Tuesday, April 19, 2022

Episode 625 (4-18-22): Ash Trees, Insect Impacts, and Water Consequences

CLICK HERE to listen to episode audio (4:38).

Sections below are the following:
Transcript of Audio
Audio Notes and Acknowledgments
Extra Information
Related Water Radio Episodes
For Virginia Teachers (Relevant SOLs, etc.).

Unless otherwise noted, all Web addresses mentioned were functional as of 4-15-22.


From the Cumberland Gap to the Atlantic Ocean, this is Virginia Water Radio for the week of April 18, 2022.  This update of an episode from July 2017 is part of a series this year of episodes related to trees and shrubs.

MUSIC – ~14 sec

That’s part of “The Ash Grove,” a traditional Welsh tune performed by Madeline MacNeil, on her 2002 album, “Songs of Earth & Sea.”  Born in Norfolk and raised in Richmond, Ms. MacNeil was a well-known and highly regarded musician based in Virginia’s Shenandoah Valley until her passing in 2020.

The music opens an episode where we revisit the status of North American ash trees and explore the water impacts of pest damage to trees generally.

As noted in the July 2017 episode on ashes, North America is home to 16 native ash species, with six of those occurring naturally in Virginia.  The two most common ash species in Virginia are White Ash, which tends toward upland habitats, and Green Ash, which is often found along streams and rivers.  In those areas, Green Ash can be a significant portion of the vegetation and help create habitats, improve water quality, and stabilize flows.  Both species provide food for a variety of animals and both have been widely planted in cities and towns.

Since the early 2000s, ash tree populations have been devastated by the spread of the Emerald Ash Borer, a beetle native to Asia.  As of April 2022, the insect had been found in at least 35 states and the District of Columbia, and in nearly all of Virginia.  In an affected tree, the insect’s larvae create a network of tunnels that impair the tree’s transport of water and nutrients, eventually killing the tree.  Once an area’s invaded, ashes are unlikely to survive for more than a few years without expensive chemical treatment of individual trees.  At the scale of whole forests, researchers and managers are exploring the use of parasitoid wasps as a biological control method.

The Emerald Ash Borer is only one of many pest species threatening different trees in Virginia and elsewhere.  Several of these pests have been the subject of research on their water-related, or hydrologic, impacts.  Researchers are interested in how loss of tree leaves or death of trees can affect evaporation, soil moisture, water-table levels, streamflows, water chemistry, and snowpack.  Those water-cycle processes are in turn connected to ecosystem pathways of carbon, nutrients, and energy, all being affected by climate changes.  From all of these connections, little ash-boring beetles become part of a biosphere-sized story.

Thanks to Janita Baker of Blue Lion Dulcimers and Guitars for permission to use Madeline MacNeil’s music, and we close with about 25 more seconds of “The Ash Grove.”

MUSIC – ~24 sec – instrumental.


Virginia Water Radio is produced by the Virginia Water Resources Research Center, part of Virginia Tech’s College of Natural Resources and Environment.  For more Virginia water sounds, music, or information, visit us online at virginiawaterradio.org, or call the Water Center at (540) 231-5624.  Thanks to Ben Cosgrove for his version of “Shenandoah” to open and close this episode.  In Blacksburg, I’m Alan Raflo, thanking you for listening, and wishing you health, wisdom, and good water.


This Virginia Water Radio episode builds upon and updates information in Episode 376, 7-10-17.

“The Ash Grove/O Spirit Sweet of Summertime” is from Madeline MacNeil’s 2002 album “Songs of Earth & Sea”; copyright held by Janita Baker, used with permission.  More information about Madeline MacNeil is available from Ms. Baker’s “Blue Lion Dulcimers & Guitars” Web site, online at https://www.bluelioninstruments.com/Maddie.html.

Virginia Water Radio thanks Daniel McLaughlin, of the Virginia Tech Department of Forest Resources and Environmental Conservation and the Virginia Water Resources Research Center, for his help with this episode.

