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Natural Communities
 Coastal Redwood and Douglas-Fir Forest
Otherwise known as conifer stands, this habitat consists of all age-classes and varying percentages of canopy closure. Other species commonly found in conifer stands may include tanoak, madrone, grand fir, Bishop pine, golden chinquapin, western hemlock, red alder, bigleaf maple, California bay laurel, and nutmeg. Understory species often found in these stands include blue blossom, coyote brush, manzanita, and California huckleberry (Mayer and Laudenslayer 1988).
Regional distribution and ecological factors
Mixed redwood and Douglas-fir stands are found along the California coast from the northern extent of California, south to San Luis Obispo County (Barbour and Major 1988). This type of conifer forest, which is not likely to occur above 1000 ft in elevation (FNAEC 1993), is the most common forest type throughout Mendocino and Sonoma counties.
Coastal redwood, as its name implies, is found within 2-10 mi (4-16 km) of the coast, in areas of consistent fog, with high summer humidity, cool temperatures, and well-developed soils (Shuford and Timossi 1989). Douglas fir, on the other hand, can occur on drier sites with poorer soils (Mayer and Laudenslayer 1988).
Habitat
Coastal redwood and Douglas-fir forest provide habitat for many rare, threatened or endangered species. In the upland and riparian portion of this natural community are northern spotted owls, marbled murrelets, Point Arena mountain beavers, and a handful of rare plants, such as Humboldt milk-vetch. The riparian portion of the forest also provides habitat for coho, chinook, steelhead, tailed frogs, red-legged frogs, foothill yellow-legged frogs, southern torrent salamanders, and various rare plants. Old-growth stands in the forest are especially important to species such as the marbled murrelet and the Pacific fisher. Many bat species are associated with old-growth as well; they use basal hollows as roost sites (Zielinski and Gellman 1999).
 Mixed Evergreen Forest
Mixed evergreen forest, otherwise known as mixed hardwood-conifer, is a combination of tree species with no specific species emerging as dominant; conifers comprise less than 75% of a stand. This natural community consists of all age-classes and all percentages of canopy closure. Conifers in this forest type are primarily coastal redwood and Douglas fir; hardwoods in this forest type are primarily tanoak and madrone.
Regional distribution and ecological factors
Hardwood is itself a forest type within mixed evergreen forest It can vary widely in species composition. In some areas, it may be pure tanoak, while in other areas it may include madrone, California black oak, live oak, California bay laurel, golden chinquapin, red alder, big-leaf maple, Oregon white oak, and eucalyptus (a non-indigenous species).
Hardwood extends throughout California, mostly west of the Sierra range crest. In northern California, it is found in most of Mendocino County and in the northern portion of Sonoma County.
Habitat
Mixed hardwood-conifer stands have elements of both hardwood and conifer stands. Because these stands are so variable, they provide habitat for a variety of wildlife. Some mast production (i.e., nuts on the forest floor) occurs in these areas offering high quality food for several species of birds and mammals.
Natural hardwood stands, particularly true oaks and pure madrone stands, are very important to wildlife, like birds and some species of mammals. In high mast years, oaks produce large quantities of acorns and madrones produce high volumes of berries.
In upland and riparian portions of this natural community, there are northern spotted owls and rare plants, such as the Humboldt milk-vetch. Watercourses and wetlands provide habitat for all the covered aquatic species and some rare plants as well.
 Riparian Forest
Riparian forest is generally associated with rivers and streams, though they can be associated with small ponds and seeps as well.
Regional distribution and ecological factors
Riparian forests are found throughout California, though the type of riparian forest in Mendocino County--montane riparian--extends from north coastal California to northern Santa Barbara County, usually below 8000 ft (2440 m) (Mayer and Laudenslayer 1988). The subtype found throughout northern California extends along the coast north through Del Norte County.
Habitat
Riparian forests provide for many needs of wildlife, such as water, cover, potential dispersal corridors, and nesting and feeding habitat. Riparian forest provides habitat for birds, mammals, amphibians, and reptiles. Since harvesting regulation is more restrictive in riparian areas, these forests tend to retain dense, large trees required by many covered species.
 Closed-Cone or Pygmy Forest
Closed-cone or pygmy forest is located on thin acidic soils where many trees and shrubs, having adapted to suboptimal growing conditions, are limited in stature. Even the oldest trees reach only limited heights. In these areas, dwarf trees make up more than 75% of a stand. Several species are characteristic of pygmy forests on MRC land, including pygmy cypress, Bolander's pine, pygmy manzanita, Bishop pine, and California sedge (Sholars 1997, CDFG 2002, CNPS 2002).
Regional distribution and ecological factors
Pygmy forest is a rare and unique ecosystem in California (Sholars 1984). The majority of pygmy forest in the world is found in Mendocino County. This ecosystem is the result of hundreds of thousands of years of interaction between soil and vegetation (Sholars 1984). Leaching of soil on the terraces has led to nutrient-poor, acidic soils. Underneath the soil surface of pygmy forest, a shallow hardpan makes it difficult for trees with deep roots to survive (Aitken and Libby 1994).
Along with soil conditions, fire is an important element of pygmy forest. Common tree species in pygmy forest (pygmy cypress, Bishop pine, and Bolander's pine) need high temperatures for cones to open and release seeds.
Habitat
Pygmy forest provides habitat for rare plants and animals that feed on them, such as the Lotis blue butterfly. Today the Lotis blue is known only in sphagnum bogs located in and near pygmy forests in Mendocino County (Arnold et al. 1994). Pygmy forest drains into coastal redwood and Douglas-fir forest. This riparian feature of pygmy forest provides habitat for many aquatic species.
 Oak Woodland and Natural Grasslands
Oak woodland occurs where precipitation falls mostly in the winter, followed by warm-to-hot dry summers (Mayer and Laudenslayer 1988). In oak woodland stands, the overstory usually consists of hardwoods with scattered conifers. On mesic sites, trees form a dense, closed canopy; on dry sites, trees are more widely spaced. Typical oaks of this natural community include Oregon white oak, California black oak, and canyon live oak. Understory plants in oak woodlands can include blackberry and creeping snowberry. In drier areas, shrubs may include greenleaf manzanita and gooseberry.
Grasslands generally occur on flat-to-rolling hill terrains (Mayer and Laudenslayer 1988). Their climate is characterized by cool, wet winters and hot, dry summers.
Regional distribution and ecological factors
Oak woodlands occur in coastal foothills and valleys from Trinity County south. They reach their southern limit in Baja California. The northwest portion of California's oak woodlands occurs between mixed evergreen forests of the coast and grasslands of the Central Valley (Jimerson and Carothers 2002).
Grasslands occur throughout the Central Valley of California, in the coastal mountains of Mendocino County and in other locations in southern California (Mayer and Laudenslayer 1988).
Habitat
Oak woodlands contain the greatest plant and animal diversity in any California habitat type, with over 330 species of birds, mammals, reptiles, and amphibians occurring there at some point in their life (CPIF 2002, Jimerson and Carothers 2002). Oak woodlands provide large quantities of acorns and high quality food, as well as important habitat, such as shelter and nest cavities (CPIF 2002).
Grasslands are important to several species of plants and animals. Rare native plants may be found in grasslands, including Blasdale's bent grass and California sedge. Non-native species can also be found in grasslands, such as soft chess and velvet grass. Vaux's swifts forage over grassland habitat. Other vertebrates in grasslands include garter snake, savannah sparrow, Botta's pocket gopher, and brush rabbit (Mayer and Laudenslayer 1988).
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