|
California mixed evergreen forest is an ecoregion, of the temperate broadleaf and mixed forests biome, that occurs in the Pacific Coast Ranges of southwestern Oregon and western California in the Coast, Transverse, and Peninsular Ranges in California. Mixed evergreen forests occur in small areas of the Klamath-Siskiyou forests, Northern California coastal forests, and California chaparral and woodlands ecoregions. The forests of each ecoregion have a somewhat different plant community composition. ==Klamath-Siskiyou mixed evergreen forest== The mixed evergreen forests of the Klamath Mountains-Siskiyou Mountains occur above 300 meters (1000 ft) elevation, and are of four main types. Douglas-fir forests are found on gentle slopes, north-facing slopes, ridges with deep soil, and river terraces with deep sediments, usually underlain with sedimentary rocks. Coast Douglas-fir (''Pseudotsuga menziesii'' ssp. ''menziesii'') is the predominant tree, occupying up to 70% of the forest cover. Broadleaf evergreen trees are relatively few. Tree species of secondary importance are: *Sugar pine (''Pinus lambertiana''), *Ponderosa pine (''Pinus ponderosa''), *White fir (''Abies concolor''). On granite soils, a similar species composition predominates, but with more broadleaf evergreens, chiefly: *Tanoak (''Lithocarpus densiflora'') and *Canyon live oak (''Quercus chrysolepis''), along with *Giant chinquapin (''Chrysolepis chrysophylla''). On steep, well drained slopes, canyon live oak is the dominant species, with coast Douglas-fir in a minor role. On serpentine soils, mixed evergreen forests are made up of: :moister areas *Lawson's cypress (also known as Port Orford cedar, ''Chamaecyparis lawsoniana'') and *Western white pine (''Pinus monticola'') :drier areas *Incense cedar (''Calocedrus decurrens''), *Jeffrey pine (''Pinus jeffreyi''), *Knobcone pine (''Pinus attenuata''). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「California mixed evergreen forest」の詳細全文を読む スポンサード リンク
|