forest pests – Page 7 – Center for Invasive Species Prevention

Invasive shot hole borers: global threat; will international phytosanitary system prevent further spread?

ISHB-infested California sycamore; photo by Beatriz Nobua-Behrmann, University of California Cooperative Extension

Numerous ambrosia beetles have become introduced species. Their invasions are facilitated by their cryptic habits and ecologies, wide host ranges, and specialized breeding systems – all of which allow extremely low populations to start an infestation. The way they breed often results in low genetic diversity in their introduced ranges, but this has not hampered their success. [Bierman et al. 2022]

Also, ambrosia beetles carry fungi, which provide food needed by their larvae. While most of these fungi don’t harm living trees, some do. The United States has been invaded by three damaging ambrosia beetle-fungal complexes: laurel wilt in the Southeast, and Fusarium dieback disease, carried to southern California with polyphagous and Kuroshio shot hole borers.

These shot hole borers and their fungi represent an especially high risk to our forests because they can be transported in both living and dead wood. So not only massive U.S. imports of live plants but also the global movement of goods enclosed in solid wood packaging offer ready pathways for them to arrive and spread here. Neither pathway is regulated effectively enough to prevent either pest imports or interstate spread.

Invasive ambrosia beetles in California and Hawai’i

The invasive ambrosia beetles introduced to California are in the genus Euwallacea. This genus has undergone several taxonomic revisions. Now, the Euwallacea are divided into four species (Stouthammer 2017), of which three are in the U.S.:

Euwallacea fornicatus s.s. – common name polyphagous shot hole borer; first came to attention in southern California in 2012; formerly known as E. whitfordiodendrus.
E. perbrevis – common name tea shot hole borer; formerly known as E. fornicatus s.l.
E. kuroshio – unchanged nomenclature since detected in California in 2013;
E. fornicatior — apparently has not invaded outside of its native range in Asia.

Those now in the U.S. have been introduced to naïve habitats here and elsewhere, often with dire consequences. E. perbrevis, and possibly other species in the complex, are established on the Hawaiian islands.

For an extensive discussion of their introduction history go here

The Fungi: U.S. and Worldwide

Several fungal associates are vectored by the polyphagous shot hole borer (PSHB) and Kuroshio shot hole borer (KSHB). The most important are Fusarium euwallacea and Fusarium kuroshium, respectively. These fungi were only described after they appeared in California in the 2010s. They cause Fusarium dieback disease.

Because the two beetle species are difficult to distinguish and the associated diseases cause very similar impacts, Californians studying them and educating stakeholders now speak of the two beetle-fungus complexes as one unit, “invasive shot hole borers”.

Both PSHB and KSHB have numerous genetic strains, or haplotypes. For PSHB, the greatest haplotype diversity is in Asia – Thailand, Vietnam and China. Remember that these same regions are also a center of diversity for the huge genus Phytophthora, blog a genus widely recognized as containing many plant pathogens. https://www.dontmovefirewood.org/pest_pathogen/sudden-oak-death-syndrome-html/ One of the PSHB haplotypes, H33, has invaded many more regions than the others, including Israel, California, and South Africa. It has also been detected in several tropical plant greenhouses in Europe (where it has been eradicated). H33apparently is native to Vietnam – near Hanoi and Ho Chi Minh City – the country’s major ports (Rugman-Jones et al 2020 and pers. comm.). Does this haplotype’s spread to three continents reflect circumstances, such as the proximity of its native range to major ports and a “bridgehead effect” from its multiple introductions (the insects can be introduced to new regions on shipments from invaded regions established earlier)? Or does it point to an unknown genetic superiority (Bierman et al. 2022). This issue seems worth exploring.

I have blogged about the rising volume of imports from Vietnam, including to ports on the Gulf Coast –a region that has climatic similarities to Vietnam and known host species, so it seems quite vulnerable to invasion by either PSHB or KSHB.

A second species in the genus, KSHB, was detected in southern California in 2012; it has now spread to Mexico. So far, only one haplotype of this species has been detected in North America; this haplotype is widespread in Taiwan.

Finally, E. perbrevis (formerly known as E. fornicatus s.l.) has been detected in Florida, Hawai`i (island of Maui), and West Australia (to which it is probably native). This species has also been detected in nurseries in the Netherlands, where authorities report that it has been eradicated (Rugman-Jones et al. 2020).

