SYNOPSES OF THE FOREST TYPES OF MOUNT RAINIER NATIONAL PARK
Tsuga heterophylla/Achlys triphylla Habitat Type
The Tsuga heterophylla/Achlys triphylla habitat type is found at low elevations, rarely as high as 1080 m (3,500 ft), primarily on well-drained alluvial flats and lower slopes in the Ohanapecosh and Cowlitz River drainages. Slopes are usually gentle, 0 to 30 percent, although as the elevation increases, this habitat is occasionally found on steeper slopes, up to about 60 percent. Slope aspect tends to be southerly. Dominant canopy species are Pseudotsuga menziesii, Tsuga heterophylla, and Thuja plicata. Pinus monticola and Abies procera may occur as codominants. Regeneration is largely Tsuga heterophylla with some Thuja plicata, Abies amabilis, and rarely Abies procera. The understory is moderately rich in herbs, with Achlys triphylla, Viola sempervirens, Cornus canadensis, Linnaea borealis, Smilacina stellata, and other herbs totaling an average of about 55 percent cover. Acer circinatum is the dominant shrub, averaging 40 percent cover; Berberis nervosa, Vaccinium parvifolium, Rubus ursinus, and other shrubs are common for an average total shrub cover of about 60 percent.
Tsuga heterophylla/Polystichum munitum Habitat Type
The Tsuga heterophylla/Polystichum munitum habitat type is found on mesic to moist sites primarily in the western half of Mount Rainier National Park (the Park). Though occurring mostly on well-drained lower slopes and benches, it can be found on slopes up to 70 percent or more with any aspect at elevations less than about 910 m (3,000 ft). Dominant canopy species are Pseudotsuga menziesii, Tsuga heterophylla, and Thuja plicata. Tsuga heterophylla dominates regeneration with occasional Abies amabilis and Thuja plicata. Polystichum munitum dominates the herb layer with Blechnum spicant, Tiarella trifoliata, and Gymnocarpium dryopteris as common associates. The herb layer averages about 40 percent cover. Berberis nervosa is the most common shrub, often commonly associated with Vaccinium parvifolium. Acer circinatum and Taxus brevifolia are occasionally abundant. Average shrub cover is about 20 percent.
Abies amabilis Phase
The Abies amabilis phase occurs in the northwest sector of the Park and is similar to the rest of the Tsuga heterophylla/Polystichum munitum habitat type except that Abies amabilis is codominant with Tsuga heterophylla in regeneration and, to a lesser extent in the canopy. Blechnum spicant usually has at least as much cover in the herb layer as Polystichum munitum.
Tsuga heterophylla/Oplopanax horridum Habitat Type
The Tsuga heterophylla/Oplopanax horridum habitat type occurs at any aspect on moist benches and valley bottoms below 1100 m (3,600 ft) throughout the Park. Slopes are usually gentle, 30 percent or less, but may be as much as 60 percent. The canopy is dominated by Pseudotsuga menziesii, Thuja plicata, and Tsuga heterophylla, all of which may be very large. Tsuga heterophylla dominates the regeneration with Thuja plicata and Abies amabilis common. Abies grandis may be locally abundant in the canopy or regeneration. Oplopanax horridum dominates the shrub layer with Acer circinatum as a common associate. Total shrub cover is usually about 35 percent. The herb layer is rich and luxiurant, averaging over 100 percent cover. Dominant herbs are Gymnocarpium dryopteris, Tiarella trifoliata, Athyrium filix-femina, and Polystichum munitum.
Alnus rubra/Rubus spectabilis Community Type
The Alnus rubra/Rubus spectabilis community type is early seral, generally less than 150 years old, and is located at low elevations, less than 910 m (3,000 ft), in valley bottoms or on wet side slopes and terraces. Alnus rubra and Tsuga heterophylla dominate the sparse canopy. Tsuga heterophylla is the main generating species with Abies amabilis common. The herb layer is rich and profuse, generally totalling over 90 percent cover. Circaea alpina, Athyrium filix-femina, Viola glabella, Gymnocarpium dryopteris, and Tiarella unifoliata are dominant herbs. Rubus spectabilis and Oplopanax horridum dominate the shrub layer, which averages over 70 percent cover.
