West has used tree ring records in his own research to add a dimension of environmental history to his studies of American Indian tribes. The tribes often have oral traditions that describe seasonal conditions, and pictographic representations of climate throughout the years that sometimes suggest droughts or hard winters, but the information is far from complete. These two fields feed each other. Paleoclimatic research gives a new perspective on the theater of historical action. In turn, written historical records, when available, enhance what researchers can learn from trees.
Tree rings provide a narrative of their growing season, but become silent during dormancy.
Historic records can provide texture to what scientists see inside the tree, West said. When you look at the climate shifts over time, the story takes on a new dimension. That dimension includes a period of abundant rainfall, which attracted Indians and settlers to the plains, followed by a prolonged drought that drove them to conflict and suffering. That part of the tale can be seen through overland diaries and letters home written by travelers, fortune seekers and homesteaders. These people were intensely aware that this would be one of the most remarkable episodes of their lives.