Print Report
M024 Tsuga heterophylla - Picea sitchensis - Sequoia sempervirens Rainforest Macrogroup
Type Concept Sentence: This macrogroup consists of lowland temperate rainforests of the Pacific Northwest, dominated by Abies amabilis, Acer macrophyllum, Alnus rubra, Arbutus menziesii, Chamaecyparis lawsoniana, Picea sitchensis, Pinus contorta var. contorta, Pseudotsuga menziesii, Sequoia sempervirens, Thuja plicata, and/or Tsuga heterophylla. Forests range from coastal very wet hypermaritime to slightly less wet leeward sites.
Common (Translated Scientific) Name: Western Hemlock - Sitka Spruce - Redwood Rainforest Macrogroup
Colloquial Name: Vancouverian Coastal Rainforest
Hierarchy Level: Macrogroup
Type Concept: This macrogroup covers coastal and inland rainforests at low elevations dominated by Abies amabilis, Acer macrophyllum, Alnus rubra, Arbutus menziesii, Callitropsis nootkatensis, Picea sitchensis, Pinus contorta var. contorta, Pseudotsuga menziesii, Sequoia sempervirens, Thuja plicata, and/or Tsuga heterophylla. Additional trees that may be present include Abies grandis, Pinus monticola, and Chamaecyparis lawsoniana. This macrogroup combines predominantly evergreen rainforests of the region and the coastal redwood forests of northern California. These forests and woodlands occur in the hypermaritime (within salt spray exposure), the submaritime, as well as more protected areas of the leeward Coast and west-side Cascade ranges. They may also occur on cool temperate lower montane slopes where winter snowpack typically lasts for several months, sometimes referred to as the "rain-on-snow" zone because of the common occurrence of major winter rainfall on an established snowpack. Climate is wet, mild maritime. Forests along the immediate coast experience a uniformly wet and mild climate, where precipitation ranges from 100 to 300 cm/year with frequent fog and low clouds during warmer months, and additional moisture from fog drip can be significant. Away from the coast, climate is still mild but with less moisture (as low as 50 cm/year) and greater temperature extremes.
Diagnostic Characteristics: Tall evergreen and broad-leaved deciduous rainforests dominated by one or a mix of the following species: Abies amabilis, Chamaecyparis lawsoniana, Picea sitchensis, Pseudotsuga menziesii, Sequoia sempervirens, Thuja plicata, and/or Tsuga heterophylla.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This macrogroup combines predominantly evergreen rainforests of the region, namely Krajina''s (1965) Coastal Western Hemlock Zone, and the Picea sitchensis, Tsuga heterophylla, and Abies amabilis zones of Oregon and Washington described by Franklin and Dyrness (1973).
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Tall (>25 m) conifer, mixed broad-leaved evergreen and mixed conifer and broad-leaved evergreen forests and woodlands.
Floristics: This rainforest macrogroup covers forests that are a mix of several species that change with substrate and aspect. Probably the most abundant forests are stands of Pseudotsuga menziesii with Tsuga heterophylla and/or Thuja plicata. These occur on a wide range of "dry-site" to "very mesic" settings. Understory species may include Acer circinatum, Achlys triphylla, Gaultheria shallon, Linnaea borealis, Mahonia nervosa, Oxalis oregana, Polystichum munitum, Rhododendron macrophyllum, and Rubus spectabilis. Understory species here may include Acer circinatum, Cornus nuttallii, Linnaea borealis, Mahonia nervosa, Paxistima myrsinites, Rubus parviflorus, Spiraea betulifolia, Symphoricarpos hesperius, and Vaccinium membranaceum.
Early-seral forests are represented by stands dominated by Alnus rubra or Acer macrophyllum which are often mixed with Abies grandis, Picea sitchensis, Pseudotsuga menziesii, Thuja plicata, and/or Tsuga heterophylla. Other major dominant broadleaf species are Frangula purshiana, and Cornus nuttallii. The understory is characterized by deciduous shrubs such as Acer circinatum, Corylus cornuta, Oemleria cerasiformis, Rubus ursinus, Symphoricarpos albus, and/or Toxicodendron diversilobum, but evergreen shrubs, including Gaultheria shallon and Mahonia nervosa, and forbs, such as Polystichum munitum and Oxalis oregana, can be dominant.
