|Scientific Name:||Chamaecyparis lawsoniana|
|Species Authority:||(A.Murray bis) Parl.|
Cupressus lawsoniana A.Murray bis
|Taxonomic Source(s):||Farjon, A. 2010. A Handbook of the World's Conifers. Koninklijke Brill, Leiden.|
|Taxonomic Notes:||In this assessment, the acronym POC stands for the name Port Orford cedar, the common name widely used by the US Forest Service|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer(s):||Thomas, P. & Stritch, L.|
The Federal area of occupancy (AOO) is approximately 1,242 km2. Historically 69% of the Port Orford Cedar (POC) "timber" was not on Federal lands, so it is logical to assume that the current AOO on non-Federal lands is at least as much as the Federal lands. The total AOO therefore is estimated to exceed 2,000 km2. The extent of occurrence (EOO) on Federal lands is 23,740 km2 and the same concept regarding non-Federal lands applies; the total EOO is in excess of 50,000 km2. There has been no reduction in AOO due to Port Orford Cedar root disease and logging has declined dramatically since 2000. Planting with resistant stock (re-introduction) is now a common occurrence and active management practices to eradicate the pathogen are in the planning stages. In fact, AOO is beginning to increase as localities within the EOO previously not occupied by POC are now being planted.
We expect this taxon to be down listed to Least Concern within the next 10 years provided that current conservation actions are successful and maintained. Until then, it is assessed as Near Threatened on the basis that its recent decline almost meets the criterion B2ab(iii) for listing as threatened.
|Previously published Red List assessments:||
Port Orford Cedar (POC) is native to a limited area along the Pacific Coast from Coos Bay, Oregon, to the mouth of the Mad River near Arcata, California, USA. Its range extends from the coast to about 50 miles inland. There is also a small disjunct population in the Scott Mountains of California.
Native:United States (California, Oregon)
|Upper elevation limit (metres):||1950|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species occurs in the greatest abundance within about 64 km of the Pacific coast. Further inland, its distribution is patchy, and it is mostly limited to sites with sufficient soil moisture.
Current Vegetation Survey
The Forest Service maintains a National System of Current Vegetation Survey (CVS) sample plots to acquire basic vegetative resource information tri-annually at the regional scale. This information allows resource specialists and others to assess the current vegetation condition and assess changes in the ecosystem, spatially and temporally. The Bureau of Land Management in western Oregon maintains inventory plots to the same establishment and re-measurement standard as the Forest Service, in order to be able to combine data sets for landscape, provincial, and regional analysis.
Data are collected on nested subplot radii within a one hectare (2.47 acres) plot. The plots are located on a 1.7 mile state-wide grid and each plot represents approximately 1,750 acres. The plots are divided into 0.2 hectare areas that contain concentric fixed area subplots that vary for each diameter class being sampled. The intensity of 1.7 miles is not usually useful for evaluating minor species such as POC within limited landscapes.
Similar inventory plots, forest inventory, and analysis (FIA) are maintained on private lands by the research branch of the FS. Forest inventory and analysis inventory data estimate that there are a total of 54,550 acres (standard error 14 percent) of POC on Oregon’s private lands with 9,820 acres (standard error 59 percent) of those lands containing dead POC. This estimate is not considered as reliable as the mapping method used for determining infested acreage on Federal lands but is the only available estimate of Oregon private lands with POC. The inventory plots are considered accurate for displaying individual tree mortality percentages for both Federal and private lands.
Distribution Across the RangePOC can be found with a variety of species with differing ecological requirements. These species differ across the range of POC. The wide ecological range of POC is reflected in the climatic diversity of the ecoregions and subsections in which it is distributed. These ecological units are defined based on their biotic and environmental factors that directly affect ecosystem function (McNab and Avers 1994). Ecoregions and subsections are used because they directly apply to various POC/other plant relationships. Presence of POC in a stand made the stand it was contained in a POC stand and counted as POC acres.
Past Harvest and Mortality of Port Orford Cedar, All Lands
Historically, 31 percent of POC “timber” was on FS and BLM land and 69 percent on private land. Most of the larger POC are assumed to have been harvested or killed by Phytophthora lateralis (PL) on the 69 percent private land; the current vegetation survey (CVS) data show 103,000 live POC over 20 inches diameter at breast height on private lands, or about 2 POC per acre. Large POC have been harvested from significant areas of Federal lands as well. The CVS data show approximately 800,000 trees over 20 inches diameter at breast height in Oregon, or about 3 per acre if averaged over the 272,000 POC acres in Oregon.
