Bark, which is available in abundance, has recently become a topic of interest when considering alternative materials for the production of pyrolysis bio-oil. Previous studies have revealed that the pyrolysis behavior of bark differs remarkably from that of wood in that bark typically generates a phase-separated bio-oil. In this study, blends of loblolly pine wood and bark were pyrolyzed to investigate the effect of blending ratio on the yield and properties of derived bio-oils. Trends of lower decomposition rate, decreased organic yield, and increased bio-char yield were observed as bark percentage in the feedstock increased, while the amount of levoglucosan in bio-oil increased. Pyrolysis reactivity, which includes yield and physical properties of the bio-oil, was found to have a linear relationship with the blending ratio of pine bark. It was found that blending up to 50% bark in the feedstock still produced a homogeneous bio-oil. (C) 2017 Elsevier B.V. All rights reserved.