Support Long-term Thinking
Support Long-term Thinking

Bristlecone Pines Feeling Rushed

by Austin Brown on November 17th, 02009

Global warming seems to be speeding up the growth of the longest living organisms we know of.  Bristlecone pines can live for almost 5,000 years and the information stored in the growth of their rings is a treasure trove of climate data.  Because their growth is a function of the weather, analyzing the size of the rings they develop each year can tell us what that period’s climate was like.

At an elevation of 12,000 feet, where almost no rain falls, temperature is the driving influence on tree growth, while lower down, rainfall is the strongest factor in tree growth, Salzer said in an interview.

Matthew Salzer,  Malcolm K. Hughes and a team of dendrochronologists from the University of Arizona have just published a paper in which they explain that the outermost rings of Bristlecones – the most recent ones – tend to be significantly larger than most of the earlier ones.  In the last 50 years, the trees have been growing faster than they did in the previous 3,700.

Salzer has done work on Mt. Washington for his studies and shared data with Long Now.  The information from the trees on the future Clock site has provided Long Now with a helpful understanding of the area’s climate dating back several thousand years.

The current study is an indication that climate change is affecting these trees and the delicate ecosystems that support them.  This high-altitude temperature change has significance for more than the Bristlecones and the local environment, however.  The mountains this phenomenon is documented in are an important source of snowmelt for much of California and Nevada:

Hughes said that increasing temperatures high in the mountains could have significant effects elsewhere. In many areas of the western U.S., mountains are a key source of water for farms and urban areas at lower elevations.

“If the snow melts earlier, the mountains won’t be able to hold onto water for as long,” Hughes said. “They won’t be as effective as water towers for us.”