We tested, compared and modified three models of stomatal conductance at the leaf level in a forest ecosystem where drought stress is a major factor controlling forest productivity. The models… More
Elevated atmospheric carbon dioxide (CO2e) increases soil respiration rates in forest, grassland, agricultural and wetland systems as a result of increased growth, root biomass and enhanced biological activity of soil… More
Eddy covariance was used to measure the net CO2 exchange and energy balance of a moist-tussock tundra ecosystem at Happy Valley, Alaska (69°08.54′ N, 148°50.47′ W), during the 1994–1995 growing… More
We used gas exchange techniques to estimate maximum rate of carboxylation (Vcmax), a measure of photosynthetic capacity, in the understory and upper crown of a closed deciduous forest over two… More
Deep root water uptake and hydraulic redistribution (HR) have been shown to play a major role in forest ecosystems during drought, but little is known about the impact of climate… More
We determined δ13C values associated with canopy gross and net CO2 fluxes from four U.S. sites sampled between 2001 and 2002. Annual mean, flux-weighted δ13C values of net ecosystem CO2exchange… More
The magnitude of changes in carboxylation capacity in dominant plant species under long-term elevated CO2 exposure (elevated pCa) directly impacts ecosystem CO2 assimilation from the atmosphere. We analyzed field CO2… More
Canopy and leaf level 2-methyl-3-butene-2-ol (methylbutenol, MBO) emissions were measured from a ponderosa pine plantation in the Sierra Nevada mountains from July to October 1998. Canopy scale fluxes were measured… More
The concentration, contents, and distribution of nutrients, metals, and soil materials were quantified at the Howland Integrated Forest Study (HIFS) site in eastern Maine. The site is a mature, low-elevation… More
We measured seasonal and canopy-level gas exchange in two stands of jack pine (Pinus banksianaLamb.) and one stand of black spruce (Picea mariana (Mill.) B.S.P.) on relatively clear days from… More