Abstract

Blue intensity, or BI, has been proposed as a new parameter in dendroclimatology. It is considered as both a labor-and-cost effective alternative to maximum latewood density (MXD) for paleoclimatic reconstruction with tree-rings. However, several major obstacles with BI greatly limit the broad application of this revolutionary technique, among which the discoloration of wood samples stands out as the most challenging. Color staining in wood is usually the result of various post-depositional processes that have been attributed to oxidation and biogenic sources. This study aims to overcome this discoloration challenge by testing a new method of color removal on subfossil wood samples recovered from sites across the Gulf of Alaska. A 24-hour soak in 15% H2O2 (hydrogen peroxide) was performed upon subfossil samples to reset the wood color back to its original coloration when they were living. These samples were then processed into BI chronologies and run through several statistical evaluations from which the quality of the hydrogen peroxide modification was evaluated. It turned out that the H2O2 method we proposed was successful in the removal of most of the extraneous color stains from the subfossil wood samples and was determined to statistically strengthen the climatic signals produced from BI chronologies. This is especially the case for the delta-BI (DBI) and latewood BI (LWBI) chronologies.

Advisor

Wiles, Gregory

Department

Earth Sciences

Disciplines

Biogeochemistry | Climate | Environmental Indicators and Impact Assessment | Environmental Monitoring | Geochemistry | Glaciology | Other Forestry and Forest Sciences

Keywords

dendrochronology, paleoclimatology, blue intensity, hydrogen peroxide, forestry, climatology

Publication Date

2023

Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis

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