Abstract: Spontaneous decay rate distributions and nonexponential decay rates of the excited emitter ensembles embedded in the basic unit cell of woodpile photonic crystals with low refractive index contrast are investigated. It is found that the spontaneous emission rate distributions and the decay rates of the emitter ensembles strongly depend on the transition frequency of the emitters. The decay rates of emitters near the upper gap edge are slower than that in the center of the pseudo-gap, which is quite a contrast to the conventional concept. Based on the decay function，the average decay lifetime is calculated. The calculation results fit the experiment well and show exactly the same trend as the experiments. These results may be supplied in probing the decay rate distribution or local density of states in future experiments.