June 8, 2005

A tale of two ecoregions

Ashland is nestled between the Cascades and the Klamath-Siskiyous, providing a rich diversity of plants and rocks

Pilot Rock sits astride the border between the Cascade and Klamath-Siskiyou ecoregions. The Cascades include Mount Shasta (shown in the distance). Photo by Gerry Ellis

By Robert Plain
Ashland Daily Tidings

It’s fairly obvious to anyone who cranes their head to both the east and the west of Ashland that there is a great difference from one side of the Bear Creek Valley to the other.

To the west are the lush, heavily forested, steep and craggy Siskiyou Mountains. To the east are the drier, less densely vegetated and more gently sloping southern end of the Cascade Mountains.

Ashland is almost perfectly situated at the convergence of these two centrally located, though vastly different, habitats known to the experts that study them as “ecoregions.”

The Cascade ecoregion extends from Mount Shasta, which is about 75 miles south of Ashland, north into Canada. It encompasses Lassen Peak and Shasta in California; Grizzly Peak, Crater Lake, Mount McLaughlin, the Three Sisters and Mount Hood in Oregon; north to Mount Rainier in Washington; and beyond.

The Klamath-Siskiyou ecoregion, which encompasses about 10 million acres in Southern Oregon and Northern California, extends from Roseburg in the north, west to the Coos Bay area where it follows the coast south until Crescent City, Calif. From there, it cuts east and south until the Yolla Bolla area near Ukiah, Calif.

The primary difference between the two, according to the local scientific community, is their age and the rocks from which these ecoregions are formed.

“The main difference is based on geology,” said Pepper Trail, an ornithologist who works for the U.S. Department of Fish and Wildlife. “The Cascades are quite young. In geologic terms, they are hardly out of diapers yet.”

The Cascades, formed some 20 million years ago, are a part of the Pacific Rim, a series of volcanoes that extends from southern Alaska, south to Mexico and west all the way to Japan and the Asian mainland.

The variety of mountains in the Klamath-Siskiyou ecoregion are much older.

The eastern side of the Bear Creek Valley, including Grizzly Peak, is part of the Cascades. Photo by Orville Hector | Ashland Daily Tidings

Dominick DellaSala, a forest ecologist for the World Wildlife Fund, estimates they are more than 150 million years old. He said these mountains were formed before the dinosaurs roamed the earth, when tectonic plates collided in the Pacific Ocean.

“The Cascades are volcanic in origin,” he said. “That’s a lot different than a bunch of plates colliding and being shoved out from the sea floor.”

This difference in origin, agreed the two environmental experts, has made all the difference in the two regions’ ecology.

The difference is easy to recognize by looking at Mount Ashland, in the Klamath-Siskiyou ecoregion, and Grizzly Peak, in the Cascade ecoregion.

The vegetation on Grizzly Peak is consistent with that of a typical conifer forest, as is the case throughout the western Cascades. Mount Ashland, on the other hand, is more of an evergreen forest with a noticeable hardwood influence in its vegetation, including madrone trees, tan oaks and live oaks.

“The forest that grows in the Cascades is a very impressive forest with big trees,” Trail said. “It’s impressive in form, but it’s not as impressive in diversity as is the Siskiyous.”

Many surmise that the lower elevations of Grizzly Peak have been logged off, causing its pasture-like appearance. However, DellaSala said this is due to the dry nature of the Cascade ecoregion.

To the west of Ashland, the mountains are part of the Klamath-Siskiyou ecoregion. Photo by Orville Hector | Ashland Daily Tidings

“This question gets asked a lot,” he said, adding that without the grazing that has been happening there, it may host more oak savannah habitat and native grasslands as opposed to the invasive vetch and cheat grass that have been brought by ranching. Other than this somewhat subtle alteration, the Cascade ecoregion, in these lower elevations at least, is naturally a bit bald.

An obvious difference to the untrained eye is between the contours of the two mountainous ecoregions. The Cascades run in an almost straight north-south line, while the many different mountain ranges in the Klamath-Siskiyou ecoregion run every which way.

DellaSala said the circuitous nature of these mountains is known as “the Klamath knot.”

“The Siskiyous are a very ancient, eroded landscape,” Trail said. “There is no dominant feature and no clear way through them. It’s a hellacious place to build a road. The geology has kept people out indirectly.”

The Cascades, formed by slow moving lava flows, are more gradual and not as steep. “If you drive out to Crater Lake from Medford you’ll notice it’s a slow, smooth incline,” Trail said. “The lava flows created these long, sweeping slopes.”

On the eastern side of the Cascade Mountains can be found sagebrush and juniper, species rarely found on the Siskiyou side.

On the other hand, the Klamath-Siskiyou ecoregion contains a plethora of endemic species found nowhere else on the planet. Examples include the Port Orford cedar, Brewer’s spruce, Jeffrey pine (a close relative of the ponderosa pine) and the serpentine rock found nowhere else but near the Kalmiopsis Wilderness Area.

These two unique ecoregions meet in the area southeast of Ashland known as the Cascade-Siskiyou National Monument; hence the name.

“The monument is the only land bridge between the two mountain ranges,” DellaSala said. “Hike to the east of Pilot Rock and you are in the Cascades. Hike to the west of Pilot Rock and you’re in the Siskiyous.”

While Trail and DellaSala were quick to point out that the Cascade ecoregion is significant in its own right, they both stressed that the Klamath-Siskiyou ecoregion is unique and among the most amazing in North America, if not the world.

“I refer to it as the Galapagos of North America,” DellaSala said, calling the area one of the 10 most significant conifer forests on the planet. “It’s a cradle of evolution for the Pacific Coast. The Cascades are important, too, but they don’t rise to the same level of importance.”

Coast Range Klamath Mountains Eastern Cascades slopes and foothills Cascades (includes Mount Shasta)

There are several environmental factors that have led to the great diversity in the Klamath-Siskiyou ecoregion, Trail said.

“Volcanic soil (like that found in the Cascades) is known to be pretty young and fertile,” he said. The soils found in the Klamath-Siskiyou ecoregion, on the other hand, are ancient, and thus less fertile.

Because of this, Trail explained, some of the plant varieties that have adapted to growing in these conditions will not grow anywhere else.

“The only plants that can grow in these areas are the specialized ones,” Trail said. “They can’t compete in other areas.”

“So you have all these weird soils that are hard to adapt to,” Trail said. “There are other soil types that are fairly widespread. The combination gives you the diversity.”

Also, because the Klamath-Siskiyou ecoregion was never completely glaciated over, it has offered refuge to some species, such as the Brewer’s spruce, which were once found elsewhere but now only in this area. “Fossils of it have been found across North America,” Trail said. “But it was only able to survive here.”

In the Klamath-Siskiyou ecoregion, there are more than 3,500 species of plants, at least 220 of which are found nowhere else in the world. There are more than 40 species of conifers alone, DellaSala said, not to mention some 115 species of butterfly and 235 species of mollusks or snails.

The view across the Bear Creek Valley from Dead Indian Memorial Road shows mountains that are part of the Klamath-Siskiyou ecoregion. Orville Hector | Ashland Daily Tidings

“What we found is the more you study [the Klamath-Siskiyou ecoregion] the more extraordinary it becomes,” DellaSala said. Indeed, the WWF set up an office in Ashland for the specific purpose of studying more closely this rare and dynamic natural area. “Scientists have known about its importance for 200 years. We are just now starting to confirm how significant and exceptional the Klamath-Siskiyou ecoregion really is.”

Staff writer Robert Plain can be reached at 482-3456 x 3040 or bplain@dailytidings.com.