forest pest insects – Page 8 – Center for Invasive Species Prevention

Help Ensure Best Pest-Countering Programs Possible!

This blog asks YOU!!! to support funding for key USDA programs. Each is essential for protecting the resilience of the Nation’s forests in the face of invasive pests. Please help by contacting your members of the House and Senate Appropriations Committees. I provide a list of members – by state – at the end of this blog.

While the two key federal programs overlap, they are separately managed: USDA’s Animal and Plant Health Inspection Service (APHIS) and USDA’s Forest Service (USFS). These two agencies are funded by different subcommittees of the House and Senate’s Appropriations committees. APHIS is funded by the Subcommittees on Agriculture and Related Agencies. USFS is funded by the Subcommittees on Interior.

Your letter or email need be no more than a couple paragraphs. To make the case for greater funding, feel free to pick-and-choose from the information that follows. Your greatest impact comes from speaking specifically about what you know and where you live.

These are the specific dollar things we’d like you to ask for. The rationale for each is below.

Appropriations for APHIS programs (in $millions)

Program	FY 2021	FY 2022 CR	FY 2023 Pres’ request	Please ask
Tree & Wood Pest	$60.456	$61.217	$63	$70
Specialty Crops	$196.553	$209.553	$219	$219
Pest Detection	$27.733	$28.218	$29	$30
Methods Development	$20.844	$21.217	$22	$23

Appropriations for USFS programs (in $millions)

Program	FY 2021	FY 2022 CR	FY 2023 Pres’ request	Please ask
Forest Health Protection Coop Lands	$30.747	$30.747	$36,747	$51
FHP Federal Lands	$15.485	$15.485	$22.485	$32
Research & Development	$258.760	$258.760	$317.773	$317.733
% for forest invaders	~1%?	?	0	$16 M

Background on the Threat

I’m sure you are familiar with the many ecosystem services provided by America’s forests and woodlands – wildland, rural, and urban. (Besides – maybe you just love trees!) I assume you also know that these forests are under threat from a growing number of non-native insects and pathogens.

For a quick review, see earlier blogs re: 1) an estimate that 41% of forest biomass in the “lower 48” states is at risk to mortality caused by the most damaging 15 species; black ash swamps of the upper Midwest; unique forest ecosystems of Hawai`i; riparian forests in the far West; stream canyons of the Appalachian range and; high-elevation forests of the West; and unique forests of Southwest Oregon. Also, see the thorough discussion of these pests’ impacts in Invasive Species in Forests and Grasslands of the United States: A Comprehensive Science Synthesis for the United States Forest Sector – blog; link available here]

Meanwhile, newly-discovered pests continue to appear and require research and management. The most troubling current example is beech leaf disease. It’s killing beech trees from Ohio to Maine and south to Virginia.

These introduced pests usually first appear in cities or suburbs because they arrive on imported goods shipped to population centers. The immediate result is enormous damage to urban forests. A recently published article (“Hotspots of pest-induced US urban tree death, 2020–2050”), projects that, by 2050, 1.4 million street trees in urban areas and communities will be killed by introduced insect pests. Removing and replacing these trees is projected to cost cities $30 million per year. Additional urban trees – in parks, other plantings, on homeowners’ properties, and in urban woodlands – are also expected to die.

As we know, newly-arrived pests don’t stay in those cities. Some spread on their own. Others are carried far and wide on firewood, plants, patio furniture, even storage pods. And so they proliferate in rural and wildland forests, including US National Forests.

As we know too well, many pests—especially the highly damaging wood-borers—arrive in inadequately treated crates, pallets, and other forms of packaging made of wood. Other pests—e.g., spotted lanternfly —take shelter, or lay their eggs, in or on virtually any exposed hard surface, such as steel or decorative stone.

Imports from Asia have historically transported the most damaging pests. Unfortunately, imports from Asia have reached unprecedented volume – currently they’re running at a rate of 20 million shipping containers per year. Research findings lead to an estimate that at least 7,500 of these containers are carrying a tree-killing pest. The “Hotspots” authors found that if a new woodborer that attacks maples or oaks is introduced, it could kill 6.1 million trees and cost American cities $4.9 billion over 30 years. The risk would be highest if this pest were introduced to the South – and southern ports are receiving more direct shipments from Asia!

Some types of pests—especially plant diseases and sap sucking insects —come on imported plants. A principle example is sudden oak death (SOD; and which attacks more than 100 species of trees and shrubs). Other examples are the rapid ʻōhiʻa death pathogen that threatens Hawai`i’s most widespread tree, ʻōhiʻa lehua; and beech leaf disease, a newly discovered threat that is killing beech trees in a band stretching from Ohio to Maine.

Background on Specific USDA Funding Requests

APHIS

To reduce the risk of new pest introductions and strengthen response to many important pests, please ask your member of Congress and Senators to support appropriations that support key APHIS programs in the table above. (I assume you know that APHIS is responsible for preventing introduction and spread of invasive pests. While most port inspections are carried out by the Department of Homeland Security’s Bureau of Customs and Border Protection, APHIS sets the policy guidance. APHIS also inspects imports of living plants.)

Thank your member for the incremental increases in funding for these programs in FY22 but suggest that a more substantial investment is warranted.

The Tree and Wood Pests account supports eradication and control efforts targeting principally the Asian longhorned beetle (ALB) and spongy (formerly gypsy) moth. Eradicating the ALB normally receives about two-thirds of the funds. The programs in Massachusetts, New York, Ohio, and South Carolina must continue until eradication succeeds.

The Tree and Wood Pests account formerly also funded APHIS’ emerald ash borer (EAB) regulatory program. APHIS terminated this program in January 2021. The probable result is that EAB will spread more rapidly to the mountain and Pacific Coast states. Indeed, the “Hotspots” article identified Seattle and Takoma as likely to lose thousands of ash trees in coming decades. This result shows what happens when APHIS programs are inadequately funded.

Re: the plant diseases and sap sucking insects that enter the country on imported plants, APHIS’ management is through its Specialty Crops program. Repeatedly, SOD-infected plants and have been shipped from nurseries in the Pacific Coast states to vulnerable states across the East and South. Clearly this program needs re-assessment and – perhaps – additional funding.

The Specialty Crops program also is home to APHIS’ efforts to counter the spotted lanternfly, which has spread from Pennsylvania to Maryland, Delaware, New Jersey, Virginia, West Virginia, Ohio, even Indiana. This pest threatens both native trees and agricultural crops – including hops, grapes, apples, and more. California has adopted a state quarantine in hopes of preventing its introduction to that state. Still, APHIS has not established a quarantine.

Please ask the Congress to support the Administration’s request for $219 million for the Specialty Crops program. However, urge them to adopt report language to ensure that APHIS allots adequate funding under this budget line to management of both sudden oak death and spotted lanternfly.

Two additional APHIS programs are the foundation for effective pest prevention. First, the Pest Detection program is key to the prompt detection of newly introduced pests that is critical to successful pest eradication or containment. Please ask the Congress to fund Pest Detection at $30 million. Second, the “Methods Development” program enables APHIS to improve development of essential detection and eradication tools. Please ask the Congress to fund Methods Development at $23 million.

Please ask your member of Congress to support the Administration’s request for a $50.794 million fund for management of emergencies threatening America’s agricultural and natural resources. This program includes a $6 million increase for work with the Climate Conservation Corps specifically targetting invasive species. Although the details are not yet clear, the program’s focus will be to improve surveillance and mitigation methods.

US Forest Service

The USFS has two programs critical to managing non-native tree-killing pests – Forest Health Management (or Protection; FHP) and Research and Development (R&D). FHP provides technical and financial assistance to USFS units (e.g., National forests and regions), other federal agencies, states, municipalities, and other partners to detect and manage introduced pests – including several that APHIS regulates and dozens that it does not. R&D funds efforts to understand non-native insects, diseases, and plants – which are usually scientific mysteries when they first are detected. Of course, this knowledge is crucial to effective programs to prevent, suppress, and eradicate the bioinvader. See the table at the beginning of the blog for specific funding requests for each program.

