Paleoecology of a Bog in the Spruce-Hemlock Climax of the Olympic Peninsula

Abstract

The wide range of climate in the Pacific Northwest of America, due to the proximity of the Pacific Ocean and variation in altitude, has caused the existence of several climax forest associations. In addition the Bunchgrass Prairie and Desert Shrub vegetational climaxes cover the dryer areas east of the Cascade Mountain Range. The great relief also permits the occurrence of numerous life zones in this region. The writer has made pollen studies of bogs located within several climax forest associations and life zones, from which were interpreted the postglacial forest succession and tentatively the climatic trends. This has been done with cognizance of the sources of error involved in pollen statistics and interpretations thereof. The bog of this study is located within the Spruce-Hemlock climax on the west side of the Olympic Peninsula, Washington. It is situated in T. 27 N., R. 13 W. in Jefferson County about six miles south of the village of Forks. It lies south of the Bogachiel River just west of the Olympic Highway, ten miles from the Pacific Ocean at an elevation of less than 500 feet above sea level. A strip along the northern and eastern sides of the Olympic Peninsula was glaciated by the Pleistocene continental glaciers, while the Olympic Mountains were subjected to local mountain glaciation. Between the mountains and the ocean is an unglaciated coastal plain from 10 to 20 miles wide and not over 400 feet in elevation except in local hilly districts. This plain is covered with glaciofluvial deposits from mountain glaciation, but due to postglacial uplift the larger streams have incised themselves and removed much of the Pleistocene deposits (Fenneman, 1931).