Although original average stocking levels are not known, clearly larger or old-growth POC is a small fraction, perhaps 10 to 20 percent, of what the Oregon distribution was historically. The total acreage itself is probably little changed from historic levels because POC readily reseeds, even if only smaller trees remained after harvest. Most POC in California is on Federal lands and has not been harvested at nearly the same rate.
|Current Population Trend:||Increasing|
|Habitat and Ecology:||
Although POC has a narrow geographic range, it occupies many different environments. The species is found at elevations from sea level to 1950 metres, in glacial basins, along streams, on terraces, and on mountain side-slopes from lower to upper one-third slope positions. POC shows adaptability to a wide range of summer evapotranspiration stress, from very high humidity along the coast to very low summer humidity inland. Soils where POC is found are derived from many parent materials, including sandstone, schist, phyllite, granite, diorite, gabbro, serpentine, peridotite, and volcanics. At lower elevations it is often found on ultramafic soil types.
POC has moderately high shade tolerance, and is more tolerant than Incense Cedar, Sugar Pine, Douglas Fir and Western White Pine, and less tolerant than Shasta Red Fir, Brewer Spruce, White Fir, Sitka Spruce, Grand Fir, Western Red Cedar, and Western Hemlock. Other studies show POC able to reproduce well in all but the darkest microsites, including late-successional stands. Zobel and Hawk (1980) found POC to survive under shade as well or better than all its competitors except Western Hemlock. In addition to being shade tolerant, POC is tolerant of repeated fire (Hawk 1977). Even as pole-sized trees, POC has a good chance of surviving fires (Zobel et al. 1985). Fire resistance is less than that of Douglas Fir, but greater than that of the true firs or Western Hemlock. POC is often the first species to reinvade after fire. POC is characterized as having fairly low drought resistance (Zobel et al. 1985), and its requirements for moisture during the growing season may limit its natural distribution. POC is considered more drought tolerant than Western Hemlock and Sitka Spruce, but is less tolerant than Douglas Fir, Jeffrey Pine, Incense Cedar, Sugar Pine, and most other trees found in its range (Zobel et al. 1985).
POC occurs in all physiographic locations from sea level to 6,400 feet elevation on the seaward slopes of the Coast Range and Klamath Mountains (Hayes 1958). POC forests occur most frequently on northwestern aspects; 82 percent of plots collected by Hawk (1977) were on aspects 200 to 45 degrees azimuth (Zobel et al. 1985). Most of the POC communities identified by Hawk (1977) were in midslope landscape positions.
Much of the range of POC usually has wet winters, dry summers, relatively uniform temperatures, high relative humidity, and frequent summer fog. Away from the coastal influences, in the south and east portion of its range, rainfall, relative humidity, and summer fog are decreased, while the temperature fluctuations in both the summer and winter are greater (USDA-FS 1965). Moisture regime strongly influences plant community development within the range of POC. To most populations of POC, a consistent abundance of water seems a critical necessity (Zobel et al. 1985). Where Douglas Fir is present it out-competes POC for water. Only in the northern part of the range does the ratio of available water to evapotranspiration compensate for this competition (Zobel et al. 1985). POC may out-compete Douglas Fir in areas with low macronutrients, or cold or saturated soils.
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Use and Trade:||
Culturally Significant Products for American Indian Tribes
The current range of POC falls within the traditional territories of numerous American Indian Tribes along the west coast of North America. Included is the 5,400-acre forest of the Coquille Indian Tribe in west-central Oregon which is managed according to many of the Standards and Guidelines of adjacent Federal land. POC continues to play a significant role in the cultural and religious life of many Tribes living within the POC range from west-central Oregon south through northwest California. Specific information concerning where, how, what time of year, and by whom POC is harvested and used is restricted from distribution.