The Forest Health Management Program (FHP) has two funding streams: Federal Lands and Cooperative Lands (all forests under non-federal management, e.g., state and private forests, urban forests). Both subprograms must be funded in order to ensure continuity of protection efforts – which is the only way they can be effective. Some members of Congress prefer to focus federal funding on National forests. However, allowing pests to proliferate until they reach a federal forest border will only expose those forests to exacerbated threats. Examples of tree-killing pests that have spread from urban areas to National forests include the hemlock woolly adelgid, emerald ash borer, polyphagous and Kuroshio shot hole borers, sudden oak death, and laurel wilt disease. [All profiled here]

Adequate funding for FHP is vital to realizing the Administration’s goals of ensuring healthy forests and functional landscapes; supporting rural economies and underserved communities; enhancing climate change adaptation and resilience; and protecting biological diversity.

Please ask your Member of Congress and Senators to provide $51 million for work on non-federal cooperative lands. This level would partially restore capacity lost over the last decade. Since Fiscal Year (FY) 2010, spending to combat 11 specified non-native insects and pathogens fell by about 50%. Meanwhile, the pests have spread. Also, please ask your Member and Senators to support a $32 million appropriation for the Federal Lands subprogram for FY23 which is allocated to pests threatening our National forests directly.

A vital component of the FHP program is its leadership on breeding pest-resistant trees to restore forests decimated by pests. FHP’s Dorena Genetic Resource Center, in Oregon, has developed Port-Orford cedar seedlings resistant to the fatal root-rot disease. and blog. These seedlings are now being planted by National forests, the Bureau of Land Management, and others. In addition, pines with some resistance to white pine blister rust are also under development. The Dorena Center offers expert advice to various partners engaged in resistance-breeding for Oregon’s ash trees and two tree species in Hawai`i, koa and ʻōhiʻa. and blog.

The USFS research program is well funded at $317 million. Unfortunately, only a tiny percentage of this research budget has been allocated to improving managers’ understanding of specific invasive species and, more generally, of the factors contributing to bioinvasions. Funding for research conducted by USFS Research stations on ten non-native pests decreased from $10 million in Fiscal Year 2010 to just $2.5 million in Fiscal Year 2020 – less than 1% of the total research budget. This cut of more than 70% has crippled the USFS’ ability to develop effective tools to manage the growing number of pests.

To ensure the future health of America’s forests, please ask your Member of Congress and Senators to request the Subcommittee to include in its report instructions that USFS increase the funding for this vital research area to 5% of the total research budget. The $16 million would fund research necessary to improving managers’ understanding of invasive forest insects’ and pathogens’ invasion pathways and impacts, as well as to developing effective management strategies. Addressing these threats is vital to supporting the Administration’s priorities of increasing adaptation and resilience to climate change and implementing nature-based solutions.

The USFS Research and Development program should expand its contribution to efforts to breed trees resistant to non-native pests; programs deserving additional funding include hemlocks resistant to hemlock woolly adelgid; ashes resistant to emerald ash borer; beech resistant to both beech bark disease and beech leaf disease; link to DMF and elms resistant to Dutch elm disease. The Research program also continues studies to understand the epidemiology of laurel wilt disease, which has spread to sassafras trees in Kentucky and Virginia.

Members of House Appropriations Committee

STATE	MEMBER	APHIS APPROP	USFS APPROP
AL	Robert Aderholt	X
Calif	Barbara Lee David Valadao Josh Harder	X X	X
FL	Debbie Wasserman Scultz	X
GA	Sanford Bishop	X
ID	Mike Simpson		X
IL	Lauren Underwood	X
MD	Andy Harris	X
ME	Chellie Pingree	X	X
MI	John Moolenaar	X
MN	Betty McCollum	X	X
NV	Susie Lee Mark Amodei		X X
NY	Grace Meng	X
OH	Marcy Kaptur David Joyce		X X
PA	Matt Cartwright		X
TX	Henry Cuellar	X
UT	Chris Stewart		X
WA	Dan Newhouse Derek Kilmer	X	X
WI	Mark Pocan	X

Members of 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

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

Harvest + Tree-Killing Pests = Threat to Forest Composion

EAB-killed ash in Ontario; photo by Michael Hunger

Lately I have become aware of articles discussing how silviculturists and timber managers in the East are responding to the threat from introduced pests.

As Holt et al. (2022; full citation at end of blog) point out, private landowners control 56% of U.S. forestland – and 80% in the East. Their collective decisions about managing those forests are one of two factors that largely determine the composition and structure of the forested landscape and the ecosystem services those woodlands provide. The second determining factor is invasive pests. If an invasive pest prompts many landowners across the East to harvest their timber, the collective impact will be enormous. In this way, invasive species carry a double threat: direct mortality of one or more tree species or genera; and stimulation of removal of the host species from the forest by land managers trying to maximize or protect their current and future monetary investment.

Projections suggest that the number of non-native woodborers established in North America will increase three- or four-fold by 2050. If these prove true (see Leung et al. 2016), the impact on eastern North America forests and associated ecosystem services would be profound.

Holt et al. explore how private landowners have responded to an actual invasive species, the emerald ash borer (EAB). They analyze the influence of EAB’s presence on:

(1) annual probability that a landowner would decide to harvest timber on his/her own lands;

(2) intensity of any such harvest (percentage of trees cut); and

(3) diameter of harvested trees.

They examined harvesting of both the host (ash) and non-host species that co-occur.

Using data from U.S. Forest Service permanent inventory plots, they compared harvest levels in counties in which EAB was detected before 2007 to harvest levels in counties that were infected after 2012. To simplify, they omitted counties in which EAB was detected during the period 2007–2012. They excluded plots that did not contain any ash trees; and plots owned by federal or state agencies. They also excluded trees with diameters less than 12.7 cm (5 inches) dbh.

Ash harvests were apparently less widespread than non-ash harvests. Ash trees were harvested on 6% of the USFS Forest Inventory and Analysis (FIA) plots compared to 9% of plots for harvests of non-ash trees. However, a higher proportion of ash basal area was removed in these harvests — 63% of ash basal area versus 32% of non-ash basal area (remember, ash trees were present in all plots).

The presence of EAB resulted in

an increased amount of biomass harvested – by approximately 25% of basal area;
harvests contained greater quantities of ash, relative to non-ash species.
harvested trees in EAB-infested areas had smaller diameters, on average; this was true of both ash and non-ash species.

Two demographic variables were analyzed. Higher median household income resulted in a lower probability of non-ash harvest. Human population density had no significant effect.

Holt et al. say their findings indicate that a wave of ash removals will follow EAB spread with a potential to alter forest development trajectories and change structural legacies, with consequences for ecosystem services and biodiversity. They consider tree species that co-occur with ash, and that are preferred timber species, are the most likely to be removed in excessive numbers as a result of EAB-induced harvest.

Holt et al. note that ash removals were perhaps underestimated by the study because landowners might have cut their ash before EAB actually was detected in their county.

Managing the Northern Forest – Emphasis on reducing the beech component

Meantime, two other groups are suggesting how forest managers should respond to current challenges, including invasive pests. Both suggest steps to reverse – or at least slow – trends under which American beech (Fagus grandifolia) is becoming more dominant. (Given beech’s ecological importance, this stance bothers me! I don’t quarrel that many timber-oriented people don’t want more beech.) Neither of these studies considers the possible impact of beech leaf disease and beech leaf miner. I recently posted a blog link reporting Reed et al.’s (2022) analysis of interactions between BBD and BLD.

Rogers et al. (2022), the first group, note that successful silviculture is the art and science of managing forests intended to achieve human defined goals. Usually this means assuring the “desired” species composition and structure. However, to succeed, silviculture must also consider site conditions, including competing vegetation and changing climates.

They focus on the northern hardwood forest – also called the beech-birch-maple forest. It is broadly defined by the dominance of sugar maple (Acer saccharum), yellow birch (Betula alleghaniensis), and American beech. The northern hardwood forest occupies about 20 M ha across northern United States and southern Canada. From a traditional management perspective, maple and birch are the desired species; American beech is widely considered undesirable.

