New England WSC seminar series Rau 20181116

Science Center Objects

Demand for biomass bioenergy has been increasing due to consumer choices, and changes in public policy in response to global climate change. Currently, in the United States, unprocessed wood waste is the primary source of biomass for energy production. 

Date/Time: Friday, November 16, 2018, 12:00 pm

Title: Environmental Effects of Short-Rotation Pine Production for Bioenergy: Findings from a Watershed Experiment

Presented by: Dr Ben Rau, USDA Forest Service

Location: USGS, Massachusetts Office, Northborough, MA

Abstract: 

Demand for biomass bioenergy has been increasing due to consumer choices, and changes in public policy in response to global climate change. Currently, in the United States, unprocessed wood waste is the primary source of biomass for energy production. However, in Europe there is a high demand for wood pellets in the renewable energy sector. In coming years, it is expected that demand for cellulosic ethanol will increase as the technology matures. Therefore, it is forecast that short rotation woody crops for biomass production will serve a role in fulfilling increasing demand. The southeastern US is the largest exporter of wood products and biomass in the world due to favorable growing conditions, and land ownership patterns. Loblolly pine (Pinus taeda) is the dominant commercial tree species in this region and is well suited for biomass production. In order to achieve high yields in shorter rotations, intensive silvicultural techniques including repeated fertilizer and herbicide applications may be necessary. With increased management intensity comes the potential for increased impacts to surface and groundwater quality. We designed a watershed scale experiment to test the impacts of intensive silvicultural management on water quality and determine if current Best Management Practices (BMPs) can mitigate intensive management. We determined that during the initial 2 years of the rotation, nitrate leaching increased in pine plantations, and that leaching increased nitrate in shallow groundwater. Conversely, nitrate has not increased in deeper groundwater or surface water 5 years into the rotation. Conservative tracer simulations suggest that nitrate should have entered surface water over the monitoring period. Additional monitoring indicates that denitrification in the riparian buffer has served a critical role in maintaining water quality, but that nitrous oxide emissions may have increased. Our initial findings indicate that standard forestry BMPs are effective for maintaining water quality, but there may be tradeoffs with greenhouse gas emissions.