Print Report

A3403 Sequoia sempervirens Forest Alliance

Type Concept Sentence: This alliance contains the forest stands where Sequoia sempervirens is the dominant tree with few other tree species in the canopy, but Abies grandis, Acer macrophyllum, Alnus rubra, Arbutus menziesii, Chrysolepis chrysophylla, Notholithocarpus densiflorus, Picea sitchensis, Pseudotsuga menziesii, Tsuga heterophylla, and Umbellularia californica may be present. Trees are <120 m tall. The canopy is intermittent or continuous and may be two-tiered. Shrubs are infrequent or common. Herbaceous layer is absent or abundant. Stands occur in moist coastal areas with heavy summer fog, generally below 600 m in elevation from southern Oregon to Santa Lucia Mountains in central California. They occur on raised stream terraces and benches at 10-975 m elevation.

Common (Translated Scientific) Name: Coastal Redwood Forest Alliance

Colloquial Name: Coastal Redwood Terrace Forest

Hierarchy Level:  Alliance

Type Concept: This alliance consists of forests where Sequoia sempervirens is the dominant tree with few other tree species in the canopy, but Abies grandis, Acer macrophyllum, Alnus rubra, Arbutus menziesii, Chrysolepis chrysophylla, Notholithocarpus densiflorus, Picea sitchensis, Pseudotsuga menziesii, Tsuga heterophylla, and Umbellularia californica may be present. Trees are less than 120 m tall, and the canopy is partly open to continuous, with two or more tiers. Shrubs are infrequent or common. Herbaceous layer is absent or abundant. Fire is the principal disturbance agent in both young and old-growth stands. Fire-return interval is variable depending on environmental site conditions. Old-growth stands show up to three or more severe fires per century, with several short intervals followed by one or more long intervals. Short fire intervals may be as frequent as 6-27 years. This alliance occurs on raised stream terraces and benches from 10-975 m elevation. Stands occur in moist coastal areas with heavy summer fog, generally below 600 m in elevation from southern Oregon to Santa Lucia Mountains in central California.

Diagnostic Characteristics: Sequoia sempervirens >50% relative cover in the tree canopy.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This alliance concept follows Sawyer et al.''s (2009) Sequoia sempervirens Forest Alliance, terrace forest associations of northern, central and southern regions. Differences between forests on alluvial streamside terraces and those on upland settings, where Sequoia sempervirens shares the canopy with other conifer and with hardwood trees, are best understood when the associations are placed in these three geographic regions (Sawyer et al. 2000b). Tsuga heterophylla plays an important role in the northern forest region, and it is absent from the other two regions where Notholithocarpus densiflorus plays an important role. Redwood genetics in the southern forest region differs from that in the other regions (Sawyer et al. 2000a, b). Precipitation varies significantly between northern and southern regions with fog-drip playing an increasingly important role in the southern portion of the range (Olson et al. 1990).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This giant temperate or subpolar, needle-leaved evergreen forest forms an intermittent to continuous canopy less than 120 m in height. A subcanopy may be present. Shrubs are infrequent to common. A herbaceous layer may be present.

Floristics: Stands of this alliance are characterized by Sequoia sempervirens which is an important or dominant species in the canopy. Other trees present may include Acer macrophyllum, Arbutus menziesii, Umbellularia californica, Pseudotsuga menziesii, Abies grandis, Notholithocarpus densiflorus (= Lithocarpus densiflorus), and Tsuga heterophylla. Shrubs and forbs may be infrequent or common, and can include Blechnum spicant, Carex globosa, Gaultheria shallon, Iris douglasiana, Mahonia nervosa, Marah fabaceus, Oxalis oregana, Polypodium californicum, Polystichum munitum, Pteridium aquilinum, Trillium ovatum, Vaccinium ovatum, Vicia sativa ssp. nigra, and Woodwardia fimbriata.

