U.S. Forest Carbon Budget

1. U.S. Forest Carbon Budget Richard A. Birdsey USDA Forest Service Northeastern Research Station Newtown Square, PA Linda S. Heath Northeastern Research Station Durham, NH Ken Skog Forest Products Laboratory Madison, WI

2. Outline of talk • Inventory data (Rich) • Forest carbon model (Linda) • Carbon in wood products (Ken)

4. Multi-tier Monitoring Design • Tier One – Remote Sensing and Mapping • Land cover and change; biomass density • Wall-to-wall coverage; stratification • Tier Two – Extensive Inventories and Surveys • Management, productivity, disturbance, ownership, land use • Representative statistical sample • Tier Three – Medium-intensity Sample (new) • Ecosystem C pools and changes, soil CO2 flux (proposed) • Representative sample of condition classes • Tier Four –Intensive Areas • Soil-plant-atmosphere processes; complete C budgets • Relatively small number of specific sites

5. Tier One – Remote Sensing Source: NAPP 1:40,000 color infrared photography Sample Points: 16 photo points located systematically over the “effective area” of each photo. Measurement: land cover Note: in process of shifting to satellite data

6. Five-Year Panel Year One Year Two Year Three Year Four Year Five 1 2 3 4 3 5 4 1 5 1 2 3 1 2 3 4 5 3 1 4 5 1 2 3 Tier Two – Field Sampling Sample Intensity = 1 sample location per 6,000 acres of land Inventory Cycle Length = Five years or 20 percent of the sample locations each year

7. Tier Two Sample Location Design Plot measurements: age, disturbance, owner, physiography, etc. Tree measurements: species, dimensions, damage, etc.

8. Tier Three – Forest Health Monitoring • FHM and FIA sample locations are co-located • Additional data: crown condition, soils, understory, coarse woody debris, etc.

9. Tier Four – Intensive Sites • Detailed observations at small number of sites • (LTER, AmeriFlux) • Complete ecosystem C stocks and fluxes • Used to develop models to aid in large-scale estimation

10. Some Inventory Considerations • Tier 1 – New remote sensing technology being applied • Tier 2 - Forest remeasurement is sparse in some areas (e.g. Alaska) • Tier 2 - Not completely consistent with NRI (gaps, overlaps, independent sampling frames) • Rangeland/forestland interface • Developed lands (urban/suburban) • Tier 2 - Public rangelands? • Tier 3 - FHM only partially implemented • Tier 4 - linkage is being pilot tested • All tiers - measurements not optimized for carbon

11. Forest Inventory Estimates as a Basis for Carbon Analysis(Trends by State and Region) • Area by land class (reconciled with NRI) • Area by forest type, owner, age class • Tree volume by species and size class • Tree biomass by species and size class

12. Gross Growth per Acre of Timberland,U.S. by Region, 1952-1997

13. Basic estimation of carbon stocks and stock changes • Carbon stock = CARBON/AREA times AREA • Carbon stock change = C stock at time 2 minus C stock at time 1 Divide by length of period = carbon/year •  Estimated values can be obtained from measured data or from using models

14. ATMOSPHERE SOIL Imports/ Exports Forest sector carbon pools and flows Growth decay decay STANDING DEAD HARVESTED CARBON Removals BIOMASS Above and Below Mortality Recycling processing Harvest residue Litterfall, Mortality Treefall decay burning DOWN DEAD WOOD FOREST FLOOR PRODUCTS disposal burning Humification burning ENERGY Decomposition LANDFILLS

15. US managed forest C pools, avg. annual 2008 Positive value indicates sink

16. Individual pools of forest C, per area • Live & standing dead tree biomass – FIA measurements and equations • Down dead wood – some data, model • Leaf litter -- model • Soil carbon –data from STATSGO • Harvested carbon – modeled, Ken Skog, FPL

17. Forest Inventory Estimates as a Basis for Carbon Analysis(Trends by State and Region) • Area by land class (reconciled with NRI) • Area by forest type, owner, age class • Tree volume by species and size class • Tree biomass by species and size class

18. Example: Two rotations of pine on a high site in SEForest C and disposition of C in harvested wood (1995) Carbon (T/ha) 0 20 40 60 80 Age NOTE: Energy and emissions are releases of C to the atmosphere

19. Forest sector system of models and data for C estimates and projections of managed U.S. forests-- Timber Assessment

20. ATLAS model yield exampleSE, Planted pine, High site, MI 5

21. Fitted equation and data points for live treesMaple-Beech-Birch, NE region 400 300 Biomass (Tons/ha dry wt.) 200 100 0 0 100 200 300 400 Growing stock volume (m /ha) 3

22. Litter layer carbon accumulation, decay, and total--Southern Pines 30 20 Litter layer C (Tons/ha) 10 0 Mixed or unknown age 0 25 50 75 Years Source: Smith and Heath (in review)

23. Down dead wood by type and basal area

24. Projected inventory of privately owned managed forests of the United States, 2000 Source: (Smith and Heath, 2001)

25. Tree carbon per hectare by U.S. county, 1997

26. Managed forest lands, US, 2008-2012Avg. annual C stock change

27. Trend of carbon sequestration on managed forests, U.S. Data Projections

28. Modeling current and projectedcarbon storage in wood and paper Ken Skog USDA Forest Products Lab Madison, WI

29. Modeling current and projectedcarbon storage in wood and paper • Model Framework • Accounting for Imports and Exports • Data needs/ uncertainty • Results

30. Cycling of Carbon Through Wood and Paper Products Atmosphere Burned Decayed Forests Harvest Products Recycling Wood-in- use Methane and CO2 Landfills

31. The System Framework –Harvested wood carbon Stock change and Atmospheric Flow approaches Emissions Imports Products in use Products in landfills Harvest Exports ΔProduct stocks = Harvest + Imports – Exports – Emissions Net Flow to system = Harvest - Emissions Atmospheric Flow = - ΔProduct stocks - Net Imports

32. The System Framework –Harvest wood carbon stocks and flowsfor Production approach Emissions Products in use Products in landfills Harvest Exports ΔProduct stocks = Harvest – Emissions Atmospheric Flow= Harvest - Emissions

33. Data needs • Low uncertainty (±10%) • Wood and paper product production • Product exports • Product imports • Product use by end use (e.g. construction) • Medium / High uncertainty (±20%+) • Waste when using products and disposition of waste • Years products are in use • Disposition of products after use – burn, decay, landfill • Rate of decay in landfills • Maximum decay in landfills (% ever emitted)

34. Decay of wood and paper in landfills

35. Disposition of 1990 harvested wood used for paper through 2050 (Tg) 24% in stocks in 2050 In use In landfills

36. Disposition of 1990 harvested wood used forfuel and solid wood products in the U.S. through 2050 (Tg) 54% in stocks in 2050 In landfills In use

37. Disposition of 1990 wood harvest used for fuel and all products in the U.S. through 2050 (Tg) 41% in stocks in 2050 In landfills In use

38. Sensitivity to use life and decay rates --Year 2000 Harvested wood carbon in 2050 58% 76% Emitted

39. U.S. Net Annual Changes to Stocks, and Emissions from Harvested Wood* Emitted Energy Landfill Products *Includes net imports. SOURCE: Skog and Nicholson, 2000

40. Managed forest lands, US, 2008-2012Avg. annual C stock change

41. Modeling current and projectedcarbon storage in wood and paper • Current studies • Develop generic national method using FAO product statistics • Assess effects of uncertainty on U.S. estimates • Project carbon storage associated with 2000 RPA Timber Assessment projections