Take a look at this. Its a series of charts that allow you to compare which fuel to burn based upon the price of each individual fuel. Based upon this, it pays to burn wood (190/cord) only when oil is over 1.50 per gallon. Its interesting to compare.
http://energy.cas.psu.edu/EnergySelector/
-- Mike
http://energy.cas.psu.edu/EnergySelector/
-- Mike