Genetic and Silvicultural Foundations for Management
Alternative Silvicultural Treatments for Young Plantations
in the Pacific Northwest
Constance A. Harrington, Dean S. DeBell,
and Leslie C. Brodie,
Pacific Northwest Research Station, 3625 - 93rd Ave. SW, Olympia, WA 98512-9193
||Many forest plantations have uniform spacing and
species composition. Wood production was usually the original management
||For some plantations, objectives have changed to
include wildlife habitat and recreation. These other values may be
produced with treatments that increase diversity in stand structure
and species composition.
What we did and why
We selected treatments that differ in their effects on stand structure
and species diversity. These treatments -- other than the control -- require
multiple entries to meet their goals.
| Silvicultural treatments
|| Future stand condition
- Uniform thinning
- Thinning, plant other species
- Thinning plus gaps
- Thinning plus gaps, plant other species
- Stand development w/o treatment
- Uniform size, structure and species composition
- Uniform size and structure, accelerated species diversity
- Diverse size and structure
- Diverse size and structure, accelerated species diversity
||The oldest installation is on the Mt.
St. Helens National Volcanic Monument. Five plots of each treatment
were installed in 1994-5. When the initial thinning was done, the
plantations were mostly Douglas-fir and 10 to 13 years old. Trees
were 7 m tall and 11 cm in diameter.
Other installations of this trial have been established in WA and OR.
We plan to measure tree growth, stand structure, and understory vegetation.
We invite others to evaluate additional responses or to establish additional
installations. For further information, contact Connie Harrington; e-mail
email@example.com, or phone