At higher elevations, Tsuga heterophylla and/or Abies amabilis dominate the canopy of late-seral stands, and Callitropsis nootkatensis (= Chamaecyparis nootkatensis) can be codominant, especially at the highest elevations and most northerly locations within this macrogroup''s range. Thuja plicata is also common and sometimes codominates in British Columbia. In more mesic settings, Pseudotsuga menziesii is relatively rare to absent, and a major understory dominant species is Vaccinium ovalifolium. Other mesic-setting understory species include Blechnum spicant, Oxalis oregana, Rubus spectabilis, and/or Rubus pedatus. Dry-setting understory species may include Achlys triphylla, Mahonia nervosa, Rhododendron macrophyllum, Vaccinium membranaceum, and/or Xerophyllum tenax. In extreme southeastern Alaska, Abies amabilis occurs in nearly pure stands and in mixture with Picea sitchensis and Tsuga heterophylla.
Further south, in California, stands of Sequoia sempervirens produce a deep shade, with diverse understories from fern-covered slopes to scattered herbs. Pseudotsuga menziesii is the common associate among the large trees. Tsuga heterophylla is found in northern old-growth stands. Sequoia sempervirens can be the sole canopy dominant while understory species include Aralia californica, Gaultheria shallon, Mahonia nervosa (= Berberis nervosa), Oxalis oregana, Rubus parviflorus, Vaccinium ovatum, and many ferns, such as Blechnum spicant, Polystichum munitum, and Polypodium spp., may be present.
Early-seral forests are represented by stands dominated by Alnus rubra or Acer macrophyllum which are often mixed with Abies grandis, Picea sitchensis, Pseudotsuga menziesii, Thuja plicata, and/or Tsuga heterophylla. Other major dominant broadleaf species are Frangula purshiana, and Cornus nuttallii. The understory is characterized by deciduous shrubs such as Acer circinatum, Corylus cornuta, Oemleria cerasiformis, Rubus ursinus, Symphoricarpos albus, and/or Toxicodendron diversilobum, but evergreen shrubs, including Gaultheria shallon and Mahonia nervosa, and forbs, such as Polystichum munitum and Oxalis oregana, can be dominant.
At higher elevations, Tsuga heterophylla and/or Abies amabilis dominate the canopy of late-seral stands, and Callitropsis nootkatensis (= Chamaecyparis nootkatensis) can be codominant, especially at the highest elevations and most northerly locations within this macrogroup''s range. Thuja plicata is also common and sometimes codominates in British Columbia. In more mesic settings, Pseudotsuga menziesii is relatively rare to absent, and a major understory dominant species is Vaccinium ovalifolium. Other mesic-setting understory species include Blechnum spicant, Oxalis oregana, Rubus spectabilis, and/or Rubus pedatus. Dry-setting understory species may include Achlys triphylla, Mahonia nervosa, Rhododendron macrophyllum, Vaccinium membranaceum, and/or Xerophyllum tenax. In extreme southeastern Alaska, Abies amabilis occurs in nearly pure stands and in mixture with Picea sitchensis and Tsuga heterophylla.
Further south, in California, stands of Sequoia sempervirens produce a deep shade, with diverse understories from fern-covered slopes to scattered herbs. Pseudotsuga menziesii is the common associate among the large trees. Tsuga heterophylla is found in northern old-growth stands. Sequoia sempervirens can be the sole canopy dominant while understory species include Aralia californica, Gaultheria shallon, Mahonia nervosa (= Berberis nervosa), Oxalis oregana, Rubus parviflorus, Vaccinium ovatum, and many ferns, such as Blechnum spicant, Polystichum munitum, and Polypodium spp., may be present.
Dynamics: There are large areas of wet rainforests that rarely burn, where fire plays a minor role and windthrow gaps are the predominant source of stand dynamics. However, fire becomes an increasingly important factor of stand dynamics where drier climatic conditions exist in the more southern and submaritime ranges of this macrogroup, as well as dry microclimate pockets throughout the range. In drier stands, where fire did/does occur, the dominant natural (pre-European settlement) process included stand-replacing fires on average every 150-500 years (Agee 1993). In these situations, where old-growth does exist, it is mostly "young old-growth" about 200-500 years in age. Natural-origin stands less than 200 years old are also common. Mixed-severity fires occur more frequently (about every 50-100 years) in the drier more submaritime and often southern parts of this macrogroup, so that forest structure, patch size and proportions can be different from northern, more mesic stands (Agee 1993, Brown and Hebda 1999).