Click here if you’d like to hear the full version (2 min./22 sec.) of the “Shenandoah” arrangement/performance by Ben Cosgrove that opens and closes this episode.  More information about Mr. Cosgrove is available online at http://www.bencosgrove.com.


Emerald Ash Borer-infected White Ash tree that cracked and fell in a Blacksburg, Va., neighborhood in 2021.  Photo taken April 19, 2022.

Nationwide range maps for ash tree species and the Emerald Ash Borer, as of January 2021.  Map from the U.S. Department of Agriculture/Animal and Plant Health Inspection Service, “Emerald Ash Borer,” online at https://www.aphis.usda.gov/aphis/ourfocus/planthealth/plant-pest-and-disease-programs/pests-and-diseases/emerald-ash-borer/emerald-ash-borer.

Adult Emerald Ash Borer.  Photo from the the U.S. Department of Agriculture/Animal and Plant Health Inspection Service, “Emerald Ash Borer,” online at https://www.aphis.usda.gov/aphis/ourfocus/planthealth/plant-pest-and-disease-programs/pests-and-diseases/emerald-ash-borer/emerald-ash-borer


The following information is quoted from the Virginia Department of Forestry, “Emerald Ash Borer in Virginia—An Introduction,” online at https://vdof.maps.arcgis.com/apps/MapSeries/index.html?appid=e2660c30d9cd46cc988cc72415101590.

From Background Tab: “After only 1-5 years of infestation, the larvae create extensive tunnels under the bark that disrupt the tree’s ability to transport water and nutrients, which eventually girdles and kills the tree. The length of this process depends on tree age, health, and EAB density in the area but no ash tree is safe - 99% of infested ash will die.” 

From Distribution Tab: “In the U.S., EAB targets 16 species of native ash trees (Fraxinus spp.) and white fringetree (Chionanthus virginicus).  In Virginia, white ash (Fraxinus americana) and green ash (Fraxinus pennsylvanica) are the most commonly found, though there are four other species that have limited ranges (pumpkin, black, blue, and Carolina ash). In the wild, ash often prefers wetter environments and are dominant species along rivers and streambanks.  Ash decline and death may have a negative impact on streambank stabilization and waterways in these rural areas.  Though only a small percentage of Virginia's forests are composed of ash (2-3%), urban areas can have tree inventories tallying up to 13% ash.  This is where dead ash poses the most risk!”

From Biological Control Tab: “Biological control (or “biocontrol”) is a management strategy that involves releasing natural enemies from the pest's native range to control the pest at a given location.  Researchers identified wasps in the early 2000s from Eastern Asia that had co-evolved with emerald ash borers as a parasite to control its populations.  They then conducted extensive research in quarantined U.S. labs to study their life cycle, environmental parameters, and host species.  After nearly a decade of trials, only four wasp species passed the strict requirements set by the USDA-APHIS (Animal and Plant Health Inspection Service) and were approved for release.  APHIS now rears these wasps in large quantities then collaborates with federal, state, and local governments, as well as land owners to release them at approved sites.  These tiny stingless wasps lay eggs in EAB eggs or larvae, effectively killing the EAB host, and are commonly called “parasitoids.” ...These wasps do not harm humans in any way, they only target emerald ash borer as a host. The use of these biocontrol agents in suppressing EAB has shown promising results, but it will take years of controlled releases and research before we see successful parasitism and a reduction of the EAB population.”


Used for Audio

Samuel H. Austin, Riparian Forest Handbook 1: Appreciating and Evaluating Stream Side Forests, Virginia Department of Forestry, Charlottesville, 2000. 

J. A. Biederman et al., “Multiscale observations of snow accumulation and peak snowpack following widespread, insect-induced lodgepole pine mortality,” Ecohydrology, Vol. 7 (2014), pages 150-162.

J. A. Biederman et al., Increased evaporation following widespread tree mortality limits streamflow response,” Water Resources Research, Vol. 50 (2014), pages 5295-5409.

