Apr 1, 2012

Forest mortality in high-elevation whitebark pine (Pinus albicaulis) forests of eastern California, USA; influence of environmental context, bark beetles, climatic water deficit, and warming

Millar, Constance I., Westfall, Robert D., Delany, Diane L., Bokach, Matthew J., Flint, Alan L., and Flint, Lorraine E.
Canadian Journal of Forest Research
  • States whitebark pine (Pinus albicaulis Engelm.) in subalpine zones of eastern California experienced significant mortality from 2007 to 2010
  • States dying stands were dense (mean basal area 47.5 m2/ha), young (mean 176 years), and even-age; mean stand mortality was 70%
  • States stands were at low elevations (mean 2993 m), on northerly aspects, and experienced warmer, drier climates relative to the regional species distribution. States white pine blister rust was not observed; mountain pine beetle infestations were extensive
  • States ring widths were negatively correlated with climatic water deficit and positively correlated with water-year precipitation.
  • Finds that although trees that survived had greater growth during the 20th century than trees that died, in the 19th century trees that eventually died grew better than trees that survived, suggesting selection for genetic adaptation to current climates as a result of differential tree mortality
  • States that air surveys (2006–2010) in the Sierra Nevada, Mt. Shasta, and Warner Mountains showed similar trends to the intensive studies
  • States that observed mortality from air surveys was highest in the Warner Mountains (38%) and lowest in the Sierra Nevada (5%); northern aspects at lower elevations within each mountain region had the highest probabilities of mortality and dying stands had higher climatic water deficit