IntensIve sIlvIculture - Forest Science Labs - Research Network ...

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269. Hobbs, S.D., S.G. Stafford and R.L. Slagle. 1987. Undercutting conifer seedlings: effect on
morphology and field performance on droughty sites. Canadian-Journal-of-Forest-Research
17(1): 40-46.
Keywords: nursery operations
tree morphology
growth
tree/stand health
Abstract: One-yr-old barerooted Douglas fir and ponderosa pine seedlings in an Oregon
nursery were subjected during Feb.-June 1980 to 5 undercutting treatments that varied by number
and depth of cuts and seedling phenology at time of treatment. Eight morphological variables
were measured in Jan. 1981 before planting the seedlings at 2 sites in Oregon. Seedling survival
and growth was recorded annually for 4 yr. All treatments significantly reduced shoot growth in
the nursery, but changes in root system morphology depended on treatment severity and species.
Treatment effects were generally more pronounced in ponderosa pine than in Douglas fir.
Discriminant analysis showed that seedlings responded similarly in all undercutting treatments
relative to control seedlings that were not undercut. No effects of undercutting were apparent
after 4 yr in the field.
270. Hobbs, S.D. and K.A. Wearstler, Jr. 1983. Performance of three Douglas-fir stocktypes on a
skeletal soil. Tree-Planters' Notes 34(3): 11-14.
Keywords: nursery operations
tree/stand health
growth
Abstract: Plug-1 bare rooted seedlings, initially grown in containers and transplanted to a
nursery for 1 yr, 2-0 bare rooted seedlings and 1-0 plug stock were planted on a steep, severe site
in the Siskiyon Mts., SW Oregon, in 1980. Height and diameter were recorded after planting and
in the autumn in 1980 and 1981. Survival was 91% for 1-0 plug seedlings, 87% for plug-1
seedlings and 56% for 2-0 bare rooted stock. There were n.s.d. in height and diameter growth.
271. Hobbs, S.D. and K.A. Wearstler, Jr. 1985. Effects of cutting sclerophyll brush on sprout
development and Douglas-fir growth. Forest-Ecology-and-Management 13(1/2): 69-81.
Keywords: release treatments
manual release
stand conditions
tree physiology
growth
Abstract: In SW Oregon, varying amount of brush were removed from a sclerophyll
brushfield dominated by Quercus chrysolepis and Arctostaphylos patula with scattered
Pseudotsuga menziesii saplings. Brush removal was accomplished by slashing (cut by chainsaw)
near ground level at three intensities: (1) total removal, (2) partial removal, and (3) an untreated
control. Sclerophyll brush species responded within 3 weeks of slashing by vigorous sprouting,
which was greatest in total brush removal areas where 861 513 sprout stems/ha developed during
the first year. Soil water potentials and predawn xylem pressure potentials of Douglas fir were
less negative in total removal areas than in partial removal and untreated control areas. Relative
growth rates of Douglas fir saplings temporarily increased in total and partial brush removal