Fossil pollen is preserved in lake and cave deposits, and provides a more generalized view of past vegetation, as most pollen grains can be identified only to plant family or genus. Pollen analysis is ideal for understanding the composition of wind-pollinated vegetation communities such as woodlands and forests. Fossils and geological deposits are almost meaningless unless they are placed within a timeframe-a chronology. The two most widely used chronological tools on the Colorado Plateau are radiocarbon dating and dendrochronology , the study of tree rings. Dendrochronology reveals local climatic and hydrologic histories stretching back in excess of 2000 years.
Trees also record fire scars which cause a sequence of overlapping wounds.
Recently, a series of other dating techniques , some quite sophisticated, are coming into use in research on the Plateau. Geological tools are used to examine inorganic materials. Lava flows, lava dams, ash falls, and even spectacular volcanic structures such as Sunset Crater have had impacts on human and vegetative life at many different temporal and spatial scales. Glacial features such as moraines and glacial striations are abundant in areas glaciated today, so their presence in some of the highlands of the Colorado Plateau suggests that in the past glaciers once flowed down a few of the region's mountains, and are an important indicator of climatic change . Materials on the surface of the earth accumulate and erode over time with changes in environmental conditions and events.