Public attitudes about tree-killing pests

The Nature Conservancy (TNC) has carried out telephone surveys of eligible voters to determine their attitudes about trees and forests and threats to them over 11 years – in 2005, 2007, 2008, 2010, and 2016. Leigh Greenwood will present these finding during a webinar on Friday 27 January. Go here to learn more and register for the webinar.


champion green ashchampion dead

Michigan champion ash before & after being killed by emerald ash borer

While those surveyed consistently ranked economic concerns as more important than environmental ones, still they have been aware of threat from forest insects and diseases.

In 2016, 23% to 26% of respondents said that they considered diseases or insects that kill trees a “very serious” problem. Notably, these concerns were equal to those expressed about fires that destroy property and forests.

Gardening, hiking, and wildlife viewing are popular activities, engaged in by half or more of the respondents. Only 35% of respondents fish; only 15% hunt.

The sources of information on forest health issues that are most trusted by survey respondents have remained steady across regions and years:

  • park “rangers” rank first, with 89% of respondents ranking them as “believable”;
  • the state division of forestry ranks second, with 84% of respondents saying it is “believable”;
  • the USDA Forest Service and scientists are tied for third, with 82% of respondents saying each is “believable”;
  • also highly trusted (trusted by more than 70% of respondents) were the State Department of Agriculture, a local forester, and conservation organizations.


The public’s level of familiarity with the concept of forest pests nationwide has been between 53% and 59% of respondents since the Conservancy began polling in 2005. Levels of awareness were higher in 2010 than in either 2005 or 2016 –probably because of media attention to the emerald ash borer.


The specific pests asked about in the polls with the highest levels of awareness have remained Dutch elm disease and European gypsy moth – with somewhat over half the respondents saying they have heard of the problem. About a quarter of respondents have heard something about chestnut blight.


Levels of awareness have changed significantly over time for some regions and some pests.

In 2016, 50% of respondents in the “east north central” region HAVE NOT heard of the Asian longhorned beetle. This contrasts with 2010, when only 18% of respondents in the region said they had not heard about ALB. Perhaps this decline in awareness is because the outbreak in Clermont County Ohio is in a semirural area and does not get the media coverage that earlier outbreaks in cities did. Alternatively, because these polls are conducted in a population proportional sample, it may be that urban residents are not aware while rural residents (in the affected area) are indeed aware but are not captured in the sampling methodology.

Similarly, in 2016 more than a third of respondents in New England said they had not heard about the ALB; this lack of awareness is greater than the quarter who said they had not heard about the insect in 2010. Still, the number of people in the region who had “heard quite a bit about it” has held steady at one-third of respondents. In the Northeast more broadly, 48% in 2016 said they had not heard about ALB, compared to 42% in 2010.

Regarding the emerald ash borer, its spread has apparently led to greater awareness in the South. By 2016, 28% of respondents in the South have heard of it — compared to 18% in 2010. Awareness of EAB has remained steady in the East North Central region – at 76% of respondents. In 2005, when three of the five states in the region were polled, awareness was far lower – 57% said they had never heard of it.

Poll results showed that the proportion of respondents nation-wide who were “extremely or very concerned about non-native forest pests and diseases has declined from 54% in 2010 to 40% in 2016. While the poll does not inform us why this change has occurred, one probable explanation is that the emerald ash borer infestation is no longer front page news in most regions.

Levels of concern are highest in major cities and rural areas.

One of the purposes of the Conservancy’s polling is to measure the effectiveness of the organization’s efforts to educate campers and others about the pest risk associated with firewood. (Visit to see the extensive outreach program and how you can become involved.)  Consequently, pollsters paid considerable attention to attitudes about using and moving firewood. In 2016, 47% of respondents say they never burn firewood at home; a different 51% say they never burn firewood when travelling away from home.

Of those who burn firewood at home or outdoors, few now admit to moving firewood – especially in the Northeast and Midwest. In those two regions, 70% plus say they never move it. Those who do move firewood say they move it shorter distances (mostly less than 50 miles).

The polls show the impact of outreach efforts nationwide. In the Northeast and Midwest, those who admit to moving firewood several times have dropped by about half. Indeed, the nation-wide proportion of respondents who admit to moving firewood in 2016 is below the proportion in the most affected region in 2007.

