Soils in Douglas-fir plantations in the Oregon Coast Range have high rates of methane uptake
Methane is a particularly potent greenhouse gas. Since the 1750s, the increase in methane in the atmosphere has contributed to about 20 percent of the enhanced greenhouse effect. Forest soils are both a source and a sink for the gas. Methane is a byproduct of chemical reactions occurring in very wet, anaerobic soil, but it is absorbed during different chemical reactions occurring in drier soils. Despite its potential to affect the Earth's climate, limited sampling has been done to determine the rates of exchange for soil uptake and production for several major ecosystems.
PNW scientists conducted the first study to report methane uptake rates by forest soil in the Pacific Northwest. Methane uptake was measured five times over a 13-month period from three Douglas-fir stands in the Coast Range of Oregon. Uptake was similar across the sites, and was high compared with most other coniferous forests globally. This is most likely due to the well-drained, highly porous, volcanic soils at the sites. The overall high rates suggest these forests offset methane emissions more than coniferous forests outside the region. This information on rates of methane uptake can be used in greenhouse gas accounting efforts.
Forest Service Partners