State 1
Reference State

Community 1.1
Pacific silver fir-western redcedar/devilsclub/western swordfern

Structure: Multistory with small gap dynamics Pacific silver fir and western redcedar are the most common overstory species in the reference community. Pacific silver fir is considered very shade tolerant, perhaps the most of any tree species in North America (Crawford, 1990). Western redcedar is shade tolerant, and it can survive up to 1,000 years of age (Minore, 1990). Douglas-fir is present, but regeneration is minimal under a closed canopy. Because of this, it may be absent in some areas. Common understory species include devilsclub (Oplopanax horridus), vine maple (Acer circinatum), salmonberry (Rubus spectabilis), thimbleberry (Rubus parviflorus), western swordfern (Polystichum munitum), deer fern (Blechnum spicant), western oakfern (Gymnocarpium dryopteris), and twinflower (Linnaea borealis). The dense canopy created by multiple age groups of trees may block most of the sunlight from the forest floor, leading to sparse understory in some areas. Most of the understory plants become established in areas where gaps in the mid-canopy and overstory allow sunlight to reach the ground. The understory tends to be more continuous in areas where there is no mid-canopy. A common disturbance is small gap dynamics (openings of 1/2 acre or smaller) following the decline of shade-intolerant species or mortality of vegetation. Community phase pathway 1.1A This pathway represents minor disturbances, such as small pockets of root disease, individual tree mortality, and windthrow, that maintain the overall structure of the reference community. Mortality of individual trees or clusters of trees creates gaps in the canopy that allow sunlight to reach the forest floor. This promotes growth of forbs and shrubs and regeneration of overstory species, maintaining a multi-storied, uneven-aged forest.

Forest overstory. The forest has multiple canopy layers. The upper layer is 160 to 225 feet in height, and it averages 115 feet. The diameter of the trees varies depending on species, but the average diameter at breast height is 25 inches. Some Pacific silver fir and western hemlock trees have a diameter of more than 30 inches.

Community 1.2
Pacific silver fir–Douglas-fir/devilsclub/western swordfern

Structure: Mosaic of mature overstory and regenerating openings Community phase 1.2 has some areas that resemble community phase 1.1, but it also has moderate-sized openings (2 to 4 acres). Pacific silver fir is subject to windthrow. The small openings in the forest allow trees that are less tolerant of shade to establish (Crawford, 1990). Many of the shrubs in the plant community, such as devilsclub, salmonberry, and vine maple, respond well to increased sunlight. This may delay or prevent reforestation of the openings.

Community 1.3
Red alder/vine maple/western swordfern

Structure: Open meadow with snags Community phase 1.3 is an early seral plant community that has been impacted by a stand-replacing disturbance, such as a wildfire, large-scale windstorm, large mass movement, or major insect infestation. Most of the trees are destroyed. Some fire-resistant trees may survive in the overstory. Standing, decaying snags are prevalent. The understory is dominantly shrubs and forbs such as red alder, vine maple, devilsclub, and salmonberry. Some grasses will establish, but they will be replaced by shrubs over time. Tree seedlings and saplings will begin to establish within 3 to 10 years, depending on the severity of the disturbance.

Community 1.4
Douglas-fir–red alder/devilsclub–vine maple/western swordfern

Structure: Single story Community phase 1.4 is an early seral forest in regeneration. Scattered remnant mature trees may be present. The species composition depends on the natural seed sources present and the intensity of the disturbance. After a moderate or severe fire, shrubs are likely to outcompete tree seedlings. Vine maple, red alder, red huckleberry, black mountain huckleberry, and devilsclub, which may have been moderate in abundance previously, have the capacity to recover rapidly and spread if top-killed. This slows regeneration of the overstory. Seed sources for tree species are from the surrounding, undisturbed forests and surviving trees. This results in a mixed stand that may include Douglas-fir, western hemlock, and western redcedar.

