Graduation Date

Spring 2016

Document Type

Thesis

Program

Master of Science degree with a major in Biology

Program

Deparment of Biological Sciences

Committee Chair Name

Alana Chin

Committee Chair Affiliation

Cal Poly Humboldt Faculty or Staff

Second Committee Member Name

Lucy Kerhoulas

Second Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Third Committee Member Name

Rosanna Overholser

Third Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Fourth Committee Member Name

Yoon Kim

Fourth Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Keywords

Redwood, Foliar water uptake, Cllimate

Subject Categories

Botany

Abstract

Coast redwood (Sequoia sempervirens D. Don) depends on foliar water uptake from fog and rain to maintain water balance during the dry summer season. As fog and rain decline across the redwood region, understanding how foliar uptake capacity responds to climate has become increasingly important. This study investigated how three peripheral leaf traits that influence foliar water uptake, visible wax coverage, stomatal density, and guard cell length, vary across climatic gradients and how those traits affect uptake across 14 sites in California. Foliar water uptake was quantified using rain-chamber rehydration experiments, climatic predictors were evaluated using least absolute shrinkage and selection operator (LASSO) regression, and trait–uptake relationships were tested using linear regression models. All three traits varied with climate, with guard cell length showing the strongest climate association (R² = 0.83), followed by stomatal density (R² = 0.73) and wax coverage (R² = 0.51). Site-level structural traits explained substantial variation in foliar water uptake (= 0.72). Uptake was negatively associated with stomatal density and initial water potential, while wax coverage and guard cell length showed weaker positive relationships. These patterns indicate that foliar water uptake in Sequoia is shaped by coordinated, climate-responsive trait variation at broader spatial scales, highlighting a potential mechanism of resilience to increasing drought and reduced fog.

Citation Style

Scientific Journal Format

Included in

Plant Biology Commons

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