S. T. Brantley et al., “Changes to southern Appalachian water yield and stormflow after loss of a foundation species,” Ecohydrology, Vol. 8 (2015), pages 518-528. 

T. R. Cianciolo et al., “Hydrologic variability in black ash wetlands: Implications for vulnerability to emerald ash borer,” Hydrological Processes, Vol. 35 (2021), e14014.

D. W. Clow et al., “Responses of soil and water chemistry to mountain pine beetle induced tree mortality in Grand County, Colorado, USA,” Applied Geochemistry, Vol. 26 (2011), pages 174-178. 

Anthony D’Amato et al., “Ecological and hydrological impacts of the emerald ash borer on black ash forests,” Northeast Climate Science Center, online at https://necsc.umass.edu/projects/ecological-and-hydrological-impacts-emerald-ash-borer-black-ash-forests.

M. J. Daley et al., “Water use by eastern hemlock (Tsuga Canadensis) and black birch (Betula lenta): implications of effects of the hemlock wooly adelgid,” Canadian Journal of Forest Research, Vol. 37 (2007), pages 2031-2040. 

J. S. Diamond et al., “Forested versus herbaceous wetlands: Can management mitigate ecohydrologic regime shifts from invasive emerald ash borer?”  Journal of Environmental Management, Vol. 222 (2018), pages 436-446.

Emerald Ash Borer Information Network, online at http://www.emeraldashborer.info/index.php.  Virginia information is online at http://www.emeraldashborer.info/state/virginia.php.  Information by county for each state is available in the table online at http://www.emeraldashborer.info/state-dectection-table.php.

Gary M. Lovett et al., “Forest Ecosystem Responses to Exotic Pests and Pathogens in Eastern North America,” Bioscience Vol. 56, No. 5 (May 2006), pages 395-405.

Steven G. Pallardy, Physiology of Woody Plants, Third Edition, Elsevier/Academic Press, Burlington, Mass., 2008.

D. E. Reed et al., “Bark beetle-induced tree mortality alters stand energy budgets due to water budget changes,” “Theoretical and Applied Climatology, Vol., 131 (2018), pages 153-165. 

W. M. Robertson et al., “Soil moisture response to white ash mortality following emerald ash borer invasion,” Environmental Earth Sciences, Vol. 77 (2018).

Anita K. Rose and James S. Meadows, “Status and Trends of Bottomland Hardwood Forests in the MidAtlantic Region,” USDA/Forest Service Southern Research Station, Asheville, N.C., November 2016; available online at https://www.treesearch.fs.fed.us/pubs/53238. 

Scott Salom and Eric Day and Scott Salomn, “Hemlock Wooly Adelgid,” Virginia Cooperative Extension (Publication 3006-1451/ENTO-228NP), Blacksburg, Va., 2016, online at https://vtechworks.lib.vt.edu/handle/10919/75419.

U.S. Department of Agriculture/Forest Service/Northern Research Station [Newtown Square, Penn.], “Forest Disturbance Processes/Invasive Species,” online at https://www.nrs.fs.fed.us/disturbance/invasive_species/.” 

U.S. Department of Agriculture/Natural Resources Conservation Service, “Plants Data Base,” online at https://plants.usda.gov/java/nameSearch. 

U.S. Department of Agriculture/Animal and Plant Health Inspection Service (APHIS):
“Asian Longhorned Beetle,” online at
“Emerald Ash Borer,” online at
“Gypsy Moth,” online at

Virginia Department of Forestry:
“Common Native Trees of Virginia,” 2020 edition, online (as a PDF) at https://dof.virginia.gov/wp-content/uploads/Common-Native-Trees-ID_pub.pdf;
“Emerald Ash Borer in Virginia—An Introduction,” online at https://vdof.maps.arcgis.com/apps/MapSeries/index.html?appid=e2660c30d9cd46cc988cc72415101590;
“Forest Management and Health/Insects and Diseases,” online at
“Forestry News: On the Wings of a Tiny Wasp,” July 24, 2020, online at https://dof.virginia.gov/on-the-wings-of-a-tiny-wasp/;
Tree and Forest Health Guide
, 2020, online (as a PDF) at https://dof.virginia.gov/wp-content/uploads/Tree-and-Forest-Health-Guide.pdf.

