Hundreds of U.S. Tree Species Endangered, Most due to Non-Native Pests

Horton House on Jekyll Island, Georgia before laurel wilt killed the giant redbay trees; photo by F.T. Campbell

Close to four hundred tree species native to the United States are at risk of extinction. The threats come mainly from non-native insects and diseases – a threat we know gets far too little funding, policy attention, and research.

As Murphy Westwood, Vice President of Science and Conservation at the Morton Arboretum, which led the U.S. portion of a major new study, said to Gabriel Popkin, writing for Science: “We have the technology and resources to shift the needle,” she says. “We can make a difference. We have to try.”

Staggering Numbers

More than 100 tree species native to the “lower 48” states are endangered (Carrero et al. 2022; full citation at the end of this blog). These data come from a global effort to evaluate tree species’ conservation status around the world. I reported on the global project and its U.S. component in September 2021. This month Christina Carrero and colleagues (full citation at the end of this blog) published a summary of the overall picture for the 881 “tree” species (including palms and some cacti and yuccas) native to the contiguous U.S. (the “lower 48”).

This study did not address tree species in Hawai`i or the U.S. Pacific and Caribbean territories. However, we know that another 241 Hawaiian tree species are imperiled (Megan Barstow, cited here).

Assessing Threats: IUCN, NatureServe, and CAPTURE

Carrero and colleagues assessed trees’ status by applying methods developed by IUCN and NatureServe. (See the article for descriptions of these methods.) These two systems consider all types of threats. Meanwhile, three years ago Forest Service scientists assessed the specific impacts of non-native insects and pathogens on tree species in the “lower 48” states and Alaska in “Project CAPTURE” (Conservation Assessment and Prioritization of Forest Trees Under Risk of Extirpation). All three systems propose priorities for conservation efforts. For CAPTURE’s, go here.

Analyses carried out under all three systems (IUCN, NatureServe, and CAPTURE) concur that large numbers of tree species are imperiled. Both IUCN and CAPTURE agree that non-native insects and pathogens are a major cause of that endangerment. While the overall number of threatened species remained about the same for all three systems, NatureServe rated threats much lower for many of the tree species that IUCN and CAPTURE considered most imperiled.

This difference arises from the criteria used to rate a species as at risk. IUCN’s Criterion A is reduction in population size. Under this criterion, even extremely widespread and abundant species can qualify as threatened if the population declines by at least 30% over three generations in the past, present, and/or projected future. NatureServe’s assessment takes into account rapid population decline, but also considers other factors, for example, range size, number of occurrences, and total population size. As a result, widespread taxa are less likely to be placed in “at risk” categories in NatureServe’s system.

In my view, the IUCN criteria better reflect our experience with expanding threats from introduced pests. Chestnut blight, white pine blister rust, dogwood anthracnose, emerald ash borer, laurel wilt disease, beech leaf disease, and other examples all show how rapidly introduced pathogens and insects can spread throughout their hosts’ ranges. (All these pests are profiled here . ) They can change a species’ conservation status within decades whether that host is widespread or not.  

Which Species Are at Risk: IUCN

Carrero and colleagues found that under both IUCN and NatureServe criteria, 11% to 16% of the 881 species native to the “lower 48” states are endangered. Another five species are possibly extinct in the wild. Four of the extinct species are hawthorns (Crataegus); the fifth is the Franklin tree (Franklinia alatamaha) from Georgia. A single specimen of a sixth species, an oak native to Texas (Quercus tardifolia),was recently re-discovered in Big Bend National Park.

Franklinia (with Bachman’s warbler); both are extinct in the wild; painting by John Jacob Audubon

The oak and hawthorn genera each has more than 80 species. Relying on the IUCN process, Carrero and colleagues found that a significant number of these are at risk: 17 oaks (20% of all species in the genus); 29 hawthorns (34.5% percent). A similar proportion of species in the fir (Abies), birch (Betula), and walnut (Juglans) genera are also threatened.

Other genera have an even higher proportion of their species under threat, per the IUCN process:

  • all species in five tree genera, including Persea (redbay, swampbay) and Torreya (yews);
  • two-thirds of chestnuts and chinkapins (Castanea), and cypress (Cupressus);
  • almost half (46.7%) of ash trees (Fraxinus).                                                    

Pines are less threatened as a group, with 15% of species under threat. However, some of these pines are keystone species in their ecosystems, for example the whitebark pine of high western mountains.

Carrero et al. conclude that the principal threats to these tree species are problematic and invasive species; climate change and severe weather; modifications of natural systems; and overharvest (especially logging). Non-native insects and pathogens threaten about 40 species already ranked by the IUCN criteria as being at risk and another 100 species that are not so ranked. Climate change is threatening about 90 species overall.

range of black ash

Considering the invasive species threat, Carrero and colleagues cite specifically ash trees and the bays (Persea spp.). In only 30 years, the emerald ash borer has put five of 14 ash species at risk. All these species are widespread, so they are unlikely to be threatened by other, more localized, causes. In about 20 years, laurel wilt disease threatens to cause extinction of all U.S. tree species in the Persea genus.

Carrero and colleagues note that conservation and restoration of a country’s trees and native forests are extremely important in achieving other conservation goals, including mitigating climate change, regulating water cycles, removing pollutants from the air, and supporting human well-being. They note also forests’ economic importance.

As I noted above, USFS scientists’ “Project CAPTURE” also identified species that deserve immediate conservation efforts.

Where Risk Assessments Diverge

All three systems for assessing risks agree about the severe threat to narrowly endemic Florida torreya and Carolina hemlock.

With three risk ranking systems, all can agree (as above), all can disagree, or pairs can agree in four different ways. Groups of trees fall into each pair, with various degrees of divergence.  Generally, only two of the three systems agree on more widespread species:

  • black ash: IUCN and Project CAPTURE prioritize this species. NatureServe ranked it as “secure” (G5) as recently as 2016.
  • whitebark pine: considered endangered by IUCN, “vulnerable” (G3) by NatureServe. The US Fish and Wildlife Service has proposed listing the species as “threatened” under the Endangered Species Act. https://www.fws.gov/species-publication-action/endangered-and-threatened-wildlife-and-plants-threatened-species-18 However, Project CAPTURE does not include it among its highest priorities for conservation. Perhaps this is because there are significant resistance breeding and restoration projects already under way.
  • tanoak: considered secure by both IUCN and NatureServe, but prioritized by Project CAPTURE for protection.
dead tanoak in Curry County, Oregon; photo by Oregon Department of Forestry

Carrero notes the divergence between IUCN and NatureServe regarding ashes. Four species ranked “apparently secure” (G4) by NatureServe (Carolina, pumpkin, white, and green ash) are all considered vulnerable by IUCN. They are also prioritized by Project CAPTURE. I have described the impact of the emerald ash borer on black ash. Deborah McCullough, noted expert on ash status after invasion by the emerald ash borer, also objects to designating this species as “secure” (pers. comm.).

This same divergence appears for eastern hemlock.

Port-Orford cedar is currently ranked as at risk by IUCN and Project CAPTURE, but not NatureServe. Growing success of the restoration breeding project has prompted IUCN to change the species’ rank from “vulnerable” to “near threatened”. IUCN is expected to reclassify it as of “least concern” in about a decade if breeding efforts continue to be successful (Sniezko presentation to POC restoration webinar February 2022).

While these differing detailed assessments are puzzling, the main points are clear: several hundred of America’s tree species (including many in Hawai`i, which – after all – is our 50th state!) are endangered and current conservation and restoration efforts are inadequate.

Furthermore, a tree species loses its function in the ecosystem long before it becomes extinct. It might still be quite numerous throughout its range – but if each individual has shrunken in size it cannot provide the same ecosystem services. Think of thickets of beech root sprouts – they cannot provide the bounteous nut crops and nesting cavities so important to wildlife. Extinction is the extreme. We should act to conserve species much earlier.

YOU CAN HELP!

Congress is considering the next Farm Bill – which is due to be adopted in 2023. Despite its title, this legislation has often provided authorization and funding for forest conservation (for example, the US Forest Service’ Landscape Scale Restoration Program).

There is already a bill in the House of Representatives aimed at improving the US Department of Agriculture’s prevention and early detection/rapid response programs for invasive pests. Also, it would greatly enhance efforts to restore decimated tree species via resistance breeding, biocontrol, and other strategies. This bill is H.R. 1389.

