1. Forest Biophysical Models: Challenges of and Opportunities for use in Economic Models
Presented at Forestry and Agriculture Greenhouse Gas Modeling Forum
Shepherdstown, WV October 11, 2002
Presented by Brian Murray
P.O. Box · 3040 Cornwallis Road · Research Triangle Park, NC Phone: · Fax: · ·

2. Policy/economic setting for GHG mitigation
Market or government offers $X/ton of C sequestered in time period t …
Principle of marginality: Landowners will undertake sequestration until the marginal cost = $X/ton
Economic models need to capture
The resource and opportunity costs of sequestration actions
How these actions translate to changes in terrestrial carbon stocks over time
Ex ante perspective
Projecting the carbon and monetary consequences of alternative future actions

3. Mitigation analysis needs (continued)
Sequestration actions are location-specific, so change in forest C stock estimates needed by …
Region
Forest type
Site conditions
Previous land use
Harvested product destination
FORCARB, tied to forest inventory data, captures these elements
Note: Economic models do not need a lot of C pool detail, except for product pool disposition over time
Also need info on Ct effects of changes in
Management actions
Climatological and other natural conditions

4. A common approach for calibrating C changes to forest management regimes … is this the best way ?
FORCARB output
ATLAS calibration
“Low”
management
“High”
Forest type A
Region B
Site index
60-79
Age class
15-20
Timber growth (ft3/yr) 40 30 50
Carbon flux
(tC/yr)
Tree
1.2
0.9
1.5
Soil
.05
0.05
Understory
.03
0.03
Litter
.02
0.02
Total
1.3
1.0
1.6

5. Question: Can we get the folllowing from FORCARB2 ?
Most recent tabular outputs, reflecting changes of last several years
Most people rely on the tables published in the American Forests pub. of 1996
Underlying detail on the sub-models (equations, parameters, regional differences etc…)
Inventory detail used for public lands components

6. Temporal aspects of C Stock Changes due to climate and other factors
Trend
E.g., effects of changes in climate, precip, CO2, and other factors on forest growth
Variability
If landowners are to be paid directly on actual C increments, payments will vary with yields
Variability will affect adoption probability of risk averse landowners
EU($1, 2=1) > EU($1, 2=2)

7. Can Economic Models offer Anything to Biophysical Models?
Economic drivers of ecological change
Harvesting
Management
Land Use Change