Pacific temperate rain forests

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Temperate rain forests often grow right up to the shoreline

The Pacific temperate rain forests of North America are the largest temperate rain forest zone on the planet. The Pacific temperate rain forests occur on west-facing coastal mountains along the Pacific coast of North America - the Pacific Northwest - from Kodiak Island in Alaska through Canada to northern California, and are part of the Nearctic ecozone. The Pacific temperate rainforests are characterized by a high amount of rainfall, in some areas more than 300 cm (120 inches) per year and moderate temperatures in both the summer and winter months (between 50-75°F).

These rain forests occur in a number of ecoregions, which vary in their species composition, but are predominantly of conifers, sometimes with an understory of broadleaf trees and shrubs. Pacific Temperate rain forests can be found in the Northern Pacific coastal forests, Queen Charlotte Islands, British Columbia mainland coastal forests, Central Pacific coastal forests, Central and Southern Cascades forests, Klamath-Siskiyou forests, and Northern California coastal forests ecoregions.

The forests in the north contain predominantly Sitka Spruce and Western Hemlock, while those in the coastal forests are home as well to Coast Redwood (Sequoia sempervirens), Coast Douglas-fir (Pseudotsuga menziesii), Western Redcedar and Shore Pine. Notably, the three tallest species of trees are found here. Dense growths of epiphytes and mosses cover the trees, and lush vegetation is present everywhere.

1 History
2 Ecology
3 Logging
4 See also
5 References
6 External links

[edit] History

About 200 million years ago (during the Triassic and Jurassic periods), the landscape was dominated by conifers which were the most diverse group of trees and constituted the greatest majority of large trees. When flowering plants emerged (in the following Cretaceous period), they quickly prevailed, causing most conifers to become extinct, and those that survived to adapt to harsh conditions. Perhaps the most significant difference in this change is that the primitive conifers invested their energy in the basic food supply for every seed, with no certainty of fertilization; by contrast, flowering plants only create the food supply for a seed after being triggered by fertilization. The Pacific temperate rain forest now remains the only region anywhere on Earth of noteworthy size and significance where, due to unique climatic conditions, the conifers flourish as they did before being displaced by flowering plants (Davis 2000).

The northern Pacific temperate rainforests are relatively young, emerging in the past few thousand years following the retreat of the ice sheets of the last ice age (Davis 2000).

[edit] Ecology

The ecosystem of Pacific temperate rain forests is so productive that the biomass in the best sites is at least four times greater than that of any comparable area in the tropics (Davis 2000).

The first survey to systematically explore the forest canopy in the Carmanah Valley of Vancouver Island yielded 15,000 new species, a third of all invertebrates known to exist in all of Canada. Among the collection were 500 species previously unknown to science (Davis 2000).

[edit] Logging

Pacific temperate rainforests have been subject to ongoing large-scale industrial logging since the end of the Second World War. In California, only 4% of the redwoods have been protected. In Oregon and Washington, less than 10% of original coastal rainforest remains.