A.S. Weakley, J.C. Ludwig, and J.F. Townsend, Flora of Virginia, Bland Crowder, ed.  Copyright by the Foundation of the Flora of Virginia Project, Inc., Richmond.  Botanical Research Institute of Texas, Fort Worth, 2012.  (The Flora of Virginia Project is online at https://floraofvirginia.org/.)

For More Information about Trees and Shrubs in Virginia and Elsewhere

Center for Watershed Protection, “Trees and Stormwater Runoff,” online at https://www.cwp.org/reducing-stormwater-runoff/.

Chesapeake Bay Program, “Field Guide: Plants and Trees,” online at https://www.chesapeakebay.net/discover/field-guide/all/plants_trees/all.

eFloras.org, “Flora of North America,” online at http://www.efloras.org/flora_page.aspx?flora_id=1.

Sanglin Lee and Alan Raflo, “Trees and Water,” Virginia Water Resources Research Center, Virginia Water Central Newsletter, pages 13-18, online at https://vtechworks.lib.vt.edu/handle/10919/49367.   (A Virginia Cooperative Extension version of this article—“Trees and Water,” by Sanglin Lee, Alan Raflo, and Jennifer Gagnon, 2018—with some slight differences in the text is available online at https://www.pubs.ext.vt.edu/content/pubs_ext_vt_edu/en/ANR/ANR-18/ANR-18NP.html.)

Texas A&M University AgriLife Extension, “How Trees Grow,” online at https://agrilife.org/treecarekit/introduction-to-tree-care/how-trees-grow/.

U.S. Department of Agriculture/U.S. Forest Service, “State and Private Forestry Fact Sheet—Virginia 2022,” online (as a PDF) at https://apps.fs.usda.gov/nicportal/temppdf/sfs/naweb/VA_std.pdf.

U.S. Department of Agriculture/Forest Service/Climate Change Resource Center, “Forest Tree Diseases and Climate Change,” online at https://www.fs.usda.gov/ccrc/topics/forest-disease. 

Virginia Botanical Associates, “Digital Atlas of the Virginia Flora,” online at http://www.vaplantatlas.org/index.php?do=start&search=Search.

Virginia Department of Conservation and Recreation/Natural Heritage Division, online at https://www.dcr.virginia.gov/natural-heritage/.

Virginia Department of Forestry, “Virginia’s Forests,” online at https://dof.virginia.gov/.

Virginia Forest Landowner Education Program, Virginia Cooperative Extension and Virginia Tech College of Natural Resources and Environment, online at https://forestupdate.frec.vt.edu/.

Virginia Forest Products Association, online at https://www.vfpa.net/.

Virginia Native Plant Society, online at http://vnps.org/.


All Water Radio episodes are listed by category at the Index link above (http://www.virginiawaterradio.org/p/index.html).  See particularly the “Plants” subject category.

Following are links to other episodes on trees and shrubs [good as of Episode 624]

Introduction to trees and water – Episode 621, 3-21-22.
American Sycamore – Episode 624, 4-11-22.
American Witch Hazel – Episode 238, 10-31-14.
Early spring wildflowers in woodlands – Episode 573, 4-19-21.
Forest lands and work in Virginia – Episode 623, 4-4-22.
Maple trees – Episode 503, 12-16-19.
Photosynthesis – Episode 602, 11-8-21.
Poison Ivy and related plants, including the shrub Poison Sumac – Episode 535, 7-27-20.
Rhododendrons – Episode 574, 4-26-21.
Tree buds – Episode 622, 3-28-22.


