Coastal Landscape Analysis and Modeling Study

Coast Range Tour

1. The natural environment

2. Humans in the Coast Range



The natural environment

The Coast Range is a major topographic and climatic divide in the Pacific Northwest region. Its mountains are rugged with sharp ridges and steep slopes. Elevations range from 450 to 750 meters (1500-2500 feet) in main ridge summits, with a high of 1,249 meters (4097 feet) on Marys Peak.
Rugged terrain gives way along the coast and major rivers to undulating hills and flat valleys where dairy farming is common. The mountain slopes are typically a mosaic of young forests of different ages, reflecting the recent historic pattern of forest management.
The Coast Range climate is characterized by mild temperatures, a long frost-free season, prolonged cloudy periods, narrow seasonal and daily temperature fluctuations, mild wet winters, cool dry summers, and heavy precipitation mostly falling from October to March. The highest precipitation occurs along the interior mountain range, while the driest areas are near the Willamette valley.
The Coast Range is among the most productive forest ecosystems in the world, more productive even than many tropical forests. It has the capacity to produce huge quantities of wood, but also produces large quantities of non-timber vegetation, wildlife, and fish, all of which depend on the same underlying factors: mild climate, abundant rainfall, and deep soils.
Streams in the Coast Range have historically contained large fallen trees, which created crucial habitat for salmonids and other aquatic vertebrates and invertebrates.


In contrast to the productivity of forest lands, the net primary productivity of streams in the Coast Range is relatively low, possibly because high forest productivity means relatively little sunlight reaches the water - less than five percent of full sunlight in some cases. However, coast range watersheds have the potential to produce large amounts of fish biomass as a result of anadromous fish runs. When these fish, particularly salmon, made their way into coastal streams in the past, they ended up as carcasses on the shore, providing a source of food and nutrients for predators, scavengers, and the ecosystem as a whole.

While the Coast Range is an ideal region to grow trees for timber, it is also ideal for species that use large live and dead trees, and their associated stream reaches, for habitat. Endangered species such as the marbled murrelet, the northern spotted owl, and the coho salmon have inhabited the province for millennia.
Large dead wood has several functions in Coast Range forest ecosystems, including: fixation of nitrogen; storage of carbon and water; development of soil structure; habitat for cavity-nesting and forest floor vertebrates; and habitat for invertebrates, plants, and fungi.
Disturbances come in many shapes and sizes in the Coast Range, all integral to the productivity and biological diversity of ecosystems. Landslides open gaps in dense forest and expose mineral soils, which may be important to maintaining some deciduous shrub and tree species. Landslides also feed large and small materials into both headwater and mainstem streams, affecting stream function and productivity.
Floods have always played a dramatic and integral role in shaping streams and riparian zones in the Coast Range. They can initiate landslides on slopes that move large and small materials into streams, and open up forest gaps. In streams, they scour stream beds, move large amounts of coarse woody debris, carry fine sediments, rearrange stream profiles, and open up the forest canopy to allow higher levels of sunlight to reach the water.

Until the advent of large-scale logging and effective fire suppression in the middle of the 20th century, wildfires were the dominant disturbance in Coast Range forests. Before Euroamerican settlement, fire return intervals ranged from 90 to 400 years, with severity ranging from light to severe (>70% of canopy trees killed). In its natural state, the Coast Range would have been a slowly shifting mosaic of large and small patches of forest, ranging from shrubby areas to dense old forests.



Humans in the Coast Range
Return to top



Current forest patterns result primarily from wildfires and historic and present-day logging. Virtually all forest lands in the Coast Range in private ownership have been harvested at least once in the past and are less than 80 years old.
Many National Forest landscapes retain the patterns created by two decades of staggering small harvest units across the landscape and harvesting them at a constant rate. Many BLM lands have a similar mosaic of clear cuts, but also frequently appear as a checkerboard of older forests mixed with young forests on the surrounding private lands. Logging of older forest on federal lands was drastically curtailed after listing of the northern spotted owl as a Threatened species under the Endangered Species Act.

Private industrial landowners seeking maximum financial returns on their lands use intensive management methods that include clearcutting most live trees and snags, preparing sites with fire or herbicides, replanting with a single species (usually Douglas-fir), periodic thinning to maintain vigorous and evenly spaced crop trees, and harvesting at 40- to 70-year intervals. Clearcut units on these lands tend to be larger than on federal or state lands, with 120 acres the current maximum allowed under the State Forest Practices Act.

Another view of private industrial lands.
Forests on non-industrial private lands reflect the distribution of parcels of individual landowners, which are typically much smaller than industrial or federal lands. These lands are often found along streams, are usually less intensively managed for timber than industrial lands, and utilize partial harvesting more often.
State lands are generally intermediate in management intensity between private industrial and federal lands. Less than 10 percent of the coastal province is State-owned, with the Tillamook and Elliott State Forests being the predominant holdings. State forest management plans and practices are changing to reflect societal concerns about biodiversity.

Forest roads have served numerous functions, including access for extraction of wood and other forest products, silvicultural activities, fire detection and suppression, and recreation. Unintended negative impacts have included effects on water runoff, erosion and effects on fish habitat, landslide initiation, invasion of exotic species and pathogens, and wildlife dispersions due to collisions or hunting. Although roads commonly occupy less than four percent of the area of a forest landscape, their effects can be more widespread.

Forests and farmland in the Coast Range have historically been subject to development, either low-density residential or sometimes urban. Although Oregon’s land use planning program attempts to concentrate development within urban growth boundaries, its success remains uncertain.
Leaving riparian buffers along streams is now a common approach to protecting aquatic habitat. However, many questions remain about how wide those buffers should be, how they should be managed, and how they should be distributed across a watershed.
Recreational uses of the coastal province are important to the economy and social well-being of Oregon. The Coast Range, coastal valleys, and beaches have long attracted visitors to their mix of fishing, hunting, hiking, birdwatching, beachcombing, cycling, camping and RV use. Decisions affecting road closures and forest and wildlife management will have impacts on recreation opportunities.
Community involvement in land use issues has steadily increased over the last several decades as forest management controversies have become more intense. Watershed Councils are examples of collaborative efforts to reach watershed goals with greater public input.


Contact the Webmaster