Field Notes: Looking Down on Tree of Heaven

By Katlin Mooneyham and Lori Chamberlin

The City of Winchester and Frederick County are in the midst of an invasion. The spotted lanternfly, a non-native invasive insect, was first discovered in Winchester in January 2018. This pest feeds on more than 70 host plants worldwide and poses a significant threat to multiple Virginian industries. There is still much to learn about the spotted lanternfly, and the Virginia Department of Agriculture and Consumer Services (VDACS) has been working hard to control it within the infested areas.

One method of slowing the spread is treatment of a preferred host, Ailanthus altissima, otherwise known as “tree of heaven”. Smaller trees are killed with herbicide and larger trees are treated with insecticide to kill spotted lanternfly that feed on them. Tree of heaven itself is an invasive species and is widespread throughout Virginia, especially along roads or other disturbed sites.

Knowing the precise location of tree of heaven would greatly facilitate treatment, so Virginia Department of Forestry (VDOF) partnered with VDACS to map tree of heaven in Frederick County and the City of Winchester. The project is supported by Farm Bill funds awarded to VDACS and accomplished with U.S. Forest Service software (Digital Mobile Sketch Mapper). Protocol was based on a 2015 Forest Science paper entitled “Aerial Detection of Seed-Bearing Female Ailanthus altissima: A Cost-Effective Method to Map an Invasive Tree in Forested Landscapes”, and personal communication with forest health professionals from the Pennsylvania Department of Conservation and Natural Resources. This type of survey requires a helicopter in December/January after leaf drop. Female tree of heaven hold onto their seed pods and are visible from above during these winter months.

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Female tree of heaven trees from above (identified by attached brown seed pods).

In January 2020, VDOF forest health staff went up in a helicopter to map tree of heaven. The survey followed pre-determined flight lines spaced at 2,000 feet (1,000 feet of visibility from either side of the helicopter) and flew at an average altitude of 400 feet above ground at a speed of approximately 80 knots. Individual female trees were marked as points, and clusters of trees were marked as polygons. Three VDOF employees conducted the survey — two spotters and a sketch mapper — with minimal Dramamine needed for motion sickness!

Photos: VDOF staff Meredith Bean (emerald ash borer coordinator) and Katlin Mooneyham (forest health specialist) (left) and Jim Pugh (GIS technician) (right) ready for take off!

It will take some time to analyze the data and quantify the results, but general observations fit with our knowledge of this invasive tree species. Tree of heaven is most commonly found along disturbed sites and the highest numbers of trees were observed along train tracks, roadsides, field edges and a quarry in the southern end of the county.

Mapping female trees only gives us data for half of the population, but this winter survey is a quick and easy method to identify tree of heaven clusters to get a better idea of overall distribution. This data will be used by both VDOF and VDACS personnel to identify priority treatment areas and locate areas where the spotted lanternfly may continue to spread.

Paper Citation:
Rebbeck, Joanne, et al. “Aerial detection of seed-bearing female Ailanthus altissima: A cost-effective method to map an invasive tree in forested landscapes.” Forest Science 61.6 (2015): 1068-1078.

Field Notes: Goodness Gracious Goats!

by VDOF Forest Health Specialist Katlin Mooneyham

Our VDOF Forest Health Program staff are often asked how to control certain invasive plant species. Most recommendations involve spraying or applying chemicals since that is often the easiest and most practical way for people to remove these plants. However, there are times when landowners and citizens are not interested in herbicides and ask for other recommendations.

One alternative option that is gaining in popularity is the use of goats to graze invasive species down to a more manageable scale. Goats are well suited to grazing plants not typically eaten by other animals because they have the ability to consume woody plants and weeds. They are also able to eat plants toxic to other animals due to the ability to detoxify absorbed anti-nutritional factors (https://articles.extension.org/pages/19363/goat-nutrition-gi-tract).

The VDOF Forest Health Program decided to test this invasive plant removal method and identified Lesesne State Forest as the perfect location due to the amount of problematic plants on the forest. A four-acre section of woods within the forest was selected to be a test area where it could fully be grazed by goats.

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VDOF Forest Health Program Manager Lori Chamberlin next to a large multiflora rose bush at Lesesne State Forest.