Abies amabilis/Oplopanax horridum Habitat Type
The Abies amabilis/Oplopanax horridum habitat type is found on moist lower slopes, benches, and valley bottoms facing any aspect at moderate elevations, 700 to 1210 m (2,300 to 4,000 ft). Slopes are usually gentle, less than 50 percent. The canopy is dominated by Pseudotsuga menziesii, Tsuga heterophylla, and Thuja plicata, individuals of which may be very large. Regeneration is codominated by Tsuga heterophylla and Abies amabilis with infrequent Thuja plicata. The herb layer is often rich and profuse, usually over 80 percent cover, with Tiarella unifoliata, Achlys triphylla, Athyrium filix-femina, and Adenocaulon bicolor as dominants. Oplopanax horridum and Vaccinium alaskaense are the dominants of the shrub layer, which averages less than 40 percent cover.
The slope phase of this habitat type occurs on moist, steep (over 40 percent) lower slopes to midslopes at up to 1460 m (4,800 ft) in elevation. The canopy dominants are the same as those in the habitat type, but several additional tree species occur: Picea engelmannii, Abies procera, and Tsuga mertensiana. Chamaecyparis nootkatensis is a local codominant in the canopy or regeneration. Rubus spectabilis is usually more important than Vaccinium alaskaense in the shrub layer. The herb layer is generally more profuse, with an average cover of 90 percent.
Tsuga heterophylla/Gaultheria shallon Habitat Type
This habitat type occurs throughout the Park on dry sites between 610 and 1090 m (2,000 and 3,600 ft). It occurs mostly on moderate to steep south- to west-facing slopes. Pseudotsuga menziesii, Tsuga heterophylla, and, to a lesser degree, Thuja plicata dominate the canopy. Regeneration is almost exclusively Tsuga heterophylla and occasionally Abies amabilis, Linnaea borealis, Achlys triphylla, Xerophyllum tenax, and Chimaphila umbellata are the most important herbs. Gaultheria shallon is the dominant shrub, averaging 45 percent cover, with Berberis nervosa, Vaccinium parvifolium, Vaccinium alaskaense, and Acer circinatum as common associates. Total shrub cover averages about 80 percent and total herb cover 20 percent.
Pseudotsuga menziesii/Ceanothus velutinus Community Type
This early seral community appears in the Ohanapecosh and Cowlitz River drainages on dry sites between 940 and 1240 m (3,100 and 4,100 ft). It occurs on steep upper slopes and midslopes with southerly aspects. Stand ages are usually less than 100 years. Pseudotsuga menziesii, Abies procera, and Pinus monticola are the dominant canopy and regenerating species. Acer circinatum, Vaccinium membranaceum, and Ceanothus velutinus are the major shrubs. Pteridium aquilinum, Eragaria spp., Achlys triphylla, and Rubus lasiococcus dominate the herbaceous layer. Both the shrub and herb layers are sparse, averaging 55 percent and 35 percent total coverage, respectively.
Pseudotsuga menziesii/Xerophyllum tenax Community Type
This early seral community occurs in scattered locations around the Park. It is found on moderate to low elevations, 1210 to 810 m (4,000 to 2,800 ft), dry benches and southerly facing midslopes to upper slopes. Steepness of slope ranges from nearly flat to 50 percent. Pseudotsuga menziesii and Tsuga heterophylla dominate the canopy, with Abies amabilis, Pinus monticola, and Abies procera as common associates. Tsuga heterophylla is the major regenerating tree, but several others may be locally important, especially Pseudotsuga menziesii. Xerophyllum tenax and Pteridium aquilinum are the dominant herbs. Gaultheria ovatifolia, Vaccinium membranaceum, Vaccinium parvifolium, and Pachystima myrsinites are important shrubs. Both shrubs and herbs average 50 percent total cover.
