一份報(bào)告說,，20世紀(jì)溫度的上升可能在全世界的一種最古老的樹的近來空前的生長(zhǎng)中起到了作用,。Matthew Salzer及其同事說,，狐尾松自很可能從1950年開始在其生長(zhǎng)線的邊緣加速生長(zhǎng),。狐尾松在美國西部干燥,、風(fēng)吹的高海拔山坡上能生存數(shù)千年,。
這組科學(xué)家說,，盡管在山上高海拔地區(qū)的這種松樹的年生長(zhǎng)受到寒冷溫度的限制，在低海拔地區(qū)的這種樹的生長(zhǎng)通常受到水氣的限制,。這組作者發(fā)現(xiàn)在生長(zhǎng)線約150米內(nèi)的這種樹從1951年到2000年期間的年輪比此前的3700年更寬,。這組作者說，生長(zhǎng)率的這種差異可能是把20世紀(jì)晚期變暖的溫度與高海拔生態(tài)系統(tǒng)不尋常的行為聯(lián)系起來的又一件證據(jù),。（生物谷Bioon.com）
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生物谷推薦原始出處：
PNAS November 16, 2009, doi: 10.1073/pnas.0903029106
Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes
Matthew W. Salzera,1, Malcolm K. Hughesa, Andrew G. Bunnb and Kurt F. Kipfmuellerc
aLaboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721;
bDepartment of Environmental Sciences, Western Washington University, Bellingham, WA 98225; and
cDepartment of Geography, University of Minnesota, Minneapolis, MN 55455
Great Basin bristlecone pine (Pinus longaeva) at 3 sites in western North America near the upper elevation limit of tree growth showed ring growth in the second half of the 20th century that was greater than during any other 50-year period in the last 3,700 years. The accelerated growth is suggestive of an environmental change unprecedented in millennia. The high growth is not overestimated because of standardization techniques, and it is unlikely that it is a result of a change in tree growth form or that it is predominantly caused by CO2 fertilization. The growth surge has occurred only in a limited elevational band within ≈150 m of upper treeline, regardless of treeline elevation. Both an independent proxy record of temperature and high-elevation meteorological temperature data are positively and significantly correlated with upper-treeline ring width both before and during the high-growth interval. Increasing temperature at high elevations is likely a prominent factor in the modern unprecedented level of growth for Pinus longaeva at these sites.