Akacia koa – native tree in Hawai“i attacked by Euwallaceae; photo by David Eckhoff, via Flickr

Some species or haplotypes have been detected in only one introduced location: E. fornicatus H35 and E. kuroshio (H20) in California; H38 in South Africa; H43 on Oahu and the Big Island of Hawai`i; and an unnamed haplotype in West Australia (Rugman-Jones et al. 2020).

This is a brief guide to worldwide invasions by one or more Euwallacea-fungus complexes (Rugman-Jones et al. 2020):

Southern California — two haplotypes of E. fornicatus s.s. (H33 & H35) and E. kuroshio (one haplotype).
Hawai`i – a unique haplotype of E. fornicatus s.s. (H43) on Oahu, the Big Island, and possibly other islands; E. perbrevis on Maui and possibly other islands.
Israel — E. fornicatus s.s. haplotype H33 only.
South Africa — E. fornicatus s.s. haplotype H33 and a unique haplotype (H38).
Western Australia — a unique haplotype of E. fornicatus s.s. and E. perbrevis (which is probably native in northern Queensland).
Greenhouses in Europe – both E. fornicatus s.s. (haplotype not specified) and – in the Netherlands — E. perbrevis; both reported eradicated.

When a location has been invaded by two or more species or haplotypes, this is probably an indication of separate introductions. Multiple introductions thus are suspected in California (Stouthamer et al. 2017; Bierman et al. 2022); South Africa (Bierman et al. 2022); and Hawai`i (Bierman et al. 2022).

As is true of other pathogens, e.g., Phytophthoras, there appears to have been a spurt of introductions in recent decades, to, e.g., California, South Africa, and the second species in Hawai`i. Bierman et al 2022 note the constantly growing number of locations with introductions.

*Indigofera jucuna* – reproductive host of PSHB in South Africa; photo by Giardano de Barcelona

Impact and Spread

As is common in the case of forest pests, especially pathogens, detection occurred only years after the initial introduction. In South Africa this delay was five years – from 2012 to 2017 or 2018. In California, identification of the species as PSHB in 2012 was nine years after the organism was first detected in the state (2003).

Over the decade since 2012, PHSB, KSHB, and the pathogens they transmit have spread through large portions of southern California. KSHB has spread through “jumps” to distant locations in Orange, Los Angeles, and as far as Santa Barbara and Ventura counties. There have also been detections in even more distant San Luis Obispo and Santa Clara. These latter apparently have not become established.

A likely explanation for this pattern is the movement of firewood. (Rugman-Jones et al 2020 and pers. comm.) See the map here The two beetles and the plant pathogens they carry are expected to spread throughout much of California wherever their many host plants occur.

On Hawai`i, PSHB is attacking several endemic species including one of the largest forest trees, Acacia koa, as well as Pipturus albidus and Planchonella sandwicensis. Numerous non-native species growing on the Islandsare also attacked, including crops (Macadamia and Mangifera) and invasive species

In South Africa, PSHB has spread faster and farther. It has been present since at least 2012 (Stouthamer et al. 2017), although it was not identified until 2018. In about a decade it has spread to every province except Limpopo – PSHB’s largest geographical outbreak of this beetle [Bierman et al. 2022]

Hosts and Areas at Greatest Risk

Hundreds of plant species in at least 33 plant families support successful reproduction of both beetle and fungus. These include many species widespread in southern California, other parts of the U.S., and South Africa. Some California ecosystems are at particular risk because they are dominated by susceptible tree or shrub species. These vulnerable ecosystems are mixed evergreen forests, oak woodlands, foothill woodlands, and riparian habitats. In San Diego County alone, more than 58,000 acres of riparian woodlands are at risk (California Forest Pest Council).

Experience with the Kuroshio shot hole borer (KSHB) in the Tijuana River valley along the California-Mexico border demonstrates the importance of ecological factors in determining disease outcomes. Following introduction, the KSHB killed a high proportion of the willows near the main river channel. However, beginning in 2016, these trees have regrown to almost pre-infestation sizes. Lead researcher John Boland is not certain why these new, fast-growing trees have not been attacked by the KSHB which remains in the area. See links to the Boland studies below.

riparian forest in Tijuana River Valley after recovery from KSHB attack; photo by John Bolton

Urban forests are at particular risk. For example, in South Africa, conservative estimates were that 25% of urban trees would be lost (Bierman et al. 2022). In California, a model developed by Shannon Lynch found the cities at greatest jeopardy are San Diego, Los Angeles, the San Francisco Bay area, and Sacramento. In other areas in the state that lack data on city tree composition, Lynch applied climate models; this approach extended the list of threatened areas to the eastern half of southern California and other parts of the Central Valley. (Lynch presentation to ISHB webinar April 2022; 2^nd day.) In my view, this model should also be applied to cities in Arizona and Nevada with similar climates.