Cedars of all types are considered the most used wood by native cultures of the Pacific Northwest. Despite declining availability, the cultural importance of POC remains high given its physical and structural characteristics, distinctive appearance, and aroma. The smells of POC also enhance the meaning of cultural rituals. Known for its durability, POC has straight grain properties allowing it to be split evenly. POC is sought as a source of planks for building traditional structures and for arrows or lances that support bone or stone projectile points. However, shortages and diminishing accessibility to mature trees sometimes relegates POC to parts of a plank house or sweat lodge, such as benches or sidewalls. This is also true for construction of canoes.
POC has other traditional uses. Boughs are used as brooms, and the bark and roots are peeled and finely shredded for use in making traditional clothing, basketry, nets, twine, mats, and other items. Limbs may be twisted into rope.
Unlike Western Red Cedar and Incense Cedar, POC has limited medicinal value due to its highly toxic character as a diuretic. Similarly, POC is less effective than Incense Cedar for preserving and storing perishable materials such as feathers, hides, and other materials. POC typically does not have the cedar-closet aroma of other cedars.
The declining availability of healthy, mature POC trees through the 20th century has increased the importance of remaining POC stands to Tribes. Although the region has experienced an economic and cultural rejuvenation by the Tribes, a declining availability of POC due to several factors, including past timber cutting, disease, endangered species protection, fish protection, and land use allocations, hinders Tribal initiatives to restore and revive cultural traditions.
Agencies issue permits for collection of special forest products including non-POC boughs, beargrass, and cones, but seldom issue permits for POC product collections. Therefore, quantitative data concerning modern-day cultural uses of POC is highly variable among the Tribes and generally not readily available outside Tribal communities. In general, however, use of POC is at modest levels.
Maintenance of POC stands on Federal lands as a culturally-important species is important to Tribes and fulfills Federal policies and goals for accommodating traditional Tribal uses. These uses are also consistent with the “American Indian Religious Act,” and other statutes that highlight the importance of traditional cultural uses of plants on Federal lands. There are no effects to the exercise of those rights, because there are no off-reservation treaty reserved rights within POC range.
Special Forest Products
POC shares the same decay-resistant properties as other cedars, such as Western Red Cedar and Incense Cedar, and is used for posts, rails, and shakes. Western Red Cedar and Incense Cedar are more sought after because they have a wider range and are more easily accessible.
POC is in greatest demand for boughs during Christmas and to a lesser degree, for year-long floral arrangements. Boughs have a graceful, flat, beaded-lace appearance that makes them ideal for tying continuous strands to a wire backing for garlands or for layering into Christmas wreaths. The foliage also combines beauty with durability and needle retention that allows it to be preserved with glycerin mixtures for long-lasting floral displays. These attributes make POC a desirable commodity for personal use and commercial harvest. Commercial buying sheds in southwest Oregon purchased more than 400,000 pounds of POC boughs during 2002, yet less than four percent came from Federal land. The existing market for POC boughs could accommodate an increase in Federal bough supply either through expansion of demand or substituting POC boughs for western red cedar boughs. The price paid by the sheds ranged from $0.25 to $0.35 per pound, making POC economically desirable to harvest during a time of year when other agricultural work is diminishing.
Timber harvest occurs for a variety of reasons on the BLM and FS units within the range of POC. An understanding of timber harvest activity and the lands involved is illustrative about the amount and nature of harvest activity on public lands, acknowledged to be a factor in POC root disease spread.
Probable Sale Quantity
Within the Oregon portion of the range of POC, long-term sustained-volume production is a Northwest Forest Plan goal on about 11 percent of the Federal forestlands. These lands which comprise the harvest landbase, the Matrix and Adaptive Management Area land allocations, are managed for regularly-scheduled timber harvest while meeting a non-declining yield policy objective. The annual timber harvest volume expected to come from these lands is called probable sale quantity, or PSQ.On most of the Federal land management units in Oregon, POC is concentrated within the riparian areas and therefore contributes little towards the PSQ. The exceptions to this are on the Coos Bay BLM lands and the Powers Ranger District of the Rogue River - Siskiyou NF. Within this area, POC is more well-distributed across the landscape resulting in about 5 percent of the volume in any given harvest unit being POC. Disease-related POC mortality does not necessarily affect attainment of the PSQ. In addition to generally being only a minor stand component, the dead trees remain salvageable for long periods of time, and their growing space, if not readily captured by existing competitors, will be naturally restocked with other tree species.
