In recent months there have been several developments affecting efforts to manage the sudden oak death infestation in West Coast states and to prevent its spread to other parts of the country.
1) APHIS regulations
Most notably, APHIS has formalized revisions to its regulations governing nursery stock. This revision was proposed last June (see my blog about this here). The revisions largely implement changes to practices that APHIS had adopted in 4014 and 1015 through Federal Orders. The final regulation is posted here. The new regulation goes into effect on May 20th.
APHIS received only 10 comments (posted here) on the proposal – from researchers, State agriculture and conservation agencies, environmental advocacy groups, research foundations, and private citizens. I summarized points raised in their comments by CISP and others in an earlier blog.
APHIS responded to most of these comments by reiterating that it has been operating under the current program since 2014 and believes the existing testing protocols and conditions are sufficient to mitigate the risk. The measures to monitor nurseries for infections include testing soil and water, that is, they do not rely exclusively on visual inspection of the plants. This is a step forward. In response to comments by CISP and California Oak Mortality Task Force that all nurseries that grow host plants are a potential source of contamination, APHIS points out that it is not authorized to regulate nurseries that don’t ship plants interstate. This limitation is a serious problem arising from the underlying statute – the Plant Protection Act. APHIS said it would continue to monitor detection of the pathogen, and would reevaluate program protocols “should the need arise” – but it made no promise on how frequently it would reevaluate the program.
APHIS did make some adjustments, based on comments. It agreed to one state’s request that it clarify the minimum number of samples that must be taken during annual inspection of nurseries that had not previously tested positive for the pathogen when those nurseries are located in counties that have SOD infestations in the environment. (Such counties are found only in California and Oregon.)
The agency also said it plans to restructure the list of host species so that it can be updated more quickly. APHIS plans to remove the lists from formal regulations (which require public notice and comment to amend) and post them on the APHIS website. APHIS also expects to merge the lists of proven and associated hosts into a single host list. However, these plans would, themselves, constitute rulemaking and require another public comment period.
APHIS also agreed to reinstate its quarterly program updates, beginning in April of 2019. I have not yet seen an alert telling me how to find the first such update, though.
2) P. ramorum in California and Washington
According to the most recent (April 2019) newsletter of the California Oak Mortality Task Force, tanoak (Notholithocarpus densiflorus) mortality in California attributed to Phytophthora ramorum increased by more than 1.6 million trees across 106,000 acres in 2018. The dead trees are concentrated west of the coastal range.
In the meantime, P. ramorum continues to be detected in nurseries shipping plants from West Coast nurseries. As of April, the California Department of Food and Agriculture had detected P. ramorum in nine nurseries – six from previous years, three new in 2019. (Sixty-four additional infected plants were found in one nursery that had been confirmed positive in an earlier year – raising questions in my mind about the efficacy of the Confirmed Nursery Protocol for eliminating the pathogen.)
As I noted in a previous blog, Washington is finding it difficult to eliminate P. ramorum from the soil of a botanical garden in Kitsap County. For the third time in less than a year, a pond that is downhill from previously “mitigated” sites has tested positive for P. ramorum.
I remind you that scientists do not believe that P. ramorum persists in water – it must be surviving on some plant tissue in both Washington and the Eastern states (see below).
3) P. ramorum in Oregon
The Oregon Department of Forestry (ODF) commissioned a study of the economic impact of Phytophthora ramorum in the state. The study found that to date, sudden oak death has caused minor impacts on the regional economy. There was no impact on timber harvest, export or log prices or recreation or tourism revenues and only anecdotal reports of losses to real estate transaction values in some areas. Meantime, the state and several federal agencies are spending $1.5 million per year to try to contain the outbreak.
However, sudden oak death has the potential to cause harm to core values that elude economic quantification, particularly to tribal cultural values and the “existence value” of tanoak-dominated forests. SOD may be an existential threat to tanoak and associated obligate species (e.g., dusky-footed woodrats, Northern flying squirrels, and Allen’s chipmunks – which are important prey items for northern spotted owl, cougar, coyote, and Pacific fisher. More widespread wildlife — e.g., deer, elk, bear, Coho salmon, and a variety of bird species – might also be harmed.)
Immediate termination of the ODF treatment regime might lead to serious impacts due to more rapid expansion of sudden oak death into Coos County, Oregon. These could include Asian governments restricting timber and fiber exports from southwest Oregon and resulting loss of 1,200 jobs and forest products harvest tax. There might also be a collapse of residential property value and real estate transaction revenues. Finally, there might be a decline in recreation and tourism in affected areas. Maintaining the current treatment regime was expected to delay the spread of SOD north of the Rogue River until 2028, and prevent infestation of Coos County beyond 2038. Continued funding SOD treatments for a total cost of $30 million over the next 20 years could offset loss of 1,200 jobs by 2028 and $580 million in wages from 2028 to 2038.
The study authors note that other factors – such as major wildfires or trade wars – could render these impacts moot.
4) P. ramorum in the East
According to the most recent newsletter of the California Oak Mortality Task Force, over the nine years since 2010, the pathogen has been detected from 11 streams in six eastern states – four in Alabama; one in Florida; two in Georgia; one in Mississippi; one in North Carolina; and two in Texas. P. ramorum has been found multiple times in eight of these streams; it is consistently present in two steams in Alabama, one each in Mississippi and North Carolina.
In 2018, seven states participated in the stream survey (which is operated by the USDA Forest Service): (AL, GA, MS, NC, PA, SC, and TX). This was the smallest number of participating states, which has fallen from14 in 2010 to seven in 2018.
The number of streams surveyed annually has ranged from 45 to 95. The number of streams sampled in 2018 was also close to the smallest number: 47. P. ramorum was detected from six streams – four in Alabama, one each in Mississippi and North Carolina. All positive streams were associated with previously P. ramorum-positive nurseries.
Remember that P. ramorum continues to be detected in West Coast nurseries that ship plants interstate (see the second section of this blog).
Posted by Faith Campbell
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