Across the country, 37% have heard that they should not move firewood – slightly above the 34% in 2010. Respondents who have heard the firewood message say this information has made them much less likely to move firewood.

However, there are huge regional differences. In the Midwest (reported as two subregions), between 56% and 70% have heard the firewood message. In New England, 49% of respondents have heard the message. In the Mid-Atlantic region, 40% remember having heard a message about not moving firewood. However, in the South and in the Pacific states, only 30% or fewer of respondents remember having seen or heard a message about firewood. In Rocky Mountain states, the proportion falls to 11%!!!. [ insert the graph? Would it be readable?]

The overwhelming majority of respondents say they are willing to buy firewood where they will burn it after hearing information about pest threat. This proportion was 84% in 2016 – although this is below the  90% who responded positively in 2005.


Types of information that respondents say they are most likely to pay attention to:

  • Brochure at a park                                         90% say would pay attention
  • Information from friend or neighbor        88%
  • Billboard on highway                                    84%
  • Radio ad                                                           78%
  • Email at time of reserving campground             77%  (major program effort)
  • Label on firewood package                            77%  (but is this information seen too late – e.g., after people have already arrived with wood in tow?)
  • Ad on TV                                                       75%
  • Booth at special event or farmers’ market 75%  (DMF has had such booths for years)

Lower proportions said they would pay attention to such other outreach methods as an article in a local newspaper, article in utility bill mailing or e-newsletter, advertisement in outdoor outfitter catalog or newspaper … or even website focused on firewood consumers. Responses vary by age groups. Predictably, digital media categories perform more persuasively in the younger demographics.

The preferred message is “buy it where you burn it.” The very similar “buy local, burn local” is also well accepted by the public according to the polling results, but due to its more limited use area (mostly Vermont and Canada at this time) the campaign recommends using Buy It Where You Burn It to be consistent.


  • Use the slogan that the public prefers – when practical; the “local” message might not fit if the state’s or agency’s program requires that the wood be treat or either allows or encourages gathering of downed wood for the fire.
  • Outreach is working – the public is changing its behavior to move firewood less frequently and for shorter distances.
  • Use trusted messengers and outlets/places where people are receptive.
  • Awareness is temporary; it fades over time — so don’t stop putting the message out!!!!

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

Posted by Faith Campbell

Sudden Oak Death – the situation worsened in 2016

Moltzan USFS

oak tree infected by P. ramorum; photo by Bruce Moltzan, USDA Forest Service


Sudden oak death (caused by the pathogen Phytophthora ramorum) might seem to be an old story – after all, mortality of oaks and other trees in the San Francisco Bay area was first noted 20 years ago. See the information here or here  or my earlier blogs at;;; and

Unfortunately, the story is very much alive – and the situation is getting worse.

In 2016, infected trees were detected in new sites in California. See the November 2016 California Oak Mortality Task Force (COMTF) Newsletter here.

Based on a “SOD Blitz” using surveys by local people, (summarized in the COMTF newsletter), the pathogen has expanded substantially in areas that received adequate moisture in winter/spring 2016.

  • For the first time, ramorum was detected in San Luis Obispo County. This is the southern-most county with wildland detections in the state. Nor is it a small single outbreak; the SOD Blitz identified the pathogen on California bay laurel at approximately eight locations throughout the county. The infestations appear to be recent, since oaks were not found to be infected.
  • New outbreaks were detected along the central and southern coasts of Mendocino County (north of the San Francisco Bay area).


Infected trees were also detected in areas where the pathogen activity had subsided as a result of the state’s recent drought, including:

  • Northern and central Sonoma County and Napa Valley.
  • Infection rates have increased in Marin County.
  • San Francisco’s Golden Gate Park and the San Francisco Botanical Garden.
  • Infection rates in Big Sur in Monterey County increased by 27%.
  • There have been sharp increases in infection in some areas that previously were marginally affected, g., western San Mateo and Santa Cruz counties.


In Oregon, the area infested by sudden oak death has been expanding since at least 2014. In 2015, 18 new outbreaks were detected. In 2016, another 65 new outbreaks were found. All are within the state’s quarantine area (which was doubled in size in 2015; it now covers nearly one-third of Curry County). Oregon officials believe this increase is a consequence of the combination of a wet/mild winter and spring and the establishment of the state-designated “Generally Infested Area” (58 square miles) where disease treatment is no longer required.


