State 1
Reference

Community 1.1
Moderate to Closed Canopy Grand Fir, Douglas-fir, Tall Shrubs, Low Shrubs, herbs, and Grasses

Growth from community 1.4 and 1.5 are the dominant pathways producing this condition. Moderate to low severity fire and background mortality (insects, pathogens, wind, etc.) processes also serve to maintain a single- to multi- layered, moderate to closed canopy forest with heterogeneous composition of medium to large trees. Small to large snags are present, as well as down wood (Mellen-McLean et al. 2017). Dominant medium to large Douglas-fir and grand fir, with medium bigleaf maple are indicators of the reference community. Other trees, such as large ponderosa pine may be found as well. Hardwoods including Oregon white oak and Pacific madrone may occur on drier, warmer sites. Incense cedar and California black oak can be found in southern foothill forests (McCain and Diaz 2001). These forests produce the highest plant diversity in western Oregon forested systems. Many of the shrubs listed above co-occur within the zone, averaging 30% to >60% cover. Many of the forbs listed above are found within the zone range. Graminoids such as brome and fescue species are found in low to moderate cover. Slender false brome (Brachypodium sylvaticum (Huds.) P. Beauv.), a shade-tolerant, non-native species, has invaded many sites that otherwise resemble community 1.1.

Community 1.2
Early Seral Grand Fir, Douglas-fir, Tall Shrubs, Low Shrubs, Herbs, and Grasses

This community is a post-disturbance, early seral condition resulting from high severity fire or regeneration harvest, or other disturbance. Open canopy conditions, with or without legacy structure, and tree regeneration characterize this phase. Douglas-fir, grand fir, and ponderosa pine may exist as scattered live legacy overstory. Post-fire conditions may consist of moderate to high densities of small to large snags, resulting in diverse cover of down wood (Mellen-McLean et al. 2017). Seedlings of various coniferous species may be present, with Douglas-fir and grand fir likely dominating. Bigleaf maple, Pacific madrone, California black oak (southern areas), and Oregon white oak may persist through basal sprouting. Early seral trees, such as bitter cherry (Prunus emarginata (Douglas ex Hook.) D. Dietr.) and ponderosa pine, may be present (Oakley and Franklin 1998.). Many shrubs in this type are adapted to disturbance and will persist through post-disturbance sprouting (e.g. vine maple, Cascade barberry, California hazelnut, snowberry). California blackberry may greatly increase in cover to dominate the ground layer. Red elderberry, (Sambucus racemosa L), willow species (Salix L.), snowbrush ceanothus (Ceanothus velutinus Douglas ex Hook), and thimbleberry (Rubus parviflorus Nutt.) are native early seral shrubs that may be present (Halpern 1988, Brown et al. 2013). Snowbrush ceanothus can dominate on drier sites after burning. Non-native shrubs such as Scotch broom (Cytisus scoparius (L.) Link) may be present in low to moderate cover. Many late seral herbs and graminoid species recover and persist. Early seral native species such as fireweed (Chamerion angustifolium (L.) Holub), and Canadian horseweed (Conyza canadensis (L.) Cronquist) may be ephemeral dominants (Halpern 1989). Bull thistle (Cirsium vulgare (Savi) Ten), woodland ragwort (Senecio sylvaticus L.) and slender false brome (Brachypodium sylvaticum (Huds.) P. Beauv.), non-native herbs, may dominate the understory if seed source is present (Halpern 1988, Halpern 1989, McCain and Diaz 2001).

Community 1.3
Mid-Seral Grand Fir, Douglas-fir, Tall Shrubs, Low Shrubs, Herbs, and Grasses