Unfortunately, from the timber point of view, Rogers et al. expect the abundance of sugar maple and yellow birch to decrease and American beech to increase. Important factors in this trend are soil types; deer numbers and preference for tree species other than beech; and high number of root sprouts stimulated by beech bark disease (BBD). Rogers et al. call for modification of traditional silvicultural approaches in the region. They call specifically for “adaptation planting” (also called “assisted migration”). They note that increased canopy openings – e.g., “irregular shelterwood system” — are important for establishing shade intolerant and mid-tolerant species, among them white ash (Fraxinus americana). They do mention the threat from emerald ash borer.

In an earlier blog I noted that the second group, Clark and D’Amato(2021), called for silvicultural management of New England forests (part of the same northern hardwood forest). Their goal was to maximize carbon sequestration. They advised management to promote retention of eastern white pine (Pinus strobus) and slow takeover by American beech and eastern hemlock (Tsuga canadensis). They say these species will fare poorly in warmer climates. Of course, all these species face non-native pests. See above for beech; hemlock is being decimated by hemlock woolly adelgid. Eastern white pine has apparently survived its own non-native pest, white pine blister rust.

I hope these pest-related hindrances to traditional timber-focused forestry will help convince the U.S. Department of Agriculture and Congressional agriculture and natural resource committees that non-native pests are a significant threat. Clearly past documentation of impacts to biological diversity and native ecosystems have not prompted them to adopt adequate protective measures or to respond effectively to established invaders. See earlier blogs, my recent article, and the Fading Forests reports (link at end of blog) for suggestions on what actions should be taken.

SOURCES

Clark, P.W. and A.W. D’Amato. 2021. Long-term development of transition hardwood and Pinus strobus – Quercus mixedwood forests with implications for future adaptation and mitigation potential. Forest Ecology and Management 501 (2021) 119654

Holt, J.R., J.R. Smetzer, M.E. Borsuk, D. Laflower, D.A. Orwig, J.R. Thompson. 2022. EAB intensifies harvest regimes on private land. Ecological Applications. 2022;32:e2508.

Leung, B., M.R. Springborn, J.A. Turner, E.G. Brockerhoff. 2014. Pathway-level risk analysis: the net present value of an invasive species policy in the US. The Ecological Society of America. Frontiers of Ecology.org

Rogers, N.S., AW. D’Amato, C.C. Kern, S. B`edardd. 2022. Northern hardwood silviculture at a crossroads: Sustaining a valuable resource under future change

Posted by Faith Campbell

APHIS – 50 years + plant pest detection month

beech leaf disease – Not one of the plant pests that APHIS is regulating! Photo by Jennifer Koch, USFS

APHIS has reminded us that 2022 is the agency’s 50th year. In its press release, APHIS claims several accomplishments over this period:

Eradicating plant pests like European grapevine moth and plum pox from the country, while reducing the impact of others plant diseases, including boll weevil and Mediterranean and Mexican fruit flies;
Eradicating serious animal diseases, including highly pathogenic avian influenza, virulent Newcastle disease, and pseudorabies, from the country’s herds and flocks, while reducing the prevalence of other animal diseases like bovine tuberculosis and brucellosis;
Improving care for laboratory animals, exhibited animals and other animals;
Ensuring genetically engineered plants do not pose a risk to plant health, while keeping up with the ever-changing technology in this field;
Reducing the impact of wildlife damage on agriculture and natural resources; and
Ensuring safe trade of agriculture commodities across the globe

APHIS also launched a new page on its website to share a series of visual timelines of its history and important milestones.

APHIS also states that USDA) has declared April 2022 to be Invasive Plant Pest and Disease Awareness Month (IPPDAM). The link Invasive Plant Pest and Disease Awareness Month connects you to APHIS’ webpage. Secretary Vilsack asks people to be alert. He noted particularly the risk that pests will hitch a ride on untreated firewood, outdoor gear and vehicles, and soil, seeds, homegrown produce, and plants.

The notice urges people to:

Familiarize yourself with the invasive pests that are in your area, and their symptoms. [Faith says – also look for pests not “here” yet – early detection!]
Look for signs of new invasive plant pests and diseases and report them to your local Extension office, State department of agriculture or your USDA State Plant Health Director’s office.
When returning from travel overseas, declare all agricultural items to U.S. Customs and Border Protection so they can ensure your items won’t harm U.S. agriculture or the environment.
Don’t move untreated firewood. Buy local or use certified heat-treated firewood, or responsibly gather it on site where permitted.
Source your plants and seeds responsibly. When ordering online, don’t assume items available from foreign retailers are legal to import into the United States. Learn how to safely and legally order plants and seeds online.
Don’t mail homegrown plants, fruits and vegetables. You may live in an area under quarantine for a harmful invasive plant pest. You could inadvertently mail a pest.
When in doubt, contact your local USDA State Plant Health Director’s office to find out what you need to do before buying seeds or plants online from an international vendor or before mailing your homegrown agricultural goods.

West Coast Responding to EAB

nearly pure stand of Oregon ash in Ankeny National Wildlife Refuge, Oregon; photo by Wyatt Williams, Oregon Department of Forestry

While Michiganders document the impacts of the emerald ash borer (EAB) there, conservationists on the West Coast are jump-starting efforts to save their regional species, Oregon ash (Fraxinus latifolia). Earlier field tests in the Midwest showed that EAB will attack Oregon ash (press release) – something West Coast state would like to counter as early and effectively as possible.

Oregon ash is a wide-ranging species, occurring from California to Washington and possibly into British Columbia. The species has not been studied extensively (it is not a timber species!), but it is clearly an imponearlrtant component of riparian forests. In wetter parts of the Willamette Valley, ash is the predominant tree species. See the photo of the riparian forest in the Ankeny National Wildlife Refuge; this forest is nearly 100% Oregon ash (ODA/ODF EAB Response Plan).

As is true in the Midwest, ash provides important food and habitat resources along creeks and rivers where seasonally high water-tables can exclude nearly all other tree species. Standing and fallen dead ash biomass can alter soil chemistry and affect rates of decomposition, nutrient, and water cycling, i.e., nutrient resource availability for the remaining trees. Gaps in tree canopy can increase soil erosion, stormwater runoff and elevated stream temperatures. In dense stands of Oregon ash, understory vegetation is often sparse, consisting primarily of sedges. The authors of the Response Plan anticipate invasion by non-native plants into canopy gaps caused by the loss of ash trees as a result of an EAB invasion. In Michigan, though, it is the sedges that dominate these gaps.

The Oregon Department of Forestry, the state Department of Agriculture, and other entities have actively participated in “don’t move firewood” campaigns for at least a decade. The Departments of Forestry and Agriculture also led a team that prepared the EAB Response Plan in 2018 (full citation at the end of this blog). It lays out in considerable detail the roles of both government agencies and non-governmental stakeholders. Oregon’s quarantine is broad, covering all insects not on an approved list (Williams, pers. comm.)

California has inspected incoming firewood for years. In April 2021 – after APHIS terminated the federal quarantine on EAB — California Department of Food and Agriculture established a state quarantine on the beetle and articles that could transport it into the state. In doing so, CDFA noted that commercially grown olive trees might also be at risk to EAB.

Washington State operates a statewide trapping program for invasive insects. There has also been significant attention to non-native insect threats to urban forests. These have included a study in 2016 led by the Washington Invasive Species Council (WISC). It involved a partnership of WISC with the Washington Department of Natural Resources Urban and Community Forestry Program as well as and statewide stakeholder meetings [Bush, pers. comm.].

Of these various state-wide initiatives, the institutions in Oregon appear to be most pro-active. The Tualatin Soil and Water Conservation District provided $10,000 to fund some of the genetics work and testing for EAB resistance. Other funding came from the USDA Forest Service Forest Health Protection unit of State and Private Forestry (not from USFS’ Research Program). As described by USFS geneticist Richard Sneizko in an article in the publication TreeLine (full citation at end of blog), participants hope to find at least some level of genetic resistance to EAB. Any such resistance might be deployed in several ways: 1) promoting reproduction by resistant trees to enhance their numbers before EAB gets to Oregon; 2) using seeds from resistant trees for restoration of natural areas; or 3) cross-breeding resistant trees to build genetically diverse stocks of resistant trees for future restoration.

