2013年6月12日星期三

Wood not so green a biofuel

Wood not so green a biofuel

June 11, 2013 — Using wood for energy is considered cleaner than fossil fuels, but a Dartmouth College-led study finds that logging may release large amounts of carbon stored in deep forest soils.






Global atmospheric studies often don't consider carbon in deep (or mineral) soil because it is thought to be stable and unaffected by timber harvesting. But the Dartmouth findings show deep soil can play an important role in carbon emissions in clear-cutting and other intensive forest management practices. The findings suggest that calls for an increased reliance on forest biomass be re-evaluated and that forest carbon analyses are incomplete unless they include deep soil, which stores more than 50 percent of the carbon in forest soils.

"Our paper suggests the carbon in the mineral soil may change more rapidly, and result in increases in atmospheric carbon dioxide, as a result of disturbances such as logging," said Dartmouth Professor Andrew Friedland, a co-author. "Our paper suggests that increased reliance on wood may have the unintended effect of increasing the transfer of carbon from the mineral soil to the atmosphere. So the intended goal of reducing carbon in the atmosphere may not be met."

The federal government is looking to wood, wind, solar, hydropower and other renewable energy sources to address concerns about climate change and energy security. Woody biomass, which includes trees grown on plantations, managed natural forests and logging waste, makes up about 75 percent of global biofuel production. Mineral soil carbon responses can vary highly depending on harvesting intensity, surface disturbance and soil type.

"Analysis of forest carbon cycles is central to understanding and mitigating climate change, and understanding forest carbon cycles requires an in-depth analysis of the storage in and fluxes among different forest carbon pools, which include aboveground live and dead biomass, as well as the belowground organic soil horizon, mineral soil horizon and roots," Friedland said.

Co-authors included Dartmouth's Thomas Buchholz, a former post-doctoral student, and Claire Hornig, a recent undergraduate student, and researchers from the University of Vermont, Lund University in Sweden and the Vermont Department of Forest, Parks and Recreation. The research was supported by awards to Friedland from the Northeastern States Research Cooperative and the Porter Fund.

Friedland's research focuses on understanding the effects of atmospheric deposition of pollutants and biomass harvesting on elemental cycling processes in high-elevation forests in the Northeastern United States. He considers many elements including carbon, trace elements such as lead and major elements such as nitrogen and calcium. He also is examining issues related to personal choices, energy use and environmental impact.

The results appear in the journal Global Change Biology-Bioenergy.



Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.


CMF55470R00JLEK CMF55470R00JLEB CMF55470R00JLBF CMF55470R00JKWF39 CMF55470R00JKWF CMF55470R00JKRE39 CMF55470R00JKR839 CMF55470R00JKR8 CMF55470R00JKR739 CMF55470R00JKR7 CMF55470R00JKR639 CMF55470R00JKKA CMF55470R00JKEK CMF55470R00JKEB39 CMF55470R00JKEB CMF55470R00JKEA39 CMF55470R00JKBF CMF55470R00JHRE CMF55470R00FKWF70 CMF55470R00FKRE CMF55475K00FKWF CMF55475K00FKRE70 CMF55475K00FKRE CMF55475K00FKR870 CMF55475K00FKR8 CMF55475K00FKR770 CMF55475K00FKR7 CMF55475K00FKR670 CMF55475K00FKR6 CMF55475K00FKEB70 CMF55475K00FKEB CMF55475K00FKEA70 CMF55475K00FKEA CMF55475K00FKBF CMF55475K00FHWF CMF55475K00FHRE CMF55475K00FHR8 CMF55475K00FHR7 CMF55475K00FHR6 CMF55475K00FHEK
http://www.suvsystem.com/a/2540.aspx