Alnus rubra, the red alder, is a deciduous broadleaf tree native to western North America. Red alder is the largest species of alder in North America and one of the largest in the world, reaching heights of 20 to 30 m; the official tallest red alder stands 32 m tall in Oregon. The name derives from the bright rusty red color that develops in scraped bark; the bark is mottled, ashy-gray and smooth colonized by white lichen and moss. The leaves are ovate, 7 to 15 centimetres long, with bluntly serrated edges and a distinct point at the end; the leaves turn yellow in the autumn before falling. The male flowers are dangling reddish catkins 10 to 15 cm long in early spring. Female flowers occur in clusters of 4–6. Female catkins are otherwise pendant, they develop into small, superficially cone-like oval dry fruit 2 to 3 cm long. The seeds are shed in late autumn and winter. Red alder seeds have a membranous winged margin. Alnus rubra grows from southeast Alaska south to central coastal California, nearly always within about 200 km of the Pacific coast, except for an extension 600 km inland across Washington and Oregon into northernmost Montana.
In southern Alaska, western British Columbia and the northwestern Coast Ranges of the United States, red alder grows on cool and moist slopes. Red alder is associated with coast Douglas-fir Pseudotsuga menziesii subsp. Menziesii, western hemlock Tsuga heterophylla, grand fir Abies grandis, western redcedar Thuja plicata, Sitka spruce Picea sitchensis forests. Along streambanks it is associated with willows Salix spp. red osier dogwood Cornus stolonifera, Oregon ash Fraxinus latifolia and bigleaf maple Acer macrophyllum. To the southeast of its range it is replaced by white alder, a tree of similar stature, but which differs in the leaf margins not being rolled under, lack of distinct lobes, lack of membranous wings on seed margins. In the high mountains it is replaced by the smaller and more shrub-like Sitka alder, east of the Cascade Mountains by thinleaf alder. In moist forest areas Alnus rubra will cover a former burn or clearcut preventing the establishment of conifers, it is a prolific seed producer, but the small, wind-dispersed seeds require an open area of mineral soil to germinate, so skid trails and other areas disturbed by logging or fire are ideal seedbeds.
Such areas may host several hundred thousand to several million seedlings per hectare in the first year after landscape disturbance. Twigs and buds of alder are only fair browse for wildlife, though deer and elk do browse the twigs in fall and twigs and buds in the winter and spring. Beaver eat the bark, though it is not a preferred species. Several finches eat alder seeds, notably common redpoll and pine siskin, as do deer mice. Alnus rubra hosts the nitrogen fixing actinomycete Frankia in nodules on roots; this association allows alder to grow in nitrogen-poor soils. A russet dye can be made from a decoction of the bark and was used by Native Americans to dye fishing nets so as to make them less visible underwater. Native Americans used red alder bark to treat poison oak, insect bites, skin irritations. Blackfeet Indians used an infusion made from the bark of red alder to treat lymphatic disorders and tuberculosis. Recent clinical studies have verified that red alder contains betulin and lupeol, compounds shown to be effective against a variety of tumors.
Alnus rubra is an important early colonizer of disturbed forests and riparian areas because of its ability to fix nitrogen in the soil. This self-fertilizing trait allows red alder to grow and makes it effective in covering disturbed and/or degraded land, such as mine spoils. Alder leaves, shed in the fall, decay to form a nitrogen-enriched humus. Red alder is used as a rotation crop to discourage the conifer root pathogen Phellinus weirii. Alnus rubra are planted as ornamental trees and will do well in Swales, riparian areas, or on stream banks, in light-textured soils that drain well. Red alder does not thrive in wet clay soils. If planted domestically, alders should be planted well away from drainpipes, sewage pipes, water lines, as the roots may invade and clog the lines. Alder lumber is not considered to be a durable option for outdoor applications, but due to its workability and ease of finishing it is used for furniture and cabinetry; because it is softer than other popular hardwoods such as maple and ash alder has not been considered of high value for timber.