The company GoatBusters, based in Afton, VA, was available and ready to help VDOF with this project. The father/son duo, Jace and Clark Goodling, have a herd of Kiko goats that they utilize on a variety of landscapes to remove invasive species. A grand total of 90 goats went out in mid-May for 13 days!  Accompanying the goats were two Anatolian shepherds that acted as guard dogs to prevent other animals from making a snack out of the workers! The goats were kept in one small (~ an acre) subsection at a time so that there would always be high grazing pressure. Once a section was grazed down, the fencing and goats would move to the next spot and grazing would continue. After the goats were well fed and done with the four-acre study area, they were removed. The area looked completely different! Many of the invasive plants in the study area were stripped of their foliage and some were completely consumed all the way to the ground! It is important to note that while the goats had an impressive immediate effect, there will need to be some sort of secondary treatment on the land as these invasive plants are prolific and re-sprout easily. Various follow-up treatments were conducted and a more comprehensive report with those results will be available on the VDOF website soon!

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Goats arrive.
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Goats depart. Quite the difference!

To summarize, there is no silver bullet that can be used against invasive plant species. Whatever treatment is utilized will require follow-up of some sort. The goats are an amazing resource to start fresh in areas that are completely inundated with invasive plants and may not even be accessible for chemical treatment. By allowing these animals to graze an area down, follow-up chemical treatments are easier and more targeted. The ability to start with a “clean slate” is not only more aesthetically pleasing, but also enables invasive plant control with less overall herbicide.

National Invasive Species Awareness Week

National Invasive Species Awareness Week kicked off this week.  A series of events and webinars offered throughout the week aim to raise awareness and identify solutions to invasive species issues at local, state, tribal, regional, international and national scales.

Invasive species are plants, insects, pathogens or other animals intentionally or accidentally introduced into a region where they did not evolve. Their introduction causes, or is likely to cause, economic or environmental harm, or harm to human health.

A fair number of invasive species are found in Virginia, many of which negatively affect the health of our forests. These pests often do not have natural controls in place to regulate their population, so eradication or containment can be challenging and very expensive. Invasive insects like the emerald ash borer continue to cause tree mortality throughout the state, and invasive plants often out-compete native flora and reduce diversity.

The Virginia Department of Forestry’s Forest Health Program detects, monitors and evaluates invasive species on state and private land. Knowing which species are present in an area and understanding their potential impact will enable landowners to make decisions regarding treatment and management. There are simple things we can all do to reduce the risk of future invasive species introductions.

Here are seven ways you can help:

  1. Learn about invasive species, especially those found in your region. Virginia Department of Forestry staff can help.
  2. Clean hiking boots, waders, boats and trailers, off-road vehicles and other gear to stop invasive species from hitching a ride to a new location. Learn more.
  3. Avoid dumping aquariums or live bait into waterways. Learn more.
  4. Don’t move firewood – instead, buy it where you’ll burn it, or gather on site when permitted. Learn more.
  5. Plant only non-invasive plants in your garden, and remove any known invaders.
  6. Use forage, hay, mulch and soil that are certified as “weed free.”
  7. Volunteer to help remove invasive species from public lands and natural areas.

Field Notes: Buy It Where You Burn It!

by VDOF Forest Health Specialist Katlin Mooneyham

Independence Day is just around the corner, and that means travel season is officially here! This year, AAA estimates that almost 47 million Americans will be travelling more than 50 miles to celebrate America’s independence. Many of these travelers will be enjoying the great outdoors by camping, and no camping trip is complete without a campfire! However, one of America’s favorite pastimes can also contribute to the unintentional movement of invasive insects, diseases and plants through firewood.

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Many of the invasive species we are battling here in Virginia most likely arrived through the movement of wood material. For example, the emerald ash borer (EAB), an insect currently attacking all species of ash in Virginia, has small larvae that bore under the bark of trees and often goes undetected due to its cryptic lifestyle. If someone were to cut an infested ash tree down and then take that wood to a campsite in a state where there is no EAB, the larvae could potentially hatch out and spread. These insects, diseases and plants do not have the means to disperse themselves long distances, but when aided by human movement they are able to travel very far and to new locations.

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This “larval gallery” is a sign of emerald ash borer infestation

So how do you enjoy your holiday camping trip without aiding and abetting potentially harmful invasive species? A simple slogan, “Buy it where you burn it!” says it all! Buying heat-treated or local firewood once you get to your destination ensures that these invasive pests don’t move to new locations. While it can sometimes be difficult to find stores in remote locations, a website called Firewood Scout has been created to show stores that sell this type of fire wood in locations across 10 states (including Virginia!). This website also includes links to rules from National and State Parks and information about key invasive threats in each state. If you are interested in learning more about how firewood can be a vehicle for invasive species, please visit https://www.dontmovefirewood.org/

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http://www.firewoodscout.org/s/VA/

Happy travels and have a safe and fun holiday!

