Fuel supply to the largely gaseous flames in an intense wildland fire is primarily a result of pyrolysis of cellulose present in live wood. Gaseous fuel released from high temperature pyrolysis of ground fuel is a complex and highly variable mixture, which includes four main gases (CO, H-2, CH4, and CO2) and other aromatics. Although a detailed reaction mechanism (over a hundred reactions and around 50 species) is possible for an accurate description of the chemistry, it is currently impractical for predicting fire behavior under adverse conditions. Therefore, the idea of reducing the detailed mechanism to a few steps has always been attractive. We have developed a reduced four-step mechanism for combustion of gaseous fuel released from high temperature pyrolysis of wood using steady state assumptions for minor species. Three test environments composed of a perfectly stirred reactor, premixed flame, and opposed diffusion flame are used to validate this mechanism by comparing calculations performed with full, skeletal, and reduced chemistry over a wide range of pyrolysis fuel gas composition, fuel/air equivalence ratio, and strain rate. The reduced mechanism designed for the methane-air system is also used to model the combustion of pyrolysis fuel gas. The reduced model developed in this paper generally provides a good description of the oxidation process of pyrolysis fuel gas. The calculated temperature distribution, species profiles, and flame speed from a reduced model. and opposed diffusion flame structure agree well with the results obtained by full mechanism.