Climate extremes, fire, and grazing herbivores are the major factors that discourage trees from growing in grassland areas. Fire especially is detrimental to tree growth, because a tree's growth points are above the ground and at the mercy of the intense heat that fire is all about. Historically indigenous folk used fire to push these woody species back to encourage more grass for more hunting opportunities. Fire was also used to reduce the dead plant material load that native grazing herds couldn't utilize fast enough. Climate extremes can be harmful to trees. When there are extended periods of dry weather with very little to no rain for months, this can cause extreme stress to a tree to the point where it will die. Rains that do come often come either as light rains, sometimes two or thr