To understand the dynamics of ecosystem carbon cycling, CO2 fluxes were measured over and under an oak–grass savanna and over a proximate grassland in California. The measurements were made from 2000 to 2006 using the eddy covariance technique. Annual net carbon exchange (NEE) ranged from −155 to −56 gC m−2 year−1 …
Journal: Agricultural And Forest Meteorology, Volume 147 (3-4): 157-171 (2007). DOI: 10.1016/j.agrformet.2007.07.008 Sites: US-Ton, US-Var
Triggers of summertime convective rainfall depend on numerous interactions and feedbacks, often compounded by spatial variability in soil moisture and its impacts on vegetation …
Journal: Global Change Biology, Volume 13 (4): 887-896 (2007). DOI: 10.1111/j.1365-2486.2007.01315.x Sites: US-Dk3
The concept of light-use efficiency (LUE) is the underlying basis for estimating carbon exchange in many ecosystem models, especially those models that utilize remote sensing to constrain estimates of canopy photosynthesis. An understanding of the factors that control the efficiency with which forest canopies harvest available …
Journal: Agricultural And Forest Meteorology, Volume 143 (1-2): 64-79 (2007). DOI: 10.1016/j.agrformet.2006.11.008 Sites: US-Bar
This study proposes a new metric called canopy geometric volume G, which is derived from small-footprint lidar data, for estimating individual-tree basal area and stem volume. Based on the plant allometry relationship, we found that basal area B is exponentially related to G (B = β1G3/4, where β1 …
Journal: Photogrammetric Engineering & Remote Sensing, Volume 73 (12): 1355-1365 (2007). DOI: 10.14358/pers.73.12.1355 Sites: US-Ton
The Ecosystem Demography (ED) model was parameterized with ecological, forest inventory, and historical land use observations in an intensively managed, wetland-rich forested landscape in the upper midwest United States. Model results were evaluated against a regional network of eddy covariance flux towers and analyzed about the …
Journal: Journal Of Geophysical Research: Biogeosciences, Volume 112 (G1): n/a-n/a (2007). DOI: 10.1029/2006JG000264 Sites: US-PFa
We determined concentrations and fluxes of dissolved organic carbon (DOC) in precipitation, throughfall, forest floor and mineral soil leachates from June 2004 to May 2006 across an age-sequence (2-, 15-, 30-, and 65-year-old) of white pine (Pinus strobus L.) forests in southern Ontario, Canada. …
Journal: Biogeochemistry, Volume 86 (1): 1-17 (2007). DOI: 10.1007/s10533-007-9138-7 Sites: CA-TP1
Ecosystem water use efficiency (EWUE) is defined as the net carbon uptake per amount of water lost from the ecosystem and is a useful measure of the functionality in semiarid shrub and grassland communities. C4 grasses have higher water use efficiency (WUE) than do C3 shrubs, although it has been postulated …
Journal: Rangeland Ecology & Management, Volume 60 (5): 464-470 (2007). DOI: 10.2111/1551-5028(2007)60[464:ewueia]2.0.co;2 Sites: US-Wkg
We analyzed 13 years (1992−2004) of CO2 flux data, biometry, and meteorology from a mixed deciduous forest in central Massachusetts. Annual net uptake of CO2 ranged from 1.0 to …
Journal: Journal Of Geophysical Research, Volume 112 (G2): (2007). DOI: 10.1029/2006JG000293 Sites: US-Ha1
In the southeastern United States (SE), the conversion of abandoned agricultural land to forests is the dominant feature of land-cover change. However, few attempts have been made to quantify the impact of such conversion on surface temperature. Here, this issue is explored experimentally and analytically in three adjacent ecosystems …
Journal: Geophysical Research Letters, Volume 34 (21): n/a-n/a (2007). DOI: 10.1029/2007gl031296 Sites: US-Dk3
We present a decadal (1994–2004) record of carbon dioxide flux in a 160-year-old black spruce forest/veneer bog complex in central Manitoba, Canada. The ecosystem shifted …
Journal: Global Change Biology, Volume 13 (3): 577-590 (2007). DOI: 10.1111/j.1365-2486.2006.01221.x Sites: CA-Man