Participants think it is vitally important to work from seeds collected over much of the range of Oregon ash – first, to search for probably very rare resistant trees; and second, to preserve the full diversity of the tree species’ genome so that restored ash will be adapted to the wide variety of conditions in which ash grow.

Participants in this effort include the forest genetics/tree improvement community – specifically, the USDA Forest Service Dorena Genetic Resource Center (located in Cottage Grove, Oregon) and Washington State University at Puyallup Research & Extension Center. Also engaged is the public gardens community, specifically the Huntington Botanical Gardens in San Marino, Los Angeles County. The garden is collecting seed of Oregon and other western ashes from California and Washington State.

The first step in assessing resistance is collecting seed from ash trees across the range of Oregon ash. This began in 2019. Carried out by, inter alia, some USFS and Interior’s Bureau of Land Management units, Oregon State University, citizen scientists [Sniezko] and the Oregon Department of Forestry [press release & Sniezko pers. comm.] Also, some seeds were collected in Washington State in 2020. Additional collections in Oregon are scheduled for 2022.

The collected seeds have been evaluated for vitality and stored by the USFS Dorena Center and at the USFS National Seed Lab (Macon, GA).

Oregon ash planting at Dorena; photo by Emily Boes

The USFS Dorena Center and Washington State University have begun germinating and growing some of the seedlings for various tests of possible resistance. There is concern that the 2021 drought might have killed some of the seedlings in Oregon; those in Washington are not affected. The initial seedlings are mostly from Oregon but there is space to add additional families from a wider geographical area. Experimenters plan to collect data annually on bud break, yearly growth, and any diseases or pests that develop on the trees. (Chastagner pers. comm.)

The next step is systematic testing whether some of the ash show genetic resistance to EAB. Richard Sneizko has sent seedlings of 17 ash families to USFS colleague Dr. Jennifer Koch. She operates a breeding facility in northern Ohio where they can be tested for resistance. Testing is expected to begin this year. [Tree Line]

The Dorena Center is also helping a researcher at Penn State University, Dr. Jill Hamilton, to set up a landscape genomics project. She will evaluate the genetic variability in the species by using leaf samples from about 20 trees from many populations across the Oregon ash’s range (California to British Columbia). This potentially includes a collection from the Dorena population of ash in late Spring 2022. [Sniezko]

These various ash plantings can also be “sentinel” plantings to assist in early detection of newly arriving EAB. [Tree Line]

SOURCES

Bush J. Executive Coordinator | Washington Invasive Species Council

ODF and ODA Emerald Ash Borer Readiness and Response Plan. 2018.

Click to access EAB+Plan+2018.pdf

ODF press release Feb 24, 2022

Treeline Newsletter May 13, 2021. Richard Sniezko. Is There a Future for Oregon Ash? Forest Genetics to the Rescue? Genetic & Emerald Ash Borer Resistance Projects https://www.nnrg.org/wp-content/uploads/2022/02/Treeline_newsletter-June-2021.pdf

The newsletter is issued by Bonneville Environmental Foundation for a consortium of conservation agencies

Sniezko pers comm Feb 2022 22-2/24

A video explaining the campaign to save Oregon ash is at https://youtu.be/uZmfLrxEA7g or https://youtu.be/S8y-XK285S8

Posted by Faith Campbell

In Michigan: Devastating News for Black Ash; Merely Bad News for Green Ash

results of EAB infestation; photo by Nate Siegert, USFS

A series of studies by Patrick J. Engelken, M. Eric Benbow, Deborah G. McCullough, Nate Siegert, Randall Kolka, Melissa Youngquist and others examine the status of ash (Fraxinus spp.) in the aftermath of the emerald ash borer (EAB) invasion. Initial studies documented the crash of biomass supporting EAB numbers when the large ash trees died (Siegert, Engelken, McCullough. 2021; full citation at end of blog.) More recent studies have focused on bogs and forests in the riparian areas where ash were especially numerous and arguably ecologically most important. I posted a blog about black ash bogs earlier.

I will focus here on the studies in riparian areas of southern and northwest Michigan. Information about impacts in forests of southern Michigan are from Engelken, Benbow and McCullough (2020); information about impacts in northwest Michigan are from Engelken and McCullough (2020). Full citations for both are at the end of the blog.

All study areas had high ash densities before EAB’s arrival. One study (Engelken and McCullough 2020) found ash densities high in the immediate riparian areas (in one case, a strip reaching 100 meters from the streambank) but scattered in surrounding forests.

In all these study areas, populations of mature (reproductive age) ash crashed within 10-15 years after EAB invasion:

In northeast Michigan, EAB carrying capacity was reduced by 94% – 99%; total ash basal area was reduced by 87 – 97.7% (Siegert, Engelken, McCullough. 2021);
In southern Michigan, more than 85% of the basal area of green (F. pennsylvanica) and black ash (F. nigra) had been killed by 2020. An estimated 96% of the overstory ash phloem area had died, thus radically reducing EAB carrying capacity (Engelken, Benbow and McCullough 2020);
In northwest Michigan, more than 95% of the overstory ash have been killed. (Engelken and McCullough 2020).

The worst impact has been on black ash– which plays such an important ecological role in riparian areas and wetlands and has enormous importance in Native American cultures. In all these study areas, there is no stump sprouting by black ash (Siegert, Engelken, McCullough. 2021; Engelken, Benbow and McCullough 2020; Engelken and McCullough 2020). In three watersheds of northwest Michigan where black ash constituted up to a quarter of the overstory species before the EAB invasion, scientists found no black ash recruits, only eight saplings, and a single seedling.

Green ash (F. pennsylvanica) has survived in much higher numbers – so far. However, this species’ ability to grow into reproductive size is still uncertain. In northwest Michigan, green ash saplings are abundant in canopy gaps created by EAB-caused mortality of mature ash. These saplings had established before the EAB invasion so some call them the “orphaned cohort”. However, there are few seedlings of any woody plant species in these gaps because sedges form such dense mats.

Green ash reproduction faces many challenges before persistence of the species can be considered assured. First, populations of EAB – now reduced by the lack of mature ash to support them – might resurge when young ash grow to larger sizes. It is not yet clear the extent to which introduced biocontrol agents and native predators, e.g., woodpeckers, will protect these trees as they grow to reproductive size. Here, again, green ash has an advantage over black ash. While green ash produce seed at a relatively young age, black ash don’t produce seed until they reach 30–40 years. Even then, they produce seeds only sporadically, with intervals of five or more years.

A second challenge is the lack of seed sources – at least until and unless young trees are able to reach reproductive size.

A third challenge is competition for resources from other plants. The canopy gaps eliminate competition for light for the taller plants, i.e., the existing ash saplings. However, the sapling cohort is not supported by a seedling cohort. There are very few seedlings of all woody plant species (including invasive species!). Seed germination is suppressed by the dense mats of wetland-adapted sedges and possibly the higher water tables (which resulted from reduced evapotranspiration following mortality of the mature trees).

Competition for resources is also a factor in the forests outside the immediate riparian zone. There, ash seedlings sprout, but shade created by lateral ingrowth suppresses their growth. In southern Michigan, Engelken, Benbow and McCullough (2020) note that the forests are apparently transitioning from red oak dominated forests to red maple and black cherry dominated forests. This transition is apparently intensified by forest mesophication resulting from reduced fire frequency, decreasing light availability in forest understories and increasing soil moisture content.

Fourth, while stump sprouting of green ash was noted in southern Michigan, in the northwestern forests all the sprouts died. I have already noted the absence of stump sprouting by black ash at all sites.

Beaver & Green Ash in Northern Virginia

photos of beaver feeding on ash saplings in northern Virginia; photos by F.T. Campbell

In spring 2022 I noticed along one stream in northern Virginia that beavers had cut down green ash saplings; McCullough and Siegert report that this does not appear to be a problem in their study areas.

By December 2022, the beaver-cut trees tried to recover: see the sprouts from a stump [below]. (I think deer or rabbits ate the tips of the sprouts.)

The beavers also continued feeding on the ash — the tree photographed in the spring when it was half-chewed through has now been felled and its branches removed [see below].

Ecosystem Impacts, Especially on Streams

Across much of the upper Midwest, massive ash mortality is causing widespread changes in forest systems.