Pseudotsuga menziesii/Viola sempervirens Community Type
This widespread early seral community occurs mostly in the southern half of the Park. It usually appears on southerly facing midslopes to upper slopes and ridges, or rarely on benches or in valley bottoms. Slopes range from nearly flat to 70 percent and from about 670 to 1300 m (2,200 to 4,300 ft) in elevation. Pseudotsuga menziesii and, to a lesser degree, Tsuga heterophylla dominate the canopy. While Tsuga heterophylla is the most abundant regenerating species, many other species may occur and be locally important (including Pseudotsuga menziesii, Abies amabilis, Pinus monticola, Abies grandis, and others). Pteridium aquilinum, Viola sempervirens, Linnaea borealis, Achlys triphylla, and Chimaphila umbellata are the most important herbs. Acer circinatum, Berberis nervosa, and Gaultheria ovatifolia are the dominant shrubs. Total shrub cover is usually about 35 percent and total herb cover 55 percent.
Abies amabilis/Gaultheria shallon Habitat Type
This habitat type occurs on steep (20 to 80 percent), well-drained, southerly facing slopes in the west and southwest sections of the Park. Elevations are moderately high, usually between 910 and 1300 m (3,000 and 4,300 ft). Tsuga heterophylla and Pseudotsuga menziesii dominate the canopy. Abies amabilis and Tsuga heterophylla are the major regenerating species. Thuja plicata seedlings occur less frequently. Xerophyllum tenax is the most important herb, usually with Linnaea borealis, Chimaphila umbellata, and Cornus canadensis. Gaultheria shallon, Berberis nervosa, Vaccinium parvifolium, Vaccinium alaskaense, and Vaccinium membranaceum are the major shrub species. Average total shrub cover is 60 percent and average total herb cover 20 percent.
Abies amabilis/Berberis nervosa Habitat Type
This widespread habitat type is found on well-drained slopes at elevations of from 770 to 1420 m (2,500 to 4,700 ft). Slope angle is usually greater than 25 percent. Aspects tend to be southerly although the type does occur on northerly facing slopes at low elevations. Sites occupied by this type are characteristically mesic to dry and warm. Abies amabilis, Tsuga heterophylla, and Pseudotsuga menziesii dominate the canopy, with Thuja plicata and Abies procera as common associates. Abies amabilis is the dominant regenerating species, with Tsuga heterophylla often abundant. Berberis nervosa is the most consistently present shrub. Acer circinatum is locally important. Chimaphila umbellata, Linnaea borealis, and Achlys triphylla are the dominant herbs. Average shrub cover is 20 percent and average herb cover 20 percent.
Abies amabilis/Xerophyllum tenax Habitat Type
This habitat occurs on midslopes to upper slopes and ridges generally above 1000 m (3,300 ft). Slopes may be flat to 90 percent or more. Aspects likewise vary from 0° to 360°. Sites are typically well drained and often rocky or thin soiled. Abies amabilis is the dominant canopy tree, but several other species may be common: Tsuga heterophylla, Abies procera, Pseudotsuga menziesii, Abies lasiocarpa, Tsuga mertensiana, and Chamaecyparis nootkatensis. Abies amabilis is by far the leading regenerating species, although Tsuga heterophylla seedlings may be common. Vaccinium membranaceum is the most important shrub and is commonly associated with several others, especially Menziesia ferruginea, Vaccinium alaskaense, and Vaccinium ovalifolium. Xerophyllum tenax is the dominant herb and is usually associated with Rubus lasiococcus, Pyrola secunda, and Linnaea borealis.
