SEASONAL TEMPERATURE AND PRECIPITATION EFFECT ON TREE-RING WIDTHS OF UPPER ELEVATION STRIP-BARK AND WHOLE-BARK TREES IN THE WHITE MOUNTAINS OF CALIFORNIA

Climatic factors like temperature and precipitation play a major role in tree growth and the resulting tree-ring widths. As stated in the literature, temperature is the limiting factor for tree growth at the upper elevation tree boundary, while precipitation governs tree growth at the lower elevation tree boundary. As part of a larger study, I reported a significant statistical difference between the growth pattern of strip-bark and whole-bark bristlecone pine (Pinus longaeva) trees within the past 200 years, as inferred from tree-ring width measurement (p<0.002, á=0.05, n=67). I concluded that strip-bark and whole-bark trees have different growth trends if compared on 50-year increments, while slope analysis for the entire period of the tree-ring chronology, 1400 – 2004 A.D, produced no significant difference due to high noise variability in the time series. Tree-ring samples were collected from the upper boundary tree line forest on Sheep Mountain and in Patriarch Grove at 3500 m in the White Mountains of California, Inyo National Forest. Strip-bark is the partial dieback of the cambium along the circumference of the tree, a phenomenon found in higher elevation pines and junipers. In this study, we test the response of each chronology for seasonal temperature and precipitation in order to isolate the effect of climate on the growth trend of the strip-bark and whole-bark trees. Although both of the chronologies respond to precipitation and temperature, whole-bark trees are more sensitive to seasonal fluctuations than strip-bark trees. These results indicate the importance of considering the condition of the bark of trees that are used in dendroclimatic reconstruction.