Management

Symptoms of PSHB attack and fungus infection differ among tree species. For illustrations of the symptoms on various species, visit here.

Most important, prevent the beetles’ spread through movement of dead or cut wood, e.g., green waste, firewood, and even large wood chips or mulch. Websites provide information on managing these sources.

Where the beetles have already established, California scientists recommend focusing management on heavily infested “amplifier trees”. On these trees, dead limbs should be pruned; dying trees and those with beetles infesting the main trunk should be removed. The wood must be disposed of properly.

Sources

Bierman, A., F. Roets, J.S. Terblanche. 2022. Population structure of the invasive ambrosia beetle, Euwallacea fornicatus, indicates multiple introductions into South Africa. Biol Invasions (2022) 24:2301–2312 https://doi.org/10.1007/s10530-022-02801-x

Boland, J.M. — all of Boland’s reports and articles on the KSHB are available at: The Ecology and Management of the Kuroshio Shot Hole Borer in the Tijuana River Valley — Tijuana Estuary : TRNERR]

California Forest Pest Council. 2015. 2015 California Forest Pest Conditions. http://bofdata.fire.ca.gov/hot_topics_resources/2015_california_forest_pest_conditions_report.pdf

Eskalen, A., Stouthamer, R., Lynch, S. C., Twizeyimana, M., Gonzalez, A., and Thibault, T. 2013. Host range of Fusarium dieback and its ambrosia beetle (Coleoptera: Scolytinae) vector in southern California. Plant Dis. 97:938-951.

Stouthamer, R., P. Rugman-Jones, P.Q. Thu, et al. 2017. Tracing the origin of a cryptic invader: phylogeography of the Euwallacea fornicatus (Coleoptera: Curculionidae: Scolytinae) species complex. Agric For Entomol 19:366-375. https://doi.org/10.1111/afe.12215

recordings of April 2022 webinar posted at https://youtu.be/RyqJYyLkshk day 1; and https://youtu.be/kWmtcbjTczw day 2

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

www.fadingforests.org

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.

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 50^th 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

STATE	Member, House Committee	Member, Senate Committee	Key members * committee leadership # forestry subcommittee leadership @ cosponsor of H.R. 1389
Alabama	Barry Moore
Arizona	Tom O’Halleran
Arkansas	Rick Crawford	John Boozman*
California	Jim Costa Salud Carbajal Ro Khanna Lou Correa Josh Harder Jimmie Panetta Doug LaMalfa
Colorado		Michael Bennet #
Connecticut	Jahana Hayes
Florida	Al Lawson Kat Cammack
Georgia	David Scott * Sanford Bishop Austin Scott Rick Allen	Raphael Warnock Tommy Tuberville
Illinois	Bobby Rush Cheri Bustos Rodney Davis Mary Miller	Richard Durbin	Note that the report was led by scientists at the Morton Arboretum – in Illinois!
Indiana	Jim Baird	Mike Braun
Iowa	Cindy Axne Randy Feenstra	Joni Ernst Charles Grassley
Kansas	Sharice Davids Tracey Mann	Roger Marshall#
Kentucky		Mitch McConnell
Maine	Chellie Pingree @
Massachusetts	Jim McGovern
Michigan		Debbie Stabenow *
Minnesota	Angie Craig Michelle Fischbach	Amy Klobuchar Tina Smith
Mississippi	Trent Kelly	Cindy Hyde-Smith
Missouri	Vicky Hartzler
Nebraska	Don Bacon	Deb Fischer
New Hampshire	Ann McLane Kuster @
New Jersey		Cory Booker
New Mexico		Ben Ray Lujan
New York	Sean Patrick Maloney Chris Jacobs	Kristen Gillibrand
North Carolina	Alma Adams David Rouzer
North Dakota		John Hoeven
Ohio	Shontel Brown Marcy Kaptur Troy Balderson	Sherrod Brown
Pennsylvania	Glenn Thompson
South Dakota	Dusty Johnson	John Thune
Tennessee	Scott DesJarlais
Texas	Michael Cloud Mayra Flores
Vermont		Patrick Leahy
Virginia	Abigail Spanberger #
Washington	Kim 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

www.fadingforests.org

Posted by Faith Campbell

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

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.

