Earthsky Interviews
Private: Sierra Treeline
September 2, 2002 - Biodiversity
_DB:_ Andy Bunn is a PhD candidate at Montana State University. He suspects that treelines around the world will expand up mountain slopes in response to global warming. He’s studying treelines in Sequoia and Yellowstone National Parks.
_Andy Bunn:_ So we use alpine treeline as a bellweather – as as an early warning system – of global climate and try to understand if treeline is responding – is treeline ebbing and flowing right now in response to climate warming?
_JB:_ The difficult task of monitoring a mountain range’s entire treeline is made easier by using computer models and satellite data to identify trees that are most likely to react to climate shifts.
_Andy Bunn:_ Once we find those areas that fit our requirements of being climate sensitive we can actually go in there and start looking at the growth rates – the growth rings of trees. We can start looking for germination of seedlings and we can start looking for these areas where there’s dead wood rooted above the current treeline …
_DB:_ Bunn hopes these studies will help determine how forests may change in the coming century. For more, come to today’s show on the web at earthsky.org. Special thanks to Andy Bunn in Montana and to “NASA”:http://www.nasa.gov/’s Earth Science Enterprise. I’m Deborah Byrd, with Joel Block, for Earth and Sky.
Link:
“Sierran Treeline Dynamics in a Changing Climate”:http://www.yosemite.org/naturenotes/Treeline1.htm (Yosemite Association)
Author’s Notes:
The importance of changing treelines is important for several reasons. Perhaps most importantly, it may act as a guage, or speedometer of global warming. The extent and rate of encroachment of forest upslope can show scientists the strength of climate shift associated with global warming. This may be cruicial as the Earth experiences what many scientists predict will be significant changes in the global climate system during the next century.
Second, scientists are eager to determine how global change may affect the various forest ecosystems. If pine forests expand as a result of global warming, they could encroach on ecosystems above the treeline and into alpine meadows. Alpine meadows which are populated by grasses, flowers and forbes and sustain many insect, bird and small mammal species – are highly valued both as wildlife habitat and for as aesthetic value enjoyed by visitors to national parks. In a globally-warmer future there is a chance that these meadows will start filling in with trees, just as may happen to the upper treeline tundra habitat
The following individuals were interviewed for today’s show. Our thanks to:
Andrew G. Bunn
Ph.D. Candidate
Department of Land Resources and Environmental Science
Montana State University
Bozeman, MT
Lisa J. Graumlich
Executive Director, Big Sky Institute for Science and Natural History
Professor, Land Resources and Environmental Sciences
Montana State University
Bozeman MT