One particularly useful approach to uncover local ecological histories has been to use dendrochronological (tree-ring) methods to reconstruct patterns of fire occurrence and forest change over the last several hundred years, primarily in the Jemez Mountains but also in the Sangre de Cristos. Old trees can tell many stories if one knows how to decipher the information contained in their wood. This tree-ring work is being accomplished through a cooperative effort involving the U.S. Geological Survey’s Jemez Mountains Field Station (located at Bandelier National Monument), Professor Tom Swetnam’s group at theLaboratory of Tree-Ring Research (University of Arizona), and the Santa Fe and Carson National Forests. Since 1988 we have determined over 4,000 prehistoric fire dates from fire scars on more than 550 sampled trees, snags, logs, and stumps at 30 sites in the Jemez Mountains. In the Sangre de Cristos we have about 170 prehistoric fire dates from over 50 sampled trees at four sites. Elevations of sampled sites ranged between about 6,500 and 11,000 ft; vegetation varied correspondingly from piñon-juniper woodlands up through ponderosa pine to mixed conifer and spruce forests. Each scar is dated to its precise year of formation, and in most cases even the season in which the fire occurred was determined. Fire dates extend back to 1422 AD in the Jemez Mts. and to 1230 AD in the Sangre de Cristos.

Where Have All the Grasslands Gone?” (part 3 of 5)