Feasibility Study of Carbon Sequestration Through Reforestation in the Chesapeake Bay Watershed of Virginia

The Chesapeake Rivers conservation area encompasses approximately 2,000 square miles of agricultural and forest lands in four Virginia watersheds that drain to the Chesapeake Bay. Consulting a time series of classified Landsat imagery for the Chesapeake Rivers conservation area, the project team developed a GIS-based protocol for identifying agricultural lands that could be reforested, specifically agricultural lands that had been without forest since 1990. Subsequent filters were applied to the initial candidate reforestation sites, including individual sites > 100 acres and sites falling within TNC priority conservation areas. The same data were also used to produce an analysis of baseline changes in forest cover within the study period. The Nature Conservancy and the Virginia Department of Forestry identified three reforestation/management models: (1) hardwood planting to establish old-growth forest, (2) loblolly pine planting to establish working forest buffer with hardwood planting to establish an old-growth core, and (3) loblolly pine planting to establish a working forest. To assess the relative carbon sequestration potential of these different strategies, an accounting of carbon and total project costs was completed for each model. Reforestation/management models produced from 151 to 171 tons carbon dioxide equivalent per acre over 100 years, with present value costs of from $2.61 to$13.28 per ton carbon dioxide equivalent. The outcome of the financial analysis was especially sensitive to the land acquisition/conservation easement cost, which represented the most significant, and also most highly variable, single cost involved. The reforestation/management models explored all require a substantial upfront investment prior to the generation of carbon benefits. Specifically, high land values represent a significant barrier to reforestation projects in the study area, and it is precisely these economic constraints that demonstrate the economic additionality of any carbon benefits produced via reforestation--these are outcomes over and above what is currently possible given existing market opportunities. This is reflected and further substantiated in the results of the forest cover change analysis, which demonstrated a decline in area of land in forest use in the study area for the 1987/88-2001 period. The project team collected data necessary to identify sites for reforestation in the study area, environmental data for the determining site suitability for a range of reforestation alternatives and has identified and addressed potential leakage and additionality issues associated with implementing a carbon sequestration project in the Chesapeake Rivers Conservation Area. Furthermore, carbon emissions reductions generated would have strong potential for recognition in existing reporting systems such as the U.S. Department of Energy 1605(b) voluntary reporting requirements and the Chicago Climate Exchange. The study identified 384,398 acres on which reforestation activities could potentially be sited. Of these candidate sites, sites totaling 26,105 acres are an appropriate size for management (> 100 acres) and located in priority conservation areas identified by The Nature Conservancy. Total carbon sequestration potential of reforestation in the study area, realized over a 100 year timeframe, ranges from 58 to 66 million tons of carbon dioxide equivalent, and on the priority sites alone, potential for carbon sequestration approaches or exceeds 4 million tons of carbon dioxide equivalent. In the absence of concerted reforestation efforts, coupled with policy strategies, the region will likely face continued declines in forest land

Natural climate solutions

Our thanks for inputs by L. Almond, A. Baccini, A. Bowman, S. CookPatton, J. Evans, K. Holl, R. Lalasz, A. Nassikas, M. Spalding, M. Wolosin, and expert elicitation respondents. Our thanks for datasets developed by the Hansen lab and the NESCent grasslands working group (C. Lehmann, D. Griffith, T. M. Anderson, D. J. Beerling, W. Bond, E. Denton, E. Edwards, E. Forrestel, D. Fox, W. Hoffmann, R. Hyde, T. Kluyver, L. Mucina, B. Passey, S. Pau, J. Ratnam, N. Salamin, B. Santini, K. Simpson, M. Smith, B. Spriggs, C. Still, C. Strömberg, and C. P. Osborne). This study was made possible by funding from the Doris Duke Charitable Foundation. Woodbury was supported in part by USDA-NIFA Project 2011-67003-30205 Data deposition: A global spatial dataset of reforestation opportunities has been deposited on Zenodo (https://zenodo.org/record/883444). This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1710465114/-/DCSupplemental.Peer reviewedPublisher PD

Natural climate solutions for the United States

© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Science Advances 4 (2018): eaat1869, doi:10.1126/sciadv.aat1869.Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)—21 conservation, restoration, and improved land management interventions on natural and agricultural lands—to increase carbon storage and avoid greenhouse gas emissions in the United States. We found a maximum potential of 1.2 (0.9 to 1.6) Pg CO2e year−1, the equivalent of 21% of current net annual emissions of the United States. At current carbon market prices (USD 10 per Mg CO2e), 299 Tg CO2e year−1 could be achieved. NCS would also provide air and water filtration, flood control, soil health, wildlife habitat, and climate resilience benefits.This study was made possible by funding from the Doris Duke Charitable Foundation. C.A.W. and H.G. acknowledge financial support from NASA’s Carbon Monitoring System program (NNH14ZDA001N-CMS) under award NNX14AR39G. S.D.B. acknowledges support from the DOE’s Office of Biological and Environmental Research Program under the award DE-SC0014416. J.W.F. acknowledges financial support from the Florida Coastal Everglades Long-Term Ecological Research program under National Science Foundation grant no. DEB-1237517

CARBON STORAGE OF BOTTOMLAND HARDWOOD AFFORESTATION IN THE LOWER MISSISSIPPI VALLEY, USA

Abstract: The emerging carbon market is an increasingly important source of finance for bottomland hardwood afforestation in the Lower Mississippi River Valley (LMV). Notwithstanding, there is a scarcity of empirical estimates of carbon sequestration specific to the region and we sought to address this outstanding need. We evaluated tree measurements from known-age bottomland hardwood stands from a chronosequence of sites in the LMV, drawing on 540 plot measurements within 67 stands. We derived a model of live tree biomass carbon as a function of stand age. The model explained 83% of the variation in live tree biomass carbon at the stand level, and provides a more accurate projection for application in the LMV than broader regional models currently available. Modeled live tree biomass carbon was greater than the corresponding regional estimate used in the U.S. Department of Energy&apos;s voluntary greenhouse gas reporting program for years 20 through 90 (up to 59% greater at year 50), but trended toward convergence at mature stages