The bill was introduced by Rep. Peter Welch of Vermont, who has been a solid ally and led on this issue for several years. As of August 2022, the bill has seven cosponsors, most from the Northeast: Rep. Mike Thompson [CA], Rep. Chellie Pingree [ME], Reps. Ann M. Kuster and Chris Pappas [NH], Rep. Elise Stefanik [NY], Rep. Deborah K. Ross [NC], Rep. Brian Fitzpatrick [PA].

Please write your Representative and Senators. Urge them to seek incorporation of H.R. 1389 in the 2023 Farm Bill. Also, ask them to become co-sponsors for the House or Senate bills. (Members of the key House and Senate Committees are listed below, along with supporting organizations and other details.)

Details of the Proposed Legislation

The Invasive Species Prevention and Forest Restoration Act [H.R. 1389]

  • Expands USDA APHIS’ access to emergency funding to combat invasive species when existing federal funds are insufficient and broadens the range of actives that these funds can support.
  • Establishes a grant program to support research on resistance breeding, biocontrol, and other methods to counter tree-killing introduced insects and pathogens.
  • Establishes a second grant program to support application of promising research findings from the first grant program, that is, entities that will grow large numbers of pest-resistant propagules, plant them in forests – and care for them so they survive and thrive.
  • [A successful restoration program requires both early-stage research to identify strategies and other scientists and institutions who can apply that learning; see how the fit together here.]
  • Mandates a study to identify actions needed to overcome the lack of centralization and prioritization of non-native insect and pathogen research and response within the federal government, and develop national strategies for saving tree species.

Incorporating the provisions of H.R. 1389 into the 2023 Farm Bill would boost USDA’s efforts to counter bioinvasion. As Carrera and colleagues and the Morton Arboretum study on which their paper is based demonstrate, our tree species desperately need stronger policies and more generous funding. Federal and state measures to prevent more non-native pathogen and insect pest introductions – and the funding to support this work – have been insufficient for years. New tree-killing pests continue to enter the country and make that deficit larger –see beech leaf disease here. Those here, spread – see emerald ash borer to Oregon.

For example, funding for the USDA Forest Service Forest Health Protection program has been cut by about 50%; funding for USFS Research projects that target 10 high-profile non-native pests has been cut by about 70%.

H.R. 1389 is endorsed by several organizations in the Northeast: Audubon Vermont, the Maine Woodland Owners Association, Massachusetts Forest Alliance, The Nature Conservancy Vermont, the New Hampshire Timberland Owners Association, Vermont Woodlands Association, and the Pennsylvania Forestry Association.

Also, major forest-related national organizations support the bill: The American Chestnut Foundation (TACF), American Forest Foundation, The Association of Consulting Foresters (ACF), Center for Invasive Species Prevention, Ecological Society of America, Entomological Society of America, National Alliance of Forest Owners (NAFO), National Association of State Foresters (NASF), National Woodland Owners Association (NWOA), North American Invasive Species Management Association (NAISMA), Reduce Risk from Invasive Species Coalition, The Society of American Foresters (SAF).

HOUSE AND SENATE AGRICULTURE COMMITTEE MEMBERS – BY STATE

STATEMember, House CommitteeMember, Senate CommitteeKey members * committee leadership # forestry subcommittee leadership @ cosponsor of H.R. 1389
AlabamaBarry Moore  
ArizonaTom O’Halleran  
ArkansasRick CrawfordJohn Boozman* 
CaliforniaJim Costa Salud Carbajal Ro Khanna Lou Correa Josh Harder Jimmie Panetta Doug LaMalfa  
Colorado Michael Bennet # 
ConnecticutJahana Hayes  
FloridaAl Lawson Kat Cammack  
GeorgiaDavid Scott * Sanford Bishop Austin Scott Rick AllenRaphael Warnock Tommy Tuberville 
IllinoisBobby Rush Cheri Bustos Rodney Davis Mary MillerRichard DurbinNote that the report was led by scientists at the Morton Arboretum – in Illinois!
IndianaJim BairdMike Braun 
IowaCindy Axne Randy FeenstraJoni Ernst Charles Grassley 
KansasSharice Davids Tracey MannRoger Marshall# 
Kentucky Mitch McConnell 
MaineChellie Pingree @  
MassachusettsJim McGovern  
Michigan Debbie Stabenow * 
MinnesotaAngie Craig Michelle FischbachAmy Klobuchar Tina Smith 
MississippiTrent KellyCindy Hyde-Smith 
MissouriVicky Hartzler  
NebraskaDon BaconDeb Fischer 
New HampshireAnn McLane Kuster @  
New Jersey Cory Booker 
New Mexico Ben Ray Lujan 
New YorkSean Patrick Maloney Chris JacobsKristen Gillibrand 
North CarolinaAlma Adams David Rouzer  
North Dakota John Hoeven 
OhioShontel Brown Marcy Kaptur Troy BaldersonSherrod Brown 
PennsylvaniaGlenn Thompson  
South DakotaDusty JohnsonJohn Thune 
TennesseeScott DesJarlais  
TexasMichael Cloud Mayra Flores  
Vermont Patrick Leahy 
VirginiaAbigail Spanberger #  
WashingtonKim Schreir  

SOURCES

Christina Carrero, et al. Data sharing for conservation: A standardized checklist of US native tree species and threat assessments to prioritize and coordinate action. Plants People Planet. 2022;1–17. wileyonlinelibrary.com/journal/ppp3

Washington Post: Sarah Kaplan, “As many as one in six U.S. tree species is threatened with extinction” https://www.washingtonpost.com/climate-environment/2022/08/23/extinct-tree-species-sequoias/

Popkin, G. “Up to 135 tree species face extinction—and just eight enjoy federal protection”, Science August 25, 2022. https://www.science.org/content/article/135-u-s-tree-species-face-extinction-and-just-eight-enjoy-federal-protection

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Firewood – How to Change Risky Behavior

The Nature Conservancy (TNC) and Clemson University have analyzed how to persuade people not to move firewood – and the tree pests that can accompany it. (Full citation at the end of this blog) Their study is based on five surveys conducted by TNC between 2005 and 2016. These surveys guided TNC’s “Don’t Move Firewood” campaign and its outreach efforts since the beginning in 2008

As Solano et al. note, wood-boring pests continue to enter the country and spread, causing immense damage. Firewood transport by campers is a significant contributor to that spread. Millions of individuals decide whether to move firewood. Yet the scientific literature is quite limited regarding their behavior and TNC’s survey data has never been published.

The patchwork of state and federal quarantines is largely reactive and has failed to prevent continuing spread. The regulatory regime has been further fragmented by APHIS’ deregulation of the emerald ash borer.  As a consequence, limiting the spread of pests depends even more on educating campers to behave responsibly – voluntarily.

The TNC’s surveys each focused on different geographic areas and asked different questions in each. So their compilation cannot show trends in awareness or other measures. Nevertheless, the authors find:

  • Most people in the United States don’t know firewood can harbor invasive forest insects and diseases, but when targeted by effective education they can learn and are likely to change their behavior.
  • The two best ways to reach the public is through emails confirming campsite reservations and flyers handed out at parks. Web-based information seemed less effective. However, most of the surveys were done before 2011, the year when 50% of adults reported using internet media.
  • Forestry-related public agencies (especially state forestry departments) are the most trusted sources of information about forest health issues.
  • It works better to “push” information, not expect people to seek it on their own.
  • Messages should focus on encouraging the public to make better choices, including how they, themselves, will benefit. Positive, empowering calls to action, like “Buy it Where You Burn It” or “Buy Local, Burn Local” are better than negative messages, such as “Don’t Move Firewood”.
  • People respond to messages that emphasize protecting forest resources, e.g., ecosystem services like clean water. They response less to messages about forest threats.
Hungerford Lake Recreation Area at Equestrian Campground. Original public domain image from Flickr

Solano et al. describe the ways that different socioeconomic groups differ in their awareness of forest pests and in how they respond to various statements about forests, pests, and messengers. The focus is on how to overcome four psychological barriers to changing behavior that had been identified in a study of climate change. In the firewood context, those barriers were: 1) lack of awareness; 2) mistrust and negative reactions to the messengers; 3) habit; and 4) social comparison, norms, conformity, and perceived poor quality of purchased firewood.

