Print Report
A3376 Tsuga heterophylla - Pseudotsuga menziesii Serpentine Soil Forest Alliance
Type Concept Sentence: This coniferous forest alliance consists of forests dominated by a mix of Pseudotsuga menziesii and Tsuga heterophylla on pockets of serpentine or ultramafic soils. Understory plants are tolerant of and endemic to serpentine soils. They occur at low elevations (0-1500 m) within the maritime-influenced region of the Pacific Northwest.
Common (Translated Scientific) Name: Western Hemlock - Douglas-fir Serpentine Soil Forest Alliance
Colloquial Name: Western Hemlock - Douglas-fir Serpentine Soil Forest
Hierarchy Level: Alliance
Type Concept: This coniferous forest alliance consists of forested stands dominated by a mix of Pseudotsuga menziesii and Tsuga heterophylla on pockets of serpentine or ultramafic soils. Understory plants are tolerant of and endemic to serpentine soils. They occurs at low elevations (0-1500 m) within the maritime-influenced region of the Pacific Northwest. Stands occur on the lower slopes of the Coast Ranges that feature high precipitation, long frost-free periods, and low fire frequencies. Much of the annual precipitation occurs as rain. Where snow does occur, it can generally be melted by rain during warm winter storms. In all settings, this alliance occurs where environmental conditions are moderated by the marine influence, with moderate drought and frost. Not many associations have been described, and the overstory conifer species are not particularly tolerant of serpentine soils; however, serpentine and ultramafic soils are common in the Siskiyou and Klamath mountains where there are patches of these soils within the range of these forest types.
Diagnostic Characteristics: Evergreen canopy of Pseudotsuga menziesii and Tsuga heterophylla with serpentine-tolerant and indicator species in the understory.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Soils are likely to be slightly serpentine or ultramafic, as the full expression of these soils would eliminate Tsuga heterophylla.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Tall coniferous trees that can grow to over 50 m in height, often with a secondary stratum of shade-tolerant, cold-deciduous or needle-leaved trees of mixed heights, but occasionally up to 35 m. A short- to tall-shrub stratum of cold-deciduous or broad-leaved evergreen shrubs is often present, but may be sparse. The herbaceous understory is often very lush, and characterized by shade-tolerant forbs and ferns. Late-successional stands have very large trees, huge amounts of woody debris including large snags and logs, and better developed understories. However, young stands are often dense-stemmed and the understory depauperate.
Floristics: These forested stands are dominated by a mix of Pseudotsuga menziesii and Tsuga heterophylla on pockets of serpentine or ultramafic soils. Understory plants are tolerant of and endemic to serpentine soils. Not many associations have been described in floristic detail.
Dynamics: These forests have a high- or moderate-severity fire regime with natural return intervals of 100-600 years. Pseudotsuga menziesii colonizes vigorously and is favored with logging and/or fire disturbance to these forests. With increasing time since disturbance, Tsuga heterophylla or Thuja plicata become more abundant in the canopy, due to their ability to regenerate under closed-canopy conditions. Logging often results in conversion to deciduous or mixed forest with Alnus rubra or Acer macrophyllum. Much of the landscape in Oregon where this alliance is found is now composed of structurally simple Pseudotsuga menziesii plantations. In outer coastal areas, windthrow during intense winter storms is the most frequent form of stand replacement.
Environmental Description: These forests are defined by serpentine or ultramafic soils. Stands occur on the lower slopes of the Coast Ranges that feature high precipitation, long frost-free periods, and low fire frequencies. Much of the annual precipitation occurs as rain. Where snow does occur, it can generally be melted by rain during warm winter storms. In all settings, this alliance occurs where environmental conditions are moderated by the marine influence, with moderate drought and frost.
Geographic Range: This alliance is found in southern Oregon and northern California Coast Ranges.
