In Texas, CABI and Hart Energy Consulting have released Biofuels and Land Use Change: A Science and Policy Review, which reviews key research that has been conducted on the subject and analyses where the gaps in knowledge lie. Marginal, abandoned, degraded and unused lands are really the only possible sources of significant land for biofuel expansion. However, they are rarely quantified. The report asks how much of this type of land is available and what problems would need to be overcome to bring these lands into production. The report can be found at the Biofuels Information Exchange portal.
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