MOUNT RAINIER The Forest Communities of Mount Rainier National Park

Dense, coniferous forests clothe the lower slopes and valleys of Mount Rainier National Park (the Park). They surround the lofty volcanic centerpiece and provide the locale for much of the visitors' activity. The forests are rich and varied—from massive, somber stands of Pseudotsuga, Tsuga, and Thuja in the valley bottoms to open groves of Abies lasiocarpa on high ridges. They are, in themselves, a major resource of the Park, providing outstanding examples of the virgin forests that once occupied the mountains and lowlands of western Washington.

The forest ecosystems of Mount Rainier have received little systematic study in contrast to the geological features and subalpine meadow regions. Yet sound management decisions, as well as accurate interpretive programs, require a basic knowledge of the sylvan landscapes. What kinds of forests are present and how are they distributed over the landscape? What role have disturbances, such as fire, played in their formation? In what direction and at what rate are successional changes taking place? What forest types do various birds and mammals use?

Our phytosociological analysis of the forest communities of Mount Rainier National Park was conducted from 1975 to 1980. The objectives of this study were to:

1. Develop a classification of the potential natural vegetation and forest habitat types (sensu Daubenmire 1966);

2. Describe the existing forest vegetation and place it in the context of the classification; and

3. Relate the forest communities to key environmental factors.

We present the results of our research in this monograph. Fourteen major plant associations, defined by mature forest stands, are identified along with five community types representing some distinctive early stages of forest succession. Each type is described and related to other types and to environmental conditions. Forest line is the upper boundary of the study area; the forest patches and tree groups of the subalpine parklands are, therefore, not included in this monograph.

The research had several purposes. First, to provide park managers with an understanding of the forest patterns. Managers and interpreters are provided detailed information on the composition and structure of the forests, as well as a scheme that shows their relationships to each other and to the landscape. Many management interpretations are obvious and are presented in Chapter 8. Some habitats have exceptional importance for elk, for example. Second, to provide scientists with a framework of forest types for their studies of various organisms and processes, a system that allows results to be extrapolated from one locale to another. Last, but not least, to provide the visitor with a better appreciation of the diversity, value, and dynamic nature of these magnificent forests; this monograph is particularly useful in providing detailed background to the narrative "The Forests of Mount Rainier: A Natural History" (Moir 1986).

A map showing the distribution of habitat types over Mount Rainier National Park is included as a basic part of this report (Plate 1). This map is based on extensive ground surveys conducted during the development and testing of the classification. A map showing the distribution of forest age classes is also included (Plate 2). This map is based on an analysis of forest disturbances during the last 1,000 years; supportive information is provided in Chapter 7 and comprehensively reported by Hemstrom and Franklin (1982).

These forest descriptions and maps are only one step in a systematic study of the forests at Mount Rainier. Permanent sample plots have been established in most of the forest types for observation of long-term changes and are yielding valuable data on the dynamics of these forests (Chapter 7). Temperature regimes of several forest types have also been studied (Greene and Klopsch 1985). Studies of the vertebrate animals characteristic of the old-growth forests are underway. Hence, this monograph is only one indication of an expanding understanding of these forests, and we hope it will lead to their greater appreciation and improved management.