A Taxonomic and Ecologic Study of the Flora of Monument Peak, Oregon

Abstract

Monument Peak is located in Linn County, Oregon on the West flank of Cascades about 25 miles due west of Mt. Jefferson and the Cascade Divide, and approximately ten miles east southeast of Mill City, (Lat. N 44042' and Long. 122020' W). The region most of which lies within the Willamette National Forest is drained by the North Santiam River. The taxonomic aims in this study were 1) to collect and identify all the species of vascular plants on the peak above 3700 feet and 2) to determine the affinities of the flora with those of other regions; while the ecologic objective was to recognize, delimit, and analyze the plant communities occurring in the region. A broad over-all obiective was to gather data that might contribute to our understanding of the origins and relationships of the flora of Western Oregon. Alone it cannot aid materially in the realization of this broad objective, but it is believed that studies of such relatively undisturbed floras of isolated peaks west of the main range of the Cascades may when correlated yield significant information on the history of the region as a whole, and indicate trends of migrationi and the effectiveness of barriers to dispersal. Two seasons, 1947 and 1948, were spent in the area collecting, observing, identifying and making statistical analyses. Determinations of species were made from fresh material *in most instances. However, all species were collected and preserved in the author's private herbarium. Duplicates of the collections are on file at the Oregon State College Herbarium at Corvallis, Oregon. In the rock-fell community studies the quadrat analysis method was used for determining dominance and successional trends. Growth-ring counts made from cores obtained by an increment borer were used in the study of relict species, in helping date the last forest fire, and as an aid in determining the relative stability of certain communities.