Feedstock Development projects

Sustainability of Woody Biofuel Feedstocks

Woody biofuels currently constitute three-fourths of global biofuel production. Short-rotation coppice forestry can produce high yields and are an attractive option for second-generation bioenergy fuels. However, there are many questions about the sustainability of coppice foresty and its impact on carbon sequestration and water cycling. This project establishes study plots within three existing forestry research sites in Wisconsin (poplar), New York (willow), and North Carollina (loblolly pine). The project synthesizes existing data and collects new data on key variables affecting carbon and water cycling. It also examines ecosystem scale properties necessary to validate model performance, such as tree growth and survival, tissue chemistry, water use efficiency, soil respiration, and other factors.

project Highlights

2014 Highlights

This project aims to gain the physiological understanding and data needed to generate model projections of carbon and water cycling by three woody biofuel feedstocks: willow, poplar and pine. Field sites in New York, Minnesota and North Carolina were established in 2012. In 2013 and 2014, our field campaigns included visits to each site during the early, middle and late portion of the growing season, with additional high-frequency data collection by on-site staff and collaborators. We have analyzed data from 2013 and are currently working with the EBI modeling group to model carbon and water cycling in the willow and poplar feedstocks. Our major finding to date is that significant variation in the slope (m parameter) of the Ball et. al. (1987) model of stomatal conductance occurs among species of C3 trees, as well as varying seasonally, regionally and within a canopy. We are now evaluating how variation in m will affect model estimates of foliar and canopy carbon and water fluxes. Additionally, as these sites are due for a harvest, we are interested in determining how major perturbations may affect carbon and water fluxes.

2013 Highlights

This project aims to gain the physiological understanding and data needed to generate model projections of carbon and water cycling by three woody biofuel feedstocks: willow, poplar and pine. Field sites in New York, Minnesota and North Carolina were established in 2012. In 2013, our field campaign included visits to each site during the early, middle and late portion of the growing season, with additional high-frequency data collection by on-site staff and collaborators. We are currently analyzing this data and have begun to work with the EBI modeling group on developing and applying new ecosystem-scale woody feedstock models. Our major finding to date is that significant variation in the slope (m parameter) of the Ball et. al. (1987) model of stomatal conductance occurs among species of C3 trees. And, accounting for this previously unrecognized source of error substantially improves the accuracy of model projections of carbon gain, water use and water use efficiency at the leaf level. We are now evaluating this issue at the canopy scale. One journal article has been submitted, one journal article is in the final stages of preparation for submission and one journal article will be submitted early in 2014.

2012 Highlights

This project aims to estimate the fluxes and pools of carbon and water for three tree species which are predicted to be heavily utilized as biofuel feedstocks: poplar (Populus) grown in Minnesota, willow (Salix spp.) grown in New York and southern pine (Pinus taeda) grown in North Carolina. The goal of the project is to support the modeling of the ecological impact incurred in using these woody crops as biofuel sources. This project is divided into two parts. First, physiological and ecological measurements will quantify key pools and fluxes of carbon and water in each of these three managed forest systems. Second, our data will be used to inform and test computer model forecasts of ecosystem function, in collaboration with staff from the EBI modeling program. The result will be improved understanding of the ecological sustainability of expanding production of woody biofuel crops in the U.S. In 2012, we established three field sites and installed equipment to monitor fine root turnover, soil moisture and whole-plant water use.


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