South County

Newly Discovered Root Disease to close Twin Arrows Dispersed Recreation Site along the South Fork of the Sacramento River

Redding, CA, June 13, 2024—The Shasta-Trinity National Forest is taking action to combat a new outbreak of Port-Orford-cedar root disease (POCRD) in the Twin Arrows area. The disease, caused by the pathogen Phytophthora lateralis (PL), is considered the most serious threat to Port-Orford-cedar (POC), a species native to a limited area along the Pacific Coast from Coos Bay, Oregon, to the Mad River north of Arcata, California.

The Shasta-Trinity National Forest contains approximately 1,200 acres of POC, which plays a significant ecological role in certain forest communities. POCRD can spread rapidly via water and soil, with infested soil transported on tires and footwear being the most common means of spread. The disease can kill up to ninety percent of the hosts on newly infested high-risk sites.

In December 2023, USFS foresters reported dead and dying POC suspected of being infected by PL to USFS Forest Health Protection (FHP) staff. FHP staff confirmed the trees showed characteristic symptoms of POCRD. Due to the high recreational use at Twin Arrows, the infestation was likely caused by visitors traveling from an infested site.

To prevent the spread of the disease, USFS has decided to treat the Twin Arrows area by girdling the POC, a method that was successful in eradicating POCRD in the Scott Camp Creek area in 2013. However, because of the high recreational use at Twin Arrows, the area will be closed to all recreational activity to prevent the disease from spreading via foot or vehicle travel. The closure will remain in effect until the disease is no longer present at the site, which may take 4-7 years.

USFS is asking the public to avoid stopping, camping, parking, walking, or otherwise traveling through the Twin Arrows area. Travel on the pavement of the South Fork Road passing by Twin Arrows will still be permitted. If you have visited the Twin Arrows area in the last year, USFS recommends cleaning any shoes, camping gear, and vehicles brought into the area to prevent the spread of active spores.

The USFS appreciates the public’s cooperation in eradicating this disease and maintaining a healthy ecosystem for future generations to enjoy.

Please see the attached Forest Order 14-24-09 for the closure of the Twin Arrows Area on the Shasta McCloud Management Unit due to Root Disease in Port-Orford cedar. Please note that the map has an error – Road 26 is and will remain open. A new map will be provided early next week.*


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