Influences of Adjacent Forest Management Activities on Migratory Elk of Mount Rainier National Park
Kurt J. Jenkins, Edward E. Starkey

CH 1: THE ELK RANGE

Elk Population Trends

The relative abundance of elk inhabiting MORA's northern summer range has been monitored from aerial surveys since 1974 (survey techniques and study design are described by Bradley 1982). Because not all elk present were observed during aerial surveys and no attempt was made to correct for unseen elk, the surveys provide only an index of relative elk numbers, not absolute densities.

Indices of elk abundance on the northern summer range increased from a population low of 200 in 1974 to a population high of 660 in 1984 (Finite Rate of Annual Increase (R) = 1.12; unpublished data, S. Schlegel, Mount Rainier National Park). Since 1984, however, indices of abundance have decreased steadily to a low of 450 in 1988 (R = 0.91). Overall, elk populations increased on MORA's northern summer range during the 1970's and early 1980's and now appear to be decreasing.

Population trends of elk on MORA's summer range may be related both to habitat conditions and to legal and illegal harvest of elk outside the park. MORA's northern elk herd inhabits two game management areas (GMU) of the Washington Department of Wildlife during the winter (GMU's 466 and 472). From 1974 until 1986, the legal harvest was limited to bulls-only in these two GMU's and averaged 235 bulls per year; no cows were harvested legally. Since 1986, in addition to the general bull-only harvest, Native Americans have harvested antlerless elk. Although harvests by Native Americans are not well-documented, legal harvest by Native Americans is estimated to have averaged approximately 100 elk per year in 1987 and 1988 (pers. comm.. R. Spencer, Washington Dept. of Wildlife).

Seasonal Range of Elk

Cooper (1987) described movement patterns of three separate home range groups of elk that inhabit high-elevation summer ranges within MORA and low-elevation winter range along the White River. Summer ranges encompassed the areas surrounding Governors Ridge, Brown Peak, and Bear Park at the headwaters of tributaries of the White River (Fig. 1.1). Elk migrated from summer ranges to lower elevations following the first heavy snowfalls in October or November (Cooper 1987).

Figure 1.1. Summer ranges of elk that winter in the upper White River drainage, Washington. (click on image for an enlargement in a new window)

Elk wintered in two primary winter ranges along the White River. One subpopulation, referred to as the North Boundary Herd, wintered predominantly in old-growth forests in bottomlands of the White River near the northern boundary of MORA (10.0 km2) (Fig. 1.2). Two additional subpopulations wintered approximately 12 km downriver in second growth forests that were managed for timber production primarily by Weyerhaeuser Company, and to a much lesser extent, by Washington Department of Natural Resources and the United States Forest Service. These two subpopulations, referred to as the Gold Hill (7.2 km²) and Crystal Village (8.7 km²) herds, were named after prominent features in each area. Crystal Village was a housing development built on a subdivision of cutover Weyerhaeuser lands. Elk inhabiting these two broadly different area, i.e. predominantly old-growth forests within MORA and second growth forests outside the park, formed the basis for studying relationships between forest management practice and diets of elk (Ch. 2).

Figure 1.2. Winter ranges of elk in the upper White River drainage, Washington. (click on image for an enlargement in a new window)

Spring movements of elk were variable in the White River (Cooper 1987). Elk in the North Boundary and Gold Hill herds inhabited winter ranges until early July. Elk in the Crystal Village herd, in contrast, moved approximately 4 km south in late May to a distinct spring range. These elk inhabited a mid-elevation spring range until early July, at which time they migrated farther upslope to summer range within MORA. Spring range of the Crystal Village herd was located on Weyerhaeuser and USFS lands on the northeastern-most end of Huckleberry Ridge (Fig. 1.3). This spring range, like the winter range, was managed primarily for timber production.

Figure 1.3. Spring ranges of elk that winter in the upper White River drainage, Washington. (click on image for an enlargement in a new window)

Climate

Cooper (1987) summarized historical weather records from a weather station in Greenwater, Washington, within the elk winter range (Table 1.1). Climate in the study area is generally cool and moist, with wet, mild winters and comparatively dry, cool summers. Forty-year average winter temperatures ranged from 31 F during January to 39 F during November and March. Average minimum temperatures, however, ranged from 10 F to 20 F in January and March, respectively.

Winter snowfall has been exceedingly variable in the study area (Table 1.1). Although average mid-winter accumulations of snow vary only between 10-20 inches, maximum snow accumulations for a month have ranged between 0-69 inches. Particularly heavy accumulations of snow have occurred periodically, for example during 1949 (72 in), 1950 (60 in), 1957 (36 in), 1959 (36 in), and 1969 (36 in). Since 1970, snowfall winters for the most part has been average or below average. Winter 1986-87, during this study, was mild and snow depths never exceeded 14 inches.

Physiography and Vegetation

Winter ranges were on bottomlands and low-lying alluvial terraces of the White River and ranged in elevation from approximately 640-960 m. Winter range of the North Boundary herd, within MORA, was constrained by steep valley side-slopes. Winter ranges at lower elevations outside the park were also delimited by mountain slopes, but alluvial terraces were broader than upriver and adjoining slopes were less steep.

