Fractional catalytic pyrolysis is a selective in situ conversion of biopolymers into desired products. Fractional catalytic pyrolysis was used to convert the lignin fraction of hybrid poplar wood into high yields of cresols and phenols while the carbohydrate fraction was selectively converted into gaseous products. Ground air-dried biomass was fractionally pyrolyzed at 450-500 degrees C in a 2-in fluidized bed reactor. The total liquid, gas, and char/coke yields were 33%, 53%, and 12.5%, respectively. The low viscosity liquid products consisted of almost pure phenolics with minor carbohydrate decomposition products. The major liquid components were phenol, cresols, methyl substituted phenols, and small fractions of indene and substituted naphthalenes. The carbon and oxygen contents and high heating value (HHV) of the oil were 71%, 21%. and 30.5 MJ/kg, respectively. About 90 wt% of the gaseous products was carbon monoxide and carbon dioxide, and the rest was a mixture of hydrocarbons.