A 616-year Douglas-fir (Pseudotsuga menziesii) chronology was developed to examine the history of drought and moisture variability in the Sooke Watershed, near Victoria, British Columbia. Ring-width chronologies were compared to historical precipitation, air temperature and drought variables (Palmer Drought Severity Index (PDSI) and Standardized Precipitation Index (SPI)) to determine the climate/radial-growth response to moisture stress on the sampled stands. Correlations between the ring-width chronologies and climate variables revealed that May to July precipitation, May-June SPI and July PDSI were significant limiting factors to radial-width growth. A transfer function was established for each of these variables to create a proxy climate reconstruction of drought in the watershed. The summer precipitation model provided the most accurate representation of past moisture variability (R2 = 0.20) and reveals substantial variation in precipitation over the past six centuries. Evidence from the periodicity of the tree-ring record to suggest that some modes of atmospheric circulation are influencing precipitation supply to the watershed.
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/883 |
| Date | 21 April 2008 |
| Creators | Jarrett, Patricia |
| Contributors | Smith, Dan, Prowse, Terry |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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