Aerodynamic canopy height (ha) is the effective height of vegetation canopy for its influence on atmospheric fluxes and is a key parameter of surface‐atmosphere coupling. However, methods to estimate ha from data are limited. This synthesis evaluates the applicability and robustness of the calculation of ha from eddy covariance momentum‐flux data. At 69 forest sites,… More
Phenology is experiencing dramatic changes over deciduous forests in the USA. Estimates of trends in phenology on the continental scale are uncertain, however, with studies failing to agree on both the magnitude and spatial distribution of trends in spring and autumn. This is due to the sparsity of in situ records, uncertainties associated with remote… More
Soil organic carbon (SOC) can be stabilized via association with iron (Fe) and aluminum (Al) minerals. Fe and Al can be strong predictors of SOC storage and turnover in soils with relatively high extractable metals content and moderately acidic to circumneutral pH. Here we test whether pedogenic Fe and Al influence SOC content and turnover… More
Forest soils represent a significant pool for carbon sequestration and storage, but the factors controlling soil carbon cycling are not well constrained. We compared soil carbon dynamics at five broadleaf forests in the Eastern US that vary in climate, soil type, and soil ecology: two sites at the University of Michigan Biological Station (MI-Coarse, sandy;… More
The AmeriFlux Tech Team has completed another successful site visit season. This year they visited six AmeriFlux sites. The team also deployed the portable profile system at two sites. Here are a few images from the site visits. The Tech Team is planning for the 2018 site visit season. If you would like to learn more… More
Biophysical controls on plant water status exist at the leaf, stem, and root levels. Therefore, we pose that hydraulic strategy is a combination of traits governing water use at each of these three levels. We studied sap flux, stem water storage, stomatal conductance, photosynthesis, and growth of red oaks (Quercus rubra) and red maples (Acer… More
Biophysical controls on plant water status exist at the leaf, stem, and root levels. Therefore, we pose that hydraulic strategy is a combination of traits governing water use at each of these three levels. We studied sap flux, stem water storage, stomatal conductance, photosynthesis, and growth of red oaks (Quercus rubra) and red maples (Acer… More
It is necessary to partition eddy covariance measurements of carbon dioxide exchange into its offsetting gross fluxes, canopy photosynthesis, and ecosystem respiration, to understand the biophysical controls on the net fluxes. And independent estimates of canopy photosynthesis (G) and ecosystem respiration (R) are needed to validate and parametrize carbon cycle models that are coupled with… More
Allocation of C to belowground plant structures is one of the most important, yet least well quantified fluxes of C in terrestrial ecosystems. In a literature review of mature forests worldwide, Raich and Nadelhoffer (1989) suggested that total belowground carbon allocation (TBCA) could be estimated from the difference between annual rates of soil respiration and… More