Annual volume of timber harvested on Federal lands in the Oregon portion of the POC range is about 49 million board feet (PSQ plus reserve thinning and salvage volume). This results in harvest on approximately 2,500 acres per year. With 20 percent of the range actually having POC, and 13 percent of that being infested with Phytophthora lateralis (PL), about 65 acres of harvest are likely to occur on PL-infested soils in any given year.
Timber Harvest on Private Lands within the Range of Port Orford Cedar
Silvicultural practices on private lands within the range of POC include commercial thinning and regeneration harvesting and their related treatments of burning, planting, spraying of herbicides, pre-commercial thinning, pruning, and fertilization. Recent declines in Federal harvests, economic conditions, and the increase in mills specializing in smaller material has led to shorter rotations and more regeneration harvesting. Rotation ages average 45 years on the coast, and 60 to 90 years in the interior. However, annual harvest of POC on private lands varies widely depending upon market conditions.
The harvest levels shown in Table 3 are probably unusually high, based on a peak in demand that drove the price to a high of $12,000 per thousand board feet for top quality logs in the early 1990s as compared to $2,500 per thousand board feet today. Most POC harvested in California is transported to mills in Oregon or export facilities in Oregon or Washington. This amounts to about 840 truckloads from Humboldt and Del Norte Counties, based on 4.2 million board feet per year (Waddell and Bassett 1996).
During Fiscal Year 2000 approximately 0.8 million board feet of POC was exported from the northwest to Japan, China, Korea, and Taiwan from the ports of Longview, Coos Bay, Portland, and Seattle. There are no POC export ports in California; all POC harvested for export in California is shipped through Oregon. Recently, POC logs shipped from the Port of Coos Bay in Fiscal Year 2000 averaged 257 thousand board feet (Warren 2002). By 2002, this had dropped to 200 thousand board feet (Green 2003). Overall export trends for POC continue to decline as the overseas demand continues to drop due to economic conditions and the increased production of Hinoki cypress (Chamaecyparis obtusa), which is used in Japanese temples.Several mills in Oregon saw about 4.5 million board feet of POC annually for lumber, paneling, and decking. These mills are located in Bandon, Glide, Myrtle Point, Riddle, and Roseburg. Since the overall export prices for POC have dropped, these mills have been able to purchase more POC. Sources of POC logs include both Oregon and northern California. Approximately 100 to 200 thousand board feet of California POC logs are shipped to Oregon mills annually representing 20 to 40 truckloads of logs. Mill production is limited by the supply of POC logs, as their product demand is strong. From 2000 to 2011, total harvest of POC on the Rogue River – Siskiyou National Forest was 293,000 board feet or between five and six log truck loads annually
|Major Threat(s):||International trade in the timber has previously put enormous pressure on the remaining old growth stands. The spread of the introduced pathogen Phytophthora lateralis continues and limits successful regeneration in many areas, especially those accessible by road.|
In Oregon, new management direction for POC and PL was adopted by the Rogue River – Siskiyou NF and the Coos Bay, Medford, and Roseburg BLM Districts in 2004. These administrative units contain about 90% of the POC on Federal lands. This management direction amended the existing land use plans. The following is a discussion of that management strategy. The Klamath, Shasta-Trinity, Six Rivers, and Suislaw National Forests as well as the Oregon Caves National Monument and Redwood National and State Parks have similar management direction but did not incorporate the 2004 management direction into their land use plans.
Integrated Management Approach. An integrated approach will be implemented to deal with PL which includes prevention, restoration, detection, evaluation, suppression, and monitoring. Management goals are directed toward maintaining POC and reducing root disease losses. Elements of the management strategy include management of POC bough cutting, community outreach, genetics, inter-agency coordination, planning, wildland fire operations, snag retention, project-specific direction, risk key, management practices, and monitoring.
In portions of the natural range, POC is widespread across the landscape. In these areas, POC conservation will emphasize management on sites naturally at low risk for infection. In many forest types, management of POC can focus on sites where conditions make it likely to escape infection by PL, even if the pathogen has already been established nearby. POC on such sites often has escaped infection because the sites have characteristics that are unfavorable for the spread of the pathogen. These sites are above and away from roads, uphill from creeks, on ridgetops, and on well-drained soils. In the majority of the natural range, POC is localized on moist microsites (such as along streams) or sites favorable for establishment of the species. In these areas, opportunities for managing for POC on sites unfavorable to the pathogen are more limited. Treatments to prevent new infestations will be emphasized in this portion of the range, and there is a potential for eradication treatments in certain circumstances.