Vegetation on winter ranges was representative of the Tsuga heterophylla vegetation zone (Franklin and Dyrness 1973). Specific plant associations reflected temperature and moisture gradients (Henderson and Peters 1984, Franklin et al. in prep.). Thuja plicata/Lysichitum americanum habitat types occurred on poorly drained, wetland sites. Overstories were dominated by western red cedar (T. plicata) and western hemlock (Tsuga heterophylla). A wide variety of wetland sedges and herbs were usually found in the understory in association with skunkcabbage (L. americanum).

T. heterophylla (TSHE)/Oplopanax horridum, and TSHE/Achlys triphylla habitat types were found on mesic bottomlands along the White River. Overstory dominants included Douglas-fir, western red cedar, and western hemlock. Sitka spruce (Picea sitchensis) occurred in a few low-elevation sites, and Pacific silver fir (Abies amabilis) increased in abundance at higher elevations. Variable understories were dominated by vine maple (Acer circinatum), salmonberry (Rubus spectabilis), devil's club (Oplopanax horridum) and a variety of moist-site forbs and ferns.

TSHE/Berberis nervosa and TSHE/Gaultheria shallon habitat types occurred on well-drained alluvial terraces and xeric uplands throughout the winter range. Overstories were dominated by Douglas-fir and western hemlock, with increasing amounts of Pacific silver fir at the higher elevations. Understories were characterized often by dense coverage of salal (Gaultheria shallon) and Oregongrape (Berberis nervosa). Variable herbaceous layers were dominated often by pipsissewa (Chimaphila umbellata) and twinflower (Linnaea borealis).

Recent logging activities have reduced mature forests on managed elk winter range outside MORA. Managed forests consisted of a mosaic of seral forest communities. Grass/sedge-dominated communities formed on cutover T. plicata/L. americanum habitat types. Grass/sedge communities were characterized by sparse regenerating overstories of Sitka spruce and dense herbaceous mats of hydrophyllic grasses, sedges and fortes. Red alder (Alnus rubra) communities formed on cutover TSHE/Oplopanax horridum and TSHE/Achlys triphylla habitat types. Red alder communities, as the name denotes, are dominated by red alder. Conifer reproduction is generally sparse, and consists of grand fir (Abies grandis), western red cedar, Sitka spruce or western hemlock. The dense herbaceous understory is often dominated by salmonberry and a variety of grasses, sedges and forbs. Seral forests of TSHE/Gaultheria shallon or Berberis nervosa habitat types are generally dominated by dense stands of regenerating Douglas-fir, variable understories of salal and Oregongrape, and low coverage of grasses and forbs.

For purposes of describing post-logging trends in forage production, the gradient of vegetation on managed forests in the study area was classified into 14 plant communities based on general soil moisture regimes, dominant cover characteristics, and age since overstory harvest (Table 1.2). Plant communities comprising a mesic sere corresponded largely to vegetation found on T. plicata/L. americanum, TSHE/O. horridum, and TSHE/A. triphyllum habitat types along the riverine bottomlands. Plant communities comprising a xeric sere corresponded to vegetation found on TSHE/G. shallon and TSHE/B. nervosa habitat types of adjoining terraces and uplands.

A variety of 21-40 year old plant communities were found in managed forests throughout the White River (Table 1.2), reflecting complex underlying influences of soils and past forest management activities. Red alder and grass/sedge communities, described above, formed on moist to wet bottomland sites 21-40 years after logging. Unthinned PSME forests corresponded to dense, regenerating Douglas-fir stands, 21-40 years old, that had not been pre-commercially thinned within 5 years. Thinned PSME stands, in contrast, were regenerating forests pre-commercially thinned within 5 years. Sparse PSME stands formed on xeric uplands where inadequate soil development and moisture appeared to inhibit forest regeneration. PSME-POTR communities were 21-40 year-old stands of Douglas-fir and cottonwood which formed on shallow river alluvium following logging.

Forest Management Practices

Clearcutting was the primary silvicultural practice throughout the managed winter and spring ranges. The majority (90%) of winter range was clearcut between 1950-69 (Table 1.3). Only 2% of the commercially merchantable forests have been left standing as old-growth forest on the managed winter range. Harvesting of old-growth forests occurred more gradually and over a longer period on spring home ranges of elk than on winter ranges at lower elevations. Nonetheless, only 11% of the commercially valuable forests have been left uncut on elk spring range in the White River (Table 1.3).

A variety of forest management practices are employed routinely in the White River to maximize reforestation. Clearcut areas are frequently broadcast burned to remove logging slash, or slash is sometimes piled and burned. Following reduction of slash, nursery-stock seedlings of Douglas-fir are planted at a rate of approximately 200-600 seedlings/acre. Competing hardwood vegetation, primarily red alder and vine maple, are controlled where needed through aerial applications of herbicide. Regenerating stands of Douglas-fir are precommercially thinned generally to a density of approximately 300 trees/acre at approximately 15-25 years of age. Although most reforestation involved planting nursery stock of Douglas-fir, as described above, western red cedar, noble fir (Abies procera), and lodgepole (Pinus contorta) or white pine (Pinus monticola) are planted occasionally on wet sites, frost pockets and dry sites, respectively.