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

www.fadingforests.org

Hemlock biocontrol – need summer parasitoids

healthy hemlocks in Cook Forest, Pennsylvania; photo by F.T. Campbell

I blogged recently about North Carolina’s multi-pronged hemlock conservation program. As noted there, scientists are putting considerable hope in biological control as the most promising strategy to protect eastern (Tsuga canadensis) and Carolina hemlocks (T. caroliniana) from the hemlock woolly adelgid (HWA; Adelges tsugae). For a more detailed discussion of the adelgid’s life cycle, go here.

A new study by Crandall, Lombardo and Elkinton (full citation at end of blog) cheers us by supporting the probable efficacy of this approach – as long as a complete suite of biocontrol agents is deployed. The study points to the need to introduce additional biocontrol agents, specifically those that feed in the summer.

The study analyzed the relative importance of two different mechanisms to protect plants from herbaceous insects: do some hemlock species have an enhanced ability to fend off the adelgid (bottom-up protection); or do predators apply sufficient pressure (top-down protection) to reduce adelgid populations to levels that the tree can withstand? The study simultaneously analyzed

(1) the relative importance of summer-active and winter-active native predators;

(2) whether HWA colonization and abundances differed on western and eastern hemlock species;

(3) the relative importance of top-down and bottom-up forces on HWA feeding on western and eastern hemlocks in the adelgid’s native range;

4) tested whether the adelgid is ubiquitous at low densities across the Pacific Northwest (PNW) and compared HWA abundance in PNW to invaded range in New England.

The study was carried out in Washington State, where both western hemlock (Tsuga heterophylla) and HWA are native. They were able to compare adelgid impacts on eastern hemlock because the tree is planted in parks and gardens in the PNW.

Eastern hemlock infested by HWA; USDAFS via Bugwood

In an earlier study, (Crandall et al. 2020) found that L. nigrinus was not able to reduce HWA densities in the east. Laricobius spp have their greatest impact on HWA by larval feeding on the progrediens eggs produced by the sistens. However, 90% of hatching progrediens die naturally because there are a finite number of needles for them to settle on. To have an impact on HWA populations, Laricobius spp would have to prey on more than 90% of progrediens eggs. The solution appears to be summer-active predators – e.g., silver flies — which feed on the progrediens eggs and the sistens eggs which the progrediens generation lays.

western hemlock in British Columbia; photo by F.T. Campbell

KEY FINDINGS

Western hemlock is a native host of the adelgid. Crandall, Lombardo, and Elkinton found no evidence that western hemlock’s structure, chemistry, or other attributes help it fend off adelgid attack. The proportion of branches colonized by HWA was significantly higher on western than on eastern hemlock. Indeed, HWA populations were able to reach levels similar to those in eastern North America and were able to persist on western hemlock for multiple generations. Thus there is no evidence for bottom-up control of HWA on western hemlock.

HWA survival was significantly lower on branches of western hemlock when predators were allowed access. Crandall assumes that the smaller, non-significant, decrease in HWA densities on eastern hemlocks in the Pacific Northwest is also attributable to predation, although the data are too few to support a definitive conclusion. These predators included a species that has been released as a biocontrol agent in the east, Laricobius nigrinus. More important, apparently, was the presence of summer-active predators, including Leucotaraxis spp. and generalists. These summer-active predators are active from the progrediens nymph stage in April through the aestivating sistens nymph stage until about October. Laricobius nigrinus doesn’t become active until September. These results support the hypothesis that predator-caused mortality is responsible for suppressing HWA during rare and localized outbreaks on western hemlock in the PNW. In the east there are no native natural enemies that attack HWA – which is introduced to the region.