Community 1.5
Douglas-fir–western redcedar/devilsclub/western swordfern

Structure: Dense single story with diminished understory Community phase 1.5 is a forest in the competitive exclusion stage. Scattered remnant mature trees may be present. Individual trees compete for available water and nutrients. Douglas-fir and western redcedar are dominant in the overstory canopy; however, saplings of more shade-tolerant species such as Pacific silver fir and western hemlock increase in basal area. The canopy is almost 100 percent closed, which leads to diminished shrubs and forbs. Some understory species better adapted to at least partial shade, such as twinflower and black mountain huckleberry, will increase in abundance. Over time, the forest will begin to self-thin from competition. The species composition depends on the original seed sources available. The forest may include a single species or mixed species, including Douglas-fir, western redcedar, western hemlock, and Pacific silver fir.

Community 1.6
Western redcedar-Pacific silver fir/devilsclub/western swordfern

Structure: Single story with few small openings Community phase 1.6 is a maturing forest that is beginning to differentiate vertically. Individual trees are dying as a result of competition, disease, insects, or windthrow, allowing some sunlight to reach the forest floor. In these areas, the understory increases and overstory tree species may regenerate. The abundance of less shade-tolerant species such as Douglas-fir increases, and the abundance of very shade-tolerant species such as western redcedar, western hemlock, and Pacific silver fir decreases.

Pathway 1.1B
Community 1.1 to 1.2

Pacific silver fir-western redcedar/devilsclub/western swordfern

Pacific silver fir–Douglas-fir/devilsclub/western swordfern

This pathway represents a larger disturbance, such as a windstorm, insect infestation, or pocket of root rot. Areas of regeneration are 2 to 4 acres in size. Historically, this spatial pattern was caused by pockets of disease such as annosum root rot (Heterobasidion annosum), minor insect infestations, or fires of low to moderate intensity. Pacific silver fir is subject to windthrow. The small openings in the forest allow trees that are less tolerant of shade to establish (Crawford, 1990).

Pathway 1.1C
Community 1.1 to 1.3

This pathway represents a major stand-replacing disturbance such as a fire of high intensity, large-scale windstorm, major insect infestation, or large mass movement. The frequency of fire on this ecological site typically is 500 years. Volcanic activity may disrupt the ecology of the landscape beyond the boundaries of the site and the purpose of this site description.

Pathway 1.2A
Community 1.2 to 1.1

Pacific silver fir–Douglas-fir/devilsclub/western swordfern

Pacific silver fir-western redcedar/devilsclub/western swordfern

This pathway represents growth over time with no further significant disturbance. The areas of regeneration go through the typical phases of stands, including competitive exclusion, maturation, understory re-initiation, until they resemble the old-growth structure of the reference community.

Pathway 1.2B
Community 1.2 to 1.3

This pathway represents a major stand-replacing disturbance, such as a high-intensity fire (typical fire interval of 500 years), large-scale windstorm, major insect infestation, or large mass movement. This results in the initiation phase of forest development.

Pathway 1.3
Community 1.3 to 1.4

This pathway represents growth over time with no further major disturbance.

Pathway 1.4B
Community 1.4 to 1.3

This pathway represents a major stand-replacing disturbance, such as a high-intensity fire, large-scale windstorm, major insect infestation, or large mass movement. This results in the initiation phase of forest development.

Pathway 1.4A
Community 1.4 to 1.5

This pathway represents growth over time with no further major disturbance.

Pathway 1.5B
Community 1.5 to 1.3

This pathway represents a major stand-replacing disturbance, such as a high-intensity fire, large-scale windstorm, major insect infestation, or large mass movement. This leads to the initiation phase of forest development.

Pathway 1.5A
Community 1.5 to 1.6

This pathway represents growth over time with no further major disturbance.

Pathway 1.6A
Community 1.6 to 1.1

This pathway represents growth over time with no further major disturbance. Continued growth over time and ongoing mortality lead to increased vertical diversification. The community begins to resemble the structure of the reference community, including small pockets of regeneration and a more diversified understory.

Pathway 1.6B
Community 1.6 to 1.3

This pathway represents a major stand-replacing disturbance, such as a high-intensity fire, large-scale windstorm, major insect infestation, or large mass movement. This leads to the initiation phase of forest development.