Science Collaborative Research Program
Willamette University
900 State Street
Salem, Oregon 97301
- Karen Borza Arabas
- Associate Professor of Geography
- Collins 214
- 503-370-6666
- 503-370-6773
- karabas@willamette.edu
Karen Borza Arabas
Associate Professor of Geography
Ph.D. in Geography from The Pennsylvania State University in 1997. She received her M.A. in Environmental and Resource Policy from George Washington University in 1991, and her B.A. in Environmental Science from Wesleyan University in 1984.
Professional Interests
Vegetation and Land Use History of Zena Forest
Our research examines vegetation and land use history of Zena Forest in the Willamette Valley. Zena Forest is a 1466 acre (594 ha) private forest located 8 miles northwest of Willamette University, and is comprised of a mosaic of forest types ranging from even aged monoculture plantations of Douglas Fir (Pseudotsuga menziesii) to remnant Oregon white oak (Quercus garryanna) savannah. Prior to European settlement, Zena Forest was predominantly oak savannah, most likely managed by periodic low intensity burning by the local Calapooia tribe. In the early 1900s, the area was converted to Douglas Fir plantations for industrial forestry: after a change in ownership in the early 1980s, Zena Forest has slowly returned to a mixed species/oak savannah trajectory through a combination of selective harvesting and invasive species removal. Using an interdisciplinary approach and incorporating both field data, Geographic Information Systems (GIS) and remote sensing technologies, we will analyze vegetation change and land use history at Zena Forest over the past 150 years. Our results will help answer questions about how natural and anthropogenic disturbance have influenced forest development in the Willamette Valley. These results will also provide valuable information to forest managers and policy makers with respect to management strategies for maintaining biological diversity and ecological integrity in remaining valley forests.
Dr. Arabas will examine vegetation change over the past 150 years by looking at the structure, composition, and disturbance history of the forest. Specifically, we will look for evidence of a variety of natural and human disturbances in the tree ring (dendroecological) record including fire, insect infestation, competition, wind, logging, and climate. The role of these disturbances in forest succession will also be analyzed. Dr. Bowersox will use GIS and remote sensing technology to investigate landscape change over time. By interpreting historic aerial photography dating to the 1930s, as well as thirty years of satellite imagery, we will track and model changes over time in species composition, canopy density, and canopy distribution. We will also ground truth the remotely sensed data and integrate these findings with the dendroecological data. This collaborative and interdisciplinary approach will produce a more sophisticated and useful understanding of the vegetation dynamics of Zena Forest over time, and the impacts of both anthropogenic (e.g., land use and land tenure) and natural factors (e.g., precipitation, climate change, disturbance) driving those dynamics.