However it is now becoming one of the more popular hardwood alternatives as it is economically priced compared to many other hardwoods. In the world of musical instrument construction, red alder is valued by some electric guitar / electric bass builders for its balanced tonality. Alder is used by Native Americans for making masks, tool handles, other small goods; the appearance of alder lumber ranges from white through pinkish to light brown, has a soft texture, minimal grain, has medium luster. It is worked, glues well
Pseudotsuga menziesii is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is known as Douglas fir, Douglas-fir, Oregon pine, Columbian pine. There are two varieties: coast Douglas-fir, Rocky Mountain Douglas-fir; the common name honors David Douglas, a Scottish botanist and collector who first reported the extraordinary nature and potential of the species. The common name is misleading. For this reason the name is written as Douglas-fir; the specific epithet menziesii is after Archibald Menzies, a Scottish physician and rival naturalist to David Douglas. Menzies first documented the tree on Vancouver Island in 1791. Colloquially, the species is known as Doug fir or Douglas pine. Other names for this tree have included Oregon pine, British Columbian pine, Puget Sound pine, Douglas spruce, false hemlock, red fir, or red pine. One Coast Salish name for the tree, used in the Halkomelem language, is lá:yelhp. Douglas-firs are medium-size to large evergreen trees, 20–100 metres tall.
The leaves are flat, linear, 2–4 centimetres long resembling those of the firs, occurring singly rather than in fascicles. As the trees grow taller in denser forest, they lose their lower branches, such that the foliage may start high off the ground. Douglas-firs in environments with more light may have branches much closer to the ground; the female cones are pendulous, with persistent scales, unlike those of true firs. They are distinctive in having a long tridentine bract. Pseudotsuga menziesii var. menziesii, the coast Douglas-fir, grows in the coastal regions from west-central British Columbia southward to central California. In Oregon and Washington, its range is continuous from the eastern edge of the Cascades west to the Pacific Coast Ranges and Pacific Ocean. In California, it is found in the Klamath and California Coast Ranges as far south as the Santa Lucia Range, with a small stand as far south as the Purisima Hills in Santa Barbara County. In the Sierra Nevada, it ranges as far south as the Yosemite region.
It occurs from near sea level along the coast to 1,800 m above sea level in the mountains of California. Another variety exists further inland, Pseudotsuga menziesii var. glauca, the Rocky Mountain Douglas-fir or interior Douglas-fir. Interior Douglas-fir intergrades with coast Douglas-fir in the Cascades of northern Washington and southern British Columbia, from there ranges northward to central British Columbia and southeastward to the Mexican border, becoming disjunct as latitude decreases and altitude increases. Mexican Douglas-fir, which ranges as far south as Oaxaca, is considered a variety of P. menziesii. Douglas-fir prefers neutral soils. However, it exhibits considerable morphological plasticity, on drier sites P. menziesii var. menziesii will generate deeper taproots. Pseudotsuga menziesii var. glauca exhibits greater plasticity, occurring in stands of interior temperate rainforest in British Columbia, as well as at the edge of semi-arid sagebrush steppe throughout much of its range, where it generates deeper taproots than coast Douglas-fir is capable.
Mature or "old-growth" Douglas-fir forest is the primary habitat of the red tree vole and the spotted owl. Home range requirements for breeding pairs of spotted owls are at least 400 ha of old growth. Red tree voles may be found in immature forests if Douglas-fir is a significant component; the red vole nests exclusively in the foliage of the trees 2–50 metres above the ground, its diet consists chiefly of Douglas-fir needles. A parasitic plant sometimes utilizing P. menziesii is Douglas-fir dwarf mistletoe. The leaves are used by the woolly conifer aphid Adelges cooleyi, it is present in large numbers, can cause the foliage to turn yellowish from the damage it causes. Exceptionally, trees may be defoliated by it, but the damage is this severe. Among Lepidoptera, apart from some that feed on Pseudotsuga in general the gelechiid moths Chionodes abella and C. periculella as well as the cone scale-eating tortrix moth Cydia illutana have been recorded on P. menziesii. The coast Douglas-fir variety is the dominant tree west of the Cascade Mountains in the Pacific Northwest, occurring in nearly all forest types, competes well on most parent materials and slopes.
