Harvested Wood Products in the U.S. National Greenhouse Gas Inventory: Methodology and Accounting

1
Harvested Wood Products in the U.S. National
Greenhouse Gas Inventory Methodology and
Accounting
2
Harvested Wood Products Topics

• Overview of U.S. Emissions and Removals
• U.S. Estimation Method and Results for Harvested
  Wood Products
• Accounting Approach

3
Overview of U.S. Greenhouse Gas Emissions, 2002
Emissions 6,935 Tg CO2 eq.
Removals 691 Tg CO2 eq.
HWP 215 Tg CO2 eq.
4
U.S. Estimation Method

• Method details for the U.S.
• Track Inputs to, and outputs from carbon pools
• Begin in 1910, track to current time
• Product carbon pools
• Products in use
• Products in dumps or solid waste disposal sites
• Use forest sector model framework the WOODCARB
  model
• to track all products from annual harvest
• to track imports/ exports

5
U.S. estimation example tracking carbon in
single family houses
6
Harvested Wood Products Methodology
Disposition of Carbon in Harvested Wood - U.S.
Average
Removals
Emissions
Source Heath and others, 1996 Skog and
Nicholson, 1998
7
U.S. data

• Annual Data Requirements
• Harvest statistics
• Product production
• Product exports and imports
• Coefficients
• Factors to convert product units to carbon
• Distribution of products to end uses
• Use life of products in end uses
• Portion of discarded wood to dumps vs SWDS vs
  burning
• Portion of wood in permanent vs temporary storage
  in SWDS
• Decay rates in dumps SWDS
• The U.S. assumes the coefficients are the same
  for products used domestically and products
  exported

8
U.S. Product Lifetime
Half lives for end uses (years) Half lives for end uses (years)
1 family homes (pre-1980) 80
1 family homes(post-1980) 100
Multifamily homes 70
Mobile homes 20
Nonresidential construction 67
Pallets 6
Manufacturing 12
Furniture 30
Railroad ties 30
Paper (free sheet) 6
Paper (other) 1
Wood and paper in SWDS Wood and paper in SWDS
Fraction that decays Fraction that decays
Solidwood 3
Newsprint 16
Coated paper 18
Boxboard 32
Office Paper 38

Half life for portion that decays Half life for portion that decays
20 years 20 years
9
Harvested Wood Products Comparison of Approaches
U.S. HWP Removals in 2002 215 Tg CO2
eq. Variables from U.S. HWP Estimation Methods
Stock Change or Flow Variables Tg CO2 eq.
A Domestic Product Stock Change (from domestic RW) 212
B Exported Product Stock Change (from domestic RW) 3
C Imported Product Stock Change 36
D Flow of imports 47
E Flow of exports 25
Approaches Production (AB) 215 Stock
Change (AC) 248 Atmospheric Flow (A C
(D E)) 227
10
Harvested Wood Products Timeline

• September 2004, UNFCCC HWP workshop
• November 2004, IPCC Guidelines (GL) revisions,
  HWP experts meeting
• December 2004, SBSTA 21
• March 2005, 1st review of IPCC GL revision by
  experts
• September 2004, 2nd review of IPCC GL revision by
  experts and governments
• May 2006, SBSTA 24, IPCC GL revision presented to
  SBSTA

11
Conclusions

• HWP is an important sink in the U.S.
• Tracking HWP will highlight opportunities to
  better manage HWP pools
• Transparency can be improved if countries report
  stock changes associated with both imports and
  exports regardless of approach
• Encourage transparent reporting now, such that
  any approach can be applied in the future
• Accounting systems should be consistent with IPCC
  default
• There is a narrow window of opportunity to
  provide guidance to IPCC authors on HWP