Forest response to cumulative disturbance and stress: Two decades of change in whitebark pine ecosystems of west-central British Columbia

Ecoscience ◽  
2014 ◽  
Vol 21 (2) ◽  
pp. 174-185 ◽  
Author(s):  
Alana J. Clason ◽  
S. Ellen Macdonald ◽  
Sybille Haeussler
1977 ◽  
Vol 14 (11) ◽  
pp. 2593-2600 ◽  
Author(s):  
J. A. Westgate

Three thin, light-coloured, ash-grade tephra beds occur within the uppermost metre of peat at Otter Creek bog in southern British Columbia. The youngest tephra is related to the ~2600 year old Bridge River tephra but is probably the product of a younger and weaker eruption that directed tephra to the southeast of the vent, believed to be located in the Meager Mountain district of southwestern British Columbia. The middle unit is ~2100 years old and is tentatively correlated with one of the upper beds of set P tephra of Mount St. Helens in Washington. The lowermost tephra is equivalent to the Yn bed of set Y, derived from an eruption of Mount St. Helens about 3400 years ago.The Yn tephra has been located as far north as Entwistle in west-central Alberta but mineralogically and chemically similar tephra elsewhere in this region is ~4300 years old and thus represents an older part of the Y set. Significant compositional differences between these two extensive members of the Y set have not yet been recognized.


2009 ◽  
Vol 121 (9-10) ◽  
pp. 1362-1380 ◽  
Author(s):  
J. Brian Mahoney ◽  
Sarah M. Gordee ◽  
James W. Haggart ◽  
Richard M. Friedman ◽  
Larry J. Diakow ◽  
...  

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.


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