California coastal redwood historically had surface fires that exposed mineral soil necessary for redwood seed germination. Less frequent disturbance can result in increases in Tsuga heterophylla in northern occurrences, as it is sensitive to fire and declines with fire and flood. Fire suppression has tended to result in increasing abundance of Acer macrophyllum, Alnus rubra, Arbutus menziesii, Notholithocarpus densiflorus, and Umbellularia californica. Other disturbances such as flood, wind and landslides, and human disturbance will also favor these species. Landslides and forest fire that eliminate upper canopies allow for full sunlight and early-successional forests dominated by Alnus rubra, Acer macrophyllum, and/or Pseudotsuga menziesii to become established. Due to human disturbance, these early-seral forests are more abundant today than other types with in the macrogroup in the Pacific Northwest. These forests, however, can persist (>200 years) and remain as mixed deciduous-conifer forests.
Fire is not a major disturbance factor in the northern range of Pseudotsuga menziesii - Tsuga heterophylla forests. Although fire is by no means common or frequent, those sites in locations most vulnerable to fire tend to have a major component of Pseudotsuga menziesii in their canopies (Agee 1993). Stand-maintaining surface fires, both aboriginal and lightning-caused, were more frequent (perhaps every 50-100 years) and likely maintained a moderately open overstory (Agee 1993, Brown and Hebda 1999). The coastal mesic forests dominated by Abies amabilis and Tsuga heterophylla rarely, if ever, burn and are dominated by trees that run from 700 to over 1000 years in age. In British Columbia, coastal rainforests may burn an average of once every 2000 years. Extreme, stand-replacing fires are infrequent to absent, with return intervals of several hundred or more years.
Gap dynamics in old forests result in multi-aged stand structure (Franklin and Dyrness 1973). Unless growing in wind-protected conditions, windthrow and breakage tend to keep these forests from becoming or remaining very old. Tsuga heterophylla, one of the leading tree species, is vulnerable to wind breakage and also to uprooting given the shallow soils. If wind exposure is limited, then stand replacement is more gradual, through the process of the mortality of individuals or small numbers of canopy trees. Where windthrow is not pervasive, the age composition of these potentially old edaphic climax forests is uneven. Within mature and old forests, small gaps result from the death of single trees or small groups of trees due to root-rots, bark beetles or windthrow.
California coastal redwood historically had surface fires that exposed mineral soil necessary for redwood seed germination. Less frequent disturbance can result in increases in Tsuga heterophylla in northern occurrences, as it is sensitive to fire and declines with fire and flood. Fire suppression has tended to result in increasing abundance of Acer macrophyllum, Alnus rubra, Arbutus menziesii, Notholithocarpus densiflorus, and Umbellularia californica. Other disturbances such as flood, wind and landslides, and human disturbance will also favor these species. Landslides and forest fire that eliminate upper canopies allow for full sunlight and early-successional forests dominated by Alnus rubra, Acer macrophyllum, and/or Pseudotsuga menziesii to become established. Due to human disturbance, these early-seral forests are more abundant today than other types with in the macrogroup in the Pacific Northwest. These forests, however, can persist (>200 years) and remain as mixed deciduous-conifer forests.
Fire is not a major disturbance factor in the northern range of Pseudotsuga menziesii - Tsuga heterophylla forests. Although fire is by no means common or frequent, those sites in locations most vulnerable to fire tend to have a major component of Pseudotsuga menziesii in their canopies (Agee 1993). Stand-maintaining surface fires, both aboriginal and lightning-caused, were more frequent (perhaps every 50-100 years) and likely maintained a moderately open overstory (Agee 1993, Brown and Hebda 1999). The coastal mesic forests dominated by Abies amabilis and Tsuga heterophylla rarely, if ever, burn and are dominated by trees that run from 700 to over 1000 years in age. In British Columbia, coastal rainforests may burn an average of once every 2000 years. Extreme, stand-replacing fires are infrequent to absent, with return intervals of several hundred or more years.