Adapted to a moist, mild climate, it grows faster than Rocky Mountain Douglas-fir. Associated trees include western hemlock, Sitka spruce, sugar pine, western white pine, ponderosa pine, grand fir, coast redwood, western redcedar, California incense-cedar, Lawson's cypress, bigleaf maple and several others. Pure stands are common north of the Umpqua River in Oregon. Poriol is a flavanone, a type of flavonoid, produced by P. menziesii in reaction to infection by Poria weirii. The species is extensiv
Oregon Coast Range
The Oregon Coast Range called the Coast Range and sometimes the Pacific Coast Range, is a mountain range, in the Pacific Coast Ranges physiographic region, in the U. S. state of Oregon along the Pacific Ocean. This north-south running range extends over 200 miles from the Columbia River in the north on the border of Oregon and Washington, south to the middle fork of the Coquille River, it is 30 to 60 miles wide and averages around 1,500 feet in elevation above sea level. The coast range has three main sections, a Northern and Southern; the oldest portions of the range are over 60 million years old, with volcanics and a forearc basin as the primary mountain building processes responsible for the range. It is part of the larger grouping known as the Pacific Coast Ranges that extends over much of the western edge of North America from California to Alaska; the range creates a rain shadow effect for the Willamette Valley that lies to the east of the mountains, creating a more stable climate and less rain than the coastal region of the state.
To the west where the range over-shadows the Oregon Coast, the range causes more precipitation to fall on that side of the mountains, contributing to the numerous rivers that flow to the Pacific Ocean. Marys Peak in the Central Coast Range is the highest peak at 4,097 feet. Logging is a major industry in the range in both private and government owned forests. Both the state and federal government manage forests in the Oregon Coast Range; the mountains are home to a variety of wildlife including black bear, deer, many species of birds, bats among others. Fish, including salmon and trout, other aquatic life inhabit the streams and rivers flowing through the range. Volcanic activity 66 million years ago in the Cretaceous Period created offshore islands beginning in the southern portion of the current range; these Roseburg volcanics were followed by the Siletz River Volcanics in the northern portions of the range, lastly a series of basalt flows from the Columbia River basalts added to these formations with some smaller flows in-between.
Much of the formations are the result of pillow basalt formations created when a hot basalt flow cooled upon meeting the salt water of the ocean. These deposits offshore were pushed into the continental plate as a forearc basin rotating over millions of years; this tectonic collision created the coastal range. Additional basalt flows originated from Eastern Oregon and added to the layers that were uplifted, as the newer Cascade Mountains had not yet been formed. By the Early Oligocene period c. 30 million years ago the current coastline was in place and erosion has continued to shape the range. Through rivers cutting deep valleys through the igneous and sedimentary rocks; the geologic boundaries of the coast range formation extend from southwest Washington state in the north to around the Coquille River in the south where the older and taller Klamath Mountains begin. In the east the mountains begin as foothills forming the western edge of the Willamette Valley and continue west to the coastline and beyond where the basalt formation tapers off into the continental shelf and ends at the continental slope with several banks and basins off shore.
Physiographically, they are a section of the larger Pacific Border province, which in turn are part of the larger Pacific Mountain System physiographic division. A mild maritime climate prevails throughout the range with temperature and precipitation varying due to elevation and distance from the coastline. Characteristic of the climate include cool dry summers followed by wet winters; the majority of precipitation accumulates in the form of rain, with snow during the winter months at the higher elevations, but no permanent snow pack. Annual precipitation differs from 60 inches in some parts to up to 120 inches, with the higher amounts coming in the higher elevations; the average high temperature in January is 36.3 °F, the average high in July is 61.9 °F with temperatures varying by elevation. The further inland and the more southerly portions have a more Mediterranean climate, more similar to the climate of the Willamette Valley; the Coast Range creates a rain shadow effect by forcing moisture laden clouds to rise by expelling moisture.
