USDA releases report on scientific methods for quantifying changes in greenhouse gas emissions and carbon storage

The U.S. Department of Agriculture (USDA) recently released a report that identifies “science-based methods for quantifying changes in GHG [greenhouse gas] emissions and carbon storage at the local farm, ranch or forest operation.” The stated objective of the report is “to create a standard set of GHG estimation methods for use by USDA, landowners, and other stakeholders to assist them in evaluating the GHG impacts of their management decisions” (USDA News Release No. 0161.14, http://www.usda.gov/wps/portal/usda/usdahome?contentid=2014/07/0161.xml).

The report, Quantifying Greenhouse Gas Fluxes in Agriculture and Forestry: Methods for Entity-Scale Inventory, was developed in response to the 2008 Food, Conservation and Energy Act which directed the Secretary of Agriculture to develop “technical guidelines that outline science-based methods” that will quantify environmental service benefits and help facilitate landowner participation in environmental markets, with an initial focus on carbon markets. USDA indicates that it “will use methods in the report to assess the GHG performance of current and future conservation programs and initiatives, and to prioritize research and data collection in order to improve agriculture and forestry GHG inventory from local to national scales.”

The report includes a chapter dealing with quantification of greenhouse gas sources and sinks in managed forest systems. This chapter provides an overview of the elements of forest carbon accounting, including definitions of the key carbon pools and basic methods for their estimation. It also provides methods for estimating carbon stocks and stock change associated with establishing and clearing forest, forest management activities, harvested wood products, urban forests, and natural disturbances of forests.

The chapter recommends different methods depending on forest landowner size. It suggests that small landowners, generally defined as those who own or manage less than
200 acres, use lookup tables based on region, forest type, and age class to estimate carbon stocks. The report suggests that large landowners collect forest inventory data and use complex models and equations.

Reference  

Eve, M., D. Pape, M. Flugge, R. Steele, D. Man, M. Riley‐Gilbert, and S. Biggar (eds). 2014. Quantifying greenhouse gas fluxes in agriculture and forestry: Methods for entityscale inventory. Technical Bulletin Number 1939. Washington, DC: U.S. Department of Agriculture, Office of the Chief Economist. www.usda.gov/oce/climate_change/estimation.htm.