- Research was conducted in a mixed-coniferous forest stand
that was clearcut, burned, and seeded in order to study early plant
succession, grazing influences on native and introduced species, big
game use, and environmental relationships vegetation, animal,
and environmental research was carried out from 1965 to 1967 in
three, five-acre exclosures which had been constructed after treatment
in 1963 and 1964. Radical treatments of clearcutting and
burning were used to reduce infection of heart rot caused by Indian
paint fungus (Echinodontium tinctorium) in grand fir (Abies grandis).
Four major tree species--Douglas-fir (Pseudotsuga menziesii),
ponderosa pine (pinus ponderosa), western white pine (pinus monticola)
and western larch (Larix occidentalis) were planted at a rate
of 880 trees per acre. Minor quantities of grand fir, lodgepole pine
(Pinus contorta), and Engelmann spruce (Picea engelmannii ) were
used to give a total population of 1000 trees per acre.
Vegetation analyses showed bull thistle (Cirsium vulgare ) to
be the most abundant species in early stages of succession. Foliage
cover of this species was significantly reduced when competing with
introduced grass seedings which included a mixture of timothy
(Phleum pralenle), orchardgrass (Dactylis glomerata), tall oatgrass
(Arrhenatherum elatius), smooth brome (Bromus inermis), white
Dutch clover (Trifolium repens) and two pure stands of mountain
brome (Bromus marginatus) and blue wildrye (Elymus glaucus).
Most thistle and other weedy production were confined to unseeded
Redstem ceanothus (Ceanothus sanguineus), ninebark (Physocarpus
malvaceus), and birchleaf spirea (Spiraea betulifolia) were
the most abundant shrubs in the study area. Canada milkvetch
(Astragalus canadensis) and redstem ceanothus--both nitrogen fixing
species--were absent from the uncut stand, and burning enhanced
Crude protein analysis of the 15 major forage species showed
the two nitrogen fixing species to be far superior to other forages
from this standpoint. Introduced grass species were more sensitive
to soil nitrogen levels than were native species.
Yearling replacement heifers stocked at a rate approximating one animal unit per acre were grazed in both cattle exclosures and
later combined for grazing the game excluded area. A 1.5 and
2.1 pound per day gain was achieved over 42 and 35-day periods
in 1966 and 1967, respectively. During these years, the heifers
consumed 7.1 and 7.5 gallons of water per day which approximated
one gallon per hundred pounds of body weight.
Heifers preferred Ross' sedge (Carex rossii), orchardgrass,
blue elderberry (Sambucus cerulea), and Canada milkvetch. Different preferences might be noted if an earlier grazing season had been used. Some tree seedling browsing occurred in 1967, but this was
believed to result from too high an animal concentration within a
Game use in the cattle exclosures markedly reduced production
of all browse and Canada milkvetch. Some woody species have been
eliminated. Pellet count data supported the hypothesis that game,
particularly mule deer, might be attracted to the area for feeding
purposes. Digging and feeding activities of small mammals caused
isolated effects on seral vegetation development.
Environmental measurements showed soil temperatures at
two inches below the surface to be generally higher in the clearcut
than uncut stand. Air temperatures and solar radiation at three
feet above the soil were also higher in the clearcut, Surface soil
moisture levels in the clearcut and uncut forest stands indicated
that depletion rates were similar in both areas.
Due to the preliminary nature of these results, no management
plans have been developed. It is believed that grazing and forest
management are compatible and essential to maximize profits from
the mixed-coniferous forest of northeast Oregon. When proper season
of use and numbers of animals are determined, conflicts between
range and forest interests should be minimized.