Forests and climate change

Posted by Tom Knudson's Sierra Summit Blog

August 26, 2008

You won't find the Journal of Forestry for sale on your supermarket shelf, but if you care about trees, you might want to visit your library and check out its June 2008 edition.

There will find an article about climate change and forests by retired U.S. Forest Service chief Dale Bosworth and three other researchers, including Connie Millar, a research paleoecologist with the Sierra Nevada Research Center of the U.S. Forest Service.

With conifers already under climate stress in the Sierra Nevada and mortality rates on the rise, too - the article is nothing if not timely and sobering. And credible, too. The Journal of Forestry - the official publication of the Society of American Foresters - is the most widely circulated scholarly forestry journal in the world.

"Average temperatures in the Northern Hemisphere have reached their highest level in 400 years and probably in a 1,000 years," the authors point out, "and they continue to climb." But that is just the prelude. As the article states:

"If carbon dioxide levels double in the 21st century (a distinct possibility), they will reach the highest concentrations in the past 80 - 100 million years. When Earth last saw such high levels of atmospheric carbon - during the Cretaceous Period, when forests were dominated by tree ferns and palm-like cycads - it was a very different place."

"Climate change will likely be too rapid for today's forests to maintain their current structure, functions and composition, given the landscape impediments that people have created," the authors write. "Land managers will face a high and growing risk of loss of local species populations as well as widespread tree mortality and increased threats from ecological stressors such as wildfire, insects, diseases, air pollution and invasive species."

The title of the article is "Climate Change and the Nation's Forests: Challenges and Opportunities." One of the biggest opportunities, it points out, is finding ways to market the carbon that trees sequester naturally. Another hope, it says, is "facilitating the removal and use of excess forest biomass for biofuel and providing incentives to increase the area of biomass energy plantations."

"There is hope," the authors say in wrapping up their piece. "We can ... modify a broad range of forestry activities to reduce greenhouse gas emissions and increase carbon sequestration. However, implementing these modifications on a broad scale while continuing to produce forest goods and services will be a formidable challenge."