From this work, the authors suggested further work::

  • Development of education and outreach programs that target those with lower education levels, since, on average, ~60% of people who camp did not graduate from college. Further research is probably needed to identify the most effective messengers and messages.
  • While 80% of the survey respondents were over 40, the proportion of campers made up of Gen X and millennials is increasing. Managers need to improve outreach for younger audiences. This includes engaging the messengers they trust: scientists, environmentalist politicians, peer networks, and social media.
  • While women trust the USDA Forest Service and conservation organizations, 55% of campers in a given year are men. Further research is needed to clarify the most effective messengers and messages for men. The outreach agencies should select the messengers that both sexes trust. 
  • Levels of awareness should be assessed both before and after implementing new educational strategies so that the strategies’ effectiveness can be determined.

Since 80% of the respondents were white, determining the most effective messages and messengers for other ethnic groups also seems necessary, although the authors did not address this.

SOURCE:

Solano, A., Rodriguez, S.L., Greenwood, L., Rosopa, P.J., and Coyle, D.R. 2022. Achieving effective outreach for invasive species: firewood case studies from 2005-2016. Biological Invasions.
https://link.springer.com/article/10.1007/s10530-022-02848-w

You can read the article – but not download it – at https://rdcu.be/cRRVH 

To request a copy of this study from the author, contact the lead author at Clemson University.

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Tree Planting – Warning from New Zealand

Pinus radiata plantation in New Zealand; photo by Jon Sullivan

As countries and conservation organizations ramp up tree planting as one solution to climate change, I worry that many of the plantings will use species not native to the region – with the risk of promoting more bioinvasions. My second fear is that inadequate attention will be paid to ensuring that the propagules thrive.

Warning from New Zealand

New Zealand has adopted a major afforestation initiative (“One Billion Trees”). This program is ostensibly governed by a policy of “right tree, right place, right purpose”. However, Bellingham et al. (2022) [full citation at end of blog] say the program will probably increase the already extensive area of radiata pine plantations and thus the likelihood of exacerbated invasion. They say the species’ potential invasiveness and its effects in natural ecosystems have not been considered.

Bellingham et al. set out to raise the alarm by evaluating the current status of radiata, or Monterrey, pine  (Pinus radiata) in the country. They note that the species already occupies ~1.6 M ha; the species makes up 90% of the country’s planted forests. Despite the species having been detected as spreading outside plantations in 1904, it is generally thought not to have invaded widely.

The authors contend that, to the contrary, radiata pine has already invaded several grasslands and shrublands, including three classes of ecosystems that are naturally uncommon. These are geothermal ecosystems, gumlands (infertile soils that formerly supported forests dominated by the endemic and threatened kauri tree Agathis australis), and inland cliffs. Invasions by pines – including radiata pine – are also affecting primary succession on volcanic substrates, landslides on New Zealand’s steep, erosion-prone terrain, and coastal sand dunes. Finally, pine invasions are overtopping native Myrtaceae shrubs during secondary succession. Bellingham et al. describe the situation as a pervasive and ongoing invasion resulting primarily from spread from plantations to relatively nearby areas.

kauri; photo by Natalia Volna, iTravelNZ

The New Zealanders cite data from South America and South Africa on the damaging effects of invasions by various pine species, especially with respect to fire regimes.

Furthermore, their modelling indicates that up to 76% of New Zealand’s land area is climatically capable of supporting radiata pine — most of the country except areas above 1000 m in elevation or receiving more than 2000 mm of rainfall per year. That is, all but the center and west of the South Island. This model is based on current climate; a warmer/drier climate would probably increase the area suitable to radiata pine.

These invasions by radiata pine have probably been overlooked because the focus has been on montane grasslands (which are invaded by other species of North American conifers). [See below — surveys of knowledge of invasive plants’ impacts.]

Bellingham et al. recognize the economic importance of radiata pine. They believe that early detection of spread from plantations and rapid deployment of containment programs would be the most effective management strategy. They therefore recommend

1) taxing new plantations of non-indigenous conifers to offset the costs of managing invasions, and

2) regulating these plantations more strictly to protect vulnerable ecosystems.

They also note several areas where additional research on the species’ invasiveness, dispersal, and impacts is needed.

Survey of Awareness of Invasive Plants

A few months later a separate group of New Zealand scientists published a study examining tourists’ understanding of invasive plant impacts and willingness to support eradication programs (Lovelock et al.; full citation at end of the blog). One of the invasive plant groups included in the study are conifers introduced from North America and Europe. These conifers are invading montane grasslands, so they are not the specific topic of the earlier article. The other is a beautiful flowering plant, Russell lupine.  These authors say that both plant groups have profound ecological, economic, and environmental impacts. However, the conifers and lupines are also highly visible at places valued by tourists. Lovelock et al. explored whether the plants’ familiarity – and beauty – might affect how people reacted to descriptions of their ecosystem impacts.

Visitors from elsewhere in New Zealand were more aware of invasive plants’ impacts and more willing to support eradication programs for these species specifically. Asian visitors had lower awareness and willingness to support eradication of the invasives than tourists from the United Kingdom, Europe, or North America. This pattern remained after the tourists were informed about the plants’ ecological impacts. All groups were less willing to support eradication of the attractive Russell lupine than the conifers.

Conifers invading montane grasslands are perhaps the most publicized invasive plants in New Zealand [as noted above]. Lovelock et al. report that New Zealand authorities have spent an estimated $NZ166 million to eradicate non-native conifers over large tracts of land on the South Island. Still, only about half the New Zealand visitors surveyed were aware of the ecological problems caused by wild conifers.

invasive lupines in New Zealand; photo by Michael Button via Flickr

Russell lupine (Lupinus × russellii) is invading braided river systems, modifying river flows, reducing nesting site availability for several endangered birds, and provides cover for invasive predators. While initially planted in gardens, the lupines were soon being deliberately spread along the roads to ‘beautify’ the landscape. Foreign tourists often specifically seek river valley invaded by the lupine because pictures of the floral display appear in both official tourism promotional material & tourist-related social media. It is not surprising, then, that even among New Zealanders, only a third were aware of the lupines’ environmental impacts.

The oldest participants (those over 60) had the lowest acceptance of wild conifers. Participants 50–59 years old were most aware of ecological problems caused by wild conifers. Participants 30–39 years old showed the highest acceptance of wild conifers and lowest awareness of ecological issues.

Female participants showed a higher preference for the landscape with wild conifers (45.90%) than males (36.89%). Female participants were also half as aware of ecological problems (25.62% v. 46.12% among male participants).

Nearly all survey participants (96.1%) preferred the landscape with flowering lupine; only 19.4% were aware of associated ecological problems. New Zealand domestic visitors were more aware. After the impacts of lupines were explained, half decided to support eradication. However, the same proportion of all survey participants (42.5%) still wanted to see lupines in the landscape.

Once again, participants older than 50 were more aware of ecological problems arising from lupine invasions.  Both men and women greatly preferred the landscape with Russell lupins.

While the authors do not explore the ramifications of the finding that younger people are less aware of invasive species impacts, I think they bode ill for future protection of the country’s unique flora and fauna. They did note that respondents had a high level of acceptance overall for these species on the New Zealand landscapes.

While the study supported use of simple environmental messaging to influence attitudes about invasive species, also showed that need to consider such social attributes as nationality and ethnicity. So Lovelock et al. call for investigation of how and why place of origin and ethnicity are important in shaping attitudes towards invasives. Conveying conservation messages will be more difficult because tourist materials often contain photographs of the lupines. Much of this information comes from informal media such as social media, which are beyond the control of invasive species managers.

SOURCES

Bellingham, P.J., E.A. Arnst, B.D. Clarkson, T.R. Etherington, L.J. Forester, W.B. Shaw,  R. Sprague, S.K. Wiser, and D.A. Peltzer. 2022. The right tree in the right place? A major economic tree species poses major ecological threats. Biol Invasions Vol.: (0123456789) https://doi.org/10.1007/s10530-022-02892-6  

Lovelock B., Y. Ji, A. Carr, and C-J. Blye. 2022.  Should tourists care more about invasive species? International and domestic visitors’ perceptions of invasive plants and their control in New Zealand.  Biological Invasions (2022) 24:3905–3918 https://doi.org/10.1007/s10530-022-02890-8

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Invasive Species Costs Point to Inadequate Effort – especially Prevention

EAB-killed ash tree falls before it can be taken down; photo courtesy of former Ann Arbor mayor John Hieftje

Concerned by growing impacts of bioinvasion and inadequate responses by national governments worldwide and by international bodies, a group of experts have attempted to determine how much invasive species are costing. They’ve built the global database – InvaCost. See Daigne et al. 2020 here.

