TY - THES T1 - A Dendroecological Assessment of Whitebark Pine in the Sawtooth Salmon River Region Idaho T2 - Department of Renewable Natural Resources Y1 - 1995 A1 - Perkins, Dana Lee KW - dendrochronology KW - dendroclimatology KW - dendroctonus ponderosae KW - dendroecology KW - idaho KW - pine beetle KW - pinus albicaulis KW - sawtooth salmon river KW - tree ring KW - whitebark pine AB -

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.

JF - Department of Renewable Natural Resources PB - University of Arizona CY - Tucson VL - Master of Science ER - TY - THES T1 - Dendrochronology and Fire History in a Stand of Northern California Coast Redwood T2 - School of Renewable Natural Resources Y1 - 1991 A1 - Brown, Peter Mark AB - Fire-scarred cross-sections from coast redwood (Sequoia sempervirens) at two sites were dendrochronologically dated and used to develop a fire history. Redwood offers a challenge for dendrochronological study due to ring wedging and complacency. Crossdating was successful in 12 of 24 trees. The fire history was developed by comparison of fire scars and fire-associated ring characteristics (resin ducts, double latewood, growth releases, and ring separations) recorded in ring series. Using only dates of fire scars from the first fire in 1714 to the last in 1962, the mean fire interval (MFI) was 9.9 years. MFI for the best represented presettlement segment 1714-1881 was 8.0 years. Using all fire-associate ring features, MFI 1714-1962 was 7.0 years and 1714-1881, 6.0 years. Use of all fire-associated ring characteristics is argued to be a more accurate representation of past fire frequency. MFIs determined are less than others reported for coast redwood and suggest fire frequency in redwood may have been underestimated in past studies. JF - School of Renewable Natural Resources PB - University of Arizona VL - MS UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=7747786571&sid=1&Fmt=2&clientld=43922&RQT=309&Vname=PDQ ER - TY - THES T1 - A Dendrochronological Assessment of Western Spruce Budworm, Choristoneura Occidentalis Freeman, in the Southern Rocky Mountains T2 - School of Renewable Natural Resources Y1 - 1987 A1 - Swetnam, T. KW - Watershed Management AB -

Tree-ring chronologies from ten mixed conifer stands in the Colorado Front Ranges and New Mexico Sangre de Cristo Mountains were used to reconstruct timing, duration, and radial growth impacts of past outbreaks of western spruce budworm, Choristoneura occidentalis Freeman. Graphical and statistical comparisons of tree-ring chronologies from host and non-host tree species, in conjunction with Forest Service records of outbreaks during the twentieth century, revealed that outbreaks were identifiable only in the host chronologies as sharply reduced growth periods. These comparisons also showed that host and non-host tree-ring chronologies were generally similar between outbreaks and that both were responding in a similar manner to climatic variation. A study of defoliation and insect population data that was available for the New Mexico stands demonstrated that host radial growth from 1978 to 1983 was highly correlated with budworm activity. The non-host chronologies from each stand were used to correct the host chronologies for climatic and other non-budworm environmental variations by a differencing procedure. The corrected chronologies were then used to estimate the dates and radial growth effects of past budworm outbreaks. Tree-ring characteristics of twentieth century documented outbreaks were used as criteria for inferring the occurrence of outbreaks in previous centuries. At least nine periods of increased budworm activity were identified in the region from 1700 to 1983. The mean duration of reduced growth periods caused by known and inferred budworm outbreaks was 12.6 years, and the mean interval between initial years of successive outbreaks was 34.9 years. The mean maximum radial growth loss was 50 percent of expected growth, and the mean periodic growth loss was 21.6 percent. There was an unusually long period of reduced budworm activity in the first few decades of the twentieth century, and since that time outbreaks have been markedly more synchronous between stands. Increased synchroneity of outbreaks in the latter half of the twentieth century suggests that areal extent of outbreaks has increased. This phenomenon may be due to changes in the age structure and species composition of forests following harvesting and fire suppression in the late nineteenth and early twentieth centuries.

JF - School of Renewable Natural Resources PB - University of Arizona VL - PhD UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=753027921&sid=16&Fmt=2&clientId=43922&RQT=309&VName=PQD ER -