Riparian forests, i.e., areas adjacent to waterways where periodic inundation occurs, are functionally linked to the aquatic systems. Loss of such a significant proportion of the overstory changes the transfer of energy to adjacent waterways that takes the form of inputs of nutrients from leaf litter and coarse woody debris. Intact forests also stabilize stream banks and maintain channel depth by preventing erosion. Forests moderate temperature of the water. Finally, forests with “coarse woody debris” increase habitat structure. These impacts might be especially important along first order streams, (defined as perennial streams that have no permanently flowing tributaries). These streams are too small to buffer the impacts of major tree loss. The scientists say they are uncertain whether these changes continue to affect larger streams downstream.

Unshaded streams have higher water temperatures that can affect populations of fish, in particular salmonids, by delaying migration, reducing egg viability and increasing egg mortality. Higher temperatures can also alter primary productivity of aquatic algae, potentially increasing eutrophication (Engelken and McCullough 2020).

The scientists expect increasing abundance of coarse woody debris in the forests and streams of northwest Michigan as the 75% of dead ash that are still standing fall. Such debris provides nutrients and habitat for an array of plants and animals, thereby influencing the abundance, activity and species compositions of several ground dwelling insects and seedling establishment. In streams, coarse woody debris provides complex habitat and refuges. It also retains organic matter. Recreationists do find that debris impedes boating.

Loss of ash specifically

As described by Engelken, Benbow and McCullough (2020), and in my earlier blog, ash leaf litter – particularly black ash leaf litter – is highly nutritious. Ash leaf litter has efficient turnover rates and contributes important soil nutrients such as nitrogen, organic carbon and exchangeable cations. Invertebrate communities in headwater streams feed largely on coarse organic material such as leaf litter (Engelken and McCullough 2020). Consequently, loss of the annual influx of ash leaf litter will likely have adverse effects on nutrient availability in riparian forests and adjacent streams.

SOURCES

Engelken, P.J., M.E. Benbow, D.G. McCullough. 2020. Legacy effects of emerald ash borer on riparian forest vegetation and structure. Forest Ecology and Management 457 (2020) 117684

Engelken, P.J. and D.G. McCullough. 2020. Riparian Forest Conditions Along Three Northern Michigan Rivers Following Emerald Ash Borer Invasion. Canadian Journal of Forest Research.

Siegert, N.W., P.J. Engelken, D.G. McCullough. 2021 Changes in demography and carrying capacity of green ash and black ash ten years after emerald ash borer invasion of two ash-dominant forests. Forest Ecology and Management Vol 494, August 2021

Posted by Faith Campbell

What Do Invasive Species Cost?

brown tree snake *Boiga irregularis*; via Wikimedia; one of the species on which the most money is spent on preventive efforts

In recent years a group of scientists have attempted to determine how much invasive species are costing worldwide. See Daigne et al. 2020 here.

Some of these scientists have now gone further in evaluating these data. Cuthbert et al. (2022) [full citation at end of blog] see management of steadily increasing numbers of invasive, alien species as a major societal challenge for the 21st Century. They undertook their study of invasive species-related costs and expenditures because rising numbers and impacts of bioinvasions are placing growing pressure on the management of ecological and economic systems and they expect this burden to continue to rise (citing Seebens et al., 2021; full citation at end of blog).

They relied on a database of economic costs (InvaCost; see “methods” section of Cuthbert et al.) It is the best there is but Cuthbert et al. note several gaps:

Only 83 countries reported management costs; of those, only 24 reported costs specifically associated with pre-invasion (prevention) efforts.
Data comparing regional costs do not incorporate consideration of varying purchasing power of the reporting countries’ currencies.
Data available are patchy so global management costs are probably substantially underestimated. For example, 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.) .

Still, their findings fit widespread expectations.

These data point to a total cost associated with invasive species – including both realized damage and management costs – of about $1.5 trillion since 1960. North America and Oceania spent by far the greatest amount of all global money countering bioinvasions. North America spent 54% of the total expenditure of $95.3 billion; Oceania spent 30%. The remaining regions each spent less than $5 billion.

Cuthbert et al. set out to compare management expenditures to losses/damage; to compare management expenditures pre-invasion (prevention) to post-invasion (control); and to determine potential savings if management had been more timely.

Economic Data Show Global Efforts Could Be – But Aren’t — Cost-Effective

The authors conclude that countries are making insufficient investments in invasive species management — particularly preventive management. This failure is demonstrated by the fact thatreported management expenditures ($95.3 billion) are only 8% of total damage costs from invasions ($1.13 trillion). While both cost or losses and management expenditures have risen over time, even in recent decades, losses were more than ten times larger than reported management expenditures. This discrepancy was true across all regions except the Antarctic-Subantarctic. The discrepancy was especially noteworthy in Asia, where damages were 77-times higher than management expenditures.

Furthermore, only a tiny fraction of overall management spending goes to prevention. Of the $95.3 billion in total spending on management, only $2.8 billion – less than 3% – has been spent on pre-invasion management. Again, this pattern is true for all geographic regions except the Antarctic-Subantarctic. The divergence is greatest in Africa, where post-introduction control is funded at more than 1400 times preventive efforts. It is also significant for Asia and South America.

Even in North America – where preventative actions were most generously funded – post-introduction management is funded at 16 times that of prevention.

Cuthbert et al. worry particularly about the low level of funding for prevention in the Global South. They note that these conservation managers operate under severe budgetary constraints. At least some of the bioinvasion-caused losses suffered by resources under their stewardship could have been avoided if the invaders’ introduction and establishment had been successfully prevented.

While in the body of the article Cuthbert et al. seem uncertain about why funding for preventive actions is so low, in their conclusions they offer a convincing (to me) explanation. They note that people are intrinsically inclined to react when impact becomes apparent. It is therefore difficult to motivate proactive investment when impacts are seemingly absent in the short-term, incurred by other sectors, or in different regions, and when other demands on limited funds may seem more pressing. Plus efficient proactive management will prevent any impact, paradoxically undermining evidence of the value of this action!

*Aedes aegypti* mosquito; one of the species on which the most money is spent for post-introduction control; photo by James Gathany; via Flickr

Delay Costs Money

The reports contained in the InvaCost database indicate that management is delayed an average of 11 years after damage was first been reported. Cuthbert et al. estimate that these delays have caused an additional cost of about $1.2 trillion worldwide. Each $1 of management was estimated to reduce damage by $53.5 in this study. This finding, they argue, supports the value of timely invasive species management.

They point out that the Supplementary Materials contain many examples of bioinvasions that entail large and sustained late-stage expenditures that would have been avoided had management interventions begun earlier.

Although Cuthbert et al. are not as clear as I would wish, they seem to recognize also that stakeholders’ varying perceptions of whether an introduced species is causing a detrimental “impact” might also complicate reporting – not just whether any management action is taken

Cuthbert et al. are encouraged by two recent trends: growing investments in preventative actions and research, and shrinking delays in initiating management. However, these hopeful trends are unequal among the geographic regions.

Which Taxonomic Groups Get the Most Money?

About 42% of management costs ($39.9 billion) were spent on diverse or unspecified taxonomic groups. Of the costs that were taxonomically defined, 58% ($32.1 billion) was spent on invertebrates [see above re: forest pests]; 27% ($14.8 billion) on plants; 12% ($6.7 billion) on vertebrates; and 3% ($1.8 billion) on “other” taxa, i.e. fungi, chromists, and pathogens. For all of these defined taxonomic groups, post-invasion management dominated over pre-invasion management.

When considering the invaded habitats, 69% of overall management spending was on terrestrial species ($66.1 billion); 7% on semi-aquatic species ($6.7 billion); 2% on aquatic species ($2.0 billion); the remainder was “diverse/unspecified”. For pre-invasion management (prevention programs), terrestrial species were still highest ($840.4 million). However, a relatively large share of investments was allocated to aquatic invaders ($624.2 million).

Considering costs attributed to individual species, the top 10 targetted for preventive efforts were four insects, three mammals, two reptiles, and one alga. Top expenditures for post-invasion investments went to eight insects [including Asian longhorned beetle], one mammal, and one bird.

