Chamaecyparis lawsoniana , Port Orford-cedar

Port Orford-cedar is a large, long-lived conifer with a narrow distribution in northwestern California and southwestern Oregon. It typically occurs in scattered stands from coastal dunes to high-elevation forests, where it often codominates with other conifer species. Port Orford-cedar requires perennial moisture availability; in dry forests it is associated with riparian zones, stream edges, and bogs. Port Orford-cedar grows on soils with a variety of parent materials including ultramafic or serpentine soils, where few other conifer species can grow. Port Orford-cedar reproduces by seed. Trees begin producing seed at 5 to 20 years old. They produce seed every year, with large seed crops every 4 to 5 years. Seeds are dispersed by gravity, wind, and water, although they are not dispersed far by wind. Most seeds are only viable for the first year after dispersal and do not form a long-term persistent seedbank. Port Orford-cedar is generally considered moderately shade-tolerant and can regenerate under a range of conditions, from shaded forest to open, recently burned areas. Large Port Orford-cedar are likely to survive most surface fires because they have thick bark, they self-prune low branches, and are resistant to decay. However, seeds, seedlings, and saplings are easily damaged or killed by fire of any severity. Seeds can germinate within the first year after fire, and seedlings can grow quickly in open areas, including recently burned sites. However, because Port Orford-cedar seeds have a relatively short dispersal distance, establishment may be limited in large, high-severity burned patches when no mature trees survive. Plant communities where Port Orford-cedar is dominant or codominant historically experienced relatively frequent, low- or mixed-severity fires. However, Port Orford-cedar also occurs in areas with a history of infrequent, stand replacing fires. Historically, Port Orford-cedar was an important timber species, with strong, decay-resistant wood. However, nearly all of the known old-growth stands have been eliminated due to the combination of Phytophthora lateralis (a nonnative root pathogen) infection, intensive harvesting in the early 20th century, and large fires in the early 21st century. Efforts to control the spread of P. lateralis include removing roadside trees, cleaning equipment, and careful timing of logging and restoration efforts. Climate change projections suggest that Port Orford-cedar may experience range contractions and shifts due to drier, warmer conditions. The potential for greater wildfire frequency, size, and/or severity, may threaten Port Orford-cedar’s long-term persistence in some areas.