This mid-seral phase is the result of growth from community 1.2. Medium to large decayed snags from previous disturbances may persist in this phase, although low levels of small snags may be more common. Down wood is variable, with high levels possible in post-fire generated conditions (Mellen-McLean et al. 2017). The live canopy has simple structure, dominated by sapling to pole sized trees, with some stands displaying some medium to large pre-disturbance legacy trees. Douglas-fir and grand fir likely dominate, with scattered ponderosa pine, Oregon white oak, California black oak (southern areas), incense cedar (southern areas), Pacific madrone, and bigleaf maple present to varying degrees depending on site conditions. Canopy cover is moderate due to site conditions and shrub, forb, and graminoid cover. There is minimal to no tree regeneration and low to moderate cover of shrub and herbs. On heavily burned sites snowbrush ceanothus may continue to dominate the shrub layer, resulting in lower tree density (Brown et al. 2013). Sprouting shrubs (e.g. vine maple, Cascade barberry, California hazelnut, snowberry) are present in low to moderate cover. Native red elderberry, willow species, snowbrush ceanothus, and non-native scotch broom may be present in stands with lower tree canopy cover. Native herbs will persist, and non-native bull thistle and slender false brome may continue to inhabit and dominate this phase.

Community 1.4
Small to Medium Sized Grand Fir, Douglas-fir, Tall Shrubs, Low Shrubs, Herbs, and Grasses

Growth from community 1.3 produces this community phase. Medium to large snags and down wood from previous disturbances are likely present but declining in abundance due to decay and fragmentation. Smaller snags are being created from background mortality due to competition, insects, and pathogens (Mellen-McLean et al. 2017). Forest structure is still simple and largely single layered. Canopy cover is moderate to high and dominated by small to medium sized Douglas-fir and grand fir. Some legacy medium and large trees may be present in some cases. Bigleaf maple can be co-dominant in some stands. Scattered ponderosa pine, incense cedar (southern areas), California black oak (southern areas), Pacific madrone, and Oregon white oak may be present to varying degrees. Regeneration varies depending on light levels. Sprouting shrubs (e.g. vine maple, Cascade barberry, California hazelnut, snowberry) are present in low to moderate cover. Herb and graminoid presence and cover vary depending on light levels.

Community 1.5
Moderately Thinned Grand Fir, Douglas-fir, Tall Shrubs, Low Shrubs, Herbs, and Grasses

This phase is the result of moderate severity fire or moderate thinning of community 1.4. Small to medium sized Douglas-fir, grand fir, and bigleaf maple may dominate the overstory canopy layer. Medium to large snags and down wood from previous disturbances are likely present but declining in abundance due to decay and fragmentation. Small and medium snags in varying densities may result from fire and may lead to later recruitment of down wood (Mellen-McLean et al. 2017). A range of shade tolerant (grand fir, bigleaf maple, incense cedar (southern areas)) and shade intolerant (Douglas-fir, ponderosa pine, Pacific madrone) trees may be present, depending on the severity and size of the disturbance. Regeneration may also include shade tolerant and intolerant species. Shrub species are varied, including sprouting shrubs (e.g. vine maple, Cascade barberry, California hazelnut, snowberry). Scotch broom may invade post-disturbance. Native and non-native herbs and graminoids are present, dependent on seed source and disturbance severity. Slender false brome may be maintained and increase in cover. Stands that reach this community phase may progress to a multi-layered reference community (CP 1.1) more quickly than undisturbed stands maturing along community phase pathway 1.4A. Disturbances such as moderately severity fire or thinning alter structure instantaneously compared with slower causes of tree mortality considered part of growth pathway 1.4A.

Pathway 1.1A
Community 1.1 to 1.2

Stand replacing fire, regeneration harvest, large scale wind event, insects, and pathogens are the dominant processes returning this phase to an early seral condition.

Pathway 1.2A
Community 1.2 to 1.3

Growth is the major process transitioning out of this early seral condition.

Pathway 1.3A
Community 1.3 to 1.4

Growth is the major process transitioning out of this phase. Pre-commercial thinning may also facilitate this phase change.

Pathway 1.4A
Community 1.4 to 1.1

Growth will serve to transition this phase into the reference community.

Pathway 1.4B
Community 1.4 to 1.2

Regeneration harvest or stand replacing fire can return this phase back to early seral conditions.

Pathway 1.4C
Community 1.4 to 1.5

Management actions such as thinning can trigger a shift in phases. Mixed severity fire can also result in a transition to more diverse stand conditions.

Pathway 1.5A
Community 1.5 to 1.1

Growth will serve to transition this phase into the reference community.

Pathway 1.5B
Community 1.5 to 1.2

Regeneration harvest or stand replacing fire can return this phase to early seral conditions.