Dynamics:  Catastrophic fires occur at irregular intervals in these forests. Sequoia sempervirens and a few of the associated tree species respond by crown-sprouting.
Environmental Description:  As defined, this alliance includes both upland and alluvial streamside stands. Stands are found on all aspects and slopes, as well as raised stream terraces and benches. Stands usually occur on soils derived from sandstone or schist. On deeper, moister soils redwoods are the only canopy tree; on steeper slopes with shallower soils redwoods share the canopy with other trees. Stands are found between 10 and 600 m elevation, and grow in areas which are inundated during the summer with coastal fog. Winters are quite wet, with precipitation averaging more than 150 cm/year. Nearly all the rain falls between November and May, though fog drip continues to provide moisture through the otherwise dry summer months.
Geographic Range: This alliance is found in extreme southern Oregon to Monterey County, California.

Nations: US

States/Provinces:  CA, OR


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.a Redwood Forest Group G235 1.B.2.Nd.3.a
Alliance A3403 Coastal Redwood Forest Alliance A3403 1.B.2.Nd.3.a
Association CEGL000081 Douglas-fir - Redwood / Western Swordfern Forest CEGL000081 1.B.2.Nd.3.a
Association CEGL000082 Douglas-fir - Redwood / Pacific Rhododendron / California Huckleberry Forest CEGL000082 1.B.2.Nd.3.a
Association CEGL003172 Redwood / Tanoak / California Huckleberry Forest CEGL003172 1.B.2.Nd.3.a
Association CEGL003173 Redwood - Douglas-fir Forest CEGL003173 1.B.2.Nd.3.a
Concept Lineage: A.110

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Sequoia sempervirens (Redwood forest) Alliance (Sawyer et al. 2009) [86.100.00]
= Sequoia sempervirens Forest Alliance (CNPS 2017) [86.100.00]
>< North Coast Alluvial Redwood Forest (#61120) (Holland 1986b)
? Redwood Forest (Cheatham and Haller 1975)
>< Redwood Series (Sawyer and Keeler-Wolf 1995)
? Redwood: 232 (Eyre 1980)
>< Upland Redwood Forest (#82320) (Holland 1986b)
Concept Author(s): G. Kittel, after Sawyer et al. (2009)

