@mastersthesis {910, title = {Stand Replacing Fire History and Aspen Ecology in the Upper Rio Grande Basin}, volume = {Master of Science}, year = {2003}, pages = {94}, school = {University of Arizona}, address = {Tucson}, abstract = {

Dendroecological techniques were applied to reconstruct stand-replacing fire history in mixed conifer and spruce-fir forests in northern New Mexico and southern Colorado. Stand-replacing fire dates with annual accuracy and precision were determined using four lines of evidence for each of twelve sites within a 75,000 square kilometer area. The four lines of evidence were: (1) aspen inner-ring dates, (2) conifer death dates, (3) tree-ring width changes, or other morphological indicators of injury, and (4) fire scars. The annual precision of dating allowed the identification of significant synchrony of stand replacing fires among the 12 sites and regional surface fire events previously reconstructed from the large network of fire scar collections in the Southwest. Nearly all of these synchronous stand-replacing and surface fire years coincided with extreme droughts. This suggests that stand-replacing fire activity occurred primarily when drought conditions allowed fires to ignite and spread within these high elevation forests and/or for the spread of surface fires between lower and upper elevations. Fifty percent of reconstructed stand-replacing fires pre-dated large-scale Euro-American settlement in this region. This may suggest that land use practices (such as logging and mining) were not as important in promoting stand-replacing fires in these study sites, as compared with other areas in Colorado.

}, keywords = {aspen, basin, colorado, conifer, dendrochronology, dendroecology, Ecology, fire, fire history, new mexico, rio grande, spruce fir, stand replacing, tree ring}, author = {Margolis, Ellis Quinn} } @mastersthesis {550, title = {A Dendroecological Assessment of Whitebark Pine in the Sawtooth Salmon River Region Idaho}, volume = {Master of Science}, year = {1995}, pages = {56}, school = {University of Arizona}, address = {Tucson}, abstract = {

Whitebark pine (Pinus albicaulis Engelm.) tree-ring chronologies of 700 to greater than 1,000 years in length were developed for four sites in the Sawtooth-Salmon River region, central Idaho. These ring-width chronologies are used to (1) assess the dendrochronological characteristics of this species, (2) detect annual mortality dates of whitebark pine attributed to a widespread mountain pine beetle (Dendroctonus ponderosae Hopk.) epidemic during the 1909 to 1940 period, and (3) establish the response of whitebark pine tree ring-width growth to climate variables. Crossdating of whitebark pine tree-ring width patterns was verified. Ring-width indices had low mean sensitivity (0.123-0.174) typical of high elevation conifers in western North America, and variable first order autocorrelation (0.206-0.551). Mortality of dominant whitebark pine caused by mountain pine beetle had a maxima at 1930 on all four sites. Response functions and correlation analyses with state divisional weather records indicate that above average radial growth is positively correlated with winter and spring precipitation and inversely correlated with April temperature. These correlations appear to be a response to seasonal snowpack. Whitebark pine is a promising species for dendroclimatic studies.

}, keywords = {dendrochronology, dendroclimatology, dendroctonus ponderosae, dendroecology, idaho, pine beetle, pinus albicaulis, sawtooth salmon river, tree ring, whitebark pine}, author = {Perkins, Dana Lee} }