HR: 0830h
AN: B51D-1001    [PDF]
TI: Carbon and Water Exchanges in a Chronosequence of Temperate White Pine Forest
AU: * Arain, M
EM: arainm@mcmaster.ca
AF: McMaster University, School of Geography and Geology, 1280 Main Street West, Room BSB-317, Hamilton, ON L8S4K1 Canada
AU: Restrepo, N
EM: restren@mcmaster.ca
AF: McMaster University, School of Geography and Geology, 1280 Main Street West, Room BSB-317, Hamilton, ON L8S4K1 Canada
AU: Pejam, M
EM: pejammr@mcmaster.ca
AF: McMaster University, School of Geography and Geology, 1280 Main Street West, Room BSB-317, Hamilton, ON L8S4K1 Canada
AU: Khomik, M
EM: khomikm@mcmater.ca
AF: McMaster University, School of Geography and Geology, 1280 Main Street West, Room BSB-317, Hamilton, ON L8S4K1 Canada
AB: Quantification of carbon sink or source strengths of temperate forest ecosystems, growing in northern mid-latitudes, is essential to resolve uncertainties in carbon balance of the world's terrestrial ecosystems. Long-term flux measurements are needed to quantify seasonal and annual variability of carbon and water exchanges from these ecosystems and to relate the variability to environmental and physiological factors. Such long-term measurements are of particular interest for different stand developmental stages. An understanding of environmental control factors is necessary to improve predictive capabilities of terrestrial carbon and water cycles. A long-term year-round measurement program has been initiated to observe energy, water vapour, and carbon dioxide fluxes in a chronosequence of white pine (Pinus Strobus) forests in southeastern Canada. White pine is an important species in the North American landscape because of its ability to adapt to dry environments. White pine efficiently grows on coarse and sandy soils, where other deciduous and conifer species cannot survive. Generally, it is the first woody species to flourish after disturbances such as fire and clearing. The climate at the study site is temperate, with a mean annual temperature of 8 degree C and a mean annual precipitation of about 800 mm. The growing season is one of the longest in Canada, with at least 150 frost-free days. Measurements at the site began in June 2002 and are continuing at present. Flux measurements at the 60 year old stand are being made using a close-path eddy covariance (EC) system, while fluxes at the three younger stands (30, 15 and 1 year old) are being measured over 10 to 20 day periods using a roving open-path EC system Soil respiration is being measured every 2-weeks across 50-m transects at all four sites using a mobile chamber system (LI-COR 6400). The mature stand was a sink of carbon with annual NEP value of 140 g C m-2 from June 2002 to May 2003. Gross ecosystem productivity (GEP) and ecosystem respiration (R) for 2002-03 were 1290 and 1150 g C m-2, respectively. A processed-based carbon simulation model was created by incorporating canopy physiology (photosynthesis - sunlit and shaded leaf, conductance), plant phenology (leaf out, senescence), and carbon balance (plant and soil respiration, ecosystem productivity) algorithms in the Canadian Land Surface Scheme. In this study, we compare observed and simulated energy, water vapour, and carbon dioxide fluxes of the mature stand with those of the younger stands. This comparison will help to resolve scaling issues for estimating water and carbon budgets from stands to regions.
UR: http://www.science.mcmaster.ca/geo/faculty/arain/research/index.htm
DE: 0315 Biosphere/atmosphere interactions
DE: 1615 Biogeochemical processes (4805)
DE: 1878 Water/energy interactions
DE: 3322 Land/atmosphere interactions
DE: 3394 Instruments and techniques
SC: Biogeosciences [B]
MN: 2003 Fall Meeting