Family forest owner enrollment in carbon programs remains below 0.1 percent in the
United States despite growing policy interest. Prior work identifies the participation barriers
qualitatively but does not measure them separately or connect them to contract design. This
paper makes four contributions. First, it develops a landowner decision model that decomposes
the minimum payment landowners require to enroll into an expected-value gap and a riskpremium
gap. Second, it estimates minimum required support across six Southern Appalachian
states, four parcel sizes, and four contract designs, producing county-level thresholds for
spatially differentiated targeting. Third, it connects the barrier diagnosis to contract design,
showing that instruments matched to the binding constraint outperform those that do not. Fourth,
it translates model-implied thresholds into adoption-threshold curves that show what share of the
modeled positive-carbon opportunity set becomes viable at alternative area-based and carbondenominated
payment levels. We find the dominant barrier is an expected-return shortfall: in the
baseline one-shot adoption framework, improved forest management is less risky than businessas-
usual, but the expected returns are too low to make enrollment privately attractive without
support. Under the 20-year baseline contract, minimum required support averages roughly
$1,200 per acre as a present-value lump-sum equivalent for 20-acre parcels, but falls to about
$215 per acre as a present-value lump-sum equivalent for 160-acre parcels, a nearly sixfold gap
driven by fixed enrollment costs falling more heavily on smaller parcels. Support varies
substantially across states, favoring county-level targeting over uniform payment
schedules. Two-part contracts reduce required performance payments by 8-12 percent at baseline
and by up to 21 percent under higher fixed-cost assumptions because the upfront component
directly offsets fixed participation costs; modest price floors have limited effects because
downside risk is not the binding constraint here. The adoption-threshold curves show that
prevailing voluntary carbon prices leave many modeled opportunities above the viability
threshold, especially for small parcels. These results imply that expanding participation requires
payment structures matched to the obstacle that actually limits enrollment, not simply higher
payments of any kind.
