Since the mid 1500s when the Spanish first arrived in North America, writers have documented their observations as well as stories from Indigenous people of the Americas about their practice of shaping and modifying trees for spiritual, medicinal, nutritional, navigational, ceremonial, utilitarian, or other purposes. NASTaP’s co-founder and President, Dr. James Jefferson, a Southern Ute born in 1933, was taught by his elders to recognize and interpret these trees. Other Native Americans have described similar practices throughout the United States and Canada. Notable contemporary documentation of these cultural traditions include those by NASTaP co-founder, John Wesley Anderson, Don and Diane Wells, Dennis Downs, Steve Houser, Linda Pelon, and Jimmy W. Arterberry. Dr. Jefferson’s teachings, as well as these resources, provide the core of NASTaP’s standards for recognizing and identifying Native American culturally modified trees (CMTs). We recognize that not all CMTs may be verified or authenticated by Native Americans, and that not all bent trees are CMTs. We offer these standards as a way to identify potential Native American CMTs with the understanding that the more indicators a tree exhibits, the more likely it is to be a Native American CMT.