Abies amabilis/Vaccinium alaskaense Habitat Type
The Abies amabilis/Vaccinium alaskaense habitat is the most common in the Park. It occurs throughout the Park on mesic sites between 640 and 1370 m (2,100 and 4,500 ft). Most of this habitat occurs on lower slopes, benches, and in valley bottoms where slopes are between 0 and 90 percent. It also appears on upper slopes in the northwest sector of the Park. Canopy dominants are Tsuga heterophylla, Pseudotsuga menziesii, and Abies amabilis. Thuja plicata, Chamaecyparis nootkatensis, Abies procera, and Tsuga mertensiana may be locally important. Regeneration is mostly Abies amabilis and, to a lesser extent, Tsuga heterophylla. The other tree species, especially Chamaecyparis nootkatensis, may be locally important in the regeneration. The habitat is predominantly shrubby. Several shrub species are common, including Vaccinium alaskaense, Vaccinium parvifolium, Vaccinium ovalifolium, and Vaccinium membranaceum. Linnaea borealis, Rubus pedatus, Clintonia uniflora, and Blechnum spicant are the most abundant herbs. Total shrub cover averages 75 percent and total herb cover 20 percent.
Berberis nervosa Phase
This phase occurs at the lower end of the elevation spectrum, from 580 to 1200 m (1,900 to 4,000 ft). Aspects tend to be southerly and westerly. Pseudotsuga menziesii is the major dominant in the canopy followed by Tsuga heterophylla. Linnaea borealis and Cornus canadensis dominate the herb layer. Berberis nervosa is a dominant shrub along with several Vaccinium species.
Rubus pedatus Phase
This phase appears mainly in the northwest sector of the Park. Tsuga heterophylla, Pseudotsuga menziesii, Abies amabilis, and, locally, Chamaecyparis nootkatensis dominate the canopy. Rubus pedatus is the dominant herb, with Clintonia uniflora as a common associate. Vaccinium parvifolium and Berberis nervosa are only minor constituents of the shrub layer.
Chamaecyparis nootkatensis Phase
This phase is scattered around the Park at 901 to 1270 m (3,000 to 4,200 ft) on moderately steep (20- to 65-percent), lower slopes. Its distinctive features are a very low total herb cover, about 5 percent, and the importance of Chamaecyparis nootkatensis as a codominant in both the canopy and regeneration.
Abies amabilis/Tiarella unifoliata Habitat Type
The Abies amabilis/Tiarella unifoliata habitat type occurs on nearly all forested moist to mesic landforms and facing any aspect between 818 and 1390 m (2,700 and 4,600 ft) elevation. Abies procera is a frequent canopy dominant along with Tsuga heterophylla, Abies amabilis, Chamaecyparis nootkatensis, and Pseudotsuga menziesii. Regeneration is mainly Abies amabilis associated with Tsuga heterophylla. The understory is usually strongly herbaceous. Average herb cover is 75 percent. Shrubs are minor, averaging 10 percent cover. Tiarella unifoliata, Achlys triphylla, Rubus lasiococcus, and Streptopus roseus dominate the herb layer. Vaccinium ovalifolium and Vaccinium membranaceum are the most common shrubs.
Abies amabilis/Rubus lasiococcus Habitat Type
Rubus lasiococcus Phase
This phase of the Abies amabilis/Rubus lasiococcus habitat type is found at elevations above 1200 m (4,000 ft) on a variety of landforms. Slopes are generally steep. Slope aspect is usually north or northeast. This type frequently is directly below the subalpine meadowland or the Abies lasiocarpa/Valeriana sitchensis community. Although several conifers occur in the canopy and as regeneration, Abies amabilis is the most important. Chamaecyparis nootkatensis, Tsuga mertensiana, Tsuga heterophylla, and Abies lasiocarpa are frequently present. Vaccinium membranaceum is the dominant shrub. Other common shrubs are several species of Vaccinium and Rhododendron albiflorum. Rubus lasiococcus is a common, abundant herb. Frequent associates are Valeriana sitchensis, Arnica latifolia, Pyrola secunda, and Rubus pedatus. This type is distinctly shrubby with an average shrub cover of 30 percent and an average herb cover of 20 percent.
