Data Gaps for Monitoring Forest Carbon in the United States: An Inventory Perspective

There is increasing interest in accurate estimates of regional carbon fluxes, and identification of the causes of land/atmosphere/ocean exchange of carbon. Improved information will lead to better policies for managing greenhouse gas emissions and sequestration. The goals of this paper are to review the capability of ongoing operational inventory programs for estimating forest carbon stocks and stock changes, and to identify opportunities to improve forest carbon monitoring by enhancing these programs and supplementing them with new monitoring capability. Carbon in forest ecosystems and wood products cannot be measured directly. Ongoing forest monitoring programs provide a statistical basis for estimating carbon stocks and stock changes, based on data already collected, with a temporal resolution of about 5 years. Improvements in inventories will shorten the reporting cycle and add some variables that enhance the content with respect to carbon estimation, but it will take about a decade for full implementation. Meanwhile, there is an important role for remote sensing measurements, modeling, and imputation techniques to fill gaps in spatial coverage and content. Elements of the proposed North American Carbon Program, if implemented, will improve the estimates of forest ecosystem carbon.