Several studies have been based on these data. In two earlier blogs, I summarized two of these articles, e.g., Cuthbert et al. on bioinvasion costs, generally, and Moodley et al. on invasive species costs in protected areas, specifically. Here, I look at two additional studies. Ahmed et al. focusses on the “worst” 100 invasives affecting conservation — as determined by the International Union of Conservation and Nature (IUCN). The second, by Turbelin et al., examines pathways of introduction. Full citations of all sources appear at the end of this blog.

It is clear from all of these papers that the authors (and I!) are frustrated by the laxity with which virtually all governments respond to bioinvasions. Thus more robust actions are needed. The authors and I also agree that data on economic costs influence political decision-makers more than ecological concerns. However, InvaCost – while the best source in existence — is not yet comprehensive enough to generate the thoroughly-documented economic data about specific aspects of bioinvasion that would be most useful in supporting proposed strategies.

Scientists working with InvaCost recognize that the data are patchy. At the top level, these data demonstrate high losses and management costs imposed by bioinvasion. The global total – including both realized damage and management costs – is estimated at about $1.5 trillion since 1960. In fact, these overall costs are probably substantially underestimates (Cathbert et al.). [For a summary of data gaps, go to the end of the blog.] Furthermore, they recognize that species imposing the highest economic costs might not cause the greatest ecological harm (Moodley et al).

citrus longhorned beetle exit hole in bonsai tree; USDA APHIS photo

Comparing estimated management costs to estimated damage, the authors conclude that countries invest too little in bioinvasion management efforts and — furthermore — that expenditures are squandered on the wrong “end” of bioinvasion – after introduction and even establishment, rather than in preventive efforts or rapid response upon initial detection of an invader. While I think this is true, these findings might be skewed by the fact that fewer than a third of countries reporting invasive species costs included data on specifically preventive actions. Cuthbert et al. notes that failing to try to prevent introductions imposes an avoidable burden on resource management agencies. Ahmed et al. developed a model they hope will overcome the perverse   incentives that lead decision-makers to either do nothing or delay.

  1. Why Decision-Makers Delay

Citing the InvaCost data, the participating experts reiterate the long-standing call for prioritizing investments at the earliest possible invasion stage. Ahmed et al. found that this was the most effective practice even when costs accrue slowly. They ask, then, why decision-makers often delay initiating management. I welcome this attention because we need to find ways to rectify this situation.

They conclude, first, that invasive species threats compete for resources with other threats to agriculture and natural systems. Second, Cuthbert et al. and Ahmed et al. both note that decision-makers find it difficult to justify expenditures before impacts are obvious and/or stakeholders demand action. By that time, of course, management of invasions are extremely difficult and expensive – if possible at all. I appreciate the wording in Ahmed et al.: bioinvasion costs can be deceitfully slow to accrue, so policy makers don’t appreciate the urgency of taking action.

Cuthbert et al. also note that impacts are often imposed on other sectors, or in different regions, than those focused on by the decision-makers. Stakeholders’ perceptions of whether an introduced species is causing a “detrimental” impact also vary. Finally, when efficient proactive management succeeds – prevents any impact – it paradoxically undermines evidence of the value of this action!

Ahmed et al. point out that in many cases, biosecurity measures and other proactive approaches are even more cost effective when several species are managed simultaneously. They cite as examples airport quarantine and interception programs; Check Clean Dry campaigns encouraging boaters to avoid moving mussels and weeds; ballast water treatment systems; and transport legislation e.g., the international standard for wood packaging (ISPM#15) [I have often discussed the weaknesses in ISPM#15 implementation; go to “wood packaging” under “Categories” (below the archive list)].

pallet “graveyard”; photo by Anand Prasad
  • Pathways of Species’ Introduction

Tuberlin et al. focus on pathways of introduction, which they say influence the numbers of invaders, the frequency of their arrival, and the geography of their eventual distribution. This study found sufficient data to analyze arrival pathways of 478 species – just 0.03% of the ~14,000 species in the full database. They found that intentional pathways – especially what they categorized as “Escape” – were responsible for the largest number of invasive species (>40% of total). On the other hand, the two unintentional pathways called “Stowaway” and “Contaminant” introduced the species causing the highest economic costs.

Tuberlin et al. therefore emphasize the importance of managing these unintentional pathways. Also, climate change and emerging shipping technologies will increase potential invaders’ survivability during transit. Management strategies thus must be adapted to countering these additive trends. They suggest specifically:

  • eDNA detection techniques;
  • Stricter enforcement of ISPM#15 and exploring use of recyclable plastic pallets (e.g., IKEA’s OptiLedge); [see my blog re: plastic pallets, here]
  • Application of fouling-resistant paints to ship hulls;
  • Prompt adoption of international agreements addressing pathways (they cite the Ballast Water Management Treaty as entered into force only in 2017 — 13 years after adoption);
  • Ensuring ‘pest free status’ (per ISPM#10) before allowing export of goods—especially goods in the “Agriculture”, “Horticulture”, and “Ornamental” trades; and
  • Increasing training of interception staff at ports.

What InvaCost Data say re: Taxa of greatest concern to me

Two-thirds of reported expenditures are spent on terrestrial species (Cuthbert et al.). Insects as a Class constitute the highest number of species introduced as ‘Contaminants’ (n = 74) and ‘Stowaways’ (n = 43). They also impose the highest costs among species using these pathways. Forest insects and pathogens account for less than 1% of the records in the InvaCost database, but constitute 25% of total annual costs ($43.4 billion) (Williams et al., in prep.). Indeed, one of 10 species for which reported spending on post-invasion management is highest is the infamous Asian longhorned beetle (Tuberlin et al.)

ALB pupa in wood packaging; Pennsylvania Dept. of Natural Resources via Bugwood

Mammals and plants are often introduced deliberately – either as intentional releases or as escapes. Plant invasions are reported as numerous but impose lower costs.

Tuberlin et al. state that intentional releases and escapes should in theory be more straightforward to monitor and control, so less costly. They propose two theories: 1) Eradication campaigns are more likely to succeed for plants introduced for cultivation and subsequently escaped, than for plants introduced through unintentional pathways in semi-natural environments. 2) Species introduced unintentionally may be able to spread undetected for longer; they expect that better measures already exist to control invasions by deliberate introductions. I question both. Their theories ignore that constituencies probably like the introduced plants … and the near absence of attention to the possible need to control their spread. This is odd because elsewhere they recognize conflicts over whether to control or eradicate “charismatic” species.

Geographies of greatest concern to me

  • North America reported spending 54% of the total expenditure in InvaCost. Oceania spent 30%. The remaining regions each spent less than $5 billion. (Cuthbert et al.)
  • North America funded preventative actions most generously than other regions. Cuthbert suggests this was because David Pimentel published an early estimate of invasive species costs. I doubt it. The Lacey Act was adopted in 1905. USDA APHIS was formed in 1972 – based on predecessor agencies — because officials recognized the damage by non-native pests to agriculture. APHIS began addressing natural area pests with discovery of the Asian longhorned beetle in 1996. Of course, most of APHIS’ budget is still allocated to agricultural pests. I conclude that North America’s lead in this area has not resulted in adequate prevention programs.
Oregon ash swamp before attack by EAB (photo by Wyatt Williams, Oregon Dept. of Forestry)

Equity Issues

Tuberlin et al and Moodley et al. address equity issues of who causes introductions vs. who is impacted. This is long overdue.

  • More than 80% of bioinvasion management costs in protected areas fell on governmental services and/or official organizations (e.g. conservation agencies, forest services, or associations). With the partial exception of the agricultural sector, the economic sectors that contribute the most to movement of invasive species are spared from carrying the resulting costs (Moodley et al.)
  • A lack of willingness to invest might represent a moral problem when the invader’s impacts are incurred by regions, sectors, or generations other than those that on whom management action falls (Ahmed et al.)
  • People are perhaps more inclined to spend money to mitigate impacts that cause economic losses than those that damage ecosystems (Tuberlin et al.)

