It's no wonder Oregon is known as The Beaver State. Aside from the coyote and wolf, no other mammal—including the cow—has figured so dramatically in the commercial history of our state as the North American Beaver. Wars were fought over beaver, and much of western Oregon was impacted by the trapping of beaver and the sale of their fur, so much so, that by the mid-1800's they were almost extinct from over-trapping.
Our native American Beaver is the largest living native rodent in North America. Adults tip the scales at about 40 pounds, measure more than three feet in length, including the tail, and their nose and ears seal out water. They are semi-aquatic, have webbed hind feet, (very) large incisor teeth, and a broad, flat tail.
The beaver's teeth deserve some discussion. Their sharp incisors—used to fell trees and peel bark while eating—are harder on the front surface than on the back, therefore, the back surface wears faster, leaving a sharp, hardened front edge, enabling them to cut through wood as if it were butter.
The incisors grow continually, but are worn down by grinding, tree cutting, and feeding. If the lower jaw is injured to the extent the upper and lower incisors no longer match up, the incisor will keep growing and eventuality go so far out of alignment that it will puncture the skull, or destroy the animal's ability to cut vegetation, resulting in death. (Next time you start gnashing your teeth, think of the beaver...)
It's not an exaggeration to say that Oregon—and most of the Northwest for that matter—was built on the back of the poor old beaver. Right from the beginning of humans' interactions with wildlife, native peoples trapped beaver and manufactured warm, sturdy coats for winter from the fur.
When Capt. Robert Gray sailed over the bar of the Columbia River (then known as the Oregon River) in May of 1792, the life of the beaver, the river, and the Northwest changed forever. The river was renamed the Columbia after Capt. Gray's ship, the Columbia Rediviva. But that was nothing compared to the impact on the economy of the Northwest after Gray spent nine days on the river bartering for fur pelts with the native people before sailing away to England.
It's not an exaggeration to say that Oregon—and most of the Northwest for that matter—was built on the back of the poor old beaver.
All it took was one look at those beautiful fur coats, and the local merchants sent trading ships off from Britain for Oregon. First off, the beaver robes were traded for beads, baled up, and sold to hat-makers in Britain and Europe. Most manufacturers found the coats satisfactory for making hats and robes, but when thousands upon thousands of freshly processed beaver pelts were shipped in place of coats and robes, the fur-processing businesses really started to grow.
Thanks to the fur of the exploited beavers, fur hats were shipped to the newly created United States of America by the millions. In Europe the demand for beaver fur was so intensive that European beavers were exterminated in Russia, with only a small population surviving in Sweden and Norway. That put the strain for raw material on the North American Beaver, which — by the mid 1800's — was almost wiped out as well. The only thing that saved them from extinction was the difficulty of finding beaver and the evolution of the fashion and clothing industry.
A hydrologist with the Whitman Ranger District of the Wallowa-Whitman National Forest in Northeastern Oregon, Suzanne Fouty, is on a quest to learn what beaver do, other than sacrifice their lives for sport and profit. Her findings make it clear that these creatures have an important impact on ecosystems. For instance:
Beaver dams create ponds of varying depths, add wood to stream channels, and create side channels;
Beaver help to create viable riparian habitat and maintain water levels for healthy vegetation, increasing species diversity.
Beaver ponds elevate groundwater tables and bring about irrigation of valley floors, thereby shifting vegetation from drought-tolerant species to more diverse water-dependent species.
Beaver ponds reconnect streams and meanders, leading to a more abundant water supply and increasing riparian species diversity. The result is that the valley floor becomes an active flood plain, decreasing flood magnitudes.
Elevated ground water from beaver ponds lowers water temperatures, creating better conditions for anadromous fish populations.
Stable beaver ponds will improve water quality and lead to increased woody riparian vegetation that stabilizes stream banks, increases resistance to stream erosion, and recycles nutrients more efficiently within the mineral and carbon cycles.
Water quantity—essentially controlled by the function of precipitation and snow packs—is greatly influenced by beaver ponds that elevate and store water.
As water levels and quantity increase because of beaver ponds, summer base flows will increase and be cooler.
Beaver ponds increase water stored in the ground and in plants that will slow the rate at which water leaves a watershed.
Ecosystem stability will be maintained through stable beaver ponds, even under climate change. Flood damage is reduced, and as a result, a more stable ecosystem will supply greater biodiversity.