There is a wide variety of wetland habitats for the naturalist willing to get wet in the pursuit of new species and unique habitats. Several grassland communities are the most diverse sites in the region, with strong floristic ties to Northwestern hot spots in the Olympic Mountains and Columbia Gorge.

Coniferous forest is the dominant habitat of the coast, and within this category, industrial timberland is the most common landuse category. Commercial timber aside, the area still has a few stands of old growth trees.

Summer drought is the reason that conifers dominate many western forests of North America. Despite wet winters, dry growing seasons along the Northwest Coast severely limit the spread of broad-leaved deciduous trees. Here hardwoods grow only in perennially damp soils. Grasslands are restricted to even drier sites. Only conifers flourish in wet winters and dry summers.

Plant communities develop through succession, involving change in species composition over time. Coast range forests north of the Nehalem River in Oregon developed without regular fire, but with regular severe windstorms. Consequently these forests exhibit highly diverse age structure with complex, multilayered
understories and a few dominant tree species. Wind throw was uncommon over large areas prior to the advent of industrial forestry. Shade tolerance characterizes the dominant tree species, allowing seedlings to establish in the shade of mature trees and wait for wind to top or topple them, creating light gaps that release the young trees and allow them to grow.

Wildfires, when they occur in these forests, are catastrophic, burning thousands of acres at a time. Restoration of conifer overstories may take fifty to one hundred years or more. Dominant conifers are thin-barked and not fire tolerant. Seeds are not fire-tolerant. Fires burn the forest duff layer, a thick layer of slowly decomposing wood, needles and bark on the forest floor that holds nutrients and water, and supports soil fungi. Elimination of duff by wildfire may seriously slow forest restoration, as soil fungi are critical partners to conifer seedlings.

Coastal Temperate Rainforest
The coastal temperate rainforest of North America is the most extensive example of this forest type in the world. Found only on the West Coast, coastal temperate rainforest occurs from Northern California near San Francisco Bay to South-central Alaska, growing in a narrow fringe, with a small parallel fringe on the west side of the Cascade Range from central Oregon to southern British Columbia. Temperate rainforests are distinguished by rarity of fire, evergreeness, and complex physical structure (abundance of epiphytes, multiple canopy layers under the main canopy, and a dense understory).

Dense coniferous forests are highly productive. Throughout the Columbia Coast, cleared patches readily return to dense forest within fifty years. Shrubby understories are legendary. Accustomed to Eastern hardwood forests, an archeologoist was hiking on Long Island in the 1970s, looking for shell middens. In his frustration at the dense, cloaking vegetation, he uttered what could be a classic statement about coastal vegetation, "You could put the White House here, walk away from it for twenty years, and we'd never find it again."

Ancient Forests
"Productive, low-elevation, old-growth temperate rainforests are among the most massive ecosystems on earth. Tremendous accumulations of biomass result from the combination of: long periods of time between stand-destroying disturbances; the great longevity of many northwestern trees; their inherent ability to grow large; and relatively slow decomposition rates. Frequently more than half of the total mass in these forests is in the form of dead trees, either snags or logs. . . The great abundance of dead, woody material in such forests has led to the development of complex communities of organisms that depend on decomposing material . . . structural attributes characteristic of older forests are a wide range of tree sizes and ages, and a patchy, open canopy punctuated by gaps beneath which the forest understory is especially well developed." Quote from Plants of the Pacific Northwest Coast, used with permission by the publisher.

Individual tree ages of 600 to >1,000 years are not uncommon in ancient forests. Growth rates vary widely by site; size cannot be used to establish tree age. Sitka spruce trees along the ocean on wet clay soils and more than five feet dbh may be less than 200 years old, while spruces of the same diameter growing 8-10 miles inland may be more than 600 years old.


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