Changes in white pine blister rust infection and mortality in limber pine over time

2013 ◽  
Vol 43 (10) ◽  
pp. 919-928 ◽  
Author(s):  
Cyndi M. Smith ◽  
David W. Langor ◽  
Colin Myrholm ◽  
Jim Weber ◽  
Cameron Gillies ◽  
...  

Limber pine (Pinus flexilis E. James) is under threat from white pine blister rust (WPBR), mountain pine beetle, drought, and fire suppression across its range in western North America. In 2003–2004, we established 85 plots to assess the mortality and incidence of WPBR on limber pine, and remeasured them in 2009. Infection was evident in 74% of the plots in 2003–2004 and 88% of the plots in 2009. The proportion of dead trees increased from 32% in 2003–2004 to 35% in 2009. The percentage of live trees infected increased from 33% in 2003–2004 to 43% in 2009. Mean live limber pine basal area in 2009 ranged from 0.03 to 77.8 m2/ha per plot. Twenty (24%) of the plots had no seedlings in the first measurement, but only 15% in the second measurement. Seedling infection was low (8% in 2003–2004 and 4% in 2009). In 12 plots that were measured three times, mortality increased from 30% of all trees in 1996 to 50% in 2003, then decreased to 46% in 2009. Infection decreased from 73% of live trees in 1996 to 46% in 2003, then increased to 66% in 2009. High mortality and infection levels suggest that the long-term persistence of many limber pine populations in the southern part of the study area are in jeopardy, and continued monitoring is needed to assist with management decisions.

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 595
Author(s):  
Christine Holtz ◽  
Anna Schoettle

Limber pine (Pinus flexilis James) co-evolved with the mountain pine beetle (Dendroctonus ponderosae Hopkins; MPB) and is now also challenged by the non-native pathogen Cronartium ribicola (J.C. Fisch.) that causes the lethal disease white pine blister rust (WPBR). Previous research suggests that trees infected with WPBR can be preferred hosts for MPB. Using resin duct traits associated with MPB resistance, we tested for a relationship between resistance to MPB and WPBR in limber pine, in the absence of either biological agent. These analyses will help evaluate if MPB historically may have contributed to natural selection for WPBR resistance in advance of WPBR invasion, and could help explain the unusually high frequency of the dominant Cr4 allele for complete resistance to WPBR in limber pine populations of the Southern Rocky Mountains. Resin duct production, density and relative duct area did not differ between healthy trees previously inferred to carry the dominant Cr4 allele and trees that lack it at 22 sites, though some duct traits varied with elevation. MPB resistance does not appear to have played an evolutionary role in contributing to the high frequency of Cr4 in naïve populations, however, MPB may affect the future evolution of resistance to WPBR in the pines where the two pests coincide and WPBR will affect forest recovery after MPB epidemics. MPB-WPBR interactions in a changing climate will affect the future trajectory of limber pine.


Ecosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Joan C. Dudney ◽  
Jonathan C. B. Nesmith ◽  
Matthew C. Cahill ◽  
Jennifer E. Cribbs ◽  
Dan M. Duriscoe ◽  
...  

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

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.


Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 595-595 ◽  
Author(s):  
D. W. Johnson ◽  
W. R. Jacobi

In June 1999, a survey was conducted north and west of Redfeather Lakes, CO (≈64 km northwest of Fort Collins) to determine the extent of white pine blister rust, caused by Cronartium ribicola. To date the disease has not been reported in Colorado on any of the known hosts. The survey was initiated after the disease was reported on limber pine, Pinus flexilis, in 1998. A total of 65 sections were traveled by driving passable roads within three townships in Larimer County in northern Colorado. Infected limber pines were observed in nine sections. Incidence of infected trees ranged from 3 to 50% of trees sampled. A minimum of 10 trees was sampled at each location. Where trees were more abundant, 40 trees were sampled. The highest incidence of blister rust was observed near the Colorado and Wyoming state line along Cherokee Park Road. Both main stem and branch cankers were observed. Cankers appeared to be 3 to 5 years old. Mortality of entire trees was not observed. Ribes spp. were observed in the vicinity of infected limber pines. However, no infection was noted on these alternate rust hosts. Infected trees were observed 18 km south of the Colorado and Wyoming state line. The southward spread of the disease into northern Colorado from infection sites in Wyoming appears to have proceeded slowly since reports of the disease in southern Wyoming during the 1970s (1). Blister rust has the potential to spread throughout the range of white pines in Colorado, which includes scattered populations of both limber and bristlecone pines, P. aristata, located along the Continental Divide from Wyoming to the Colorado and New Mexico state line. References: (1) D. B. Brown. Plant Dis. Rep. 62:905, 1978.


