Vol14 No.10: 1961-1968
【Title】Mixed signals in trends of variance in high-elevation tree ring chronologies
【Author】George P MALANSON
【Addresses】Department of Geographical & Sustainability Sciences, University of Iowa, Iowa City, IA 52242 USA
【Citation】Malanson GP (2017) Mixed signals in trends of variance in high-elevation tree ring chronologies. Journal of Mountain Science 14(10) . https://doi.org/10.1007/s11629-017-4425-9
【Abstract】Increases in climate variability, including extremes, may be expected with anthropogenic climate change, but some evidence is contrary. The issue is important because the consequences of variability can be critical for ecosystems. It has long been known and often rehearsed that ecological consequences of increased variability may be greater than those that result from expected changes in mean temperature and precipitation. Tree rings have been useful indicators of ecological response to climate change and used as proxies for climate variability; work in the Rocky Mountains, USA, has been particularly informative. Chronologies from two high elevation species ranging over 2500 km were analyzed for changes in variance through time. These spatially extensive and disaggregated tree ring records do not show a consistent pattern of change in variance over the past 500 or 100 years; heteroscedasticity has recently been greater. A lack of consistent response in growth over a period encompassing changes in mean climate indicates that mountain environments, with inconsistent trends in temperature and precipitation, may be too complex to act as sentinels.
【Keywords】Climate change; Variance; Pinus albicaulis; Pinus flexilis; Rocky Mountains