Kathy Maas-Hebner, Forest
Science, Oregon State University, Corvallis, OR
Large scale disturbances,
such as past practices that clear-cut forests down to stream banks and fires,
have left many Oregon Coast Range stream reaches dominated by hardwoods. Large conifer logs have been identified as
important components in streams to enhance salmonid habitats by increasing
habitat complexity, aiding the development of pools and the accumulation of
gravel, providing cover from predators, and creating off-channel habitat for
fish during high flows. Four studies along second- and third-order streams
examined methods to restore conifers in hardwood-dominated forests. Three
studies examined a variety of methods to reintroduce conifers by planting
native species under undisturbed red alder canopies, under felled or girdled
alder canopies, or in alder clear-cuts.
A fourth study looked at the efficacy of releasing suppressed conifers
in red alder stands. Each study encountered several obstacles to success
including severe damage from elk/deer and river beavers, floods, erosion, and
falling overstory debris. The type,
frequency, and intensity of problems encountered indicate that operations need
to be site specific. High seedling
mortality was common to all studies indicating that proper site selection is
necessary. Planted seedlings that
survived grew best when the overstory tree density was reduced by at least 50%
and accompanied by some level of understory vegetation management. Conifers were released by both the felled
and girdled overstory treatments and candidate trees should be based on vigor,
growth form, and location.
Keywords: Oregon Coast
Range, conifers, riparian areas, underplanting, release.