State 1
Reference

Community 1.1
Sitka Spruce, White Fir, Evergreen Huckleberry, Salmonberry, and Western Swordfern

Structure: Mosaic of mature overstory and regenerating openings
Sitka spruce and white fir are the most common overstory species in the reference community. Douglas-fir likely is present; however, minimal regeneration occurs in a closed canopy forest. The dense canopy created by the multiple age groups of trees may block most of the sunlight from the forest floor, which leads to sparse understory in some areas.
Gaps in the mid canopy and overstory allow sunlight to reach the ground, and a majority of the understory plants establish in these gaps. The gaps also allow red alder to regenerate, and mature stands of red alder may be throughout this community. The understory tends to be more continuous in areas where there is no mid canopy. Common understory species include evergreen huckleberry, red huckleberry, salal, salmonberry, red elderberry (Sambucus racemosa), and western swordfern.

Community 1.2
Red Alder, Salmonberry, Red Elderberry, and Western Swordfern

Structure: Open forest with abundant regeneration and snags
Community phase 1.2 is an early seral plant community that has been impacted by a stand-replacing disturbance such as a wildfire, a large-scale wind event, mass movement, or major insect or disease infestation. Nearly all trees are absent, but some fire-resistant trees may survive in the overstory. Standing, decaying snags are prevalent. Vegetative regeneration occurs quickly following disturbance. The understory is dominantly early seral species of trees, shrubs, and forbs such as red alder, thimbleberry (Rubus parviflorus), red elderberry, salmonberry, and western swordfern. Red alder has several competitive advantages and can establish quickly as compared to conifers. It can sprout and establish in full sunlight and fixes nitrogen, which provide an early competitive advantage (Villarin, 2009). Seeds of deciduous species are light and can be transported long distances by wind and water, which allows for rapid recolonization. Depending on the severity of the disturbance, tree seedlings and saplings typically establish within 3 to 10 years. Some grasses will establish, but they will be replaced by shrubs over time.

Community 1.3
Red Alder, Sitka Spruce, Salmonberry, Evergreen Huckleberry, and Western Swordfern

Structure: Dense single story
Community phase 1.3 is an early seral forest in regeneration. Scattered remnant mature trees may be present. Species composition depends on the natural seed sources present and the intensity of the disturbance. After a moderate or severe fire, shrubs likely will outcompete tree seedlings. Red alder, red huckleberry, evergreen huckleberry, salmonberry, and western swordfern may be abundant in the understory if sunlight is sufficient (Bailey, 1968).
Red alder will begin to die 40 to 70 years following disturbance and more light will penetrate the newly nitrogen-rich soil (Naiman, 2009). As a result, conifer regeneration becomes more prevalent in this community phase. Seed sources for tree species are the surrounding areas of undisturbed forest. The combination of new growth and survivors of the disturbance result in a mixed stand that could include Sitka spruce, Douglas-fir, and white fir. Sitka spruce is vulnerable to outbreaks of white pine weevil during this community phase.

Community 1.4
Sitka Spruce, White Fir, Salmonberry, Evergreen Huckleberry, and Western Swordfern

Structure: Dense single story with diminished understory
Community phase 1.4 is a forest in the competitive exclusion stage. Scattered remnant mature trees may be present. Competition among individual trees for available water and nutrients is increased. Sitka spruce and white fir are dominant in the overstory canopy; however, more shade-intolerant species such as Douglas-fir and red alder may be present. The canopy closure is nearly 100 percent, which leads to diminished shrubs and forbs. Some understory species better adapted to at least partial shade will begin to increase. Over time, the forest will begin to self-thin due to the elevated competition.

Pathway 1.1A
Community 1.1 to 1.2

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

Pathway 1.2A
Community 1.2 to 1.3

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

Pathway 1.3A
Community 1.3 to 1.2

This pathway represents a major stand-replacing disturbance such as a high-intensity fire, timber harvesting, a large-scale wind event, a major infestation of insects, or large mass movement that leads to the stand initiation phase of forest development.

Pathway 1.3B
Community 1.3 to 1.4

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

Pathway 1.4B
Community 1.4 to 1.1

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

Pathway 1.4A
Community 1.4 to 1.2

This pathway represents a major stand-replacing disturbance such as a high-intensity fire, timber harvesting, a large-scale wind event, a major infestation of insects, or large mass movement that leads to the stand initiation phase of forest development.

State 2
Disturbed

Community 2.1
Red Alder, Salmonberry, and Common Gorse

Structure: Open forest with regeneration and downed woody debris
Community phase 2.1 represents a recently disturbed forest that is naturally regenerating. Following large-scale disturbances, large woody debris commonly is prolific. This inhibits establishment of vegetation under natural conditions. Areas that are not replanted immediately (1 to 3 years) following timber harvesting or a large-scale disturbance may become vulnerable to infestation by invasive species.
Typically, commercially managed forests will be replanted following disturbance. Species preference depends on site conditions and long-term economic decisions. Overall, species biodiversity is diminished in forests managed for short-rotation timber.
Natural reforestation depends on available seed sources following disturbance. Early seral species such as red alder and salmonberry tend to regenerate quickly under abundant sunlight. The plant community typically is homogenous and even-aged. Common gorse (Ulex europaeus) and Scotch broom (Cytisus scoparius) commonly are dominant after a disturbance. They tend to outcompete establishment of native species. Invasive species management is critical during this phase.

Community 2.2
Sitka Spruce, Red Alder, Salmonberry, and Common Gorse

Structure: Single story
Community phase 2.2 represents an even-aged regenerating forest. Sitka spruce, white fir, western hemlock, shore pine, and Douglas-fir can regenerate quickly on nurse logs or in recently disturbed soils. A higher soil temperature favors seed germination of Sitka spruce, which commonly is the first coniferous tree species to re-establish following logging (Peterson, 1997). Shade-intolerant red alder remains a large component in the overstory until it reaches maturity (Fonda, 1974).
The vegetation in areas that have been replanted commonly is dense and even aged, and the understory species are sparse in areas that have a high percentage of canopy cover. Salmonberry, common gorse, and Scotch broom increase in prominence in areas that receive abundant sunlight. Management techniques such as pre-commercial or commercial thinning and mitigation of invasive species will accelerate the maturation and improve the health of the forest.

Community 2.3
Sitka Spruce, White Fir, and Salmonberry

Structure: Dense single story with diminished understory
Community phase 2.3 represents a maturing forest that has increased plant diversity. White fir can regenerate under a dense, shrubby canopy. It will begin to establish in the overstory canopy along with Sitka spruce. The dense, shrubby understory is prone to wildfires. Commercial logging operations commonly take place during this phase as trees reach economical maturity in size and volume. It is presumed that without timber management during this phase, an old-growth stand of Sitka spruce and western hemlock will develop.

Pathway 2.1A
Community 2.1 to 2.2

This pathway represents growth over time with no further major disturbance or active forest management.

Pathway 2.2A
Community 2.2 to 2.3

This pathway represents growth over time with no further major disturbance or active forest management.

Pathway 2.3A
Community 2.3 to 2.1

This pathway represents a major stand-replacing disturbance such as a high-intensity fire, a large-scale wind event, a major infestation of insects or disease, large mass movement, or logging activities that lead to the stand initiation phase of forest development.

Transition T1A
State 1 to 2

This pathway represents a major disturbance that has removed most of the overstory. Large-scale disturbances may increase the vulnerability to infestation by invasive species if a seed source is nearby or introduced into the site. This type of disturbance will impact the natural feedbacks that maintained the reference state.

Transition T2A
State 2 to 1

This pathway represents intensive management to restore the historic plant community.