequently, and MPB brood production in P. longaeva is limited. Because greater lignification of feeding tissues has been shown to provide defense against bark beetles in related genera, such as Picea , we hypothesized that P. longaeva and P. balfouriana would have greater lignin concentrations than P. flexilis . Contrary to expectations, we found that the more MPB-susceptible P. flexilis had greater phloem lignin levels than the less susceptible P. longaeva and P. balfouriana . No differences in outer bark lignin levels among the species were found. We conclude that lignification in Pinus phloem and outer bark is likely not adaptive as a physical defense against MPB.


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