Seattle.gov Home Page
Seattle.gov This Department

Forests

old growth

Old-growth forest. View other habitats.

Current forested habitats reflect historic logging patterns.

Lower Watershed

Currently, only about 734 acres of unharvested native forest remain in the lower Cedar River Watershed. (See Map of Lower Cedar River Watershed (pdf)) The old growth that remains typically has been “high-graded” (some trees removed) and is found in relatively small, isolated stands surrounded by expansive stands of young and mature second-growth forest.

Today, second-growth forest dominates the lower watershed—95 percent (12,255 acres) is covered with second-growth forest ranging in age from 70 to 119 years.

Current forests are dominated by a homogeneous canopy of second-growth coniferous or mixed coniferous/deciduous forest that regenerated naturally after the original timber harvest and slash fires of the late 1800s and early 1900s. Major tree species include:

  • Douglas-fir (Pseudotsuga menziesii)
  • western hemlock (Tsuga heterophylla)
  • western red cedar (Thuja plicata)
  • red alder (Alnus rubra)

Western hemlock dominates the mid-understory of most stands and is also the most prolific tree species naturally regenerating under existing canopies in second-growth forests.

Less frequent species include:

  • true firs (noble fir [Abies procera] and grand fir [A. grandis])
  • Sitka spruce (Picea sitchensis)
  • big leaf maple (Acer macrophyllum)

Under tree canopies that are relatively closed, understory plant communities are typically dominated by shrub species such as:

  • vine maple (Acer circinatum)
  • salal (Gaultheria shallon)
  • sword fern (Polystichum munitum)

Where tree canopies are more open or where deciduous trees dominate, we typically find:

  • salmonberry (Rubus spectabilis)
  • sword fern (Polystichum munitum)

Mixed stands having both coniferous and deciduous species are present in many areas of the lower watershed, but are found mostly in forested wetland and riparian habitats.

Pure hardwood stands, dominated by red alder, are infrequent and found mostly in wet or riparian areas.

Upper Watershed

The upper watershed landscape has a much wider range of forest types than the uniform second-growth forest canopy of the lower watershed. The forested landscape of the upper watershed is dominated by coniferous forests, largely a mosaic of recently harvested areas and unharvested old growth. (See Map of Upper Cedar River Watershed (pdf)).

Extensive younger stands are regenerating from harvests occurring from the late 1970s to mid 1990s. Most of the old-growth forest in the watershed ranges from 190 to 350 years old, but a few scattered stands—particularly in the upper Rex River basin—are up to 850 years old.

Of the 13,889 acres of unharvested native coniferous forest greater than 190 years old, 13,155 acres (95 percent) lie in the upper watershed. The unharvested forest is scattered in blocks that range in size from a few acres to 3,000 acres. At the eastern end of the watershed, there are three contiguous areas of old-growth forest that are 2,000 to 3,000 acres each in size.

Little of the unharvested native forest remains below an elevation of 2,500 feet, or west of the Cedar River delta in Chester Morse Lake. A few fragmented and isolated unharvested native stands are located in small upper drainage basins and scattered along the highest ridge lines.

Douglas fir, western hemlock, and western red cedar gradually decrease in abundance as elevation increases. Old growth forests at higher elevations in the watershed are typically dominated by:

  • Pacific silver fir (Abies amabilis)
  • noble fir (Abies procera)
  • western hemlock (Tsuga heterophylla)
  • mountain hemlock (Tsuga mertensiana)

Understories tend to have abundant tree regeneration of those species, as well as abundant shrub and forb species such as:

  • huckleberries (Vaccinium species)
  • devils-club (Oplopanax horridus)
  • fools-huckleberry (Menziesia ferruguinea)
  • strawberry bramble (Rubus lasiococcus)

At the highest elevations, dominant species are:

  • subalpine fir (Abies lasiocarpa)
  • mountain hemlock (Tsuga mertensiana)

Associated understory species include:

  • huckleberry species
  • beargrass (Xerophyllum tenax)

Characteristics of the vegetation regenerating in commercially harvested areas vary widely and depend on soil, exposure, and elevation, among other variables. Regeneration stands can vary from open areas with few tree seedlings dominated by shrub and herbaceous vegetation [e.g., huckleberries (Vaccinium species) and beargrass] to over-stocked stands of conifer regeneration so dense that walking through them is challenging or impossible.

Most second-growth coniferous forest below 2,500 feet in the upper watershed ranges in age from 40 to 80 years old. These stands often have dense, closed canopies that allow minimal light penetration. As a result, older second growth stands are often devoid of tree and shrub understory layers, and herbaceous vegetation can be nearly non-existent in stand interiors.

History

When Eurasian settlers first arrived in the Cedar River Watershed in the early 1870s, virgin forests 100 to over 800 years old covered the landscape. Low- and mid-elevation forests in this region were among the tallest and most productive in the world. Average tree heights exceeded 200 feet and a typical stand stored more than 600 megagrams of carbon per hectare (or over 267 tons of carbon per acre). Also noteworthy were the large amounts of fine and coarse woody debris on the forest floor.

Wildfire was the main disturbance to these forests, typically recurring every 300 to 400 years. Windthrow, landslides, fungal root rots, and lateral stream channel erosion were important secondary disturbances and continue to be important today.

The spatial distribution and condition of today’s forest reflect the historic pattern of harvest of old-growth forest in the watershed. Commercial timber harvest by private landowners began during the 1880s and accelerated throughout the lower elevations until the 1930s.

Intensive logging activity largely ended in the lower watershed and expanded in the upper watershed by the early 1930s, propelled by a shift from railroad-based to truck-based logging operations.

Until the mid-1940s, logging of old-growth forest was concentrated around Chester Morse Lake, in the lower two-thirds of the Rex River drainage, and in the lower reaches of the upper Cedar River east of Chester Morse Lake.

From the mid 1940s through the 1960s, logging activity expanded eastward through the Cedar River valley and moved higher into many smaller tributary systems within the Cedar and Rex river basins.

In the 1970s and early 1980s, logging activity intensified and was concentrated in the upper, higher-elevation basins of both major and minor tributaries, including the Cedar and Rex rivers and Boulder, Lindsay, Seattle, and Goat creeks, as well as in smaller basins along the northern boundary of the watershed.

As of 1996, 99.3 percent of the watershed is under City ownership. No additional commercial harvest activity has taken place. The City is now implementing a 50 year Habitat Conservation Plan that includes no commercial harvest and a long-term restoration program that is attempting to restore the ecological damage caused by historic forest harvest activity.

Related Links

Habitat types in the watershed: