A paradigm/model widely held within Climate Change and Renewable Energy Circles (e.g., Scientists, Policymakers) is that energy crops would primarily be grown on traditional farm lands. Since soil science is very clear that: (1) soils have a finite capacity to hold carbon and (2) most traditional farming lands are already near or at a carbon saturation level -- energy crops have not been considered a meaningful tool in CO2 sequestration.

However, if this paradigm is expanded to using degraded or marginal lands such as closed mining sites, the potential of energy crops to create significant levels of permanent carbon sinks can dramatically change.

In the Southern U.S., pre-mined lands were most likely in native forest for hundreds/thousands of years. As such, these sites' soils were probably at carbon saturation. After mining however, empirical research is clear that post-mined lands often have little soil carbon.

Thus, any incremental build-up of carbon from post-mined sites (starting from a low percentage close to zero) to a carbon saturation level (present before mining) would be creating a permanent carbon sink. This concept of "incremental build-up" of carbon levels on mined lands is illustrated in the yellow bar of the graph below.

Carbon Saturation Levels of Pre and Post Mined Soils

Soil research performed by the U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) at our mined site provides empirical data for this argument. In 2.5 years after energy crop tree establishment, soil carbon levels had increased 200% from the pre-existing site conditions (last mined over 60 years ago).

Soil Carbon Percentages Found Before
& 2.5 Years After Tree Planting

Go to the U.S. Department of Energy's Oak Ridge National Lab Report on Carbon Sequestion Research at our Treefarm [PDF document].