Nations: US
States/Provinces: CA, OR
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899500
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 1 Forest & Woodland Class | C01 | 1 |
| Subclass | 1.B Temperate & Boreal Forest & Woodland Subclass | S15 | 1.B |
| Formation | 1.B.2 Cool Temperate Forest & Woodland Formation | F008 | 1.B.2 |
| Division | 1.B.2.Nd Vancouverian Forest & Woodland Division | D192 | 1.B.2.Nd |
| Macrogroup | 1.B.2.Nd.3 Western Hemlock - Sitka Spruce - Redwood Rainforest Macrogroup | M024 | 1.B.2.Nd.3 |
| Group | 1.B.2.Nd.3.c Douglas-fir - Western Hemlock / Salal Rainforest Group | G240 | 1.B.2.Nd.3.c |
| Alliance | A3376 Western Hemlock - Douglas-fir Serpentine Soil Forest Alliance | A3376 | 1.B.2.Nd.3.c |
| Association | CEGL000110 Western Hemlock / Deer Oak Forest | CEGL000110 | 1.B.2.Nd.3.c |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: >< Douglas fir-western hemlock, # 230 (Küchler 1964)
>< Douglas-fir - Western Hemlock: 230 (Eyre 1980)
>< Western Hemlock Series (Sawyer and Keeler-Wolf 1995)
>< Western Hemlock: 224 (Eyre 1980)
>< Western Needleleaf Forests: 2: Cedar-Hemlock-Douglas Fir Forest (Thuja-Tsuga-Pseudotsuga) (Küchler 1964)
>< Douglas-fir - Western Hemlock: 230 (Eyre 1980)
>< Western Hemlock Series (Sawyer and Keeler-Wolf 1995)
>< Western Hemlock: 224 (Eyre 1980)
>< Western Needleleaf Forests: 2: Cedar-Hemlock-Douglas Fir Forest (Thuja-Tsuga-Pseudotsuga) (Küchler 1964)
- Atzet, T., and D. L. Wheeler. 1984. Preliminary plant associations of the Siskiyou Mountains Province, Siskiyou National Forest. USDA Forest Service, Pacific Northwest Region, Portland, OR.
- Atzet, T., and L. A. McCrimmon. 1990. Preliminary plant associations of the southern Oregon Cascade Mountain Province. USDA Forest Service, Pacific Northwest Region, Siskiyou National Forest, Grants Pass, OR. 330 pp.
- Dyrness, C. T., J. F. Franklin, and C. Maser. 1974b. Wheeler Creek Research Natural Area. Supplement #1 to "Federal Research Natural Areas in Oregon and Washington. A guidebook for scientists and educators" by Franklin, J. F., F. C. Hall, C. T. Dryness, and C. Maser. USDA Forest Service.
- Eyre, F. H., editor. 1980. Forest cover types of the United States and Canada. Society of American Foresters, Washington, DC. 148 pp.
- Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
- Franklin, J. F., and C. T. Dyrness. 1973. Natural vegetation of Oregon and Washington. General Technical Report PNW-8. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR. 417 pp.
- Halverson, N. M., C. Topik, and R. van Vickle. 1986. Plant association and management guide for the western hemlock zone Mt. Hood National Forest. R6-ECOL-232A-1986. USDA Forest Service, Pacific Northwest Region, Portland, OR. 111 pp.
- Hemstrom, M. A., S. E. Logan, and W. Pavlat. 1987. Plant association and management guide, Willamette National Forest. Report R6-Ecol 257-B-86. USDA Forest Service, Pacific Northwest Region, Portland, OR. 312 pp.
- Hemstrom, M. A., and S. E. Logan. 1986. Plant association and management guide Siuslaw National Forest. Report R6-Ecol 220-1986a. USDA Forest Service, Pacific Northwest Region, Portland, OR. 121 pp.
- Küchler, A. W. 1964. Potential natural vegetation of the conterminous United States. American Geographic Society Special Publication 36. New York, NY. 116 pp.
- Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 pp.
- Topik, C., N. M. Halverson, and D. G. Brockway. 1986. Plant associations and management guide for the western hemlock zone. R6-ECOL-230a-1986. USDA Forest Service, Gifford Pinchot National Forest, Pacific Northwest Region, Portland, OR. 137 pp.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.