Asian longhorned beetle

Just two of the costliest species were in both categories: insects red imported fire ant(Solenopsis invicta) and Mediterranean fruitfly (Ceratitis capitate). None of the species with the highest pre-invasion investment was among the top 10 costliest invaders in terms of damages. However, note the lack of data on fungi, chromists, and pathogens. (I wrote about this problem in an earlier blog.)

Discussion and Recommendations

Cuthbert et al. conclude that damage costs and post-invasion spending are probably growing substantially faster than pre-invasion investment. Therefore, they call for a stronger commitment to enhancing biosecurity and for more reliance on regional efforts rather than ones by individual countries. Their examples of opportunities come from Europe.

Drawing parallels to climate action, the authors also call for greater emphasis on during decision-making to act collectively and proactively to solve a growing global and inter-generational problem.

Cuthbert et al. focus many of their recommendations on improving reporting. One point I found particularly interesting: given the uneven and rapidly changing nature of invasive species data, they think it likely that future invasions could involve a new suite of geographic origins, pathways or vectors, taxonomic groups, and habitats. These could require different management approaches than those in use today.

As regards data and reporting, Cuthbert et al. recommend:

1) reducing bias in cost data by increasing funding for reporting of underreported taxa and regions;

2) addressing ambiguities in data by adopting a harmonized framework for reporting expenditures. For example, agriculture and public health officials refer to “pest species” without differentiating introduced from native species. (An earlier blog also discussed the challenge arising from these fields’ different purposes and cultures.)

3) urging colleagues to try harder to collect and integrate cost information, especially across sectors;

4) urging countries to report separately costs and expenditures associated with different categories, i.e., prevention separately from post-invasion management; damage separately from management efforts; and.

5) creating a formal repository for information about the efficacy of management expenditures.

While the InvaCost database is incomplete (a result of poor accounting by the countries, not lack of effort by the compilers!), analysis of these data points to some obvious ways to improve global efforts to contain bioinvasion. I hope countries will adjust their efforts based on these findings.

SOURCE

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

Seebens, H. S. Bacher, T.M. Blackburn, C. Capinha, W. Dawson, S. Dullinger, P. Genovesi, P.E. Hulme, M.van Kleunen, I. Kühn, J.M. Jeschke, B. Lenzner, A.M. Liebhold, Z. Pattison, J. Perg, P. Pyšek, M. Winter, F. Essl. 2021. Projecting the continental accumulation of alien species through to 2050. Glob Change Biol. 2021;27:970-982.

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

Urban Forests at Risk: Thousands of Communities, Millions of Trees, & Tens of Millions of Dollars

EAB-killed ash tree lying on highway in Fairfax County, Virginia; photo by F.T. Campbell

A recent study (Hudgins, Koch, Ambrose & Leung 2022; full citation at end of blog) projects that, by 2050, 1.4 million street trees in urban areas and communities will be killed by introduced insect pests. This represents 2.1- 2.5% of all urban street trees. Nearly all of this mortality will occur in a quarter of the 30,000 communities evaluated. Additional urban trees – in parks, other plantings, on homeowners’ properties, and in urban woodlands – are also expected to die.

Loss of these trees will undercut all the ecosystem services provided by urban trees.

The principal cause of mortality will be the emerald ash borer (EAB). Already, an estimated 230,000 ash trees have been killed by EAB. The authors predict that 6,747 communities not yet affected by the EAB will suffer the highest losses between now and 2060. Most of these communities are in a 350,000 square mile area of the northeast and central states. However, the risk is far wider, reaching as far as Seattle.

This ash tree has been standing – dead – since 2016. When will it fall?

In the top ‘hotspot cities’ projected mortality is in the range of 5,000–25,000 street trees. These include Milwaukee; the Chicago area (Chicago / Aurora / Naperville / Arlington Heights); Cleveland; and Indianapolis. As in previous studies, the highest insect impacts are in the Northeast. Pests impacting this region – in addition to the emerald ash borer – include the spongy moth (formerly called gypsy moth) and hemlock woolly adelgid.

Because insect-killed trees must be treated or removed to minimize the risk to human life and property, the pest risk represents an economic as well as ecological threat. Removing and replacing just the street trees is projected to cost cities $30 million per year. Considering the cities I mentioned above, Milwaukee faces costs estimated at $13 million; Warwick, RI $2.5 million; Baltimore $1.7; Richmond and Virginia Beach $7.3 million and $700,000 respectively; and three New Jersey cities (Jersey City, Elizabeth City, and Patterson) $1.6 million combined.

USDA APHIS ended the federal quarantine for EAB in 2021. Therefore these cities and states are on their own to protect themselves from not only this and other damaging insects but also their extraordinarily high economic costs.

The study evaluated the risk to 48 genera of trees in about 30,000 communities. The most widely planted genera are maples (Acer spp.) and oaks (Quercus spp.). Consequently, they will die in largest numbers. An estimated 26.5 million maples and 5.9 million oaks are at risk, primarily in the East. As noted above, EAB is expected to kill 99% of ash trees in 6,747 communities across the country. In the Southwest, there are 3.4 million pines (Pinus spp.); the threat to them is not woodborers, but scale insects (San Jose scale [Quadraspidiotus perniciosus] and calico scale [Eulecanium cerasorum]).

As we know, urban forests are easily invaded because they are close to ports of entry and are often composed primarily of highly susceptible species. Hudgins, Koch, Ambrose and Leung analyzed the potential risk associated with introduction of a new woodboring insect from Asia – which they point out is the source of most imported goods. They determined that if such an introduced pest were to attack maples or oaks, it could kill 6.1 million trees and cost American cities $4.9 billion over 30 years. The risk would be highest if this pest were introduced via a port in the South.

In an earlier blog I reported that the U.S. is currently importing about 20 million shipping containers filled with goods from Asia per year. I have often blogged about the pest risk associated with wood packaging accompanying these imports. The number of containers from Asia entering Southeastern ports rose by more than 10% from December to January.

Hudgins, Koch, Ambrose & Leung combined four sources of information to produce these estimates:

a model of spread for 57 species of introduced insect pests already determined to cause significant damage to trees;
the distribution of genera of urban street trees across 30,000 US communities;
a model of host mortality in response to each insect-host combination; and
the cost of removing and replacing dead trees, linked to tree size (dbh).

They excluded several categories of pests. One of the most damaging, Asian longhorned beetle, was excluded because scientists have already developed control methods to limit its spread. Also excluded were species present in the U.S. for less than five years; species with no known economic impacts; and species for which no hosts in natural North American forests have been identified. Also excluded – although the authors do not mention this – are species that did not qualify for inclusion in the Aukema et al. study (see reference at end of this blog) because they have been introduced from nearby portions of North America, e.g., goldspotted oak borer. Finally, the study does not include pathogens. Some pathogens have caused huge losses of urban trees in the past, e.g., Dutch elm disease; some are causing losses now, e.g., sudden oak death. The authors do mention the Fusarium disease vectored by polyphagous (and Kuroshio) shot hole borers in southern California.

Consequently, the study’s estimate of 1.4 million street trees dead and costs of $30 million per year are underestimates.

The study has generated considerable media interest, including in the Washington Post.

SOURCES

Aukema, J.E., D.G. McCullough, B. Von Holle, A.M. Liebhold, K. Britton, & S.J. Frankel. 2010. Historical Accumulation of Nonindigenous Forest Pests in the Continental United States. Bioscience. December 2010 / Vol. 60 No. 11

Hudgins, E.J., F.H. Koch, M.J. Ambrose, B. Leung. 2022. Hotspots of pest-induced US urban tree death, 2020–2050. Journal of Applied Ecology 2022;00:1-11 DOI: 10.1111/1365-2664.14141

Posted by Faith Campbell

Forest Pest Threat to Africa

Eucalyptus plantation in Kwa-Zulu-Natal, South Africa; Kwa-Zulu-Natal Dept. of Transportation

Graziosi et al. (full citation at the end of the blog) point out that trees are crucial for Africa’s future. Eight hundred of the 4,500–6,000 indigenous tree species provide significant food. As elsewhere, trees provide wood and other extractive resources essential for economic growth. They also support biodiversity and mitigate current and impending climatic variations. Africa– especially the Sub-Saharan countries – is already considered highly vulnerable to climate change.