This shields the Willamette Valley and causes a more climate with mild winters and less precipitation than the Oregon Coast. The Oregon Coast Range is divided into three separate sections: North and South. In the south is the oldest portion of the range with formation beginning in the Paleocene era with the Roseburg volcanics, while the newest section is the northernmost portion formed first with the Siletz River Volcanics; the Central and Northern sections contain more sedimentary rocks from the mud, silt and other volcanic debris than the lower Southern section. The Oregon Coast Range is home to over 50 mammal species, over 100 species of birds, nearly 30 reptile or amphibian species that spent significant portions of their life cycle in the mountains. Located in the northwest portion of Oregon this section of the range has peaks as high as 3,706 feet for Rogers Peak. Forests here are considered to be some of the most productive timber land in the world. Trees include Sitka spruce, western redcedar, Douglas-fir, western hemlock.
Other plants include huckleberry, salal, vine maple, Oregon grape, bracken fern, thimble-berry among others. The northern boundary is the Columbia River, with some mountainous features on the north side of the river, contin
United States National Forest
National Forest is a classification of protected and managed federal lands in the United States. National Forests are forest and woodland areas owned collectively by the American people through the federal government, managed by the United States Forest Service, a division of the United States Department of Agriculture; the National Forest System was created by the Land Revision Act of 1891, signed under the presidency of Benjamin Harrison. It was the result of concerted action by Los Angeles-area businessmen and property owners who were concerned by the harm being done to the watershed of the San Gabriel Mountains by ranchers and miners. Abbot Kinney and forester Theodore Lukens were key spokesmen for the effort. In the United States there are 155 National Forests containing 190 million acres of land; these lands comprise 8.5 percent of the total land area of the United States, an area about the size of Texas. Some 87 percent of National Forest land lies west of the Mississippi River in the mountain ranges of the Western United States.
Alaska has 12 percent of all National Forest lands. The U. S. Forest Service manages all of the United States National Grasslands, around half of the United States National Recreation Areas. There are two distinctly different types of forests within the National Forest system; those east of the Great Plains in the Midwestern and Eastern United States were acquired by the federal government since 1891, may be second growth forests. The land had long been in the private domain and sometimes logged since colonial times, but was purchased by the United States government in order to create new National Forests; those west of the Great Plains in the Western United States, though established since 1891, are on lands with ownership maintained by the federal government since the U. S. acquisition and settling of the American West. These are lands that were kept in the public domain, with the exception of inholdings and donated or exchanged private forest lands. Land management of these areas focuses on conservation, timber harvesting, livestock grazing, watershed protection and recreation.
Unlike national parks and other federal lands managed by the National Park Service, extraction of natural resources from national forests is permitted, in many cases encouraged. However, the first-designated wilderness areas, some of the largest, are on National Forest lands. There are management decision conflicts between conservationists and environmentalists, natural resource extraction companies and lobbies, over the protection and/or use of National Forest lands; these conflicts center on endangered species protection, logging of old-growth forests, intensive clear cut logging, undervalued stumpage fees, mining operations and mining claim laws, logging/mining access road-building within National Forests. Additional conflicts arise from concerns that the grasslands and forest understory are grazed by sheep, and, more rising numbers of elk and mule deer due to loss of predators. Many ski resorts and summer resorts operate on leased land in National Forests. List of U. S. National Forests United States National Grassland National Forests of the United States topics State forest National Forest Management Act of 1976 Protected areas of the United States USDA Forest Service USDA Forest Service - The First Century 100 Years of Federal Forestry
Thuja plicata called western redcedar or Pacific redcedar, giant arborvitae or western arborvitae, giant cedar, or shinglewood, is a species of Thuja, an evergreen coniferous tree in the cypress family Cupressaceae native to western North America. It is not a true cedar of the genus Cedrus. Thuja plicata is among the most widespread trees in the Pacific Northwest, it is associated with western hemlock in most places where it grows. It is found at the elevation range of sea level to a maximum of 2,290 m above sea level at Crater Lake in Oregon. In addition to growing in lush forests and mountainsides, western redcedar is a riparian tree, growing in many forested swamps and streambanks in its range; the tree is able to reproduce under dense shade. It has been introduced to other temperate zones, including western Europe, New Zealand, the eastern United States, higher elevations of Hawaii; the species is naturalized in Britain. Thuja plicata is a large to large tree, ranging up to 65 to 70 m tall and 3 to 4 m in trunk diameter, exceptionally larger.
