Estimating the potential carbon supply from changes in land use: afforestation of grazing lands in the US as a case study Sandra Brown Winrock International Third USDA Symposium on Greenhouse Gases & C Sequestration in Agriculture and Forestry Baltimore, March 2005

©Winrock International A key question …..  What amount of carbon is available and where from changing land use and management practices at what price? Goes beyond just technical potential— also includes economic potential

©Winrock International Acknowledgements Winrock Team: Timothy Pearson David Shoch Brent Sohngen John Kadyszewski Jonathan Winsten California Dept. Forestry: Mark Rosenberg Doug Wickizer Support American Electric Power Ogelthorpe CA Energy Commission/PIER Electric Power Research Institute US DOE

©Winrock International Overall Methodology  Identify and locate land classes suitable for increasing carbon stocks  Estimate rates of carbon accumulation for each major potential class of project activity for each land class  Assign costs to each contributing cost factor  Estimate carbon supply

©Winrock International Regional analyses of carbon supply California-WESTCARB partnership Southern region-SSEB partnership Details of analyses are in reports at

California-WESTCARB Afforestation of rangelands

©Winrock International Identify and locate land suitable for increasing carbon stocks Determine which rangelands could support forests—suitability analysis Land-use suitability analysis based on Biophysical factor- dependent suitability for forest habitats

©Winrock International Identify rangelands suitable for conversion to forests  Analyze the relationship between existing forests and several biophysical factors using GEOMOD =“suitability for forest map”  Cross-reference suitability map to areas of current rangelands to select areas with afforestation potential. Product = map of rangeland areas suitable to support forests

©Winrock International Inputs to GEOMOD Converted to forest probability maps based on existing extent in each class Prepare factor maps Mean annual temperature Slope

©Winrock International Overlap of rangeland classes in areas that have the same biophysical characteristics as current forests ~ 9.3 million ha Area of existing rangelands suitable for forest growth Montane chaparral

©Winrock International Map of populated places, montane chaparral areas, and selected populated places with names that refer to forests or forestry—e.g. Pine Grove, Pine Valley, Pinehurst, Redwoods, Sequoia, Seven Oaks, Sherwood Forest, Stallion Oaks, Sugarpine, Tall Timber Camp

©Winrock International Map of rangeland areas (in yellow) suitable for afforestation Represent about 9.3 million ha or 23% of State area Areas where forest crown cover high, suggesting not suitable

©Winrock International Afforestation of grazing lands: -Estimate rates of C accumulation and costs Step 1 Step 2

©Winrock International Step 1  Generate carbon sequestration curves from establishing forests on grazing lands from integration of many data bases

©Winrock International Potential carbon accumulation in conifer and hardwood forests (no harvest) Select species for afforestation based on incidence of existing forests with same suitability score/bioregion

©Winrock International Net carbon accumulation applied to potential woody- species distributions over three time periods

©Winrock International Step 2  Economic analyses

©Winrock International Cost of carbon sequestration  Opportunity costs: Using the same biophysical factors, a multivariate model was used to extrapolate STATSGO forage productivity data samples to a state-wide coverage. Product = map forage production Economic analysis of forage value derived from national databases and field interviews Mean annual profit/cow ($68/cow) Number of cows supported based strongly on forage production (1 animal unit month for CA = 791 lbs) Net present value analysis of total costs using 4% discount rate Product = map total cost

©Winrock International Estimated forage productivity across rangeland classes This map used to estimate number of cows per acre based on AUM and opportunity cost based on profitability per cow lbs per acre per year

Combine quantities of carbon accumulation with cost data to generate C supply in $/t C

©Winrock International Cost of carbon sequestration through afforestation of California rangelands

©Winrock International Carbon supply curves for afforestation activities for 20, 40 and 80 years

©Winrock International Take home messages  Depending on the price, afforestation of grazing lands can provide substantial quantity of carbon offsets in the US Little to no new technology needed, can be adopted quickly, and provide other environmental benefits  Protocols and registries for implementing carbon sequestration activities in advanced state (e.g. CCAR) and markets developing  Incentive for adoption likely to be driven by states rather than feds