Abies amabilis/Rubus lasiococcus Habitat Type
Erythronium montanum Phase
This phase of the Abies amabilis/Rubus lasiococcus habitat type occurs at high elevations, above 1300 m (4,300 ft), on midslopes to upper slopes, benches, and ridges that receive a heavy, late-melting snow pack. Slopes range from flat to 70 percent or more and can face any aspect. Abies amabilis is the dominant tree species from the seedling layer to the canopy. Chamaecyparis nootkatensis and Tsuga mertensiana are common components of both the canopy and regeneration. Vaccinium membranaceum, Rhododendron albiflorum, and other species of Vaccinium are the most important shrubs. Erythronium montanum, Rubus lasiococcus, and Rubus pedatus are the dominant shrubs. Total shrub cover averages 20 percent and total herb cover 40 percent.
Abies lasiocarpa/Valeriana sitchensis Community Type
This widespread community commonly occurs at and just below the ecotone between subalpine meadow and closed forest. It usually occurs above 1400 m (4,600 ft) on sites with almost any combination of slope and aspect. The canopy is dominated by Abies lasiocarpa. Abies amabilis may be common. Several other tree species may occur. Regeneration is commonly sparse and mostly Abies lasiocarpa and Abies amabilis. This community may be successional to various Abies amabilis habitats over a very long time. The dominant shrub is Vaccinium membranaceum with Vaccinium scoparium and several shrubs common. Many herbs of the subalpine meadows occur in combination with some more characteristic of the deep forest. Most common are Valeriana sitchensis, Rubus lasiococcus, Arnica latifolia, and Luzula spp. Pedicularis rainierensis occurs in this type at some locations.
Abies amabilis/Menziesia ferruginea Habitat Type
This habitat type usually occurs on steep sites at moderate to high elevations, 1000 to 1400 m (3,300 to 4,600 ft), especially on northerly facing upper slopes. Several tree species are common. Abies amabilis dominates both canopy and regeneration. Tsuga heterophylla, Chamaecyparis nootkatensis, and Tsuga mertensiana are frequent associates. Large Pseudotsuga menziesii occasionally appear. Menziesia ferruginea is the dominant shrub and is commonly associated with Vaccinium spp. and Rhododendron albiflorum. The principal herbaceous species are Rubus pedatus, Rubus lasiococcus, Xerophyllum tenax, and Clintonia uniflora. This type is conspicuously shrubby with an average shrub cover of 45 percent and an average herb cover of 20 percent.
Chamaecyparis nootkatensis/Vaccinium ovalifolium Habitat Type
The Chamaecyparis nootkatensis/Vaccinium ovalifolium habitat type occurs mostly on northerly facing moist slopes and benches between 1200 and 1370 m (4,000 and 4,500 ft) in elevation. Slopes are generally moderately steep, 10 to 60 percent. Tsuga mertensiana, Abies amabilis, and Chamaecyparis nootkatensis dominate the canopy. Abies amabilis, Chamaecyparis nootkatensis, and Tsuga heterophylla dominate regeneration with only occasional Tsuga mertensiana. The herb layer is moderately rich and is dominated by Rubus pedatus, Tiarella unifoliata, and Rubus lasiococcus. Erythronium montanum may be locally abundant. Shrubs are mostly Vaccinium ovalifolium, Menziesia ferruginea, and Vaccinium membranaceum. Average herb cover is 60 percent and average shrub cover 35 percent.
Abies amabilis/Rhododendron albiflorum Habitat Type
This habitat type occurs at moderate to high elevations, 1200 to 1750 m (4,000 to 5,800 ft), on cold, wet sites. Slopes are generally moderate to steep and northerly facing. Landform varies from lower slopes and benches to ridges. Several tree species are common in the canopy and regeneration. Abies amabilis is the most important; Tsuga mertensiana, Chamaecyparis nootkatensis, and Tsuga heterophylla are common associates. Large Pseudotsuga menziesii may occur. This type is very shrubby with an average shrub cover of 70 percent. Rhododendron albiflorum, Menziesia ferruginea, and Vaccinium spp. are the dominant shrubs. Herbaceous cover is usually low and averages 30 percent. Erythronium montanum, Rubus pedatus, and Rubus lasiococcus are the most important herbs.
Last Updated: 06-Mar-2007