By expanding energy biomass production on marginal lands that are not currently used for crops, food prices increase and indirect climate change effects can be mitigated. Studies of the availability of marginal lands for dedicated bioenergy crops have focused on biophysical land traits, ignoring the human role in decisions to convert marginal land to bioenergy crops. Recent history offers insights about farmer willingness to put non-crop land into crop production. The 2006–09 leap in field crop prices and the attendant 64% gain in typical profitability led to only a 2% increase in crop planted area, mostly in the prairie states. At this rate, a doubling of expected profitability from biomass crops would expand cropland supply by only 3.2%. Yet targets for cellulosic ethanol production in the US Energy Independence and Security Act imply boosting US planted area by 10% or more with perennial biomass crops. Given landowner reluctance to expand crop area with familiar crops in the short run, large scale expansion of the area in dedicated bioenergy crops will likely be difficult and costly to achieve.