State 1
PC 1.1: Reference State, Douglas-fir Forest

Community 1.1
PC 1.1: Reference State, Douglas-fir Forest

The reference plant community is dominated by Douglas-fir (Pseudotsuga menziesii) in the overstory, with giant chinquapin (Chrysolepis chrysophylla) and tanoak (Lithocarpus densiflorus) in the sub-canopy. Scattered Pacific madrone (Arbutus menziesii) may be found on some sites. Overstory composition and structure of this plant community may vary greatly based on past logging or fire history. The understory is shrub-dominated, with California huckleberry (Vaccinium ovatum), Pacific rhododendron (Rhododendron macrophyllum), salal (Gaultheria shallon) and the shrub form of tanoak. The forb layer may include beargrass (Xerophyllum ssp.). The tree age for this community is estimated to be 200 years or more. Community Pathway 1.1a: This community will transition to PC 1.2 in the event of a block harvest with either a post-harvest burn or a moderate fire. The plant community will be initially dominated by sprouting giant chinquapin and tanoak. The understory is shrub dominated primarily with California huckleberry or greenleaf manzanita, if there is seed banked in the soil. The hardwoods sprout readily following cutting or fire and may form stable communities that persist 50 years or more (Adams, 1992). Community Pathway 1.1b: Partial cutting or harvesting of Douglas-fir could transition PC 1.1 to PC 1.4. Both tanoak and giant chinquapin will respond rapidly when released from the competition of Douglas-fir, and will quickly dominate the canopy (Adams, 1992).

Forest overstory. The main overstory of the interpretive plant community is dominated by Douglas-fir, with giant chinquapin and tanoak in the sub-canopy. On some sites Pacific madrone may be present.

Main canopy average percent

Douglas-fir (Pseudotsuga menziesii) 5-35%

Sub-canopy

Giant chinquapin (Chrysolepis chrysophylla) 15-45%
Tanoak (Lithocarpus densiflorus) 5-60
Pacific madrone (Arbutus menziesii) 0-5%

Forest understory. The understory is dominated by shrubs, including California huckleberry, Pacific rhododendron, salal, and tanoak. Greenleaf manzanita is frequently found on sites that have been burned. Beargrass is common on most sites.

Greenleaf manzanita (Arctostaphylos patula) 15-40%
California huckleberry (Vaccinium ovatum) 5-25%
Pacific rhododendron (Rhododendron macrophyllum) 5-15%
Salal (Gaultheria shallon) 0-5%
Tanoak (Lithocarpus densiflorus) 5-35%
Beargrass (Xerophyllum ssp.) 5-15%

State 2
PC 1.2: Young Giant Chinquapin and Taoak Forest

Community 2.1
PC 1.2: Young Giant Chinquapin and Taoak Forest

Both tanoak and giant chinquapin will sprout quickly following a disturbance, often forming pure stands (Adams, 1992). Sprouting shrubs may include California huckleberry, Pacific rhododendron, and greenleaf manzanita, if there is a seed source present. Community Pathway 1.2a: PC 1.2 will transition to PC 1.3 if given an extended period of time without disturbance. Tanoak and giant chinquapin grow rapidly into tree form, with tanoak forming multiple stems that support a large crown area (Tappenier etal, 1984). Pure stands may dominate areas for 50 years or more (Adams, et al, 1992). Community Pathway 1.2b: Chemical control or brush management, in addition to conifer tree planting, could accelerate the reestablishment of a Douglas-fir-dominated plant community and transition this community back to PC 1.1.

State 3
PC 1.3: Giant Chinquapin, Tanaok, and Douglas-fir Forest

Community 3.1
PC 1.3: Giant Chinquapin, Tanaok, and Douglas-fir Forest

Plant Community 1.3 – Giant chinquapin and tanoak grow rapidly in height and crown area, and may become the dominant overstory species for an extended period of time (Adams et al, 1992). The estimated tree age for this community ranges from 10 to 80 years. Douglas-fir stocking is highly variable, and will either establish itself at the time of the initial disturbance or it could take decades to colonize the area (Agee, 1991). The growth and survival of Douglas-fir may be reduced significantly when in competition with hardwoods (Adams et al, 1992). Shrub cover eventually declines under significant hardwood canopy cover. Community Pathway 1.3a: With fire exclusion and growth over time, Douglas-fir will eventually overtop the tanoak to become the dominant tree species, transitioning this community to PC 1.1. If Douglas-fir was successful established at the time of disturbance, tanoak and giant chinquapin will form the sub-canopy below (Thornburg, 1982). Community Pathway 1.3b: PC 1.3 could transition back to PC 1.2 with block harvesting or periodic fire. These disturbances could favor hardwood dominance by removing the young Douglas-fir for an undetermined period of time. Greenleaf manzanita may dominate the shrub cover if a seed bank is present.

State 4
PC 1.4: Giant chinquapin and Tanaok Forest

Community 4.1
PC 1.4: Giant chinquapin and Tanaok Forest

Plant Community 1.4 – The mature giant chinquapin and tanoak plant community may be maintained for an extended period of time as a result of the partial cutting or harvesting of Douglas-fir. The estimated tree age for this community ranges from 40 to 80 years. Young tanoak will continue to exist in the understory and will respond by filling into any canopy openings created by disturbance. Community Pathway 1.4: Douglas-fir may slowly colonize the area, but it may take decades or longer than the growth seen in PC 1.3. This growth will eventually transition the community to PC 1.3, if given an extended period of time without disturbance.