Gap dynamics in old forests result in multi-aged stand structure (Franklin and Dyrness 1973). Unless growing in wind-protected conditions, windthrow and breakage tend to keep these forests from becoming or remaining very old. Tsuga heterophylla, one of the leading tree species, is vulnerable to wind breakage and also to uprooting given the shallow soils. If wind exposure is limited, then stand replacement is more gradual, through the process of the mortality of individuals or small numbers of canopy trees. Where windthrow is not pervasive, the age composition of these potentially old edaphic climax forests is uneven. Within mature and old forests, small gaps result from the death of single trees or small groups of trees due to root-rots, bark beetles or windthrow.
Environmental Description: This broad rainforest type occurs on a variety of settings from sea level to mid-montane elevations (0-1067 m) and includes dry to wet mid- and toeslopes, valley floors and side terraces both exposed to the ocean and of interior valleys, and stabilized coastal sand dunes. Climate is relatively mild and moist to wet. Mean annual precipitation is mostly 90-254 cm (35-100 inches) (but as low as 50 cm [20 inches] in the extreme rainshadow areas) falling predominantly as winter rain. Snowfall ranges from rare to regular, but not persistent, and summers are relatively dry. Some forests within this macrogroup are limited to the fog belt found along the coast from northern California to British Columbia. Soils range from dry to subirrigated, are generally deep, fine- to moderately coarse-textured, with some subsurface seepage or richer parent material.
Geographic Range: These forests cover nearly 30° of latitude (about 36° to 62°N latitude), extending from the Gulf of Alaska to northern California but lying within 60-120 km of the Pacific coast. Areas occupied include southeastern Alaska, much of the coastal mountain ranges of British Columbia, Washington, and Oregon, the western slope of the Cascade Range and maritime lowlands of western California.
Nations: CA,US
States/Provinces: AK, BC, CA, OR, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.835948
Confidence Level: High
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.a Redwood Forest Group | G235 | 1.B.2.Nd.3.a |
| Group | 1.B.2.Nd.3.b Beach Pine Forest & Woodland Group | G205 | 1.B.2.Nd.3.b |
| Group | 1.B.2.Nd.3.c Douglas-fir - Western Hemlock / Salal Rainforest Group | G240 | 1.B.2.Nd.3.c |
| Group | 1.B.2.Nd.3.d Pacific Silver Fir - Western Hemlock Rainforest Group | G241 | 1.B.2.Nd.3.d |
| Group | 1.B.2.Nd.3.f Western Hemlock - Sitka Spruce North-Central Pacific Rainforest Group | G751 | 1.B.2.Nd.3.f |
| Group | 1.B.2.Nd.3.g Red Alder - Bigleaf Maple Rainforest Group | G237 | 1.B.2.Nd.3.g |
| Group | 1.B.2.Nd.3.h Alaskan Maritime Western Hemlock - Sitka Spruce Rainforest Group | G750 | 1.B.2.Nd.3.h |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: ? Coastal Western Hemlock Zone (Krajina 1965) [combines four zones from Franklin and Dyrness (1973): the Picea sitchensis, Tsuga heterophylla, and Abies amabilis Zones of Oregon and Washington, and the coastal redwood forest of northern California.]
< Major Temperate Forest Types: Pseudotsuga menziesii-Tsuga heterophylla, Picea sitchensis-Tsuga heterophylla, and Sequoia sempervirens Forests. (Barbour and Billings 2000) [pp. 127-134]
< Major Temperate Forest Types: Pseudotsuga menziesii-Tsuga heterophylla, Picea sitchensis-Tsuga heterophylla, and Sequoia sempervirens Forests. (Barbour and Billings 2000) [pp. 127-134]
- Agee, J. K. 1993. Fire ecology of Pacific Northwest forests. Island Press, Washington, DC. 493 pp.
