Global ChangeIntersection of Nature and Culture

Earth’s oldest organisms reacting to climate warming

Monday, November 16th, 2009

Imagine being a tree growing incredibly slowly for the last 4,600 years and then suddenly experiencing a significant growth spurt in the last half century.

In this week’s early edition of the Proceedings of National Academy of Sciences (open access), Matthew Salzer and colleagues report that several stands of bristlecone pines growing at treeline in California have experienced such a jump.

The growth of trees at high elevation is often limited by temperature.  There has been debate among plant physiological ecologists as to why this is the case.  It appears that tissue formation is limited in this species by very cold conditions. By warming up climate, trees are able to create wider growth rings. The result is faster growth and a great paleothermometer to help us further document the significance of modern climate warming.

The researchers also factored out possible effects of precipitation and CO₂ fertilization, indicating that the growth increase, unprecedented over the past several millennia, is likely caused by temperature.

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Photo credit:  http://www.flickr.com/photos/mariozama/ / CC BY-NC-ND 2.0