@mastersthesis {439, title = {Fire Histories of Upper Elevation Forests in the Gila Wilderness, New Mexico via Fire Scar and Stand Age Structure Analyses}, volume = {Master of Science}, year = {1997}, pages = {120}, school = {University of Arizona}, address = {Tucson}, abstract = {

Fire-scar analysis to identify fire events and stand age structure analysis to identify fire effects on survivorship of trees were used to reconstruct surface and crown fire regimes in upper elevation forests of the Gila Wilderness, NM. Fire regimes varied across forest type, but not necessarily across elevation. Prior to the twentieth century, (from 1706 to 1904), the mean interval for large fires was 8 years. During the twentieth century, (from 1904 to 1995), the mean fire return interval for large fires was 46 years. The virtual end of historically frequent fire regimes due to livestock grazing and fire suppression since the turn of the century has affected successional pathways of forest types across elevations, favoring later successional forest species and structures.

}, keywords = {dendrochronology, fire, fire regime, fire scar, gila wilderness, new mexico, stand age, suppression, tree ring, upper elevation}, author = {Abolt,Rena Ann Peck} } @mastersthesis {904, title = {Fire Regime of the Lodgepole Pine (Pinus contorta var. murrayana) Forests of the Mt. San Jacinto State Park Wilderness, California}, volume = {Master of Science}, year = {1984}, note = {

Please contact the Laboratory of Tree Ring Research to view this thesis.

}, month = {08/1984}, pages = {93}, school = {Cornell University}, address = {Ithaca}, abstract = {

For the purpose of providing recommendations for the fire management plan of the Mt. San Jacinto State Park Wilderness, California, the natural fire regime of the lodgepole pine forests within the wilderness was determined. Fire-scarred lodgepole pine trees were cored, and their growth rings crossdated against a composite ring series, to obtain fire date estimates of fires that have burned within the forests during the last 300 years. U.S. Forest Service fire records and personal accounts were also used to determine recent fire history.

Results indicate that the fires within the lodgepole pine forests of Mt. San Jacinto probably were quite small (\< 0.4 ha). Because of this, the fire regime is probably one of low-intensity fires. Fires started principally by lightning and they generally did not spread far because of low woody fuel loading on the ground. These small fires, however, occurred quite frequently throughout the lodgepole pine forests. Fires probably burned every one to two years, and in many years, more than one fire burned. The average fire return interval for separate locations within the lodgepole pine forests was not determined exactly because most of the burned trees had only one fire-scar.

The effects of this fire-regime on the forest vegetation composition was determined. This was accomplished with multiple regression analyses of vegetative and physiographic data collected from the area of each verified fire.

In the 2500 to 2900 m elevation range, white fir generally increased in importance (relative basal area) over lodgepole pine as years since the fire increased. However, the relationships of lodgepole pine and white fir importances to the time since the fire were not statistically significant. Above 2800 m elevation, neither lodgepole pine nor limber pine importance was affected by the fire regime. Throughout the lodgepole pine forests of this wilderness area, the fire regime has not greatly affected the forest vegetation composition.

To compare two methods of obtaining fire year estimates from living, fire-scarred trees, both wedging and coring was done on ten fire-scarred lodgepole pine trees. The rings of the wedges and cores were then crossdated against a composite ring series, and the respective fire year estimates of each method were compared for each tree. Seven pairs of wedges and cores were crossdated, and each pair gave the same fire year estimate for the respective tree. In the situation of single-scarred trees, the coring method, along with dendrochronology dating, should be attempted instead of wedging, which is more destructive to the tree than coring.

Based on this study, I recommend that the fire management plan for the lodgepole pine forests of the Mt. San Jacinto State Park Wilderness contain two options for fire control. First, in areas that have heavy use by recreationists and cultural or historical benefits, fire suppression should begin immediately after a fire has been detected. Second, in all other areas, a \“let burn\” policy should be attempted, whereby the fire would be allowed to die out on its own. This would save the expense of fire suppression, which can be very costly in remote wilderness areas. These fires should be monitored in case they do burn near valuable areas. Prescribed burning is not recommended because of the weak relationship of the fire regime to the forest vegetation composition.

}, keywords = {california, coring, dendrochronology, fire, fire management, fire scar, Limber pine, lodgepole, mt san jacinto, mt san jacinto state park wilderness, pine, pinus contortata, regime, suppression, tree ring, var murrayana, wedging, white fir}, author = {Paul Sheppard} } @mastersthesis {573, title = {Fire History of the Gila Wilderness, New Mexico}, volume = {Master of Science}, year = {1983}, pages = {156}, school = {University of Arizona}, address = {Tucson}, abstract = {

A data base of fire occurrence was established for the Gila Wilderness by analyzing fire scars and compiling fire records. Cross sections of 44 fire scarred ponderosa pine trees (Pinus ponderosa Laws.) were collected from three study areas. Crossdating of more than 800 individual fire scars revealed that extensive surface fires were a common occurrence prior to 1900. Mean fire intervals for a 250-year period prior to 1900 were approximately four to eight years and fire intervals ranged from one to 26 years. Intensive grazing and fire suppression efforts after 1900 resulted in a sudden decrease in number of fires recorded by the sample trees.

A 72-year record (1909-1980) of fire occurrence in the Gila National Forest was compiled from Forest Service records. The fire records and fire scar evidence suggest a need for continued emphasis on fuels reduction and greater flexibility in the Prescribed Natural Fire program.

}, keywords = {crossdate, dendrochronology, fire, fire history, fire scar, gila national forest, gila wilderness, new mexico, pinus ponderosa, ponderosa pine, tree ring}, author = {Swetnam, T.} }