- BCMF [British Columbia Ministry of Forests]. 2006. BEC Master Site Series Database. British Columbia Ministry of Forests, Victoria, BC. [http://www.for.gov.bc.ca/hre/becweb/resources/codes-standards/standards-becdb.html]
- Banner, A., W. H. MacKenzie, J. Pojar, A. MacKinnon, S. C. Saunders, and H. Klassen. 2004. A field guide to ecosystem classification and identification for Haida Gwaii. Province of British Columbia, Victoria. Land Management Handbook Number 68. [www.for.gov.bc.ca/hfd/pubs/Docs/Lmh/Lmh68.htm]
- Banner, A., W. MacKenzie, S. Haeussler, S. Thomson, J. Pojar, and R. Trowbridge. 1993. A field guide to site identification and interpretation for the Prince Rupert Forest Region. Ministry of Forests Research Program. Victoria, BC. Parts 1 and 2. Land Management Handbook Number 26.
- Barbour, M. G., T. Keeler-Wolf, and A. A. Schoenherr, editors. 2007a. Terrestrial vegetation of California, third edition. University of California Press, Berkeley.
- Barbour, M. G., and J. Major, editors. 1988. Terrestrial vegetation of California: New expanded edition. California Native Plant Society, Special Publication 9, Sacramento. 1030 pp.
- Barbour, M. G., and W. D. Billings, editors. 2000. North American terrestrial vegetation. Second edition. Cambridge University Press, New York. 434 pp.
- Brown, K. J., and R. J. Hebda. 1999. Long-term fire incidence in coastal forests of British Columbia. Northwest Science 73:41-43.
- Cadrin, C. M., and M. Wolowicz. 2005. Application of terrestrial ecosystem mapping on coastal British Columbia to conservation status assessments of ecological communities. British Columbia Conservation Data Centre, Ministry of Sustainable Resource Management, Victoria, BC.
- Carstens, B. C., J. R. Demboski, J. M. Good, S. J. Brunsfeld, and J. Sullivan. 2005. The evolutionary history of the northern Rocky Mountain mesic forest ecosystem. Evolution 59:1639-1652.
- Chappell, C., and J. Christy. 2004. Willamette Valley-Puget Trough-Georgia Basin Ecoregion Terrestrial Ecological System EO Specs and EO Rank Specs. Appendix 11 in: J. Floberg, M. Goering, G. Wilhere, C. MacDonald, C. Chappell, C. Rumsey, Z. Ferdana, A. Holt, P. Skidmore, T. Horsman, E. Alverson, C. Tanner, M. Bryer, P. Lachetti, A. Harcombe, B. McDonald, T. Cook, M. Summers, and D. Rolph. Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment, Volume One: Report prepared by The Nature Conservancy with support from The Nature Conservancy of Canada, Washington Department of Fish and Wildlife, Washington Department of Natural Resources (Natural Heritage and Nearshore Habitat programs), Oregon State Natural Heritage Information Center and the British Columbia Conservation Data Centre.
- Comer, P., D. Faber-Langendoen, R. Evans, S. Gawler, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, K. Snow, J. Teague, and R. White. 2003-present. Ecological systems of the United States: A working classification of U.S. terrestrial systems. NatureServe, Arlington, VA.
- Crawford, R. C., C. B. Chappell, C. C. Thompson, and F. J. Rocchio. 2009. Vegetation classification of Mount Rainier, North Cascades, and Olympic national parks. Plant association descriptions and identification keys: Appendices A-G. Natural Resource Technical Report NPS/NCCN/NRTR--2009/D-586. National Park Service, Fort Collins, CO. 586 pp.
- DeMeo, T., J. Martin, and R. A. West. 1992. Forest plant association management guide, Ketchikan Area, Tongass National Forest. R10-MB-210. USDA Forest Service, Alaska Region. 405 pp.
- DeVelice, R. L., C. J. Hubbard, K. Boggs, S. Boudreau, M. Potkin, T. Boucher, and C. Wertheim. 1999. Plant community types of the Chugach National Forest: South-central Alaska. Technical Publication R10-TP-76. USDA Forest Service, Chugach National Forest, Alaska Region. 375 pp.
- Dorner, B., and C. Wong. 2003. Natural disturbance dynamics on the North Coast. Background report for North Coast LRMP, British Columbia. 51 pp.
- 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, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- 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.
