Print Report

G235 Sequoia sempervirens Forest Group

Type Concept Sentence: The California coastal redwood group occurs from the Klamath Mountains of extreme southwestern Oregon south to Monterey County, California, always within the oceanic fog belt, and contains the tallest forests in North America (over 100 m), dominated by Sequoia sempervirens or Chamaecyparis lawsoniana, with associates of Pseudotsuga menziesii, Tsuga heterophylla (northward), Notholithocarpus densiflorus, or Picea sitchensis.

Common (Translated Scientific) Name: Redwood Forest Group

Colloquial Name: Californian Coastal Redwood Forest

Hierarchy Level:  Group

Type Concept: This is one of the tallest conifer forests in the world, dominated by 75- to 120-m tall evergreen needle-leaved trees. This group occurs from the Klamath Mountains south to Monterey County, California. Mature stands of Sequoia sempervirens may produce a deep shade, so understories can be limited, and coarse woody debris from past disturbance can be quite large. Pseudotsuga menziesii is the common associate among the large trees. Tsuga heterophylla is found in old-growth stands in the northern portion of the range, and Notholithocarpus densiflorus occurs as a subcanopy in almost all stands, becoming more important in the central and southern sections of the range (possibly as a result of fire suppression). The moist, coastal Chamaecyparis lawsoniana or Picea sitchensis stands from southwestern Oregon and northwestern California (often mixed with Sequoia sempervirens, Pseudotsuga menziesii, or Tsuga heterophylla) are included in this group, as ecologically they function in the same way and have the same overall floristic composition. Shade-tolerant understory species include Rubus parviflorus, Oxalis oregana, Aralia californica, Mahonia nervosa, Gaultheria shallon, and many ferns, such as Blechnum spicant, Polystichum spp., and Polypodium spp. The coastal redwood group generally can be found in areas of low rainfall (Mediterranean climate of dry summers and wet winters) but stands always occur within the coastal fog belt, and interior stands are limited to the fog belts inward extent. In the northern portion of the range, stands occur on upland slopes, riparian alluvial zones, or riverine terraces that are flooded approximately every 50-100 years. In the southern portion of the range, annual precipitation may be as little as 50 cm, and the group is limited to coves and ravines. Throughout its range, it is commonly found on moderately well-drained marine sediments (non-metamorphosed siltstones, sandstones, etc.).

Diagnostic Characteristics: This group is characterized by the presence and dominance of Sequoia sempervirens and/or Chamaecyparis lawsoniana, the northern limit within a few miles of 42°N latitude (the Oregon and California border). Pseudotsuga menziesii, Tsuga heterophylla, and Notholithocarpus densiflorus are common associates. Ecological correlates include the Mediterranean Pluviseasonal-Oceanic climate (a subsection of Mediterranean climate that has the smallest amount of annual temperature variation and the wettest microclimate within that climate (Rivas-Martínez and Loidi-Arregui 1999, Rivas-Martínez and Rivas-Saenz 2015)), on upland slopes, coves and in riparian zones.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Stands dominated or codominated by Chamaecyparis lawsoniana, Picea sitchensis, or Tsuga heterophylla that are within 25 km (15 miles) of the coast that have some or no Sequoia sempervirens are either part of this group (G235) (in extreme southern Oregon and northern California), or ~North-Central Pacific Western Hemlock - Sitka Spruce Rainforest Group (G751)$$ (central and northern coastal Oregon). This group (G235) is dominated by coastal redwood and/or Port Orford-cedar, while G751 is dominated by western hemlock, Sitka spruce and/or western red-cedar. Forests in the same vicinity as this redwood group that do not have Sequoia sempervirens or Picea sitchensis present and are on non-serpentine soils are considered part of ~North Pacific Maritime Douglas-fir - Western Hemlock Rainforest Group (G240)$$. Chamaecyparis lawsoniana associations away from the coast are members of ~North-Central Pacific Western Hemlock - Sitka Spruce Rainforest Group (G751)$$. That is not within the fog belt, and these are pretty far north, so its not as confusing as it sounds.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This group forms the tallest forests in North America, with individuals reaching 120 m high (tallest being 115 m [380 feet]). Trees are needle-leaved evergreen. Typically, mature stands of Sequoia sempervirens produce a deep shade, so understories can be limited (perhaps more common in southern stands), and coarse woody debris from past disturbance can be quite large (perhaps most large in northern stands?).

