The Roosevelt elk (Cervus elephus roosevelti) is a
National Forest management indicator species on the westside
of the Cascade mountains, Western Oregon. A Habitat
Effectiveness model is used by State and Federal agencies to
evaluate elk habitat in the region. Concerns about the
model's lack of differentiation between winter and summer
ranges in the analyses and assumptions that burning will
increase forage quality on winter range prompted this study.
I investigated the effect of broadcast burning, plant
association, and time since disturbance on the quality of
trailing blackberry (Rubus ulna), red huckleberry (Vaccinium
parviflorum), willow (Salix spp.), vine maple (Acer
circinatum), salal (Gaultheria shallon), and red elderberry
(Sambucus racemosa). Crude protein, neutral detergent fiber,
acid detergent fiber, acid insoluble ash, lignin,
astringency, condensed tannin, and hydrolyzable tannin
contents were measured.
No significant effects of burning, plant association, or
age were observed for crude protein, hydrolyzable tannins, or
neutral detergent fiber. Crude protein varied among taxa:
trailing blackberry contained 9.65%, and the other taxa
ranged from 5.21-7.24%. Neutral detergent fiber was highly
variable: trailing blackberry contained 30.90%, and the other
taxa ranged from 52.20%-65.06%. Acid detergent fiber content
ranged from 44.88%-49.49% for all taxa except trailing
blackberry (17.78%).
Lignin varied among taxa: trailing blackberry had the
lowest content (6.37%) and salal had the highest (30.25%).
Lignin content in salal was greater on recently disturbed
sites.
Astringency ranged from 0.0015 mg protein precipitated
per mg plant tissue in vine maple to 0.6737 in trailing
blackberry. Salal and willow had intermediate astringencies:
elderberry, huckleberry, and vine maple had the lowest.
Hydrolyzable tannins were present in all species except red
elderberry. Burning and plant association effected
astringency and condensed tannin content in trailing
blackberry and huckleberry. Samples from burned, very dry
and resource-poor sites had higher astringencies than on
similar unburned units and non-resource-limiting sites.
Condensed tannin contents increased with unit age in
salal, huckleberry, and trailing blackberry, possibly
accumulating during peak years of re-establishment after
disturbance.
Vine maple and red huckleberry were the only taxa with
positive digestible protein levels. Digestible protein
content may be higher in winter forage on less severe sites.
Elk forage enhancement in winter range should be
evaluated on a site-specific basis. Burning did not promote
a detectable increase in quality for these forage taxa, and
it decreased the quality of species sensitive to site
conditions. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/38154 |
| Date | 02 May 1991 |
| Creators | Friesen, Cheryl Ann |
| Contributors | McComb, William |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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