Invasion of subalpine meadows by trees in the Cascade Range, Washington and Oregon
Franklin JF, Moir WH, Douglas GW, Wiberg C. 1971. Invasion of subalpine meadows by trees in the Cascade Range, Washington and Oregon. Arctic and Alpine Research. 3(3):215-224
In the forest-tundra ecotone region of the WA and OR Cascades, massive invasion into subalpine meadows by a variety of tree species expecially Abies lasiocarpa and Tsuga mertensiana, has been noted. The most intense period of establishment in most areas was during 1928-1937. Little invasion has been noted in the range since about 1945. We consider fire, grazing and forest edge effect as possible factors influencing the massive establishment of trees during this time, but suggest that climatic change is the most probable causative factor. At Paradise Valley on the slopes of Mount Rainier, trees invaded meadows during the period when the mass budget of the Nisqually Glacier was generally negative; after 1945, this mass budget was positive or balanced. The snow-free period in certain subalpine meadow communities is probably the most critical factor affecting tree establishment. Invasion densities were low on tall-forb-dominated (Valeriana sitchensis) and grass (Festuca viridula) communities and were high on low-forb-dominated (Potentilla flabellifolia) and shrub (Phyllodoce empetriformis-Vaccinium deliciosum) meadow types. However, growth rates of established trees appeared greatest on the tall-forb and grass communities.
- Type
- Journal Article
- Authors
- Franklin, Jerry; Moir, William; Douglas, George; Wiberg, Curt
- Units
- MORA , SODN
- Keywords
- Management, Oregon, Plant Communities, Plant Studies, Subalpine Zone, Succession, Trees, Washington