Composition, Structure, and Distribution of Oregon Ash-dominated Bottomland Riparian Forests in the Tualatin River Basin - A Closer Look at These Imperiled Ecosystems
Start Date
3-11-2024 4:00 PM
Abstract
Over the last two decades, natural resource conservation partners in the Tualatin River watershed have made tremendous progress in restoring and enhancing riparian forests to bolster ecological functions such as stream shading for cooler waters, streambank stabilization for erosion control, and filtering sediments and pollutants to enhance water quality. In bottomland riparian zones of the Pacific Northwest, where low-gradient floodplains support frequent flooding, Oregon ash (Fraxinus latifolia) is a dominant overstory tree species and, until recently, a “restoration workhorse” used in revegetation efforts.
Unfortunately, Oregon ash is now threatened by the recent introduction of the emerald ash borer (EAB), a wood-boring beetle native to Asia. Natural resource conservation partners are developing strategies to preserve the ecological functions of bottomland riparian forests ahead of the widespread EAB bioinvasion in the Pacific Northwest. However, reference conditions of mature, bottomland riparian forests including the canopy composition and spatial distribution of Oregon ash in Tualatin River basin is not comprehensive.
To characterize the reference conditions of mature, bottomland riparian forests and estimate the magnitude of EAB-induced canopy loss, we surveyed the vegetation of eight low-gradient riparian forest stands in over 100 plots along the major tributaries of the Tualatin River in the summer of 2023. Our study attempts to establish a connection between riparian canopy species diversity and lateral distance from a stream, share the promising method of quantifying canopy cover and composition with a smartphone, and address the implications for management actions in our threatened forests.
Subjects
GIS / modeling, Habitat assessment, Land/watershed management, Plant ecology
Persistent Identifier
https://archives.pdx.edu/ds/psu/41404
Creative Commons License
This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License.
Composition, Structure, and Distribution of Oregon Ash-dominated Bottomland Riparian Forests in the Tualatin River Basin - A Closer Look at These Imperiled Ecosystems
Over the last two decades, natural resource conservation partners in the Tualatin River watershed have made tremendous progress in restoring and enhancing riparian forests to bolster ecological functions such as stream shading for cooler waters, streambank stabilization for erosion control, and filtering sediments and pollutants to enhance water quality. In bottomland riparian zones of the Pacific Northwest, where low-gradient floodplains support frequent flooding, Oregon ash (Fraxinus latifolia) is a dominant overstory tree species and, until recently, a “restoration workhorse” used in revegetation efforts.
Unfortunately, Oregon ash is now threatened by the recent introduction of the emerald ash borer (EAB), a wood-boring beetle native to Asia. Natural resource conservation partners are developing strategies to preserve the ecological functions of bottomland riparian forests ahead of the widespread EAB bioinvasion in the Pacific Northwest. However, reference conditions of mature, bottomland riparian forests including the canopy composition and spatial distribution of Oregon ash in Tualatin River basin is not comprehensive.
To characterize the reference conditions of mature, bottomland riparian forests and estimate the magnitude of EAB-induced canopy loss, we surveyed the vegetation of eight low-gradient riparian forest stands in over 100 plots along the major tributaries of the Tualatin River in the summer of 2023. Our study attempts to establish a connection between riparian canopy species diversity and lateral distance from a stream, share the promising method of quantifying canopy cover and composition with a smartphone, and address the implications for management actions in our threatened forests.