Effective control of HWA on the eastern naïve hosts will require establishment of a suite of predators which – together — attack the adelgid during both summer and winter.While several possible biocontrol agents have been introduced in the region, and at least some – e.g., Laricobius nigrinus – have established self-sustaining populations, are spreading, and have high predation rates, they have had very limited success in reducing HWA populations. Crandall, Lombardo and Elkinton say these data support the recent decision by the USDA Forest Service to augment the HWA biocontrol effort by introducing two species of silver flies, Leucotaraxis argenticollis and Le. piniperda, that feed on both the sistens and progrediens generations in PNW.

Tree-adelgid interactions are probably significantly affected by the lineage of both – whether the tree species has co-evolved with the specific lineage of the adelgid with which it is interacting. Crandall, Lombardo and Elkinton think evaluation of any Tsuga species’ resistance to HWA or any potential biocontrol agent needs to be studied in relation to the appropriate lineage of the adelgid.

When they compared HWA abundance (in 2021) on hemlock forests in western Washington with HWA abundance at introduced HWA range in New England, Crandall, Lombardo and Elkinton found that HWA abundance was higher in New England. They note that these comparisons are between two different linages of HWA – the lineage native to PNW and the introduced Japanese lineage in the East.

The authors note that HWA densities in the PNW are higher at the urban site (Seattle) than rural sites. Perhaps the reason is lower densities of HWA predators in non-forest settings because some, e.g., La. nigrinus, require a duff layer for pupation. Duff layers are rarely permitted to accumulate in urban areas. The authors call for studies to assess the relative abundance and identify factors affecting the abundance of HWA predators in rural and urban settings.

SOURCES

Crandall R.S., Jubb C.S., Mayfield A.E., Thompson B., McAvoy T.J., Salom S.M. and J.S. Elkinton. 2020. Rebound of Adelges tsugae spring generation following predation on overwintering generation ovisacs by the introduced predator Laricobius nigrinus in the eastern United States. Biological Control 145, 104-264. https://doi.org/10.1016/j.biocontrol.2020.104264

Crandall, R.S., J.A. Lombardo, and J.S. Elkinton. 2022. Top-down regulation of hemlock woolly adelgid (Adelges tsugae) in its native range in the Pacific Northwest of North America. Oecologia 199, 599-609. https://doi.org/10.1007/s00442-022-05214-8

Posted by Faith Campbell

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)

PROGRAM	FY22 FUNDING	FY23 ADMIN REQ	HOUSE $	SENATE COMM RECOMM	CISP ASK
Border inspections (AQI appropriated)	33.849	36.725		36.650	X
Pest Detection	28.218	29.137	29.825	29.075	30
Methods Development	21.217	21.854	31.807	23.557	23
Specialty Crops	209.533	219.533	219.698	222.072	219
Tree & Wood pests	61.217	62.854	62.562	62.719	70
Subtotal, Plant health	379.144	385.560		397.603	X
Emerg. Prepare & Response	42.021	44.242		44.317	X

Specific programs mentioned:

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
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:

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.
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):

PROGRAM	FY22 FUNDING	FY ADMIN REQUEST	HOUSE $	S COMM RECOMM	CISP ASK
Research	296.616	317.733	$360.4	$302.773	317.733
State & Private Forest Health Protection TOTAL	48	59.232	$52.232	50	83
S&P FHP Federal lands	16,000	22,485	?	17,000	51
S&P FHP non-federal lands	32,000	36,747	?	33,000	32

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

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;

(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

realize the problem (threat to a tree species’ role in the environment);
acknowledge that resistance breeding offers the best avenue for maintaining the species of concern; and
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; 1^st Edition. Elsevier

Posted by Faith Campbell

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

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!

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

www.fadingforests.org

Funding APHIS & USFS – speak up!

To forest pest mavens:

The House Appropriations Committee has acted on funding for APHIS & USFS in Fiscal Year (FY) 23 – which begins on October 1. While several programs have been funded at an adequate level, funding for others – e.g., APHIS’ “Tree & Wood Pests) still falls short. Please contact your senators and ask them to urge members of the Senate Appropriations Committee to increase funding for this program. Members of the Senate Agriculture and Interior Appropriations subcommittees (those with jurisdiction) are listed at the end of this blog. My rationale for the “asks” are in my earlier blog.