Trees growing in the open may have a crown that reaches the ground, whereas trees densely spaced together will exhibit a crown only at the top, where light can reach the leaves. It is long-lived; the foliage forms flat sprays with scale-like leaves in opposite pairs, with successive pairs at 90 degrees to each other. The foliage sprays are green marked with whitish stomatal bands below; the individual leaves are 1 to 4 mm long and 1 to 2 mm broad on most foliage sprays, but up to 12 mm long on strong-growing lead shoots. The cones are slender, 10 to 18 mm long, 4 to 5 mm broad, with 8 to 12 thin, overlapping scales, they are green to yellow-green, ripening brown in fall about six months after pollination, open at maturity to shed the seeds. The seeds are 1 mm broad, with a narrow papery wing down each side; the pollen cones are 3 to 4 mm long, red or purple at first, shed yellow pollen in spring. Thuja plicata is one of two Thuja species native to North America, the other being Thuja occidentalis.
The species name plicata derives from the Latin word plicāre and means "folded in plaits" or "braided," a reference to the pattern of its small leaves. Most authorities, both in Canada and the United States cite the English name in two words as western redcedar, or hyphenated as western red-cedar, to indicate it is not a true cedar, but it is cited as western red cedar in some popular works. In the American horticultural trade, it is known as the giant arborvitae, by comparison with arborvitae for its close relative Thuja occidentalis. Other names include giant redcedar, Pacific redcedar, British Columbia cedar, canoe cedar, red cedar. Arborvitae comes from the Latin for "tree of life". One endonymous name for the tree is the Halkomelem word xepá:y, from the roots xíp, meaning "scratch" or "line", á:y, "bark"; the largest living specimen is the Cheewhat Giant, in Pacific Rim National Park Reserve on Vancouver Island, at 15,870 cubic feet. The tallest known individual is the Willaby Creek Tree south of 195 feet in height.
The "Quinault Lake Redcedar" was the largest known western redcedar in the world, with a wood volume of 17,650 cubic feet. Located near the northwest shore of Lake Quinault north of Aberdeen, about 34 km from the Pacific Ocean, it was one-third the volume of the largest known tree, a giant sequoia named "General Sherman"; the Quinault Lake Redcedar was 174 feet tall with a diameter of 19.5 feet at breast height. The "Quinault Lake Red Cedar" was destroyed by a series of storms in 2014 and 2016 and is now only a glorified stump; the fifth known largest was the Kalaloch Cedar in the Olympic National Park, at 12,370 cubic feet, until it was destroyed by storm in March 2014. A redcedar over 71 m tall, 4.5 m in diameter, over 700 years old stood in Cathedral Grove on Vancouver Island, British Columbia, before it was set on fire and destroyed by vandals in 1972. That tree now lies in a self-dug ` grave' created by the force of its own impact; the soft red-brown timber has few knots. It is valued for its distinct appearance and its high natural resistance to decay, being extensively used for outdoor construction in the form of posts, decking and siding.
It is used for the framing and longwood in lightweight sail boats and kayaks. In larger boats it is used in sandwich construction between two layers of epoxy resin and/or fibreglass or similar products. Due to its light weight—390 to 400 kg/m3 dried—it is about 30% lighter than common boat building woods, such as mahogany. For its weight it can be brittle, it glues well with epoxy resorcinol adhesive. The wood used as an insect-repelling closet lining and to make cedar chests is a different species, Juniperus virginiana, its light weight and dark, warm sound make it a popular choic
John Day Fossil Beds National Monument
John Day Fossil Beds National Monument is a U. S. National Monument in Wheeler and Grant counties in east-central Oregon. Located within the John Day River basin and managed by the National Park Service, the park is known for its well-preserved layers of fossil plants and mammals that lived in the region between the late Eocene, about 45 million years ago, the late Miocene, about 5 million years ago; the monument consists of three geographically separate units: Sheep Rock, Painted Hills, Clarno. The units cover a total of 13,944 acres of semi-desert shrublands, riparian zones, colorful badlands. About 210,000 people visited the park in 2016 to engage in outdoor recreation or to visit the Thomas Condon Paleontology Center or the James Cant Ranch Historic District. Before the arrival of Euro-Americans in the 19th century, the John Day basin was frequented by Sahaptin people who hunted and gathered roots and berries in the region. After road-building made the valley more accessible, settlers established farms, a few small towns along the river and its tributaries.