Following are some Virginia Standards of Learning (SOLs) that may be supported by this episode’s audio/transcript, sources, or other information included in this post.

2020 Music SOLs 

SOLs at various grade levels that call for “examining the relationship of music to the other fine arts and other fields of knowledge.”

2018 Science SOLs 

Grades K-4: Living Systems and Processes
1.4 – Plants have basic life needs (including water) and functional parts that allow them to survive; including that plants can be classified based on a variety of characteristics.
2.4 – Plants and animals undergo a series of orderly changes as they grow and develop, including life cycles.
2.5 – Living things are part of a system.
3.4 – Adaptations allow organisms to satisfy life needs and respond to the environment.
4.2 – Plants and animals have structures that distinguish them from one another and play vital roles in their ability to survive.
4.3 – Organisms, including humans, interact with one another and with the nonliving components in the ecosystem.

Grades K-5: Earth Resources
1.8 – Natural resources can be used responsibly, including that most natural resources are limited.
2.8 – Plants are important natural resources.
3.8 – Natural events and humans influence ecosystems.
4.8 – Virginia has important natural resources.

Grade 6
6.6 – Water has unique physical properties and has a role in the natural and human-made environment.
6.8 – Land and water have roles in watershed systems.
6.9 – Humans impact the environment and individuals can influence public policy decisions related to energy and the environment.

Life Science
LS.5 – Biotic and abiotic factors affect an ecosystem.
LS.6     – Populations in a biological community interact and are interdependent.
LS.7 – Adaptations support an organism’s survival in an ecosystem.
LS.8 – Change occurs in ecosystems, communities, populations, and organisms over time.
LS.9 – Relationships exist between ecosystem dynamics and human activity.
LS.11 – Populations of organisms can change over time.

Earth Science
ES.8 – Freshwater resources influence and are influenced by geologic processes and human activity.

BIO.7 – Populations change through time.
BIO.8 – Dynamic equilibria exist within populations, communities, and ecosystems. 

2015 Social Studies SOLs

Grades K-3 Economics Theme
2.8 – Natural, human, and capital resources.

Civics and Economics Course
CE.6 – Government at the national level.
CE.7 – Government at the state level.
CE.10 – Public policy at local, state, and national levels.

World Geography Course
WG.2 – How selected physical and ecological processes shape the Earth’s surface, including climate, weather, and how humans influence their environment and are influenced by it.

Government Course
GOVT.7 – National government organization and powers.
GOVT.8 – State and local government organization and powers.
GOVT.9 – Public policy process at local, state, and national levels.

Virginia’s SOLs are available from the Virginia Department of Education, online at http://www.doe.virginia.gov/testing/.

Following are links to Water Radio episodes (various topics) designed especially for certain K-12 grade levels.CLICK HERE to listen to episode audio (4:38).

Episode 250, 1-26-15 – on boiling, for kindergarten through 3rd grade.
Episode 255, 3-2-15 – on density, for 5th and 6th grade.
Episode 282, 9-21-15 – on living vs. non-living, for kindergarten.
Episode 309, 3-28-16 – on temperature regulation in animals, for kindergarten through 12th grade. Episode 333, 9-12-16 – on dissolved gases, especially dissolved oxygen in aquatic habitats, for 5th grade.
Episode 404, 1-22-18 – on ice on ponds and lakes, for 4th through 8th grade.
Episode 407, 2-12-18 – on snow chemistry and physics, for high school.
Episode 483, 7-29-19 – on buoyancy and drag, for middle school and high school.
Episode 524, 5-11-20 – on sounds by water-related animals, for elementary school through high school.
Episode 531, 6-29-20 – on various ways that animals get water, for 3rd and 4th grade.
Episode 539, 8-24-20 – on basic numbers and facts about Virginia’s water resources, for 4th and 6th grade.
Episode 606, 12-6-21 – on freezing and ice, for kindergarten through 3rd grade.