Field Notes: Hope for Hemlocks?

by VDOF Forest Health Specialist Katlin Mooneyham

Since its introduction to the United States in the 1950s, hemlock woolly adelgid (HWA) has been an unwanted resident in our hemlock forests. Feeding on eastern and Carolina hemlocks, this tiny sap sucking insect has established itself throughout most of the native range of both species. Unlike most insects, this tiny insect is active in the winter months, feeding on the stored nutrient reserves that help our hemlock trees produce new growth and foliage in the spring. You may not be familiar with the actual insect, but chances are you are very familiar with the “cotton ball” appearance of its protective covering found on the underside of hemlock branches.

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The white “cotton balls” indicative of HWA on hemlock branches

 

This pest is originally from Asia, and most likely arrived on imported nursery stock. Since it has made itself comfortable in our eastern forests for more than half a century, its impact on hemlocks is far and wide, leaving skeletons of what were once hemlock giants.

While this is a depressing tale, there is hope in the form of an unlikely hero- a small predatory beetle that feeds exclusively on HWA. The beetle, Laricobius osakensis, is also active in the winter and feeds on all life stages of HWA.

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Laricobius spp. adult under a microscope

It has been shown to only complete its life cycle by feeding on HWA and won’t feed on any other adelgid species. Many people are hopeful that this beetle will be able to establish and maintain HWA populations below damaging levels in our forests. Chemical options are available to protect trees, but are not feasible in large scale, forested settings. Natural predators, like our friend L. osakensis, are our best bet at naturally combatting the invasive HWA in the native range of our hemlock species.

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L. osakensis larva eating a HWA egg

These beetles have been mass reared to the tune of 51,000, released at 52 sites in eight states. Two of these sites are in Shenandoah National Park (SNP), and a number of interested parties helped get them there. Virginia Tech Department of Entomology has been mass rearing these beetles for release purposes since 2011. In November of 2015, biologists from SNP made their first release of 500 beetles after obtaining the necessary paperwork and public review period. Another release was done last November at another site within the park. Because this release site was done on a park boundary, approval was also granted from the City of Charlottesville, whose property borders the release site. On April 2, Dale Meyerhoeffer (Biological Science Technician with SNP), Jeremiah Foley (graduate student in the Entomology Department at Virginia Tech), and I, Katlin Mooneyham (Forest Health Specialist here at VDOF) met at these release sites to study beetle establishment and overall stand health. We were very enthusiastic to find a fair number of beetles at both sites. Jeremiah also took soil samples to look at differences between the two sites and how it might affect beetle populations.

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Jeremiah Foley (left) and Dale Meyerhoeffer (right) take samples and look for beetles in SNP

These sites will be continuously monitored over the next few years to determine how the beetles move through the forest and their impact on HWA populations. We are hopeful that these predators will continue to feast on HWA throughout the park and that we will see our hemlocks improve!

Image at top: Adult L.osakensis on a branch with HWA

Field Notes: What’s in the Woods Today? Jan. 23, 2018

by Area Forester Lisa Deaton

English Ivy

English Ivy is a non-native species introduced to North America by European settlers.  In the woods, it is often found near old home sites and cemeteries.  While many homeowners consider it an attractive ground cover in landscaped yards, English ivy can deliver a double whammy in the forest.  It competes with trees and other plants for water, nutrients, sunshine and space on the ground, and then starts to climb everything.ivy in tree tops

Once in the canopy, the vines cover tree foliage and can grow heavy enough to break branches and tree tops.  Because English ivy has the ability to grow in the wild and have harmful effects on our native species, we consider it an invasive species.  English ivy has the competitive advantage of being able to grow in all light conditions, from deep shade to full sun.

Part of our work at the Department of Forestry is to alert landowners to invasive species on their land, with the hope of eliminating them before they become a large problem or spread to adjoining properties.

Many national, state, and local resources have been devoted to the elimination of invasive species in America because invasives can alter local ecosystems in so many ways.  Food chains can be disrupted at their base simply by one native plant disappearing that supports one type of insect required by a larger insect, bird, or animal for food.  Our agency participates in the Blue Ridge PRISM effort, a coalition for regional invasive species management focused on ten counties surrounding Shenandoah National Park. It is interesting to note that on other continents, natural resource agencies work equally hard to eliminate species introduced from North America. english ivy last photo