Riparian Forest

Riparian forest is cruical habitat for wildlife/Photo Courtesy of Rollin Bannow

Give Me Shelter 

The Julia Butler Hansen Refuge is home to riparian forests that are characteristic of the historic lower Columbia River. These forested areas house a diversity of plants and trees of many ages. The variety of plant life benefits many types of animals, such as Columbian white-tailed deer, migratory and resident birds, native reptiles and amphibians, and many other species, who use the forest for food and shelter.

Riparian forest and shrub habitat is dominated by woody vegetation that lies adjacent to a stream, channel, seep, or other body of flowing water. It is typically within or very close to the flood plain of a stream and the vegetative composition is influenced by moist soils. For the purpose of Refuge planning, the term riparian forest refers to woodlands that are along the estuary; they are not swamps, and they are not flooded with consistent regularity. Riparian shrub is a transition habitat that will soon mature into riparian forest. These definitions include nearly all wooded habitats (other than swamps) on the refuges.

Discover more about the diversity of riparian forests in the refuge:

  • Early-Successional Forest - This youthful forest has small trees and a diversity of shrubs adapted to a pioneering lifestyle.
  • Mid-Successional Forest - This “tween” forest stage is beginning to develop the more complex characteristics of an older forest.
  • Late-Successional Forest - A “mature” forest, the late-successional forest gives a lot to wildlife.

At the Julia Butler Hansen Refuge, riparian forest/shrub habitat is found primarily on the diked areas of the Mainland and Tenasillahe Island units, although a small amount occurs on the highest parts of Crims and Price islands. Riparian forest within the diked areas is characterized by a diverse mix of tree species. Cottonwood, red alder, Sitka spruce, western red cedar, big leaf maple, Oregon ash, and tree sized willows are prominent. Understory shrubs include salmonberry, red-osier dogwood, snowberry, red elderberry, trailing blackberry, and currant. Riparian forests on the un-diked river islands tend be less diverse, with cottonwood (downstream islands) and cottonwood/willow/Oregon ash (upstream islands) being the dominant tree species.

Riparian forests typically support a diversity of plants and are structurally complex. These forests also support a great diversity and abundance of wildlife. Red-eyed vireos, uncommon in Washington, nest and forage in the trees along with downy woodpeckers, Swainson’s thrushes, and Cooper’s hawks. The shrub understory is a favorite habitat of yellow warblers, among other species. Winter wrens, red-legged frogs, and northwestern salamanders forage on the forest floor. Columbian white-tailed deer find browse and cover. The trees shade waterways, thus improving water quality for salmon and other fish. A large amount of the organic matter produced by the forest finds its way to the estuary, where it nourishes the food chain. In turn, spawned salmon and trout are pulled into the forest by scavengers where their nutrient-rich bodies feed the plants as they decompose – a complex circle of life!

The refuge is working, over time, to re-establish 50% forest cover on refuge-lands to support wildlife. Find out more about conservation efforts...