Data deficiencies

  • Only 41% of countries (83 out of 204) reported management costs; of those, only 24 reported costs specifically associated with pre-invasion (prevention) efforts (Cuthbert et al.).
  • Reliable economic cost estimates were available for only 60% of the “worst” invasive species (Cuthbert et al.)
  • Only 55 out of 266,561 protected areas reported losses or management costs (Moodley et al.).
  • Information on pathways of introduction was available for only three species out of 10,000 (Turbelin et al).
  • Taxonomic and geographic biases in reporting skew examples and possibly conclusions (Cuthbert et al.).

SOURCES

Ahmed, D.A., E.J. Hudgins, R.N. Cuthbert, .M. Kourantidou, C. Diagne, P.J. Haubrock, B. Leung, C. Liu, B. Leroy, S. Petrovskii, A. Beidas, F. Courchamp. 2022. Managing biological invasions: the cost of inaction. Biol Invasions (2022) 24:1927–1946 https://doi.org/10.1007/s10530-022-02755-0

Cuthbert, R.N., C. Diagne, E.J. Hudgins, A. Turbelin, D.A. Ahmed, C. Albert, T.W. Bodey, E. Briski, F. Essl, P. J. Haubrock, R.E. Gozlan, N. Kirichenko, M. Kourantidou, A.M. Kramer, F. Courchamp. 2022. Bioinvasion costs reveal insufficient proactive management worldwide. Science of The Total Environment Volume 819, 1 May 2022, 153404

Moodley, D., E. Angulo, R.N. Cuthbert, B. Leung, A. Turbelin, A. Novoa, M. Kourantidou, G. Heringer, P.J. Haubrock, D. Renault, M. Robuchon, J. Fantle-Lepczyk, F. Courchamp, C. Diagne. 2022. Surprisingly high economic costs of bioinvasions in protected areas. Biol Invasions. https://doi.org/10.1007/s10530-022-02732-7

Turbelin, A.J., C. Diagne, E.J. Hudgins, D. Moodley, M. Kourantidou, A. Novoa, P.J. Haubrock, C. Bernery, R.E. Gozlan, R.A. Francis, F. Courchamp. 2022. Introduction pathways of economically costly invasive alien species. Biol Invasions (2022) 24:2061–2079 https://doi.org/10.1007/s10530-022-02796-5

Williams, G.M., M.D. Ginzel, Z. Ma, D.C. Adams, F.T. Campbell, G.M. Lovett, M. Belén Pildain, K.F. Raffa, K.J.K. Gandhi, A. Santini, R.A. Sniezko, M.J. Wingfield, and P. Bonello 2022. The Global Forest Health Crisis: A Public Good Social Dilemma in Need of International Collective Action. Submitted

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Funding APHIS & USFS in FY23 – Senate Recommendations

The Senate Appropriations Committee has adopted its recommendations for funding APHIS and the US Forest Service in Fiscal Year 2023, which begins on October 1. The full Senate has not yet acted; most people expect that it will not act before October, so the agencies will have to operate under a “continuing resolution” for at least the first several months. Under a “CR”, funding is maintained at the current level.

SOD-infected rhododendron plants detected by state officials in Indiana in 2019

Funding for APHIS in FY23

The Senate Appropriations Committee issued a report [available here] that recognizes APHIS’ objective of protecting the animal and plant resources of the Nation from diseases and pests. These objectives are carried out through, inter alia, Safeguarding and Emergency Preparedness/Response and Safe Trade and International Technical Assistance.

The Committee recommends the following funding for specific APHIS programs (in $millions)

PROGRAMFY22 FUNDINGFY23 ADMIN REQHOUSE $SENATE COMM RECOMMCISP ASK
Border inspections (AQI appropriated)33.84936.725 36.650X
Pest Detection28.21829.13729.82529.07530
Methods Development21.21721.85431.80723.55723
Specialty Crops209.533219.533219.698222.072219
Tree & Wood pests61.21762.85462.56262.71970
Subtotal, Plant health379.144385.560 397.603X
Emerg. Prepare & Response42.02144.242 44.317X

Specific programs mentioned:

  1. Northern (Asian) giant hornet eradication: $1.75 million to continue cooperation with Washington State to eradicate this pest; also to improve monitoring methods and lures, and build a rapid response platforms
  2. sudden oak death (SOD): recognize that the EU1 and NA1 strains of this pathogen threaten Douglas-fir / tanoak forests and lead foreign governments to impose quarantines on U.S. timber exports. So APHIS should spend no less that FY22 funding to better understand threat and treatment methods in wildlands. This earmark disappoints because it focuses on APHIS’ role as certifying timber exports as pest-free rather than the spread of the pathogen within the U.S. via the nursery trade. The same language appears in the report’s discussion of the Agriculture Research Service (see below).

Pertinent action re: Agriculture Research Service

The Senate Committee report sets several priorities, including the following:

  1. Invasive Pests: The Committee is concerned about the threats invasive pests pose to agriculture, the economy, environment, human health, and national security of the Pacific region. The Committee directs ARS to continue working with stakeholders in the region to assess options for combatting invasive species, including biocontrol research facilities, containment facilities, additional laboratory space.
  2. Sudden oak death: the same language as for APHIS. Again, I wish the language referred to the pathogen’s spread via the nursery trade.

These numbers are disappointing; the increase for “specialty crops” demonstrates the lobbying clout of the nursery and berry industries! I appreciate the attention to sudden oak death – with the caveat I mentioned.

SOD-infected tanoaks in southern Oregon; photo by Oregon Department of Forstry

Forest Service

The Senate Appropriations Committee issued a report [available here] . The Senate Appropriations Committee recommends the following funding levels for USFS programs that address non-native forest pests and other invasive species (in $millions):

PROGRAMFY22 FUNDINGFY ADMIN REQUESTHOUSE $S COMM RECOMMCISP ASK
Research296.616317.733$360.4$302.773317.733
State & Private Forest Health Protection TOTAL4859.232$52.2325083
S&P FHP Federal lands16,00022,485?17,00051
S&P FHP non-federal lands32,00036,747?33,00032

R&D

The Senate wants to retain the current structure of five regional stations, International Institute of Tropical Forestry, and Forest Products Laboratory.

The Senate listed several research priorities. Two pertain to forest health: 1) needle pathogens, and 2) Northeastern States Research Cooperative working to sustain the health of northern forest ecosystems and biological diversity management. I am disappointed that no mention is made of the need to respond to 400 introduced tree-killing insects and pathogens.

planting to test ash trees’ resistance to emerald ash borer; photo courtesy of Jennifer Koch, USFS

S&P

The Senate Committee recommends a significant increase in S&P overall ($8 million above FY22 level), but not for Forest Health Management. This is disappointing.

The Committee is concerned about high tree mortality on National Forests due to bark beetle infestations and instructs USFS to work with states and tribes to prioritize insect prevention, suppression & mitigation projects.

The Committee expects the Forest Service and Bureau of Land Management (BLM) to continue efforts to treat sudden oak death in California and Oregon. It provides $3 million for this purpose, including for partnerships with private landowners.

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Breeding Tree Resistance: New Science and Call to Action on New Legislation

grafted beech at Holden Arboretum – for resistance breeding tests

Two USFS experts have published a chapter describing the components needed to succeessfully breed trees resistant to threatening pests. [See full citation at end of blog.]

As Sniezko and Nelson note, the threat from non-native pests and pathogens to forest health and associated economic and ecological benefits is widespread and increasing. Further, once such a pest becomes well-established – as some 400 pest species now are — few strategies to save affected species exist except a program to enhance the species’ pest resistance.

From a technical point of view, Sneizko and Nelson find reason for hope. Most tree species have some genetic variation on which scientists can build. It is likely that a well-designed and well-focused breeding program can identify parent trees with some pest resistance; select the most promising; and breed progeny from those parents with sufficient resistance to restore a species.

Furthermore, they say, progress can be made fairly quickly. Scientists can focus on developing genetically resistant populations while postponing studies aimed at understanding details of the mechanisms and inheritance of the obtained resistance.

Fifty years of breeding have revealed the techniques and strategies that work best. As a result, application of classical tree improvement procedures can lead to development of pest-resistant populations within a decade or so in some cases, several decades in others. The time needed depends on the specifics of the pest-host relationship, level of resistance required – and resources available.