Floristics: Typically, mature stands of Sequoia sempervirens produce a deep shade. Stands where Chamaecyparis lawsoniana is dominant along moist coastal alluvial terraces in the north are also included in this group. Understories are quite varied from fern-covered slopes to scattered herbs, and coarse woody debris from past disturbance can be quite large. Pseudotsuga menziesii is the common associate among the large trees. Tsuga heterophylla is found in northern old-growth stands. Upland stands of Sequoia sempervirens south of Humboldt Bay are various mixtures of Sequoia sempervirens, Pseudotsuga menziesii, and hardwoods, especially Notholithocarpus densiflorus (= Lithocarpus densiflorus), Arbutus menziesii, and Umbellularia californica (Noss 2000). Chamaecyparis lawsoniana can be dominant along moist coastal alluvial terraces in the north, and Notholithocarpus densiflorus is uncommon in these stands. Sequoia sempervirens can be the sole canopy dominant on river terraces. Shade-tolerant understory species include Rubus parviflorus, Oxalis oregana, Aralia californica, Mahonia nervosa (= Berberis nervosa), Gaultheria shallon, Vaccinium ovatum, and many ferns, such as Blechnum spicant, Polystichum munitum, and Polypodium spp.

Dynamics:  Historically, surface fires likely exposed mineral soil for redwood seed germination. Less frequent disturbance can result in increases in Tsuga heterophylla in northern occurrences, as it is sensitive to fire and is a decreaser with fire and flood. Fire suppression has tended to result in increasing abundance of Lithocarpus densiflorus, Umbellularia californica, Alnus rubra, Arbutus menziesii, and Acer macrophyllum; all respond favorably to fire, flood, wind and slides, becoming more abundant in areas of frequent disturbance. Recent studies find that many occurrences now have multi-tiered structures with tall-shrub layers and subcanopies of a variety of other trees, creating fuel ladders which can result is severe fires and increased mortality of Sequoia sempervirens when fires occur. In addition, Sillett and Van Pelt (2000) and Sillett and Bailey (2003) report that canopies of Sequoia sempervirens support significant biomass of epiphytic ferns and shrubs that are also contributing to an altered crown structure in these forests, which is impacting the fire regime.
Environmental Description:  Climate: The coastal redwood group generally can be found only in the Mediterranean climate of northern California, in areas of relatively low rainfall but still within the fog belt. In the southern portion of the range, annual precipitation may be as little as 50 cm, and the group is limited to coves and ravines. Soil/substrate/hydrology: Across its range, this type is commonly found on soils derived from moderately well-drained marine sediments (non-metamorphosed siltstones, sandstones, etc.). In the northern portion, it occurs on upland slopes and in riparian zones and on riverine terraces, above the active floodplain (flooded approximately every 50-100 years).
Geographic Range: This group occurs from the westernmost Klamath Mountains of southern Oregon south 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 A0104 Port Orford-cedar Forest Alliance A0104 1.B.2.Nd.3.a
Alliance A3403 Coastal Redwood Forest Alliance A3403 1.B.2.Nd.3.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: >< Port Orford-Cedar: 231 (Eyre 1980) [Coastal Port Orford-cedar stands occur in this group.]
= Redwood: 232 (Eyre 1980)
Concept Author(s): F.H. Eyre (1980)

Author of Description: G. Kittel, D. Faber-Langendoen

Acknowledgements: J. Sawyer

Version Date: 11-09-15
  • 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.
  • 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.
  • 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]
  • Holland, V. L., and D. J. Keil. 1995. California vegetation. Kendall/Hunt Publishing Company, Dubuque, IA. 516 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.
  • Noss, R. F. 2000. The redwood forest: History, ecology, and conservation of the coast redwoods. Island Press, Covelo, CA.
  • Rivas-Martínez, S., and J. Loidi-Arregui. 1999. Bioclimatoloy of the Iberian Peninsula. Itinera Geobotanica 13:41-47.
  • Rivas-Martínez, S., and S. Rivas-Saenz. 2015. Worldwide Bioclimatic Classification System. Phytosociological Research Center, Spain. [http://www.globalbioclimatics.org]
  • 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.
  • 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.