1. Carbon dioxide, methane, and nitrous oxide exchanges in an age-sequence of temperate pine forests.
- Author
-
PEICHL, MATTHIAS, ARAIN, M. ALTAF, ULLAH, SAMI, and MOORE, TIM R.
- Subjects
GREENHOUSE effect ,GLOBAL warming ,CARBON dioxide ,METHANE ,IRRIGATED soils ,SOIL moisture ,CARBON in soils ,WHITE pine ,AFFORESTATION ,CONIFERS - Abstract
We investigated soil carbon dioxide (CO
2 ), methane (CH4 ), and nitrous oxide (N2 O) exchanges in an age-sequence (4, 17, 32, 67 years old) of eastern white pine ( Pinus strobus L.) forests in southern Ontario, Canada, for the period of mid-April to mid-December in 2006 and 2007. For both CH4 and N2 O, we observed uptake and emission ranging from −160 to 245 μg CH4 m−2 h−1 and −52 to 21 μg N2 O m−2 h−1 , respectively (negative values indicate uptake). Mean fluxes from mid-April to mid-December across the 4, 17, 32, 67 years old stands were similar for CO2 fluxes (259, 246, 220, and 250 mg CO2 m−2 h−1 , respectively), without pattern for N2 O fluxes (−3.7, 1.5, −2.2, and −7.6 μg N2 O m−2 h−1 , respectively), whereas the uptake rates of CH4 increased with stand age (6.4, −7.9, −10.8, and −23.3 μg CH4 m−2 h−1 , respectively). For the same period, the combined contribution of CH4 and N2 O exchanges to the global warming potential (GWP) calculated from net ecosystem exchange of CO2 and aggregated soil exchanges of CH4 and N2 O was on average 4%, <1%, <1%, and 2% for the 4, 17, 32, 67 years old stand, respectively. Soil CO2 fluxes correlated positively with soil temperature but had no relationship with soil moisture. We found no control of soil temperature or soil moisture on CH4 and N2 O fluxes, but CH4 emission was observed following summer rainfall events. LFH layer removal reduced CO2 emissions by 43%, increased CH4 uptake during dry and warm soil conditions by more than twofold, but did not affect N2 O flux. We suggest that significant alternating sink and source potentials for both CH4 and N2 O may occur in N- and soil water-limited forest ecosystems, which constitute a large portion of forest cover in temperate areas. [ABSTRACT FROM AUTHOR]- Published
- 2010
- Full Text
- View/download PDF