In addition, advances in biotechnology can accelerate development of resistance. Tools include improved clonal propagation, marker-assisted selection, and genetic engineering to add resistance gene(s) not present in the tree species.

Port-Orford cedars in controlled breeding stage at Dorena; photo by Richard Sniezko, USFS

Sniezko and Nelson identify basic facilities needed to support successful breeding programs:

(a) growing space (e.g., greenhouses);

(b) seed handling and cold storage capacity;

(c) inoculation infrastructure;             

(d) field sites for testing;

(e) database capability for collecting, maintaining, and analyzing data;

(f) areas for seed orchard development;

(g) skilled personnel (tree breeders, data managers, technicians, administrative support personnel, and access to expertise in pathology and entomology).

Absolutely essential is continuity of higher-ups’ and public’s support.

Sniezko and Nelson note that a resistance breeding program differs from other research projects in its objectives, magnitude and focus. It is an action-oriented effort that is solution-minded—countering the impact of a major disturbance caused by a pest (in our case, a non-native pest).  

See the article for more detailed descriptions of each step in the process.

There are two basic stages:

Phase 1:exploration to assess whether sufficient genetic variation in resistance exists in the species. This involves locating candidate resistant trees, preferably across the affected geographic range impacted by the pest; developing and applying short-term assay(s) to screen hundreds or thousands of candidate trees; and determine the levels of resistance present. In addition to those objectives Phase 1 also begins to evaluate the durability and stability of resistance. It is vital to inform stakeholders of progress and engage them in deciding whether and how to proceed.

Phase 2: develop resistant planting stock for use in restoration. This stage relies on tree improvement practices developed over a century, and applies the knowledge gained in Phase 1. Steps include scaling up the screening protocol; selecting the resistant candidates or progeny to be used; establishing seed orchards or other methods to deliver large numbers of resistant stock for planting; and additional field trials to further validate and delineate resistance.

The authors argue that, at present U.S. forestry programs lack a coordinated, focused resistance breeding program based on the components described above. The Dorena Genetic Resource Center (DGRC) – established in 1966 in Oregon and supported primarily by the USDA Forest Service’s regional State and Private Forestry program and National Forest System — fits the bill. The DGRC has sufficient facilities and resources to screen simultaneously tens of thousands of seedlings from thousands of parent trees belonging to several species. Its staff have built up invaluable experience.

However, the Center is regional in scope and focus. (Staff are pleased to offer advice to colleagues working in other parts of the country.) Who will ensure that we make progress on restoring the dozens of tree species in the East under threat from invasive pests? The ashes, hemlocks, elms, beeches, oaks, Fraser fir, dogwoods, redbay and swamp bays, sassafras all need help (Profiles of these trees’ pest challenges can be found at here. [Chestnut and possibly the chinkapins have the benefit of a well-established charity …]

ash killed by EAB; photo by Nate Siegert, USFS

Three case studies illustrate how the process has worked for three groups of species: 1) five-needle pines (subgenus Strobus);  2) Port-Orford cedar (Chamecyparis lawsonii); 3) resistance to fusiform rust (Cronartium quercuum f. sp. fusiforme – a native pathogen) in southern pines.

New Possibilities

Resistance breeding programs are simplest to undertake when tree improvement facilities and experienced staff are already in place. It is most unfortunate that their number has declined significantly. However, a Congressional mandate to pursue resistance breeding as a strategy can partially retrieve and add needed resources.

Some members of Congress have taken steps to partially restore resistance breeding programs.  H.R. 1389, cosponsored by Reps. Welch (D-VT), Kuster and Pappas (both D-NH), Stefanik (R-NY), Fitzpatrick (R-PA), Thompson, (D-CA), Ross (D-NC) Pingree (D-ME). Then-Rep. Antonio Delgado also co-sponsored, before resigning to become Lieutenant Governor of New York.

The bill would establish separate grant programs to fund work under the two phases outlined by Sniezko and Nelson. It relies on grants rather than setting up Dorena-like facilities in other parts of the country. Scientists are already setting up consortia to provide the needed facilities and long-term stability e.g., Great Lakes Basin Forest Health Collaborative. Will that be enough?

The most likely way to create a national tree resistance program is to incorporate these ideas into the next Farm Bill – due to be adopted next year (2023).

You can help by contacting members of the House and Senate Agriculture committees and urging them to include in the bill either H.R. 1389 or a more comprehensive program that does establish centers analogous to Dorena.

Also convey your support to USDA leadership – especially the Forest Service and Agriculture Research Service. (APHIS should be part of the team, but its focus is on strategies with more immediate effect.)

As Sniezko and Nelson state, a key component for success is a core group of stakeholders who

  1. realize the problem (threat to a tree species’ role in the environment);
  2. acknowledge that resistance breeding offers the best avenue for maintaining the species of concern; and
  3. express a willingness to invest in a solution that could take one or more decades.

Will YOU be part of this team?

I note that Bonello et al., 2020 (citation below) suggested a new structure to provide the needed focus and coordination. Adoption of H.R. 1389 would partially realize this. The bill calls for a study to examine the benefits of establishing a more secure foundation within USDA for addressing tree-killing pests.

Scott Schlarbaum made similar points in Chapter 6 of Fading Forests III, published in 2014. See links below.

SOURCES

Bonello, P., F.T. Campbell, D. Cipollini, A.O. Conrad, C. Farinas, K.J.K. Gandhi, F.P. Hain, D. Parry, D.N. Showalter, C. Villari, K.F. Wallin. 2020. Invasive tree Pests Devastate Ecosystems – A Proposed New Response Framework. Frontiers in Forests and Global Change. January 2020. Volume 3. https://www.frontiersin.org/articles/10.3389/ffgc.2020.00002/full

Sniezko, R.A. and C.D. Nelson.  2022. Chapter 10, Resistance breeding against tree pathogens. In Asiegbu and Kovalchuk, editors. Forest Microbiology Volume 2: Forest Tree Health; 1st Edition. Elsevier

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Urgent Update on Beech Leaf Disease

banding symptoms of beech leaf disease; photo by Dr. Chagas de Freitas, Ohio State

Experts on beech leaf disease (BLD) hold conference calls every two months. I reported on the May meeting earlier in July. The July conference call of the experts emphasized not only the alarming spread of the disease but also the dilemmas frustrating efforts to slow its spread and protect beech.

Jerry Carlson, chief of forest health protection for the New York Department of Environmental Conservation called beech leaf disease “the next chestnut blight.

Yet forestry, plant health, and conservation entities have been slow to support research needed to develop protective measures.

As was noted by participants, 10 years after scientists from Lake MetroParks (in Cleveland) first detected disease symptoms, scientists still are unsure about all aspects of BLD and how it spreads. Experts agree that the nematode (Litylenchus crenatae ssp mccannii) must be present to initiate the disease. Other possible factors, especially fungi in the genus Colletotrichum, appear to play important roles in causing the symptoms.

The lack of clarity about the causal agent means that USDA APHIS has not recognized the disease as a priority species for tracking. APHIS has provided some funds. However, scientists seeking to obtain funding through the Plant Pest and Disease Management and Disaster Prevention Program [laid out in the Plant Protection Act’s Section 7721] can’t get traction. Other funding sources also don’t quite fit. For example, the National Science Foundation funds basic, hypothesis-driven, research – not the more applied science needed to address BLD. Some participants wondered whether funding might be sought from wildlife-oriented sources, since beech are so important in providing hard mast, den and nest sites, etc., for a variety of wildlife.

Participants discussed ways to raise awareness – and alarm – in order to build a broader coalition. This effort should include Europe. Although the disease has not yet been detected in Europe, the native beech is vulnerable.

European beech in Rhode Island infected by BLD; photo by Dr. Nathaniel A. Mitkowski, University of Rhode Island

Data indicate that the disease is now significantly more widespread than was known last year. That is, BLD is more widespread from New York to Maine, with New Hampshire reporting its first detection. To the west, BLD has been detected in Michigan and in a forest fragment in western Ohio (near Toledo). Disease severity has also intensified. Of course, the disease is present at least a year before it is detected because leaf symptoms appear in the spring following infection. Therefore its presence is probably wider.

map of BLD presence as of early July 2022 (some states have not yet reported); note the many counties in fuschia – 2022 detections

While mortality of mature beech is still rarely documented, this might be related to difficulties determining the cause of mortality during standard forest health surveys. Participants discussed how to rectify this situation.