EU1 strain in forests in Oregon

Oregon has determined that the presence of the EU1 lineage of Phytophthora ramorum is more widespread than originally known. (My blog of August 2015 described the initial finding of a single tanoak infected by this lineage in 2015 and the importance of finding a genetically different form of the pathogen in the wild in North America.)  As of late 2016, scientists had identified a second outbreak of the EU1 pathogen – on 1 grand fir seedling and 12 tanoaks. Additional trees might be infected; results were pending for another grand fir and 11 additional tanoaks. This outbreak was detected through follow-up on a stream bait detection. This new EU1 infestation is located between the 2015 EU1-positive tanoak site and a now closed ornamental nursery, which, based on molecular testing, was the probable source of the 2015 EU1 infestation. The new EU1 infestation was top priority for treatment in the fall; these activities have already begun (Information from Sarah Navarro, pathologist for Oregon Department of Forestry).


While  sudden oak death has already killed more than 3 million tanoaks reaching from Monterey County north into Oregon, large areas occupied by tanoaks are still not infested. It is important to slow the spread of this pathogen.


The spreading devastation is particularly galling since scientists have shown than an aggressive, well-funded containment effort begun in 2002 could have measurably slowed spread of the disease. See reference and news report below.




Cunniffe, N.J., R.C. Cobb, R.K. Meentemeyer, D.M. Rizzo, and C.A. Gilligan. Modeling when, where, and how to manage a forest epidemic, motivated by SOD in CalifPNAS, May 2016 DOI: 10.1073/pnas.1602153113


We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

Lack of Regulation and Funding Shortfalls Raise Probability of Pests’ Spread

Photo by John Boland – willows killed by Kuroshio shot hole borer, Tijuana River, California


The polyphagous (PSHB) and Kuroshio (KSHB) shot hole borers are causing havoc in riparian and planted landscapes in four counties in southern California and are spreading north. (For current information go here or here .

As I described in a blog last July, the two insects are known to attack hundreds of tree species; at least 40 are reproductive hosts. Trees known to support PSHB include box elder, big leaf maple, California sycamore, willows, cottonwoods, and several California oaks. The insect-fungi combinations threaten more than a third of trees in the urban forests in southern California, with a cost for the trees’ removal and replacement estimated at $36 billion. Costs and hosts are discussed more fully in the July blog linked to above.


The High Cost of Management

 Already, UC Irvine has spent close to $2 million to manage trees on campus that have been attacked.

Orange County has both polyphygous and Kuroshio shot hole borers. One agency – Orange County parks – has spent $1.7 million on shot hole borer surveys, tree inventory, public outreach materials, staff training, and some research. The parks agency is trying to engage other county agencies, such as Public Works and Waste & Recycling to get their help. For example, Public Works is putting together a tree ordinance with enforceable provisions.


While scientists have not yet published their analysis of the vulnerability of forest areas in other parts of the country, we do know that some reproductive hosts are widespread across the country — box elder, sweet gum, Japanese wisteria, and tree of heaven. Less is known about the hosts for Kuroshio shot hole borer. For a full list of known hosts, visit the two sources linked to in the first paragraph.


How Agencies Should Respond to this Threat

The shot hole borers and associated fungi clearly represent serious threats to urban, rural, and wildland forests across California and probably much of the rest of the country. Clearly it is important that we:

  • Increase our understanding of these insects and their associated fungi – including their possible geographic and host ranges;
  • Use this evolving understanding to develop detection tools; and
  • Use this evolving understanding to develop methods to slow their spread or to protect trees.


So what is being done? Individuals – academics; staff of local, state, and federal agencies; and concerned conservationists – are working hard. But they get little support from state or federal phytosanitary agencies.


The Need for New State and Federal Regulations

I have written earlier about the refusal of California Department of Food and Agriculture to either designate the polyphagous and Kuroshio shot hole borers as quarantine pests [] or to regulate movement of firewood – one of the major pathways for spread of the insects.


Nor has USDA APHIS designated the insects and their fungi as quarantine pests. The apparent explanation for the agency’s inaction is the considerable taxonomic confusion about the beetles and the possibility that the insects are already established elsewhere in the U.S. In addition, since the two shot hole borers are currently known only from California, APHIS is unlikely to take action unless California does.  However, there is no legal requirement that APHIS defer to the state on this matter.


