Title
Decline in the health and vigor of Oregon white oak
Date
5-30-2013 2:00 PM
Location
Werner University Center (WUC), Pacific Room
Department
Biology
Session Chair
Ava Howard
Session Chair
Jeffrey Snyder
Session Title
Research in the Biological Sciences
Faculty Sponsor(s)
Ava Howard
Presentation Type
Poster session
Abstract
Oregon white oak (OWO) is a dominant component of savannah and woodland habitats that were once a large part of our landscape. Land use changes have removed much of this habitat and have threatened or endangered species. We hypothesized that changes in competition are associated with decline in OWO vigor. We selected six OWO that were healthy and six that showed declining health. We measured growth and health of each study tree and assessed competition from surrounding trees in a 16 m radius. OWO study trees had similar height, but trees with good health had larger mean trunk width than trees with declining health. Dominance of Douglas firs was high, and tree density was 2.5 times greater in declining OWO plots compared to healthy OWO plots. These results support the hypothesis that shade intolerant OWO are declining as forest density and Douglas fir dominance increases.
Recommended Citation
Sims, Valerie, "Decline in the health and vigor of Oregon white oak" (2013). Academic Excellence Showcase Schedule. 8.
http://digitalcommons.wou.edu/aes_event/2013/biol/8
Decline in the health and vigor of Oregon white oak
Werner University Center (WUC), Pacific Room
Oregon white oak (OWO) is a dominant component of savannah and woodland habitats that were once a large part of our landscape. Land use changes have removed much of this habitat and have threatened or endangered species. We hypothesized that changes in competition are associated with decline in OWO vigor. We selected six OWO that were healthy and six that showed declining health. We measured growth and health of each study tree and assessed competition from surrounding trees in a 16 m radius. OWO study trees had similar height, but trees with good health had larger mean trunk width than trees with declining health. Dominance of Douglas firs was high, and tree density was 2.5 times greater in declining OWO plots compared to healthy OWO plots. These results support the hypothesis that shade intolerant OWO are declining as forest density and Douglas fir dominance increases.