Meanwhile, concern is rising – as reflected in Dr. Carlson’s statement.

You can help by asking your state and national officials and conservation organizations to support applied research aimed at clarifying how the disease spreads, what ecological conditions are conducive to disease, improved detection and prediction tools, and possible containment strategies. Let’s overcome the roadblocks impeding protection of this magnificent and ecologically vital tree species.

Is this not worth protecting?

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

More & bigger ships, deeper ports = more pests?

Port of Houston – Bayport Container Terminal; photo by Ray Luck via Flickr

The U.S. continued to import large amounts of goods from Asia in the first three months of 2022. During this period, total volume imported from Asia increased to 1.62 million TEU — 31.1% higher than in the same period in pre-pandemic 2019 (Mogelluzzo, B. April 22, 2022).

Due to congestion in West Coast ports, the proportion of Asian goods entering the country through East Coast and Gulf Coast ports also rose in the first quarter of 2022 compared to the same period in 2021: by about 33% along the Atlantic and 6% along the Gulf (Mogelluzzo, B. April 22, 2022). Increases were particularly steep in the south: 9.2% at Savannah; 12.5% at Norfolk; 26% at Charleston; and an astonishing 52.1% through Houston.

Due to Covid-19-related port and factory shutdowns in China, a rising share of imports to the U.S. in 2022 came from other countries in Asia. Imports grew especially from Vietnam but also Thailand, Malaysia, Indonesia, and South Korea (Wallis, K. May 11, 2022).

Port of Long Beach Pier G – ITS – MOL vessel; photo by port authority

Starting in May 2022, West Coast ports began to recover their dominant role – probably because East Coast and Gulf Coast ports were now suffering their own congestion-related delays. Virtually all the restored traffic entered through the Los Angeles-Long Beach port complex; these ports imported a monthly record of 851,956 TEU from Asia in May. Imports through Seattle and Tacoma actually declined from the previous month, while Oakland’s imports from Asia remained steady (Mongelluzzo, June 15, 2022).

Thus, the “baseline” for US imports from Asia each month is now 20 to 30% higher than it was before COVID-19 disrupted supply chains (Mongelluzzo, June 15, 2022).

East Coast Ports Deepening and Expanding to Accept Larger Ships

Meanwhile, East Coast ports continue efforts to deepen their channels and expand their infrastructure so that they can service the larger container ships.

In late June 2022 the US Army Corps of Engineers approved the plan by the Port of New York-New Jersey (PANYNJ) to dredge channels to accommodate more post-Panamax ships. The largest ship that has called at NY-NJ was 16,000 TEU; port officials hope to accommodate ships up to 21,000 TEU, apparently using current capacity (Angell, June 23, 2022; Angell, May 27, 2022). PANYNJ Port Director Bethann Rooney says the port expects to see annual volumes rise to 17 million TEU by 2050, almost double its throughput in 2021 (Angell, May 27, 2022).

The Corps found the PANYNJ plan to be both environmentally and economically sound. The Corps will now seek Congressional funding for the project in the 2024 Water Resources Development Act; the Port Authority will also contribute to the project (Angell, June 23, 2022).  We need to be more active in commenting on these port expansion environmental assessments!

The Port of NY-NJ is also seeking to expand storage facilities for incoming shipping containers. Several sites are at various stages of consideration and development; one – part of the “Port Ivory” site on Staten Island – includes a tidal wetland.  A November 2021 application by PANYNJ a change-in-use permit is under review by New York State Department of Environmental Conservation (NYSDEC) (Angell, May 27, 2022). Can those interested in environmental protection express their opposition?

The Port of Charleston is expected to finish dredging its inner harbor and channel this year. Last year, the Port of Virginia has received initial funding for a dredging project that should be completed by 2024 (Angell, May 27, 2022).

As we know, numerous tree-killing insects have been introduced from Asia to the ecologically similar forests of eastern North America – often in wood packaging. ALB in Charleston These include Asian longhorned beetle, emerald ash borer, redbay ambrosia beetle, phytophagous and Kuroshia shot hole borers (for profiles of each visit here). Indeed, 15 of 16 non-native bark beetles in the Xyleborini (a tribe of ambrosia beetles) detected in the United States since 2000 are from Asia (Bob Rabaglia, USFS Forest Health Protection, presentation at IUFRO meeting in Prague, September 2021).

Growing numbers of containers entering Atlantic and Gulf Coast ports raises the risk of additional introductions. Insects associated with imports from semi-tropical ports in Vietnam entering the U.S. through Gulf or southern Atlantic ports might well find these regions hospitable. I worry, for example, about the polyphagous and Kuroshio shot hole borers – surely the Gulf Coast provides a more suitable environment for insects from Vietnam and Taiwan than does southern California? And known hosts are present – box elder, willows, sweetgum, mimosa, tree of heaven …

Of course, containers are then sent on from the ports to distribution centers – presenting opportunities for pest introductions in inland areas. New or expanded distribution centers include Atlanta and Appalachian Regional Port and Statesboro Airport in Georgia, Rocky Mount, North Carolina; Huntsville, Alabama; Portsmouth and Front Royal, Virginia (Ashe and Angell July 5, 2022). Front Royal is at the northern end of Shenandoah National Park!

photo by Daveylin via Flickr

European Trade

Meanwhile, U.S. imports from Europe continued at high levels – although they were not breaking records. In the first half of 2022, the U.S. imported just under 1.77 million TEU from Europe. The largest category of commodity from Northern Europe was foodstuffs — 410,930 TEU. Machinery and mechanical products imports – the type of good often associated with infested wood packaging – numbered 228,521 TEU. Vehicles, aircraft, and vessels imports were 107,526 TEU. “Miscellaneous manufactured articles” that include furniture, bedding, mattresses, and light fittings were 132,979 TEU. I expect – although the source does not so state – that this last category includes decorative stone and tile – again, a category often associated with infested wood packaging.

 While fewer damaging pests have been introduced from Europe in recent decades, the risk remains.

Updated Haack Analysis

As has been documented repeatedly (e.g., my blogs, including 248), the current approach to curtailing pest introductions associated with wood packaging is not sufficiently effective. Customs officials continue to detect live quarantine pests in wood packaging as it enters the country. However, the exact level of this threat is unclear since the only assessment was based on data from 2009 (Haack et al., 2014).  I eagerly await the results of Bob Haack’s updated analysis, which I hope will be published soon.

SOURCES

Angell, M. NY-NJ port lays groundwork for larger ships ahead of dredging. May 27, 2022.  https://www.joc.com/port-news/us-ports/port-new-york-and-new-jersey/ny-nj-port-lays-groundwork-larger-ships-ahead-dredging_20220527.html

Angell, M. NY-NJ deepening study gets US Army Corps blessing. June 23, 2022. https://www.joc.com/port-news/us-ports/port-new-york-and-new-jersey/ny-nj-deepening-study-gets-us-army-corps-blessing_20220623.html?utm_campaign=CL_JOC%20Ports%206%2F29%2F22%20%20%20REDO_PC00000_e-production_E-140850_SA_0629_0900&utm_medium=email&utm_source=Eloqua

Ashe, A. and Angell, M. Rising volumes slowing port flow on East, Gulf coasts. July 5, 2022. https://www.joc.com/port-news/us-ports/rising-volumes-slowing-port-flow-east-gulf-coasts_20220705.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%207%2F6%2F22%20NONSUBSCRIBER_PC015255_e-production_E-141183_KB_0706_0617

Knowler, G. Rising US imports keep pressure on trans-Atlantic. July 18, 2022.  https://www.joc.com/port-news/international-ports/rising-us-imports-keep-pressure-trans-atlantic_20220718.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%207%2F19%2F22%20NONSUBSCRIBER_PC015255_e-production_E-141796_KB_0719_0617

Mongelluzzo, B. Q1 US imports from Asia show no slowing in consumer demand. Apr 22, 2022. https://www.joc.com/maritime-news/container-lines/q1-us-imports-asia-show-no-slowing-consumer-demand_20220422.html

Mongelluzzo, B. U.S. imports from Asia surge to unexpected record in May. June 15, 2022. https://www.joc.com/port-news/us-ports/us-imports-asia-surge-unexpected-record-may_20220615.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%206%2F16%2F22%20NONSUBSCRIBER_PC015255_e-production_E-140076_KB_0616_0617

Wallis, K. Asia shippers plug trans-Pacific export gap from China COVID-19 disruption. May 11, 2022.

https://www.joc.com/maritime-news/trade-lanes/asia-shippers-plug-trans-pacific-export-gap-china-covid-19-disruption_20220511.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%205%2F12%2F22%20NONSUBSCRIBER_PC015255_e-production_E-137446_KB_0512_0617

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Canada’s 64th Forest Pest Management Forum — in Short

spruce budworm; photo by Jerry E. Dewey, USFS; via Bugwood

The 64th Forest Pest Management Forum was held in December 2021. This is the largest and most significant gathering of forest pest management experts, managers, and practitioners in Canada. The proceedngs are available here. I summarize the contents. (This is my third review of recent reports on invasive species by Canadians. See also here and here. I appeciate the opportunity to learn about forest pest issues across such a large proportion of North America!