According to Graziosi et al., the cumulative economic impact of all invasive species in Africa is expected to exceed $1.2 billion per year. The total invasion cost as a proportion of GDP for many African countries is among the highest in the world. This raises the stakes for developing locally appropriate management strategies across the continent.

Responding effectively to this threat is hampered by gaps in data as well as some countries’ limited capacity for biosecurity. Graziosi et al. say that improved knowledge of taxonomy, distribution, and damage caused by these organisms is essential. Such knoledge will be crucial to develop continent-wide strategies to manage this emergency and to enhance capacity for country-level interventions.

Native and alien pests. Indigenous and plantation trees

Africa’s trees and their services are threatened by both native pests and accelerating introductions of pests and diseases from elsewhere. Long-established and new invaders increasingly affect planted forests of exotic eucalypts, pines, and Australian acacias, as well as important indigenous trees. Graziosi et al. note that the U.N. Food and Agriculture Organization (FAO) in an annex to a report issued in 2009 recorded about100 species of forest pests affecting trees in planted and natural forests across Africa. Half are native insects and pathogens, a third are alien; about 15% are of unknown origin. Considering all pests, broadleaf trees (predominantly native) are most affected.

The result is damage from the local – e.g., to rural livelihoods – to the continental – e.g., to economic development and biological diversity across Africa. Moreover, pests exacerbate widespread loss of forest cover. Overall, African forests are shrinking at the rate of almost 0.5% annually. This deforestation is affecting particularly natural forests; planted forests are actually growing 1.3% annually.

Exotic plantation trees face severe threats. More than 47 native and 19 non-indigenous defoliators, sap-feeders, wood- and shoot-borers attack plantations of Acacia spp., Eucalyptus spp., Pinus spp., and teak (Tectona grandis). About 90% of pathogens of plantation forestry are either non-indigenous or of uncertain origin. Eucalyptus alone are severely damaged by 15 species of pathogens. These organisms are listed in Tables 1 and 2.

Numerous native insect species, known as pests of indigenous trees, have reportedly widened their host range and now damage exotic trees too. Some introduced insects appear to pose significant threats to native tree species. One example is the Cypress aphid Cinara cupressi, which is attacking both exotic cypress plantations and the native African cedar Juniperus procera. Some fungi in the family Botryosphaeriaceae are latent pathogens infecting a wide range of hosts including indigenous Acacia. Dieback of large baobab trees was recently reported from southern Africa. While various microorganisms are associated with these symptoms, the specific cause is still uncertain.

A baobab tree in Limpopo region of South Africa; Wikimedia

The risk currently appears to be particularly high in South Africa. The country’s flora is highly diverse and has a high level of endemism. In fact, South Africa is home to the Earth’s smallest floral kingdom, the Cape Floral Kingdom. It is also the apparent hot spot for pest introductions from overseas (see below). Phytophthora cinnamomi is attacking native Proteaceae in South Africa. According to Graziosi et al., an “incredible diversity” of Phytophthora taxa is present, portending threats to additional plant species. Other pathogens are attacking native conifers in the Podocarpus genus, Ekebergia capensis (Meliaceae), and Syzygium trees.

*Protea repens* and fynbos vegetation near Table Mountain; photo by Mike Wingfield

There is a clear pattern to further spread: pests first introduced to South Africa often spread. Examples include several insects and pathogens on Eucalyptus and the wood-boring pest of pine Sirex noctilio. This pattern is explained by two main factors. South Africa has a high capacity to detect introduced species. Also, there is an active plantation forestry sector that imports propagules. This offers opportunities for contaminating organisms to be introduced simultaneously.

Furthermore, as Graziosi et al. note, determining the geographic origin of significant proportion of pathogens is extremely difficult – an issue I will discuss in a separate blog based on a publication by primarily South African scientists. Some non-indigenous pathogens have been on the African continent for a long time. The Armillaria root rot pathogen apparently was introduced to South Africa with potted plants from Europe in the 1600s! They note also that many non-indigenous pathogens are probably already established on the continent but not yet detected due to the organisms’ cryptic nature and lagging detection abilities.

The future of African forests

African countries expect economic growth with associated increased trade with countries off-continent. The probable result will be to accelerate the rate of species introductions and spread. However, as climate change worsens, managers will find it increasingly difficult both to predict introduced species’ impact and to implement management programs.

This led Graziosi et al. to call for urgent improvements in plant biosecurity across the continent. They advocate improved coordination at regional and international levels. The list of needed actions is a familiar one: development and application of improved diagnostic tools, updated plant exchange regulations, and revised trade policies.

Graziosi et al. also call for development of effective control and management options. They suggest biocontrol, innovative silviculture practices, and selection of resistant trees. The good news is that African countries have already initiated programs to conserve tree germplasm and domesticate indigenous species, including establishment of field gene banks of high-priority indigenous trees. I have previously praised South African efforts, specifically reports here and here.

Mudada, Mapope, and Ngezimana (2022) describe the risk from introduced species to agriculture and human well-being in southern Africa beyond forestry. The region is already ravaged by food insecurities and hidden hunger. It would be devastated if the global average of crop loss due to plant diseases (10-16%) occurs there. They say these losses can be avoided with improved biosecurity mechanisms focused primarily on pest exclusion and plant quarantine regulations.

SOURCES

Graziosi, I. M. Tembo, J. Kuate, A. Muchugi. 2020 Pests and diseases of trees in Africa: A growing continental emergency. Plants People Planet DOI: 10.1002/ppp3.31

Mudada, N. Mapope, N., and Ngezimana, W. 2022 – The threat of transboundary plant pathogens to agricultural trade in Southern Africa: a perspective on Zimbabwe’s plant biosecurity – A review. Plant Pathology & Quarantine 12(1), 1–33, Doi 10.5943/ppq/12/1/1

Posted by Faith Campbell

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

Imports from Asia Continue to Surge; Awaiting Better Analysis

The surge in US imports from Asia that began in the second half of 2020 continued through 2021 and into January 2022. As of September 2021, import volumes from Asia averaged almost 20% higher than the historical monthly average for every month of 2021 (Mongelluzzo, October 13, 2021). The surge continued into 2022. In January 2022, US containerized imports from Asia hit the highest monthly total ever recorded — 1.7 million TEU. This was a 14.6% increase over December 2021 – and a 4.5% increase from a year earlier (January 2021). [Mongelluzzo Feb 23]

The 2022 increase in import volumes was on top of the record-breaking levels seen in 2021. For example, average monthly import volumes during 2021 at the principal ports for receipt of goods from Asia — Los Angeles-Long Beach — were 23% over the 2019 average (Mongeluzzo April 2021).

Increases in volume from December 2021 occurred at ports across the country. Pacific coast ports saw increases – 25.8% at the LA/LB complex (which handles ~50% of US imports from Asia); 39.1% at Northwest Seaport Alliance (Seattle and Tacoma); 19.7% at Oakland. So did ports in the Southeast – 12.7% in Savannah and 14.1% in Charleston. However, New York/New Jersey saw a decrease of 2.2% and Norfolk saw a decrease of 10.6%. [Mongelluzzo Feb 23] New York had seen a steep increase in mid-2021 (Angell Dec. 22, 2021), but apparently this did not hold up through the year.

The southern California ports report that ships leaving China in early March will – as expected – increase import volumes before the end of the month. Long Beach projected that numbers of arriving shipping containers will rise 34% in the week beginning March 20, compared with the week of March 7; Los Angeles projected an increase of 63% [Mongelluzzo March 10].

Volumes Will Probably Continue to Rise Along the Gulf

Containerized imports from Asia through US Gulf ports had risen 27.2% to 1.14 million TEU in 2021. At the port of Mobile, specifically, imports from Asia last year rose 25% from 2020 to 230,347 TEU in 2021. Imports from Asia through Houston jumped 34 % to 807,376 TEU in 2021 [Mongelluzzo Feb 2 2022]

Increasing manufacturing and distribution industries in the Gulf region are probably an important factor in rising import volumes there. Mongelluzzo Feb 2 2022 notes the presence of a Hyundai factory in Alabama, a Tesla factory and Amazon fulfillment center near Austin, as well as several retail chains’ distribution centers near Houston. Many of these facilities opened in 2021.

