A two-dimensional pyrolysis model has been developed to study the effects of the cracking of the char layer during pyrolyzation of a 1cm x 1cm wood particle. The pyrolysis times of cracked and uncracked particles are compared. The conductivity of the uncracked particle is increased until the pyrolysis times of the uncracked particle match those of a particle with a particle size and shape of crack. An effective conductivity is found for various types of cracks. This effective conductivity can be used to include the effects of cracking in models that do not include crack geometry. The model shows that the equivalent conductivity increases according to the total crack area and the external radiant temperature. For large amounts of cracking, the effective conductivity can be twice that of an uncracked particle.