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A pygmy forest is a forest which, for pedological and geological reasons, contains only miniature trees. Pygmy forests may occur over various world locations with notable occurrences at the Ross of Mull on the Isle of Mull in Scotland,〔C.Michael Hogan, (2011) (''Sea of the Hebrides'' ). Eds. P. Saundry & C.J.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. Washington DC.〕 as example locations. A variant of the pygmy forest is sometimes called elfin forest in parts of Southern California, Mexico, and Central America. ==Ecological staircase== In the case of coastal Pygmy forests in northern California and Oregon, the formation began with a series of marine terraces and should be viewed as part of that formation. A combination of uplift and changes in ocean level formed a system of terraces, resulting in an “ecological staircase,” with each terrace approximately 100,000 years older than the one below it and supporting a distinct association of soils, microbes, plants, and animals. A dune being pushed farther away from the coast by fluctuating sea levels solidified and slid under the one before it, raising the terraces. Pioneer plant communities colonized and took over the young terrace. The succession of plant communities that repeated on each terrace eventually formed a very specific podzol known as the Blacklock series,〔https://soilseries.sc.egov.usda.gov/OSD_Docs/B/BLACKLOCK.html〕 which offers an inhospitable environment for species and greatly stunts further growth on the terrace. Part of this soil profile includes an underlying clay or iron hardpan. Each terrace is relatively level and many are footed by paleo-dunes. Drainage is poor at best on these stairs and plants sit in a bath of their own tannins and acids for much of the wet season. Plant communities on this terrace have reacted to limited root mobility and acidic soil by evolving stunted forms. Remnants of ecological staircases doubtless exist, however most have been destroyed for development or logging. Examples of high-terrace podzol pygmy forests include: * Mendocino Pygmy Forest in Mendocino County, California, for example, is an oligotrophic community caused by podzolized (nutrient-poor, highly acidic) soils. The forest flora is dominated by dwarfed Bishop pine, Bolander pine (a variety of shore pine), and Mendocino cypress. The latter two species are endemics to the pygmy forest. Bishop pine occurs in both dwarfed and full size form, the latter being trees who's roots have broken through the hardpan layer into the more fertile soil beneath. This forest is found in several discontinuous areas, with significant portions on the following public lands: * * Jug Handle State Natural Reserve, where it is the feature of the highest portion of the Ecological Staircase Trail. * * Russian Gulch State Park. * * Jackson Demonstration State Forest includes a large pygmy forest area east of the towns of Mendocino and Casper. * * The Hans Jenny Pygmy Forest Reserve, comanaged by the University of California Natural Reserve System and The Nature Conservancy.〔http://nrs.ucop.edu/reserves/jenny_pygmy/jenny_pygmy_forest.htm〕 * * The Van Damme State Park pygmy forest, designated a National Natural Landmark.〔http://www.nature.nps.gov/nnl/site.cfm?Site=PYFO-CA〕 A self-guided nature trail built entirely on an elevated walkway forms a short loop through the site.〔http://www.parks.ca.gov/?page_id=25144〕 * Salt Point State Park in Sonoma County, California has a much smaller pygmy forest and a fifth terrace prairie ranging from 900 to 1000 feet and formerly supporting elk populations. Like the Mendocino forest, the dominant trees are also Bishop pine, Bolander pine, and Mendocino cypress. Most of Salt Point is on the northernmost portion of the Salinian Block and the terrace staircase drops suddenly into the gulch that lies over the San Andreas fault. * SFB Morse Botanical Reserve in the Del Monte Forest of the Monterey Peninsula is centered on the small Huckleberry Hill pygmy forest of Bishop pine and Gowen cypress, in the middle of a more extensive forest of native Monterey pine. Bishop pine, which tolerates extreme podzol conditions better than Monterey pine, is found in the most heavily podzolized areas, with a zone of Bishop pine/Monterey pine hybrids dominating the less heavily podzolized area. 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「pygmy forest」の詳細全文を読む スポンサード リンク
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