Bio-oils were produced within a fast-pyrolysis micro-reactor at 400°C from Loblolly Pine (Pinus Taeda) with varying residence times. This preliminary study has considered two boundary values for the residence time, evaluating the products of the reaction at 20 seconds and 120 seconds. The collected bio-oils were analyzed for their calorific values (LHV) and biomass conversion efficiencies. Heating rates greater than 100°C/s were achieved for the biomass, allowing for isothermal conditions to exist throughout the majority of the reaction despite short residence times. This study shows the effect that reaction duration has on the mass of the bio-oil yield and energy content present for the isothermal fast pyrolysis of Loblolly Pine and evaluates the predictive capabilities of TGA derived Arrhenius coefficients.