@mastersthesis {500, title = {Sierra Nevada Tree Rings and Atmospheric Circulation}, volume = {PhD}, year = {1998}, school = {University of Arizona}, abstract = {

The primary objective of this research is to investigate relationships between extremes in central Sierra Nevada tree growth, temperature and precipitation and winter and summer atmospheric circulation. Using existing Sierra Nevada chronologies, I developed two mean chronologies for the period of overlap between instrumental and tree-ring records (1900-1987), one for giant sequoia (Sequoiadendron giganteum) and one for treeline pines (Pinus balfouriana, Pinus albicaulis) and selected the highest and lowest quintiles of tree growth as extreme years. For these years, I constructed and analyzed maps of composite anomalies for the following climatic data: tropospheric pressure (SLP, 700 mb, 500 mb), storm track (positive vorticity advection [PVA], a variable not previously used in dendroclimatology), temperature, precipitation, and snow (a variable often assumed have the same effects on growth as winter precipitation). Results suggest that extreme growth in these trees is associated with distinct patterns of winter atmospheric circulation and snow depth that are consistent with instrumental studies for the Western U.S. The storm track and snow analyses, seldom used in dendroclimatology, added substance to inferences based on analyses of tropospheric and surface climate parameters. This study shows the strong potential for reconstruction of these variables using Sierra Nevada trees. Synthesis of these results suggests that sequoia exhibit low growth during years with meridional winter and summer circulation, winter storms primarily occluded in the Gulf of Alaska, and low snow depth; sequoia exhibit high growth during years with low winter pressure in the north Pacific, long duration storms, a SW-NE oriented storm track entering North America at the California-Oregon border, high snow depth and zonal summer flow. Treeline pines exhibit low growth during years with enhanced ridging over the eastern Pacific, cool, short duration winter storms along a northern track, low snow depth and high east Pacific summer SLP; these pines exhibit high growth during years with warm, long duration winter storms following a southern track, a quasi-PNA atmospheric circulation pattern, average snow depth and a northeastward displaced summer subtropical high. Evidence presented herein suggests that variation in extreme treeline pine growth tracks low frequency changes in north Pacific atmospheric circulation.

}, keywords = {Paleoecology}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=733009441\&sid=28\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Garfin, Gregg Marc} } @mastersthesis {451, title = {Spatial and Temporal Reconstruction of Twentieth-century Growth Trends in a Naturally-seeded Pine Forest}, volume = {PhD}, year = {1994}, school = {University of Arizona}, abstract = {

This research uncovered growth trends from 1920 to 1990 in a stand of south-western ponderosa pine (Pinus ponderosa Dougl. ex Laws. var. scopulorum), and investigated the role of climate and competition in shaping the observed trends. I focused on a 800 x 400-m permanent plot maintained by the U.S. Forest Service since 1920 near Flagstaff, Arizona. Temporal growth trends were quantified by size class using a mixed linear model applied to forest inventories, repeated at 10-year intervals. Tree density and stand basal area increased from 1920 to 1990, but growth rates of individual trees declined regardless of size class. Growth of large pines, whose density increased slightly, declined more than that of small pines, whose density almost tripled. I argued that competition for resources reduced growth rates of large trees more than those of small trees. Geostatistical analyses showed that, from 1920 to 1990, stem size was spatially autocorrelated over distances no greater than 30 m, a measure of average patch diameter. Tree density increased by increasing the number of pine groups rather than their horizontal dimension. Increased tree crowding corresponded to lower average, variance, and spatial dependence of individual growth rates. Since growth variation was less related to inter-tree distance at higher tree densities, density-dependent limitation of tree growth did not necessarily correspond to distance-dependent growth rates. No significant trend from 1910 to 1990 was found in climatic variables computed from daily meteorological records. Dendroclimatic analyses showed that climate-tree growth relations had not significantly changed over the twentieth century. Annual growth of both large and small pines was positively related to winter snowfall and to July monsoon rainfall. Periodic basal area increment obtained from dendrochronological data revealed that forest inventories over-estimated growth rates, especially for small pines. On the other hand, tree-ring chronologies developed using different standardization options showed different temporal trends. Repeated forest inventories quantified growth of individual trees and of the entire stand, but integrated bark and wood increment. Dendrochronological data had superior temporal resolution and accuracy, but their limited spatial coverage hindered representation of growth trends for the entire stand.

}, keywords = {Paleoecology}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=740900561\&sid=29\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Biondi, Franco} } @book {753, title = {Climate from Tree Rings}, note = {

Copies of this are available in the Tree Ring Laboratory. Please contact the curator for more information. pcreasman@ltrr.arizona.edu

}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, keywords = {climate, dendrochronology, paleoclimatology, tree rings}, author = {Hughes, M.K. and LaMarche, V.C. and Pilcher, J.R. and Kelly, P.M.} }