Plant Communities of the Olympic Peninsula

Plant Communities of the Olympic Peninsula

One of the most impressive ecological aspects of the Olympic Peninsula is the diversity of habitats found here. The physical structure of the Peninsula has much to do with this diversity. Being located near the sea provides a moderating effect that keeps the climate of our peninsula relatively mild. The stark elevational changes of the Olympic Mountains create the conditions for dramatic shifts in temperature and precipitation patterns as elevation changes. All of these changes happen in relatively short distances.

The plant communities range from the lowland temperate rainforests along the coastal plain (mainly a western hemlock-dominant community), to the mixed conifer forests of higher elevations that have mixed stands of Douglas fir, noble fir, western hemlock and western red cedar, big-leaf maples and red alder. Higher in elevation, the mixed conifer communities shift to one more populated with Alaska yellow cedar, mountain hemlock and Sitka alder. Eventually, once you get to the higher elevations of the Olympics, one enters a near monospecific community of subalpine fir with some Alaska yellow cedar thrown in for balance.

The lower elevations have a range of communities as well. Depending on where you are on the Peninsula, you can have very different conditions. On the west end, the precipitation can range all the way to nearly 200 inches per year near the headwaters of the Hoh and the other river valleys in this region. The forests on this end are dominated be Douglas fir, western red cedar and Selaginella-moss-covered big leaf maples. On the coastal fog-belts of the Peninsula, the Sitka Spruce community dominates.

On the other hand, in the rain-shadow belt of the northeastern stretches of the Peninsula, Garry oak and prairie communities are (or at least were…) common. Along the river habitats of the Peninsula great riparian communities exist with their stands of black cottonwoods and red alders and willow species. Many of the Peninsula's riverine habitats are still wild with only a few dams present. And this is changing! Within the next two years, the two dams on the Ehlwa River will be coming down and a major effort to restore one of North America's most productive river systems will ensue. Can't wait!

All of these communities promote a healthy floral biodiversity which exceeds 1200 species. (Vist our "Flora of the Olympic Peninsula" pages for an idea of the diversity found here)

Click here to visit our Olympic Peninsula image galleries!

	The Riparian Community located along the banks of the Elwha River. Note the Black Cottonwood (tall with orange foliage in fall) and the Red Alders populating the river edges.
*A Subalpine meadow located at Hurricane Ridge. Note the stand of Subalpine Fir (Abies lasiocarpa) in the background.*

	The Selaginella-dense maple (Acer macrophylum) forest common in the river edge and river terrace communities of the Peninsula. This is the famous "Hall of Mosses" in the Hoh Valley located on the west end of the Olympic Peninsula.
Owing its existance to the dramatic rainshadow formed by the Olympic Mountains and Bailey Range, the Garry Oak (Quercus garryana) woodland shown here in Sequim is a remnant of a much warmer and dryer era on the Peninsula.

	The mixed conifer forest characteristic of the lowland temperate rainforest community in the Olympic Peninsula. This particular forest is a Western Hemlock (Tsuga heterophyla)-dominant forest. Douglas Fir (Psuedotsuga menziesii) and Grand Fir (Abies grandis) are also common in this community.
Coastal grasslands and interior grassland prairies were once common on the north end of the Peninsula. The Sequim Prairie was once vast and maintained by native American populations by controlled burns. This practice encouraged the grasslands and made browse readily available to the species they hunted.

	The subalpine community shown here is subject to intense winter snows. Subalpine Fir (Abies lasiocarpa) is shown here covered with snow. Snow burdon causes the twisted nature of many of these old trees.
An alpine grassland on top of Hurricane Hill.

The Big Leaf Maple (Acer macrophylum) community found in the Elwha Valley near Madison Falls. Note the Licorice Ferns growing among the various bryophyte (moss) species.

A spectacular view of some transitions between plant communities as seen from Rica Canyon trail. Here we can see a riparian community with Black Cottonwood (Populus trichocarpa) and Red Alder (Alnus rubra) transitioning in to a mixed conifer community dominated by Douglas Fir, Western Red Cedar (Thuja plicata) and Western Hemlock (Tsuga heterophyla). Note the grassland meadow situated on the river terrace. This is a favorite haunt for Roosevelt Elk and Black Bears.

	An estuary community seen near the mouth of the Dungeness River. In winter months this is an excellent place for waterfowl. One can often seen thousands of American Wigeons in a single morning visit.
An example of Hemlock and Douglas Fir-dominant mixed conifer forest as seen from the road to Hurricane Ridge.

The fog-dependent Sitka Spruce (Picea sitchensis) community hugs the coastal margins and the lowland river valleys of the Peninsula. This community will exist in various forms wherever fog can reach. The burls seen in this image are somewhat of a mystery but are thought to be caused by a fungus.

A good view of an alpine meadow punctuated with stands of Subalpine Fir and Alaska Yellow Cedar (Chamaecyparis nootkatensis).

Click here to visit our Olympic Peninsula image galleries!