The Results of Funding and Regulatory Shortfalls

 Both CDFA and APHIS are providing some funds to support research and development. Research on  detection, spread, and possible biocontrols — for the insects or fungi — have received a total of $385,000 in FY16 and $419,549 in FY17 from a grant program operated under the USDA Plant Pest and Disease Management and Disaster Prevention Program (Farm Bill Sec. 10007). Still, the principal investigators and affected county, state, and federal agencies are scrambling to fill funding gaps – projects that will improve our understanding and put forward practical advice.

The San Diego Association of Governments (SANDAG) and Natural Communities Coalition (NCC) of Orange County are supporting research by Akif Eskalen and Shannon Lynch of UC Riverside on both (a) biocontrol using endophytes naturally occurring in various host tree species and (b) models to predict the disease’ behavior in native vegetation. Dr. Eskalen and Dr. John Kabashima of Orange County Cooperative Extension are seeking funds to support additional work on outreach and extension for advisors, land managers, master gardeners and homeowners.

Santa Barbara County officials – where at least one of the shot hole borer species was recently detected – are struggling to fund an expanded trap program to detect the insects. The CDFA does have traps deployed but UC Santa Barbara is considering launching a trapping program in riparian areas (where many of the host trees play especially important ecological roles). Officials are still not certain which species of insect is present (they think it is KSHB) and whether the beetles are carrying the typical fungal complex or something novel.

In the past, some of the work on the shot hole borers has been funded by associations of avocado growers. However, it is now clear that the beetle attacks only avocado tree branches, so it does not kill the tree. No longer facing a dire threat to their industry, the avocado commission is no longer funding research work on this pest-disease complex.

The experts – Dr. Eskalen for the fungi and his colleague Dr. Richard Stouthamer for the insects – have no funds to process samples sent to their laboratories for the confirmation of the beetles and fungi. They might soon have to charge fees for each sample – thereby discouraging collections that track each species’ spread and find new introductions.

In the absence of CDFA designation of the shot hole borers as regulated pests, neither state nor county agencies have a firm foundation on which to base regulations to curtail movement of firewood, green waste, or other pathways by which these pests can be spread to new areas.


Conservation Agencies are Cobbling Together Responses As Best They Can

Southern California staff of the California Department of Fish and Wildlife agency, responding to the damage caused by the Kuroshio shot hole borer in the Tijuana River estuary (described here and here), have formed a coalition to develop strategies for natural resource and urban forestry settings and ensure coordination. Natural resource agencies have access to some funding sources, such as Natural Communities Coalition (NCC) grants and funding for management of invasive species in protected habitats.

Southern California staff of the U.S. Fish and Wildlife Service are seeking grants from internal agency sources – citing the threat to riparian-dependent wildlife, especially the endangered Least Bell’s vireo.

Santa Monica National Recreation Area and the three National forests in the vicinity – the Angeles, Cleveland, and San Bernardino National forests – have taken actions that should help prevent the shot hole borers’ introduction via firewood.  Santa Monica Recreation Area does not allow wood fires, only charcoal (this action probably is in response to the high fire danger in the area rather than the pests specifically). The National forests’ webpages on camping include a graphic with the statements “Buy It Where You Burn It” and “Be aware that firewood can harbor insects and diseases; transporting it can move these pests to new locations.”  (See my earlier blog about firewood alerts on National forests, parks, etc. here).


What You Can Do


Many Californians are pushing for action … they need our help! If you live in California, contact your state legislators. If you live elsewhere, your forests are also at risk from California’s failure to act. So, if you know someone who lives there, ask that person to contact his/her legislators. Ask the legislators to (a) demand state designation of PSHB, KSHB, and GSOB as quarantine pests and adoption of state firewood regulations and (b) support funding for these programs.


The U.S. Congress has a role in convincing APHIS to play a bigger role. Contact your federal Senators and Member of Congress and urge them to ask USDA APHIS to regulate movement of firewood, green waste, and nursery stock from areas infested by the polyphagous or Kuroshio shot hole borers and goldspotted oak borer.

President Trump will soon propose funding levels for government programs, including APHIS’ “tree and wood pest” program. Please keep informed about these proposals – and contact your Congressional representative to express support for adequate funding. Contact me using the “Contact us” button on our website if you wish to receive informative alerts about the upcoming appropriations process.


Posted by Faith Campbell


We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.