Restoration of Port Orford Cedar. Restore POC to sites within its natural range where the species measurably contributes to meeting Land and Resource Management Plan objectives for both aquatic and terrestrial ecosystems, Tribal, or product uses or function. This will be accomplished using resistant stock for reforestation and other elements of the integrated management approach.
Adaptive Management. Adaptive management is a continuing process of action-based planning, monitoring, researching, evaluating, and adjusting with the objectives of improving the implementation and achieving the goals of the selected alternative. Under the concept of adaptive management, new information will be evaluated and a decision made whether to make adjustments. The Agencies will continue to develop and evaluate techniques to protect POC, and prevent disease intensification and spread within and around areas where PL infestations already occur.
Bough Cutting. To reduce or eliminate the spread of PL by POC bough cutters, limit POC bough cutting to roadside sanitation, commercial thinning, and precommercial thinning units (or stewardship contracts with specific provisions to protect and enhance POC). POC bough collection will be by permit only, and require dry season operations, designation of access and egress routes, designation of parking areas, unit scheduling (collect all uninfested areas prior to infested areas), washing of boots and equipment, daily inspections, stopping operations during and after rains, and easily identifiable areas where boughs are to be collected.
Community Outreach. Continue to improve public awareness of the root disease and the need to control it by using methods such as periodic press releases; distributing posters and pamphlets; coordinating with Tribal groups; creating and maintaining POC websites; conducting public symposiums; preparing and installing informational signs on or at trailheads, gates, and other closures; and/or other measures. Consider focusing these efforts on user groups most likely to engage in activities at more risk for spreading PL. Coordinate with state, local, industrial, and small woodland owners to help meet overall POC management objectives.
Eradication. In watersheds or other geographic areas where PL infestations are localized or infrequent in comparison to the amount of POC, POC eradication may be tried as a management technique to prevent/reduce spread of the disease and reduce the need for other management practices in the long term. If experience demonstrates techniques and conditions where this treatment can be effective, its use can be increased. Additional tools for eradicating PL in the soil will be sought, developed, and implemented as evidence warrants.
Genetics. In 1989, disease resistance testing was begun for POC and the most resistant trees were incorporated into an interregional breeding program to develop genetically resistant stock. The objectives of the POC breeding program are to (1) select and evaluate families for resistance and develop durable resistance to Phytophthora lateralis (PL), the pathogen that causes POC root disease, while maintaining broad genetic diversity within the species, and (2) produce seed genetically resistant to PL for deployment throughout the range of POC where PL is present. In May, 2005, the range of POC was subdivided into 5 Breeding Blocks (BBs) and 13 Breeding Zones (BZs).
The existing interagency resistance breeding program will be continued as needed, contingent on available funding. The objectives are to (1) select and evaluate families for resistance and develop durable resistance to PL while maintaining broad genetic diversity within the species, and (2) produce seed genetically resistant to PL for deployment throughout the range of where PL is present. The POC resistance breeding program will continue as follows (1) develop operational resistant seed for breeding zones (breeding blocks plus elevation zones) based upon management needs within the range of POC, (2) continue efforts to inform the public about the availability and use of resistant seed find ways to provide resistant seed to non-Federal landowners and (3) monitor the operational performance of resistant plantings.
In addition, collect and maintain about 0.5 pound of resistant seeds for each POC breeding zone in organized conservation seedbanks. This seed will be reserved exclusively for reforesting areas after the occurrence of stand-replacement events such as large-scale wildfires. Where possible, resistant POC seedlings will be planted in such locales, with the goal to reintroduce POC to all pre-event locations.
Interagency Coordination. The agencies will continue to coordinate management practices including research, genetic resistance breeding, and public education.