APHIS funding in $ millions

Program	FY 2021 (millions)	FY 2022 enacted	FY 2023 Pres’ request	Our ask	House bill
Tree & Wood Pests	$60.456	$61.217	$62.854	$70	$62.562
Specialty Crops	$196.553	$209.553	$219.533	$219	$219.698
Pest Detection	$27.733	$28.218	$29.854	$30	$29.825
Methods Development	$20.844	$21.217	$21.854	$23	$31.807

The House bill provides significant funding for many traditional agricultural concerns – livestock health, cotton pests, citrus diseases and pests. Programs we lobbied for received less than the Administration requested with the exceptions of Methods Development and Specialty Crops. I found no explanation for the $10 million increase for methods development.

The Committee Report specifies increases for several pests under Specialty Crops, e.g., citrus and grapes. The report also specifies that $18.3 million should be spent to control spotted lanternfly, which is a pest of both agriculture (especially grapes) and forests. The Committee asks APHIS to keep it informed about progress tackling this pest. (Rep. Andy Harris, ranking Republican on the Agriculture Appropriations subcommittee, has an active SLF infestation in his district.)

The report also instructs APHIS to maintain funding for Asian longhorned beetle at previous levels – within the Tree & Wood Pest account. This means that any savings arising from APHIS’ declaration that parts of the Ohio infestation have eradicated must still be spent on this pest. There are several outbreaks where such funds might be spent, including in New York, Massachusetts, remaining areas in Ohio, and South Carolina.

As in past years, the House Report reiterates members’ expectation that the USDA Secretary will use the authority provided in this bill to transfer funds from the USDA Commodity Credit Corporation to obtain funds to address animal and plant pest emergencies that threaten American agriculture. The Committee has appropriated additional money which is intended to enhance, not replace, use of CCC funds. [The Office of Management and Budget has severely curtailed APHIS access to emergency funds.]

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The House Committee has asked that USFS develop a research program that reflects priorities on, inter alia, invasive species. This falls short of my request for earmarking a specific (small) percentage of research funding for invasive species, but it does show Congressional interest in this problem.

one of the diseases needing USFS research: beech leaf disease (photo by Dr. Chagas de Freitas)

In the part of the budget that funds actual management work, Forest Health Management, apparently the $52 million appropriation reflects only a modest increase of funding for managing invasive species everywhere – on federal lands, i.e. National forests and non-federal lands, i.e., “coop” lands. I appreciate the attention to invasive species, especially emerald ash borer; but worry about allocating most funding to managing the impacts rather than pro-actively addressing introduction and spread to new areas.

USFS funding in $ millions

Program	FY 2021	FY 2022 enacted	FY 2023 Pres’ request	My ask	House bill
R&D		$296.6	$317.8	$317.8	$360.4
[FIA]					$37.7 ($15 M increase)
S&P FHM	$46,232	same?	$59.232	$82	$52.232

Research & Development – The Committee Report noted members’ interest in funding specific laboratories, programs, & projects, including several listed areas. The Committee expects USFS to develop a research program that reflects members’ priorities & other priorities critical to forest health, particularly with respect to climate change adaptation, preventing spread of insects and diseases, and watershed improvement

The report states several times that the USFS should assist in control of the emerald ash borer and other invasive pests, especially in areas where ash tree mortality has been high. Such statements are under State and Private Forestry, under both the Forest Health Management and Urban and Community Forests programs. The Committee earmarks $4 million under UCF for management & reforestation – including tree planting & removals — in communities most severely impacted by EAB and other pests. The efforts should prioritize regional, multi-organization collaborations in urban communities most severely impacted by invasive pests like EAB. The committee asks for a report from USFS on major invasive species and progress of remediation and replanting programs.

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Key Members of the Senate Appropriations Committee

STATE	MEMBER	APHIS APPROP	USFS APPROP
AK	Lisa Murkowski		X
Calif	Diane Feinstein	X	X
FL	Marco Rubio		X
HI	Brian Schatz	X
IN	Mike Braun	X
KS	Jerry Moran	X
KY	Mitch McConnell	X	X
MD	Chris Van Hollen		X
ME	Susan Collins	X
MS	Cindy Hyde-Smith	X	X
MO	Roy Blunt	X	X
MT	Jon Tester	X	X
ND	John Hoeven	X
NM	Martin Heinrich	X	X
OR	Jeff Merkley	X	X
RI	Jack Reed		X
TN	Bill Hagerty		X
VT	Patrick Leahy	X	X
WV	Shelly Moore Capito		X
WI	Tammy Baldwin	X

Posted by Faith Campbell