- Goward, T., and T. Spribille. 2005. Lichenological evidence for the recognition of inland rain forests in western North America. Journal of Biogeography 32:1209-1219.
- Green, R. N., and K. Klinka. 1994. A field guide to site interpretation for the Vancouver Forest Region. British Columbia Ministry of Forests. ISSN 0229-1622 Land Management Handbook 28. 285 pp.
- Hessburg, P. F., B. G. Smith, R. B. Salter, R. D. Ottmar, and E. Alvarado. 2000. Recent changes (1930s-1990s) in spatial patterns of interior northwest forests, USA. Forest Ecology and Management 136(1-3):53-83.
- Hessburg, P. F., B. G. Smith, S. C. Kreiter, C. A. Miller, R. B. Salter, C. H. McNicoll, and W. J. Hann. 1999. Historical and current forest and range landscapes in the interior Columbia River Basin and portions of the Klamath and Great Basins. Part 1: Linking vegetation patterns and landscape vulnerability to potential insect and pathogen disturbances. General Technical Report TNW-GTR-458. USDA Forest Service, Pacific Northwest Research Station, Portland, OR. 357 pp.
- Holland, V. L., and D. J. Keil. 1995. California vegetation. Kendall/Hunt Publishing Company, Dubuque, IA. 516 pp.
- Krajina, V. J. 1965. Biogeoclimatic zones and biogeocoenoses of British Columbia. Pages 1-17 in: V. J. Krajina, editor. Ecology of western North America. University of British Columbia, Department of Botany, Vancouver, BC.
- Lillybridge, T. R., B. L. Kovalchik, C. K. Williams, and B. G. Smith. 1995. Field guide for forested plant associations of the Wenatchee National Forest. General Technical Report PNW-GTR-359. USDA Forest Service, Pacific Northwest Research Station, Portland, OR. 335 pp.
- Lorimer, C. G, D. J. Porter, M. A. Madej, J. D. Stuart, S. D. Veirs, Jr., S. P. Norman, K. L. O''Hara, and W. J. Libby. 2009. Presettlement and modern disturbance regimes in coast redwood forests: Implications for the conservation of old-growth stands. Forest Ecology and Management 258:1038-1054.
- Martin, R. R., S. J. Trull, W. W. Brady, R. A. West, and J. M. Downs. 1995. Forest plant association management guide, Chatham Area, Tongass National Forest. R10-RP-57. USDA Forest Service, Alaska Region.
- Noss, R. F. 2000. The redwood forest: History, ecology, and conservation of the coast redwoods. Island Press, Covelo, CA.
- Sawyer, J. O., T. Keeler-Wolf, and J. Evens. 2009. A manual of California vegetation. Second edition. California Native Plant Society, Sacramento CA. 1300 pp.
- Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 pp.
- Sillett, S. C., and M. G. Bailey. 2003. Effects of tree crown structure on biomass of the epiphytic fern Polypodium scouleri (Polypodiaceae) in redwood forests. American Journal of Botany 90:255-261.
- Sillett, S. C., and R. Van Pelt. 2000. A redwood tree whose crown is a forest canopy. Northwest Science 74:34-43.
- Topik, C. 1989. Plant associations and management guide for the Abies grandis zone Gifford Pinchot National Forest. R6-ECOL-TP-006-88. USDA Forest Service, Pacific Northwest Region, Portland, OR. 110 pp.
- Topik, C., N. M. Halverson, and T. High. 1988. Plant associations and management guide of the ponderosa pine, Douglas-fir, and grand fir zone, Mt. Hood National Forest. R6-ECOL-TP-004-88. USDA Forest Service, Pacific Northwest Region, Portland, OR. 136 pp.
- Viereck, L. A., C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska vegetation classification. General Technical Report PNW-GTR286. USDA Forest Service, Pacific Northwest Research Station, Portland, OR. 278 pp.
- Waring, R. H., and J. F. Franklin. 1979. Evergreen coniferous forests of the Pacific Northwest. Science 204:1380-1386.
- Zinke, P. J. 1977. The redwood forest and associated north coast forests. Pages 679 in: M. G. Barbour and J. Major, editors. Terrestrial vegetation of California. Wiley-Interscience, reprinted by the California Native Plant Society 1988, Sacramento, CA.