Paleontologists have been unearthing and studying the fossils in the region since 1864, when Thomas Condon, a missionary and amateur geologist, recognized their importance and made them known globally. Parts of the basin became a National Monument in 1975. Averaging about 2,200 feet in elevation, the monument has a dry climate with temperatures that vary from summer highs of about 90 °F to winter lows below freezing; the monument has more than 80 soil types that support a wide variety of flora, ranging from willow trees near the river to grasses on alluvial fans to cactus among rocks at higher elevations. Fauna include more than 50 species of migratory birds. Large mammals like elk and smaller animals such as raccoons and voles frequent these units, which are populated by a wide variety of reptiles, fish and other creatures adapted to particular niches of a mountainous semi-desert terrain; the John Day Fossil Beds National Monument consists of three separated units—Sheep Rock, Painted Hills, Clarno—in the John Day River basin of east-central Oregon.
Located in rugged terrain in the counties of Wheeler and Grant, the park units are characterized by hills, deep ravines, eroded fossil-bearing rock formations. To the west lies the Cascade Range, to the south the Ochoco Mountains, to the east the Blue Mountains. Elevations within the 13,944-acre park range from 2,000 to 4,500 feet; the Clarno Unit, the westernmost of the three units, consists of 1,969 acres located 18 miles west of Fossil along Oregon Route 218. The Painted Hills Unit, which lies about halfway between the other two, covers 3,132 acres, it is situated about 9 miles northwest of Mitchell along Burnt Ranch Road, which intersects U. S. Route 26 west of Mitchell; these two units are within Wheeler County. The remaining 8,843 acres of the park, the Sheep Rock Unit, are located along Oregon Route 19 and the John Day River upstream of the unincorporated community of Kimberly; this unit is in Grant County, although a small part extends into Wheeler County. The Sheep Rock Unit is further subdivided into the Mascall Formation Overlook, Picture Gorge, the James Cant Ranch Historic District, Cathedral Rock, Blue Basin, the Foree Area.
Some of these are separated from one another by farms and other parcels of land that are not part of the park. The park headquarters and main visitor center, both in the Sheep Rock Unit, are 122 miles northeast of Bend and 240 miles southeast of Portland by highway; the shortest highway distances from unit to unit within the park are Sheep Rock to Painted Hills, 45 miles. The John Day River, a tributary of the Columbia River, flows west from the Strawberry Mountains before reaching the national monument, it turns north between the Mascall Formation Overlook and Kimberly, where the North Fork John Day River joins the main stem. Downstream of Kimberly, the river flows west to downstream of the unincorporated community of Twickenham, north thereafter. Rock Creek enters the river at the north end of Picture Gorge. Bridge Creek passes through Mitchell north along the eastern edge of the Painted Hills Unit to meet the John Day downstream of Twickenham. Intermittent streams in the Clarno Unit empty into Pine Creek, which flows just beyond the south edge of the unit and enters the John Day upstream of the unincorporated community of Clarno.
