Grantee Research Project Results
Assessing the Hydrological Costs of Carbon Sequestration in Managed Forests and Biofuel PlantationsEPA Grant Number: FP917194
Title: Assessing the Hydrological Costs of Carbon Sequestration in Managed Forests and Biofuel Plantations
Investigators: Marchin, Renee Michelle
Institution: North Carolina State University
EPA Project Officer: Just, Theodore J.
Project Period: August 16, 2010 through August 15, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010)
Research Category: Academic Fellowships , Fellowship - Global Change
Afforestation and tree plantations have been promoted as greenhouse gas mitigation options in the Kyoto Protocol. Growth of trees, however, is inseparably connected to water loss by stomatal control of gas exchange, and thus productivity is dependent upon water availability. It is important that carbon sequestration strategies consider all environmental consequences, especially in regions where water resources are expected to be stressed by population growth and climate change. This research project will quantify tree species differences in carbon uptake and water loss in forests and biofuel plantations of the southeastern United States in order to better match land management decisions with the ecohydrology of local sites.
Afforestation and tree plantations have been promoted as greenhouse gas mitigation options in the Kyoto Protocol. Forests store more carbon, but also require more water, and it is important that carbon sequestration strategies consider all environmental consequences, especially in regions where water resources are limited. This project analyzes the trade-off between carbon uptake and water loss in trees, emphasizing species differences in water use efficiency under variable climates.Approach:
This project will compare the stomatal regulation of tree species with different growth strategies (e.g., yellow poplar, sycamore, red maple, hickory, white oak) under experimentally manipulated levels of temperature, soil moisture, and atmospheric vapor pressure deficit. To explore differences among land uses, trees will be measured in three different sites: natural forest ecosystems, managed forests, and biofuel tree plantations. Water use efficiency (WUE) is the ratio of carbon dioxide uptake to water consumption in an individual tree and will provide a direct measure for species comparisons of the tradeoff between carbon and water. Other physiological measurements, including seasonal changes in transpiration and photosynthesis, will be used to assess the impact of climate variability on plant growth and survival.Expected Results:
Forest tree species responses to climate change are complex and currently unpredictable. Climate changes that physiologically stress trees will decrease overall forest growth and increase susceptibility to pests and disease. This research will address the effects of changing climatic conditions on tree growth and survival. The results of this project can be used to inform selection of tree species for forests and biofuel plantations, allowing maximization of carbon sequestration for a given water budget and minimizing climate change-induced death of trees.
Potential to Further Environmental/Human Health Protection:
This project will provide information on how land management practices will affect local ecosystems. By comparing quantitative estimates of water use among tree species to predicted water availability in the Southeast, it will be possible to determine which species to plant in forests and biofuel plantations. For example, while species such as oaks and hickories have a reputation for high drought tolerance, it has been shown that severe drought can cause more dieback in these species than in co-occurring species. Through intensive measurement of trees under varying climatic conditions, such as experimentally increased temperature and imposed drought, these results can be used to model how future climate variability will affect growth and carbon sequestration in forests.Supplemental Keywords:
climate change, carbon sequestration, tree physiology, land management, water use efficiency, species traits,