Fire occurrence, behavior and the effect of fire on deer mouse density in oakbrush at Camp Williams National Guard Base, Utah


Category:  Forestry
Linked Publication
Language: English
Author(s): Joel E. Godfrey
Description: Fire occurrence and behavior were determined by collecting and analyzing fuel, weather, and fire history data. Fuel plots were used to measure average fuel loading by vegetation type and integrated with weather to make worst-case fire behavior predictions. A fire history was developed using oakbrush (Quercus gambelli Nutt.) sprouts to determine age and the Global Positioning System (GPS) for mapping the burned areas. Average fuel loading was highest in the oakbrush fuel type with 16.8 t/ha, then juniper (Juniperus osteosperma Torrey) with 6.72 t/ha, and the lowest was in sagebrush (Artemisia tridentata Nutt.) with 4.93 t/ha. Fire behavior predictions were similar for all fuel types. The fire rotation for the study area was calculated to be 130 years. The fire history showed the most hectares burned were in the oakbrush fuel type due to fuel loading and horizontal continuity. Prescribed burns and vegetative fuel breaks were suggested as management alternatives. The effect of fire on deer mouse (Peromyscus maniculatus) density in oakbrush was determined by using a trapping web design with distance sampling techniques. Webs were set in four pairs with one web of each pair being in 7 year-old burned oakbrush and the other web in unburned oakbrush. Variables such as shrub height and litter depth were recorded in order to reduce variance. Trapping occurred in June 1994 with each web set for two consecutive nights using 80 Museum Special snap traps spaced 6 m apart on eight lines. Density estimates were determined by using a computer program called DISTANCE and then analyzed using analysis of variance with a randomized block design. No significant differences between deer mouse densities were detected between burned and unburned oakbrush. Although litter depth and shrub height were both significantly less in burned sites, it did not affect deer mouse density. The conclusion from these results was that after 7 years oakbrush had recovered to a point that the effect of fire on deer mouse density was negligible.