Early inhabitants of north-central Oregon included Sahaptin-speaking people of the Umatilla and Warm Springs tribes as well as the Northern Paiutes, speakers of a Uzo-Aztecan language. All were hunter-gatherers competing for resources such as elk and salmon. Researchers have identified 36 sites of related archeological interest, including rock shelters and cairns, in or adjacent to the John Day Fossil Beds National Monument. Most significant among the prehistoric sites are the Picture Gorge pictographs, consisting of six panels of rock art in the canyon at the south end of the Sheep Rock Unit; the art is of undetermined origin and age but is "centuries old". The John Day basin remained unexplored by non-natives until the mid-19th century. Lewis and Clark noted but did not explore the John Day River while traveling along the Columbia River in 1805. John Day, for whom the river is named visited only its confluence with the Columbia in 1812. In 1829, Peter Skene Ogden, working for the Hudson's Bay Company, led a company of explorers and fur trappers along the river through what would
Tide pools or rock pools are shallow pools of seawater that form on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide. Many tide pools are habitats of adaptable animals that have engaged the attention of naturalists and marine biologists, as well as philosophical essayists: John Steinbeck wrote in The Log from the Sea of Cortez, "It is advisable to look from the tide pool to the stars and back to the tide pool." Tidal pools exist in the intertidal zones. These zones are submerged by the sea at high tides and during storms, may receive spray from wave action. At other times the rocks may undergo other extreme conditions, baking in the sun or exposed to cold winds. Few organisms can survive such harsh conditions. Lichens and barnacles live in this region. In this zone, different barnacle species live at tightly constrained elevations. Tidal conditions determine the exact height of an assemblage relative to sea level; the intertidal zone is periodically exposed to sun and wind, which desiccate barnacles, which need to be well adapted to water loss.
Their calcite shells are impermeable, they possess two plates which they slide across their mouth opening when not feeding. These plates protect against predation; the high tide zone is flooded during each high tide. Organisms must survive wave action and exposure to the sun; this zone is predominantly inhabited by seaweed and invertebrates, such as sea anemones, chitons, green algae, mussels. Marine algae provide shelter for hermit crabs; the same waves and currents that make life in the high tide zone difficult bring food to filter feeders and other intertidal organisms. Called the lower littoral zone; this area is submerged and is exposed only during unusually low tide. It teems with life and has much more marine vegetation seaweeds. There is greater biodiversity. Organisms in this zone do not have to be as well adapted to drying temperature extremes. Low tide zone organisms include abalone, brown seaweed, crabs, green algae, isopods, limpets and sometimes small vertebrates such as fish; these creatures can grow to larger sizes because there is more available energy and better water coverage: the water is shallow enough to allow more sunlight for photosynthetic activity, the salinity is at normal levels.
This area is relatively protected from large predators because of the wave action and shallow water. Tide pools provide a home for hardy organisms such as starfish and clams. Inhabitants must be able to deal with a changing environment — fluctuations in water temperature and oxygen content. Hazards include strong currents, exposure to midday sun and predators. Waves can draw them out to sea. Gulls drop sea urchins to break them open. Starfish are eaten by gulls themselves. Black bears sometimes feast on intertidal creatures at low tide. Although tide pool organisms must avoid getting washed away into the ocean, drying up in the sun, or getting eaten, they depend on the tide pool's constant changes for food; the sea anemone Anthopleura elegantissima reproduces clones of itself through a process of longitudinal fission, in which the animal splits into two parts along its length. The sea anemone Anthopleura sola engages in territorial fights; the white tentacles, which contain stinging cells, are for fighting.
The sea anemones sting each other until one moves. Some species of starfish can regenerate lost arms. Most species must retain an intact central part of the body to be able to regenerate, but a few can regrow from a single ray; the regeneration of these stars is possible. Sea palms look similar to palm trees, they live in the middle to upper intertidal zones in areas with greater wave action. High wave action may increase nutrient availability and moves the blades of the thallus, allowing more sunlight to reach the organism so that it can photosynthesize. In addition, the constant wave action removes competitors, such as the mussel species Mytilus californianus. Recent studies have shown that Postelsia grows in greater numbers when such competition exists — a control group with no competition produced fewer offspring than an experimental group with mussels. Alternatively, the mussels may prevent the growth of competing algae such as Corallina or Halosaccion, allowing Postelsia to grow after wave action removes the mussels.
Intertidal fish List of British Isles rockpool life Rocky shore Tidal swimming pools in Britain