Planning. Consideration of how to achieve the POC management objectives will be addressed, as applicable, in new NEPA documents, watershed analyses, Late-Successional Reserve assessments, wild and scenic river management plans, transportation planning (roads analysis process or transportation management objectives), fire management plans, recreation planning, and other activities or strategies in all watersheds with POC.Wildland Fire Operations. Management strategies to prevent/reduce spread of PL will be a part of wildland fire preparedness planning. When practicable, these measures will be incorporated into firefighting activities. Such practices may include treating firefighting water with Clorox bleach or other registered material to kill waterborne PL spores, washing vehicles, and washing tools and clothing. However, POC issues may become a secondary priority during wildland fire operations. While management objectives for POC are a concern, safety of firefighters and the public, and protection of property is always a higher priority. Existing or “in-place” disease-controlling management practices such as road closures may be compromised. Road closures and other compromised POC disease-controlling measures will be reinstalled following suppression and emergency rehabilitation unless changed circumstances indicate otherwise. Fire rehabilitation efforts would include POC and PL considerations.
Disease Export. Where the agencies have reason to believe heavy equipment working in infested stands will next travel through or to substantially uninfested private or public POC areas, such as in uninfested watersheds or different administrative units, heavy equipment, including road maintenance equipment that has left surfaced (rocked or paved) roads in infested POC areas, will be washed upon leaving infested project areas to minimize transport of infested soil to uninfested areas. Washing areas will be located as described under Management Practice 11 (Washing Project Equipment) in the following Management Practices section.
Port Orford Cedar program objectives are to maintain POC as an ecologically and economically significant species on BLM and FS lands. Port Orford Cedar management will provide cost-effective mitigation for controllable activities creating appreciable additional risk to important uninfected POC, not to reduce all risk to all trees at all cost (USDA-FS 2004). Port Orford Cedar management slows the spread of the non-native pathogen Phytophthora lateralis (PL) enough to maintain POC’s significant ecological and economic functions, without the cost of the management strategy exceeding its effect on the value of these functions.An attempt to have this species listed in Appendix II of CITES (Oregon Natural Resources Council 1994) was unsuccessful.
Betlejewski, F. 2009. Persistence of Phytophthora lateralis After Wildfire: Preliminary Monitoring Results From the 2002 Biscuit Fire. In: E.M. Goheen and S.J. Frankel (eds), Proceedings of the fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party S07.02.09 Gen. Tech. Rep. PSW-GTR-221. U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, Albany, CA.
IUCN. 2013. IUCN Red List of Threatened Species (ver. 2013.1). Available at: http://www.iucnredlist.org. (Accessed: 12 June 2013).
USDA. 2003. A Range-wide Assessment of Port-Orford-Cedar (Chamaecyparis lawsoniana) on Federal Lands. Unites States Department of Agriculture – Forest Service and Unites States Department of the Interior –Bureau of Land Management, Portland, OR.
USDA. 2004. Final Environmental Impact Statement –Biscuit Fire Recovery Project, United States Department of Agriculture – Forest Service and Unites States Department of the Interior –Bureau of Land Management, Medford, OR.
USDA. 2004. Final Supplemental Environmental Impact Statement – Management of Port-Orford-Cedar in Southwest Oregon. Unites States Department of Agriculture – Forest Service and Unites States Department of the Interior –Bureau of Land Management, Portland, OR.
USDA. 2004. Record of Decision and Land and Resource Management Plan Amendment for Management of Port-Orford-Cedar in Southwest Oregon, Siskiyou National Forest. U.S. Department of Agriculture, Bureau of Land Management, U.S. Forest Service, Portland, OR.
USDA. 2006. Managing for Healthy Port-Orford-cedar in the Pacific Southwest Region. Unites States Department of Agriculture – Forest Service, Pacific Southwest Region, Vallejo CA.
USDA. 2010. Port-Orford-cedar Root Disease Resistance Breeding Program- Regions 5 and 6 Reforesting Burned Areas with Port-Orford-cedar Using Genetically Resistant Planting Stock in Post-Fire Reforestation Efforts. Unites States Department of Agriculture – Forest Service, Pacific Northwest and Pacific Southwest Regions, Vallejo CA.
Zobel, D.B., Roth, L.F. and Hawk, G.M. 1985. Ecology, Pathology and Management of Port-Orford Cedar (Chamaecyparis lawsoniana). General Technical Report PNW 184. Pacific Northwest Forest and Range Experiment Station, USDA, Portland.
|Citation:||Farjon, A. 2013. Chamaecyparis lawsoniana. The IUCN Red List of Threatened Species 2013: e.T34004A2840024. . Downloaded on 13 February 2016.|
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