Import volumes entering via Gulf and Southeastern ports are expected to continue growing in coming months and years. Several carriers have announced new direct Asia-to-US-east coast transport services. These include South Korea’s HMM (to Houston); CMA CGM; and Maersk (Vietnam and China to Houston and Norfolk; China and Indonesia to Charleston and Newark)

Those who follow shipping expect import volumes to drop in February because many factories in Asia were closed for two weeks or more for the Lunar New Year holidays, which began on Febrary 1. Imports should surge again in March. [Mongelluzzo Feb 23]

The Risk

Remember, Asia is the origin of many of the most damaging forest pests. 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).

It seems to me that the beetles native to southeast Asia, e.g., the phytophagous and Kuroshio shot hole borers, are likely to find the climate along the Gulf of Mexico to their liking. Indeed, the redbay ambrosia beetle profile already has!

dead redbay in Georgia killed by laurel wilt disease

Li et al. (2021) assessed fungi associated with Eurasian bark and ambrosia beetles and their potential to impact North American trees. They assessed 111 fungal associates of 55 beetle species. They found that none was “highly virulent” on four important pines or oaks of the Southeast. However, I note two caveats. First, they tested only four host species – two pines (Pinus taeda and P. elliottii var. elliottii) and two oaks (Quercus shumardii and Q. virginiana). They did not test against the many other tree species that comprise important components of forests of the region. Second, their bar for concern was extremely high: to qualify as “highly virulent,” the pathogens had to be as damaging as laurel wilt disease or Dutch elm disease! Both have had extremely damaging impacts on their hosts across North America.

Updated Haack Analysis

As has been documented repeatedly (e.g., my blogs), 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 by mid-year.

SOURCES

Angell, M. NY-NJ vessel backlog creeps back up amid bigger ship calls. Journal of Commerce. Dec. 22, 2021 https://www.joc.com/maritime-news/ny-nj-vessel-backlog-creeps-back-amid-bigger-ship-calls_20211222.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%2012/23/21%20SUBSCRIBER%20%28Copy%29_PC00000_e-production_E-122936_KB_1223_0617

Angell, M. Maersk to debut new Houston, Norfolk trans-Pac service in March. Journal of Commerce. Feb. 10, 2022 https://www.joc.com/maritime-news/container-lines/maersk-line/maersk-debut-new-houston-norfolk-trans-pac-service-march_20220210.html?utm_campaign=CL_JOC%20Ports%202%2F16%2F22%20_PC00000_e-production_E-127385_TF_0216_0900&utm_medium=email&utm_source=Eloqua

Haack, R.A., K.O. Britton, E.G. Brockerhoff, J.F. Cavey, L.J. Garrett. 2014. Effectiveness of the International Phytosanitary Standard ISPM No. 15 on Reducing Wood Borer Infestation Rates in Wood Packaging Material Entering the United States. PLoS ONE 9(5): e96611. doi:10.1371/journal.pone.0096611

Li, Y., C. Bateman, J. Skelton, B. Wang, A. Black, Y-T. Huang, A. Gonzalez, M.A. Jusino, Z.J. Nolen, S. Freeman, Z. Mendel, C-Y. Chen, H-F. Li, M. Kolařík, M. Knížek, J-H. Park, W. Sittichaya, P. H. Thai, S. Ito, M. Torii, L. Gao, A.J. Johnson, M. Lu, J. Sun, Z. Zhang, D.C. Adams, J. Hulcr. 2021. Pre-invasion assessment of exotic bark beetle-vectored fungi to detect tree-killing pathogens. Phytopathology. https://doi.org/10.1094/PHYTO-01-21-0041-R

Mongeluzzo, B. Additional port capacity alone can’t solve congestion issues: LA-LB. Journal of Commerce. April 2021 https://www.joc.com/port-news/us-ports/additional-port-capacity-alone-can%E2%80%99t-solve-congestion-issues-la-lb_20210407.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%204%2F8%2F21_PC00000_e-production_E-95420_KB_0408_0837

Mongelluzzo, B. September imports show no relief for stressed US ports. Journal of Commerce. Oct. 12, 2021. https://www.joc.com/port-news/us-ports/september-imports-show-no-relief-stressed-us-ports_20211013.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%2010%2F14%2F21_PC00000_e-production_E-116084_KB_1014_0617

Mongelluzzo, B. Gulf Coast import growth propels regional warehousing boom. Journal of Commerce. Feb. 2, 2022. https://www.joc.com/port-news/us-ports/port-mobile/gulf-coast-import-growth-propels-regional-warehousing-boom_20220202.html?utm_campaign=CL_JOC%20Ports%202%2F9%2F22%20%20_PC00000_e-production_E-126647_TF_0209_0900&utm_medium=email&utm_source=Eloqua

Mongelluzzo, B. Asian imports to US surged to new record in January. Journal of Commerce. Feb 23, 2022

https://www.joc.com/maritime-news/container-lines/asian-imports-us-surged-new-record-january_20220223.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%202%2F24%2F22%20NONSUBSCRIBER_PC015255_e-production_E-128466_KB_0224_0617

Mongelluzzo, B. Coming LA-LB cargo surge to rebuild vessel backlog, say terminals. Journal of Commerce. March 10, 2022. https://www.joc.com/port-news/us-ports/coming-la-lb-cargo-surge-rebuild-vessel-backlog-say-terminals_20220310.html?utm_source=Eloqua&utm_medium=email&utm_campaign=CL_JOC%20Daily%203/11/22%20NONSUBSCRIBER_PC015255_e-production_E-130350_KB_0311_0617

Reminder: ask your MC & Senators to sponsor tree-restoration bill!

The Invasive Species Prevention and Forest Restoration Act (H.R. 1389) is before Congress. It is co-sponsored by Reps. Peter Welch [VT], Ann Kuster and Chris Pappas [NH], Chellie Pingree [ME], Elise Stefanik and Antonio Delgado [NY], Brian Fitzpatrick [PA], Mike Thompson [CA], Deborah Ross [NC].

Ask your Member of Congress/Representative to co-sponsor this bill. Ask your Senators to sponsor a companion bill.

In summary, this bill will:

Expand USDA APHIS’ access to emergency funds to eradicate or contain newly detected pest outbreaks.
Establish a pair of grant programs to support strategies aimed at restoring tree species decimated by non-native plant pests or noxious weeds. Such strategies include biological control of pests and enhancement of a tree host’s pest resistance.
1. One grant program supports research to explore and develop these strategies.
2. The second program support application of resistance breeding and other measures to restore forest tree species. Funded programs must incorporate a majority of the following components: collection and conservation of native tree genetic material; production of sufficient numbers of propagules; preparation of planting sites in the species’ former habitat; planting and post-planting maintenance.
Mandate a study to identify actions to overcome the shortfall of mission, leadership, and prioritization; identify agencies’ expertise and resources; improve coordination among agencies and with partners; and develop national strategies for saving tree species.

Organizations eligible for these grants include federal agencies; state cooperative institutions; colleges or universities offering a degree in the study of food, forestry, and agricultural sciences; and nonprofit entities with non-profit status per §501(c)(3) of the Internal Revenue Code.

Endorsements: Vermont Woodlands Association, American Forest Foundation, The Association of Consulting Foresters (ACF), Audubon Vermont, Center for Invasive Species Prevention, Ecological Society of America, Entomological Society of America, Maine Woodland Owners Association, Massachusetts Forest Alliance, National Association of State Foresters (NASF), National Woodland Owners Association (NWOA), The Nature Conservancy (TNC) Vermont, New Hampshire Timberland Owners Association, North American Invasive Species Management Association (NAISMA), Pennsylvania Forestry Association, Reduce Risk from Invasive Species Coalition, The Society of American Foresters (SAF), and a broad group of university professors and scientists.

Legislative Point of Contact: Alex Piper, Legislative Assistant, office of Rep. Welch. Contact me – providing your email! – if you wish me to send you Alex’ contact information. [The “contact” form does not provide your email and I will not reply in a public way.]

Posted by Faith Campbell