Blue Light Intensity (BI) offers the potential to provide high sensitivity climate reconstructions using tree density measurements. This innovative and cost-effective technique merely requires a commercially available flat bed scanner and several software programs. BI considers parameters other than ring-width (RW), such as latewood and earlywood density, which are often overlooked in traditional ring width-based measurements. BI data is generated for five sites on the Gulf of Alaska and for a portion of the Alaska Peninsula. Resulting BI chronologies demonstrate strong positive summer climate signals relative to the ring width chronologies for each corresponding site, suggesting BI is sensitive to summer climate and can serve as a proxy for summer temperature. A comparison of BI and RW data denotes that BI data is associated with higher interannual frequency and RW is associated with decadal-centennial frequency trends. Future research should consider combining high and low frequency trends to enhance climate reconstruction.


Wiles, Gregory




Physical Sciences and Mathematics

Publication Date


Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis



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