As usual, much of the attention was given to native pests, e.g.,

  • mountain pine beetle (Dendroctonus ponderosae) in Yukon, Alberta [declining numbers and areas affected]; Saskatchewan [none found in boreal forest]
  • Jack pine budworm (Choristoneura pinus) – Saskatchewan, Manitoba, Ontario.  [damage to jack pine in the Northwest Territories is caused by an unknown agent]
  • spruce pests, including spruce budworm (Choristoneura fumiferana) across the country: from  Yukon and Northwest Territories to New Brunswick; Nova Scotia; Newfoundland and Labrador
  • aspen defoliators – British Columbia; Northwest Territories; Alberta; Saskatchewan;
  • Swiss Needle Cast – British Columbia
  • Septoria leaf and stem blight in hybrid poplars (Populus genus) spreading in British Columbia; fears it could threaten black cottonwood, a keystone species in riparian ecosystems
hemlock mortality caused by HWA in Nova Scotia; photo by Celia Boone, NSDLF

The meeting also reported the following on non-native forest pests:

  • Asian longhorned beetle (Anoplophora glabripennis) — Canada has been declared free of ALB; national grid-based detection surveys continue – visual surveys at 10 sites; none found
  • emerald ash borer (Agrilus planipennis) trapping focused on high-risk locations and urban centers outside established regulated areas with no new detections in 2021. Saskatchewan continues to regulate EAB as a quarantine pest – after its detection in Winnipeg in November 2017. In New Brunswick, EAB has spread throughout the region where it was originally discovered in early 2021. In Nova Scotia, EAB remains undetected outside of the regulated area of Halifax
  • spongy moth (Lymantria dispar dispar) – trapping continues across Canada; detections in all provinces except Newfoundland – Labrador. Officials think they have eradicated an incipient population in Manitoba. Outbreaks are intensifying in Ontario and Québec (spongy moth is also expanding in northern US)
  • brown spruce longhorned beetle (Tetropium fuscum) – widespread trapping in Nova Scotia detected no new finds.
  • hemlock woolly adelgid (Adelges tsugae) is a priority species. Hemlock is a major component of the forested regions in the eastern provinces and HWA threatens to cause potentially irreparable damage to hemlock-dominated areas. Visual detection surveys were conducted at more than 180 high risk locations in eastern Canada. HWA has been confirmed in 7 counties of Nova Scotia – 2 of them new; plus a new infestation in Ontario.
  • beech leaf-mining weevil (Orchestes fagi continues to spread, with 22,129 ha of damage and mortality in areas near Halifax, Nova Scotia. The report makes no mention of beech leaf disease and here.
  • Dutch elm disease (Ophiostoma ulmi & O.novo-ulmi) – spreading rapidly in parts of Saskatchewan; major control effort in Manitoba, where 38 communities are participating in a provincial program and Winnipeg has its own program.
  • elm zig zag sawfly (Aproceros leucopoda) – Canadian authorities are apparently considering what their response should be  [see also Martel et al. 2022. (open access!) 
elm zigzag sawfly; photo by Gyorgy Csoka Hungarian Forest Research Organization; via Bugwood

Canadian authorities have active surveillance programs targetting three species established in the U.S. which they worry will enter Canada:

spotted lanternfly eggs; New York Dept. of Environmental Conservation photo
  • oak wilt (Ceratocystis fagacearum) – visual surveys at more than 60 sites in Ontario, Québec, New Brunswick and Nova Scotia; so far, no detections.
  • spotted lanternfly (Lycorma delicatula) authorities noted the many possible pathways of introduction
  • brown-tail moth (Euproctis chrysorrhoea) – rising population in Maine; several additional public reports of sightings in New Brunswick.

Policy

Canada has a National Forest Pest Strategy adopted by the Canadian Council of Forest Ministers (CCFM) in 2007. The CCFM Forest Pest Working Group (FPWG) plays a major role in advancing this Strategy. It also provides a national forum for generating ideas and exchanging information about forest pest management among federal, provincial, and territorial government agencies.

According to officials of the Canadian Food Inspection Agency (CFIA), the government has initiated limited pathway-based surveys to detect introduced pests associated with wood packaging material (crates, pallets, etc.). [See additional blogs posted here under “wood packaging” category. E.g., this one.  The agency is also developing an efficient, safe and feasible management program for handling shipborne dunnage. CFIA expected to publish a revised directive in spring 2022, then fully implement it by fall 2022.

Presentations on Individual Pests

The Proceedings include abstracts of presentations on individual species. The abstracts rarely provide the final findings.

Emma J. Hudgins, of Carleton University, reported on ways to optimize control of EAB in the U.S. She found that the best management strategy combined site-focused activities – such as biocontrol — and spread-focused (quarantine) management measures. This combined strategy vastly outperformed efforts based on limiting propagule pressure or managing single sites. In other words, quarantines should be refined rather than abandoned – as the US has done.

Oregon ash forest on the Willamette River, Oregon; photo by W. Williams, Oregon Dept. of Forestry

Chris MacQuarrie of the Canadian Forest Service reviewed use of biocontrol agents targetting EAB. Canada has approved release of three agents also approved in the United States: Tetrastichus planipennisi in 2013; Oobius agrili in 2015; Spathius galinae in 2017. Canada began trying to evaluate their impacts in 2018 – but the results are not included in the abstract.

Lucas Roscoe, also of the Canadian Forest Service, reviewed biocontrol efforts targetting hemlock woolly adelgid. The abstract doesn’t provide conclusions.

Kevin Porter and James Brandt assessed the risk of the spruce budworm (Choristoneura fumiferana) outbreaks in Eastern Canada’s Forests. The insect is the most widely distributed and destructive pest of spruce-fir forests in Canada; it is native to much of boreal and hemiboreal North America. Outbreaks occur periodically. Cumulative tree defoliation and mortality can result in significant losses of important timber and non-timber resources, affecting the forest industry and forest-dependent communities.

Stefan Zeglen and Nicolas Feau reported on the importance of environmental conditions in causing one disease. Swiss Needle Cast (caused by the usually innocuous endophyte Nothophaeocryptopus gaeumannii) has become pathogenic on Douglas-fir, causing up to 60% growth loss. This results from changing climate – and is expected to worsen with rising temperatures and humidity.

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org

Search for Asian giant hornet

Asian giant hornet (Vespa mandarinia); photo by University of Florida Dept. of Entomology

Washington State’s “Giant Hornet – Hornet Herald” for June asks people to help with detecting this pest by monitoring paper wasp nests (hornets attack them). Hornet visits last 5 – 10 minutes while the hornet removes paper wasp larvae.  How to help:

  • Locate paper wasp nests that you have access to and can monitor through October. Then log the nest locations using the form here
  • Visit the nests each week, observe them, and then log your nest activity on a different form – here. Please monitor the nests for at least 5 minutes during the day once per week, but you can check the nests for as long and as often as you would like.

If you would like guidance on how to become a citizen-science monitor or trapper of Asian giant hornets – or presumably other bioinvaders – go here

Meanwhile, Washington State Department of Agriculture entomologists are in South Korea testing several hornet attractants and studying hornet foraging behavior. The goal  is to improve Washington’s trapping and tracking techniques.

Of course, 2022 is only half over, but so far neither Washington nor British Columbia has confirmed any detections.

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

or

www.fadingforests.org