Management of Port-Orford-cedar (Chamaecyparis lawsoniana) in the presence of the non-native pathogen Phytophthora lateralis

Port-Orford-cedar (POC), a unique and valuable tree native to SW Oregon and NW California, is affected by a virulent, non-native pathogen, Phytophthora lateralis. Infection results in death of hosts of all ages. The goal of the POC management by the Forest Service and BLM is to maintain POC as an ecologically and economically significant species on federal lands. The integrated strategy developed seeks to maintain POC where risk of infection is low, reduce disease spread and severity in high risk areas, protect uninfested watersheds, and reestablish the tree species where appropriate. Techniques such as road closures, sanitation treatments and washing vehicles are routinely used. Successful breeding of POC with various degrees of resistance to P. lateralis has been an encouraging recent development. The species' range has been divided into breeding zones, and seed orchards of resistant parents have been established for some. Field trials have been established on a range of cooperator's lands. For some zones, seed for reforestation and restoration is now available, and planting has begun. As plantings of genetically resistant POC reach reproductive maturity, dispersal of pollen and seed will help increase number and frequency of resistant trees in neighboring forests. A current challenge involves finding opportunities to deploy resistant stock on federal lands where planting has declined due to decreased harvests and increased dependence on natural regeneration in silvicultural prescriptions.