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Exploring the beautiful nature of California
California Nature: Redwood Ecosystem
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California's boundaries cover almost 156,000
square miles. It includes many diverse ecosystems including
redwood forests, kelp forests and
Death Valley's deserts.
According to the California Chaparral Institute, the
shrubland
ecosystem is the most prevalent ecosystem in California with
over 4 million acres.
An ecosystem encompasses all the living organisms and the
physical features of an area. It also includes the interactions
between them. An ecosystem stands apart from others because of
its dominant feature, for example ocean, desert, forest or
estuarine ecosystems. A habitat refers to a single population of
organisms within the ecosystem.
It is important to remember that redwoods are not just trees,
they are part of complex ecosystems that depend on and support
them. About 82 percent of the remaining ancient coast redwood
forests is protected in parks and reserves; more than 90 percent
of giant sequoia acreage is in public ownership. Much work
remains to ensure that future generations can enjoy these
magnificent forests.
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Three species of trees are commonly referred to as redwoods: California's coast redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum), and China's dawn redwood (Metasequoia glyptostroboides).
Redwoods get their common name from their bark and heartwood, the reddish-brown color of which stems from high tannin levels. Other chemicals found in the leaves, branches and bark give these trees a remarkable resistance to fungal disease and insect infestation.
Their thick bark holds large quantities of water, which protects them from periodic, naturally occurring fires.
All three redwoods are descendents of a group of conifers (cone-bearing trees) that flourished more than 144 million years ago when dinosaurs roamed the Earth. At that time, the Earth’s climate was warmer and more humid than it is today, so redwood species grew throughout North America, Europe and Asia. Over time and in response to an ever-changing environment, they retreated from most of their former range, and many once-abundant redwood species became extinct.
Successive ice ages, including the last one that ended about 10,000 years ago, have restricted the remaining redwood species to three small, distinct regions, each supporting one of the species. Each region is the only place in the world where you will find native populations of that species.
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In California, thousands of acres of ancient
coast redwood forest are on private land and could still be
logged for lumber or to make room for development. While mature
giant sequoia trees themselves are too brittle to produce useful
lumber, real-estate development near the groves threatens the
ecosystem on which they depend.
The Northern California Coastal Forests are largely defined by
two features, the largely persistent moist environments provided
by Pacific storms in the winter and coastal fogs in the summer,
and the distribution of the redwood tree.
Redwoods range from central California to the Oregon border, and
are typically found within 40 miles of the coast. Redwood groves
are patchily distributed among a variety of natural communities
found within this coastal belt, including Douglas-fir-tanoak
forests, oak woodlands, closed-cone pine forests, bogs, and
coastal grasslands. |
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In California, redwoods and Douglas-fir dominate many lowland areas. These ancient and spectacular conifers are among the biggest, tallest, and oldest trees in the world, often exceeding 200 feet
in height, they are sometimes more than 369 feet tall in some individuals.
Redwoods average 15 feet in diameter, and can be 2,200 years
old. Redwood groves have the greatest biomass accumulation known
for any terrestrial ecosystem. They are globally unique forests,
and only a few other forests in the world have a similar
assemblage and structure of ancient, giant conifers.
Redwood distribution is patchy, but they generally occur in the fog belt ranging from five to thirty-five miles wide along the coast and from 100 to 2,000 feet in elevation. Redwood dominated forests tend to occur in valley bottoms, where there is abundant fog drip, alluvial soils, and periodic floods about every thirty to sixty years. On the uplands where fire was a reoccurring disturbance, a more diverse assemblage of trees occur with redwoods, including Douglas-fir, grand fir, western hemlock, Sitka spruce, western red cedar, tanoak, bigleaf maple, California bay, and Port Orford cedar. Without periodic disturbances, some ecologists suspect that redwood groves may be eventually be replaced by western hemlock.
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Redwood forests harbor a diversity of animal
life including bears, fishers, pine martens, numerous warblers, and the endangered marbled murrelet
which nests in mature forest canopies. A number of amphibians
live here including the Pacific giant salamanders, red-bellied
newts, and tailed frogs. Old-growth redwood forests contain a
unique ecosystem, home to rare animals such as coho salmon,
spotted owls, and marbled murrelets.
Silver salmon and steelhead trout breed in coastal rivers and
streams. Also found in the redwood ecosystem is the
extraordinary bright yellow-orange banana slug, a mature forest
specialist and a candidate for California’s state invertebrate.
A number of other invertebrate species, including beetles,
harvestman, spiders, millipedes, and freshwater mussels are
specialists on habitats modified by old Redwood and other
conifer forests and maintain very local distributions. Given the
propensity of species in these invertebrate groups for very
restricted ranges and the virtual elimination of mature forests
in the redwood ecosystem, the probability that numerous species extinctions have already occurred is high. |
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