Most grassland environments are conducive to the ignition and spread of fire. The vegetation provides flammable fuel which when burned facilitates new growth and restricts tree encroachment. The grassland community exhibits various adaptations to fire environment. Fire intensity and frequency of burning are important variables in effecting its stability. Higher frequencies are associated with the moist grasslands where the potential for fuel accumulation is greatest. Grazing reduces litter buildup promoting less frequent fires. Excessive utilization by herbivores results in extended intervals or even cessation promoting site deterioration, composition changes in the plant community, and tree invasion.