2016 ◽  
Vol 46 (9) ◽  
pp. 1173-1178 ◽  
Author(s):  
Richard A. Sniezko ◽  
Robert Danchok ◽  
Douglas P. Savin ◽  
Jun-Jun Liu ◽  
Angelia Kegley

Limber pine, Pinus flexilis E. James, a wide-ranging tree species in western North America, is highly susceptible to white pine blister rust (WPBR), caused by the non-native fungal pathogen Cronartium ribicola J.C. Fisch. The Canadian populations in particular have been heavily impacted, and in 2014, limber pine was designated endangered in Canada by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Little is known about genetic resistance to WPBR in limber pine, but major gene resistance (MGR) has been characterized in some populations in the United States. This study examines resistance in seedling families from 13 parent trees from British Columbia, Alberta, and Oregon, representing the northern- and northwestern-most populations. Most families were susceptible, with 100% of the seedlings cankered, but one family from Alberta segregated 1:1 for cankered and canker free. This is the first report of (a) MGR in Canada of any of the four species of five-needle pines native to Canada and (b) any resistance in limber pine in Canadian populations and is the northernmost known incidence of putative R-gene resistance in a natural stand of any five-needle pine species. Many of the Canadian selections were from stands with high incidence of WPBR infection, and their high susceptibility in this trial suggests that further infection and mortality is likely in the Canadian populations.


2007 ◽  
Vol 42 (3) ◽  
pp. 345-353 ◽  
Author(s):  
Diana L. Six ◽  
Joel Adams

We investigated whether white pine blister rust (Cronartium ribicola) (J.C. Fischer in Rabenh.) severity, tree diameter at breast height (DBH), bark and phloem thickness, and sapwood moisture content influence the preference of the mountain pine beetle (Dendroctonus ponderosae Hopkins) for individual trees of whitebark (Pinus albicaulis Engelm.) and lodgepole pine (P. contorta Loud.). We measured these variables at 5 sites in Montana and Idaho and found a significant relationship between blister rust severity and attack of trees by D. ponderosae, with trees exhibiting greater blister rust severity being more likely to be attacked by the beetle. Sapwood moisture content was negatively correlated (P = 0.0004) with blister rust severity indicating that as severity increases there is an increasingly negative effect on water relations within the tree. Sapwood moisture content was significantly lower in P. albicaulis than in P. contorta at sites with beetle activity suggesting that there may be an interaction between blister rust severity and drought stress that, in turn, may affect beetle preference. DBH and bark and phloem thickness did not appear to influence beetle preference for individual trees. As blister rust spreads in P. albicaulis stands across the western U.S., this may translate to increasing levels of beetle-caused mortality in these areas.


2002 ◽  
Vol 32 (7) ◽  
pp. 1265-1274 ◽  
Author(s):  
Stefan Zeglen

A survey of the health of whitebark pine (Pinus albicaulis Engelm.) was conducted throughout its range in British Columbia, Canada. Over 3 years, 24 070 trees were examined for mortality, incidence of white pine blister rust (Cronartium ribicola J.C. Fisch.), or other damage. About 19% of whitebark pine (>1.3 m in height) were dead, and another 31% had active blister rust infections. Tests of relationships between the proportion of healthy, infected, or dead trees and elevation, latitude, and longitude produced mixed results. The ratio of healthy to infected whitebark pine varies considerably across the province, with a trend of increasing incidence from west to east. Losses to mountain pine beetle (Dendroctonus ponderosae Hopkins) proved minor, but bark stripping by mammals was common. Whitebark pine seedlings (<1.3 m in height) revealed lower rates of mortality (11%) and rust infection (4%) than larger trees. However, the pioneer species whitebark pine was found in less than half the regeneration plots and was usually outnumbered by subalpine fir (Abies lasiocarpa (Hook.) Nutt.). The combination of mature tree mortality, lack of suitable substrate for regeneration, and the incursion of climax species indicates a continued decline in whitebark pine populations in British Columbia.


Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 35 ◽  
Author(s):  
Jonathan C.B. Nesmith ◽  
Micah Wright ◽  
Erik S. Jules ◽  
Shawn T. McKinney

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.


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