Author of Description: G. Kittel

Acknowledgements: No Data Available

Version Date: 09-26-14
  • AIS [Aerial Information Systems, Inc.]. 2005. Vegetation maps for Sierra Azul, South Skyline, La Honda, and Purisima Creek Redwoods. Unpublished GIS maps produced for Mid-Peninsula Open Space District, San Mateo, CA.
  • Azevedo, J., and D. L. Morgan. 1974. Fog precipitation in coastal California forests. Ecology 55:1135-1141.
  • Borchert, M., D. Segotta, and M. D. Purser. 1988. Coast redwood ecological types of southern Monterey County, California. General Technical Report PSW-107. USDA Forest Service, Pacific Southwest Research Station, Berkeley, CA.
  • CNPS [California Native Plant Society]. 2015-2017. A manual of California vegetation [online]. California Native Plant Society, Sacramento, CA. [http://vegetation.cnps.org/].
  • Cheatham, N. H., and J. R. Haller. 1975. An annotated list of California habitat types. Unpublished report. University of California, Natural Land and Water Reserves System.
  • Cheng, S. 2004. Forest Service research natural areas in California. General Technical Paper PSW-GTR-188. USDA Forest Service, Pacific Southwest Research Station, Albany, CA.
  • Combs, W. E. 1984. Stand structure and composition of the Little Lost Man Creek Research Natural Area, Redwood National Park. Master''s thesis, Humboldt State University, Arcata, CA.
  • Evens, J. M., and E. Kentner. 2006. Classification of vegetation associations from the Mount Tamalpais Watershed, Nicasio Reservoir, and Soulajule Reservior in Marin County, California. Report for the Marin Municipal Water District. California Native Plant Society, Sacramento.
  • 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. 1988. Pacific Northwest forests. Pages 104-130 in: M. G. Barbour and W. D. Billings, editors. North American terrestrial vegetation. Cambridge University Press, New York.
  • Griffin, J. R., and W. B. Critchfield. 1972. The distribution of forest trees in California. Research Paper PSW-82/1972. USDA Forest Service, Pacific Southwest Forest and Range Experiment Station, Berkeley, CA. 114 pp.
  • Griffith, R. S. 1992. Sequoia sempervirens. In: Fire Effects Information System [Online]. USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). [http://www.fs.fed.us/database/feis/]
  • Holland, R. F. 1986b. Preliminary descriptions of the terrestrial natural communities of California. Unpublished report prepared for the California Department of Fish and Game, Nongame-Heritage Program and Natural Diversity Database, Sacramento. 156 pp.
  • Jimerson, T. J. 1994. A field guide to the Port Orford cedar plant associations in northwestern California. Pacific Southwest Research Station PSW-R5-ECOL-TP-OO2. Six Rivers National Forest, Eureka, CA. 109 pp.
  • Keeler-Wolf, T. 1990a. Ecological surveys of Forest Service Research Natural Areas in California. General Technical Report PSW-125. USDA Forest Service, Pacific Southwest Research Station, Berkeley, CA. 165 pp.
  • Keeler-Wolf, T., M. Schindel, and S. San. 2004. Point Reyes National Seashore, Golden Gate National Recreation Area, San Francisco Water Department Watershed Lands, Mount Tamalpais, Tomales Bay, and Samuel P. Taylor State Parks. Appendix B. Point Reyes National Seashore, Golden Gate National Recreation Area, and surrounding wildlands plant community classification and mapping project. Final report. California State Department of Fish and Game, Sacramento, CA.
  • Lenihan, J. M. 1990. Forest associations of Little Lost Man Creek, Humboldt County, California: Reference level in the hierarchical structure of old-growth coastal redwood vegetation. Madroño 37:69-87.
  • Mahoney, T. M. 1999. Old growth forest associations in the northern range of redwood. Master''s thesis. Humboldt State University, Arcata, CA.
  • Mathew, S. C. 1980a. Old-growth forest associations of the Bull Creek watershed, Humboldt Redwoods State Park, California. Master''s thesis, Humboldt State University, Arcata, CA.
  • Mathew, S. C. 1980b. Vegetation map and inventory of old-growth forest in Humboldt Redwoods State Park. Unpublished report. State of California. The Resources Agency, Department of Parks and Recreation, Sacramento, CA.
  • Noss, R. F. 2000. The redwood forest: History, ecology, and conservation of the coast redwoods. Island Press, Covelo, CA.
  • Olson, D. F. 1983. Redwood. Pages 37-40 in: R. M. Burns, editor. Silviculture systems for the major forest types of the United States. Agriculture Handbook 445. USDA Forest Service, Washington, DC.
  • Olson, D. F., D. F. Roy, and G. A. Walters. 1990. Sequoia sempervirens, redwood. Pages 541-551 in: R. M. Burns and B. H. Honkala, editors. Silvics of North America. Volume 1: Conifers. Agriculture Handbook 654. USDA Forest Service, Washington, DC.
  • Roy, D. F. 1980. Redwood. Pages 109-110 in: F. H. Eyre, editor. Forest cover types of the United States and Canada. Society of American Foresters, Washington, DC.
  • Sawyer, J. O., J. Gray, G. J. West, D. A. Thornburgh, R. F. Noss, J. H. Engbeck, B. G. Marcot, and R. Raymond. 2000a. History of redwood and redwood forests. Pages 7-38 in: R. F. Noss, editor. The redwood forest; history, ecology, and conservation of the coast redwoods. Island Press, Covelo, CA.
  • Sawyer, J. O., S. C. Sillett, J. H. Popenoe, A. LaBanca, T. Sholars, D. L. Largent, F. Euphrat, R. F. Noss, and R. Van Pelt. 2000c. Characteristics of redwood forests. Pages 39-80 in: R. F. Noss, editor. The redwood forest; history, ecology, and conservation of the coast redwoods. Island Press, Covelo, CA.
  • Sawyer, J. O., S. C. Sillett, W. J. Libby, T. E. Dawson, J. H. Popenoe, D. L. Largent, R. Van Pelt, S. D. Veires, R. F. Noss, D. A. Thornburgh, and P. Del Tredici. 2000b. Redwood trees, communities and ecosystems: A closer look. Pages 81-118 in: R. F. Noss, editor. 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.
  • Thorne, J. H., J. A. Kennedy, J. F. Quinn, M. McCoy. T. Keeler-Wolf, and J. Menke. 2004. A vegetation map of Napa County using the manual of California vegetation classification and its comparison to other digital vegetation maps. Madrono 51(4):343-363.