Authors: David Saldana*, California State University Dominguez Hills, Michelle Danielle Mohr, Caifornia State University Domiguez Hills, Gabriel Santiago Angulo, California State University Dominguez Hills, Raju Bista, Califonia State University Dominguez Hills, Parveen Kumar Chhetri, California State University Dominguez Hills
Topics: Mountain Environments, Paleoenvironmental Change, Biogeography
Keywords: Tree-ring, Drought, Climate, Ring Width, Jeffrey Pine, Dendrochronology
Session Type: Poster
Presentation File: Download
The forest ecosystem is responding to climate change worldwide by advancing to higher altitudes, increasing recruitment, and changing radial growth pattern. To understand the future response of sub-alpine forests on the western slope of the Sierra Nevada, we analyzed the radial growth of trees using ring width index (RWI) and basal area increment (BAI). Tree cores were collected near South Lake Tahoe in the Cascade Creek watershed. Tree-ring cores were processed with standard dendrochronological methods. Ring-width was measured with the Velmex tree-ring measurement system and software (J2X). Visual crossing dating and statistical packages (COFECHA, ARSTAN, treeclim, and dplR) were used in the cross-dating and removal of age-related error. We developed a 370 year-long (1648-2018) chronology from 44 cores (24 trees). Our analysis using RWI inferred the years 1729, 1730, 1752, 1753, 1757, 1763, 1771, 1777, 1781-83, 1796 were drought events in the 18th century, and years 1822, 1844, 1846, 1859, 1886 were events in the 19th. Using BAI showed the years 1757, 1782, 1886, 1859, 1876, 1920, 1929, 1977, 1988, 2001, 2002, 2008 demonstrate below average growth (narrow ring). Furthermore, our BAI analysis also indicated that 1928-30, 1987-1989, and 2013-2014 were low growth periods associated with extreme drought events. We found a significant positive correlation with precipitation in previous year’s August and September, and positive correlation with June precipitation of current year. We observed an inverse relationship with correlation regarding previous year’s temperature in May, August, September, October and in current year’s temperatures in June and July.