To test the hypothesis that variation in soil respiration is related to plant production across a diverse forested landscape, we compared annual soil respiration rates with net primary production and the subsequent allocation of carbon to various ecosystem pools, including leaves, fine roots, forests floor, and mineral soil for 36 …
Journal: Global Change Biology, Volume 10 (11): 1857-1869 (2004), ISBN . DOI: 10.1111/j.1365-2486.2004.00850.x Sites: US-Me2, US-Me4, US-Me5
Savannas and open grasslands often co-exist in semi-arid regions. Questions that remain unanswered and are of interest to biometeorologists include: how do these contrasting landscapes affect the exchanges of energy on seasonal and annual time scales; and, do biophysical constraints imposed by water supply and water demand …
Journal: Agricultural And Forest Meteorology, Volume 123 (1-2): 13-39 (2004), ISBN . DOI: 10.1016/j.agrformet.2003.11.006 Sites: US-Ton, US-Var
We used a spatially nested hierarchy of field and remote-sensing observations and a process model, Biome-BGC, to produce a carbon budget for the forested region of Oregon, and to determine the relative influence of differences in climate and disturbance among the ecoregions on carbon stocks and fluxes. The simulations suggest that …
Journal: Global Change Biology, Volume 10 (9): 1429-1444 (2004), ISBN . DOI: 10.1111/j.1365-2486.2004.00822.x Sites: US-Me2, US-Me4, US-Me5
Understanding how environmental variables affect the processes that regulate the carbon flux over grassland is critical for large-scale modeling research, since grasslands comprise almost one-third of the earth’s natural vegetation. To address this issue, fluxes of CO2 (Fc, flux toward the …
Journal: Agricultural And Forest Meteorology, Volume 123 (1-2): 79-96 (2004), ISBN . DOI: 10.1016/j.agrformet.2003.10.004 Sites: US-Var
We calculated carbon budgets for a chronosequence of harvested jack pine (Pinus banksianaLamb.) stands (0-, 5-, 10-, and∼29-year-old) and a∼79-year-old stand that originated after wildfire. We measured total ecosystem C content (TEC), above-, and belowground net primary productivity (NPP) for each stand. All values are …
Journal: Global Change Biology, Volume 10 (8): 1267-1284 (2004), ISBN . DOI: 10.1111/j.1529-8817.2003.00804.x Sites: CA-SJ1
We investigated the relative importance of climatic versus biotic controls on gross primary production (GPP) and water vapor fluxes in seasonally drought-affected ponderosa pine forests. The study was conducted in young (YS), mature (MS), and old stands (OS) over 4 years at the AmeriFlux Metolius sites. Model simulations showed that …
Journal: Global Biogeochemical Cycles, Volume 18 (GB4007): n/a-n/a (2004), ISBN . DOI: 10.1029/2004GB002234 Sites: US-Me2, US-Me4, US-Me5
We combined a detailed field study of canopy gap fraction with spectral mixture analyses of Landsat 7 ETM+ satellite imagery to assess landscape and regional dynamics of canopy damage following selective logging in an eastern Amazon forest. Our field studies encompassed measurements of ground damage and canopy gap fractions along …
Journal: Ecological Applications, Volume 14 (sp4): 280-298 (2004), ISBN . DOI: 10.1890/01-6019 Sites: BR-Sa3
The soil water regimes of two areas of open savanna (campo sujo) near Brasilia, Brazil, were monitored between August 1999 and November 2000. Each area was subjected to a different fire regime. Soil water …
Journal: Ecological Applications, Volume 14 (sp4): 33-41 (2004), ISBN . DOI: 10.1890/01-6017 Sites: BR-Sa1
Radon-222 (Rn-222) is used as a transport tracer of forest canopy–atmosphere CO2 exchange in an old-growth, tropical rain forest site near km 67 of the Tapajós National Forest, Pará, Brazil. Initial results, from month-long periods at the end of the wet season (June–July) and the end of the dry season (November–December) …
Journal: Global Change Biology, Volume 10 (5): 618-629 (2004), ISBN . DOI: 10.1111/j.1365-2486.2004.00764.x Sites: BR-Sa1
Recent and long-term accumulation rates of carbon (C), using 210Pb- and 14C-dating, were examined in 23 ombrotrophic peatlands in eastern Canada, where average 1990–1996 atmospheric wet nitrogen (N) deposition ranged from 0.3 to 0.8 g N m−2 yr−1. The average recent rate of C accumulation …
Journal: Global Biogeochemical Cycles, Volume 18 (3): n/a-n/a (2004), ISBN . DOI: 10.1029/2003gb002154 Sites: CA-Mer