Wednesday, 13 January 2021

Feds relent on emerald ash borer quarantine

Image of ash trees crowns thinning from emerald ash borer

Emerald ash borer kills trees slowly over several years.

MARK HORN, Conservation Digest
January 4, 2021

On Jan 14, 2021 the USDA will remove the federal quarantine on emerald ash borer (EAB). Wisconsin declared all 72 counties in the state a quarantine zone in 2018. The state’s administrative rules restricted movement of wood products from quarantine counties into “clean” counties. Once all counties were considered under quarantine, the rule restricting movement of wood products became moot.

Quarantine measures in Wisconsin were effective at reducing spread of emerald ash borer in nursery stock and commercial forestry lands. These industry groups stepped up and did their part.  EAB still made its way to many parts of the state in firewood. Adult beetles also spread because they can fly up to 35 miles in a season.

Cause for Concern

Emerald ash borer attacks all species of ash in Wisconsin; green, white, black, blue and pumpkin. The mortality rate for infested stands appears to be between 95-99%, with many stands losing every mature tree. Adult beetles lay eggs in the bark of ash trees. When the eggs hatch, the larvae spend the more than a year eating their way through the sapwood beneath the bark. Woodpeckers chip away at bark looking for EAB larvae. This causes large patches of exposed blond inner bark. Foresters call this bark blonding.

Image of dying ash trees with obvious bark blinding.

Bark blonding caused by woodpeckers who strip outer bark to get at EAB larvae.

Impact on Woodland Owners

Lifting of the USDA quarantine removes restrictions on shipping logs across state boundaries. Some states still restrict those shipments. One of those is Minnesota whose state quarantine restrictions remain in place. Until an agreement between our states is reached, logs from Wisconsin will still have to be inspected and meet MN regulations. Since most logs cut in Wisconsin are processed inside the state, landowners should still be able to find markets for their timber. International trade with China dried up when trade talks broke down, so that market is not likely to return any time soon.

Image of snow covered wood pile

Emerald ash borer arrived in Wisconsin on infested firewood and moved quickly to most corners of the state.

Firewood Movement

Firewood brought into state parks must be from local suppliers within 25 miles of the park. This restriction remains in effect regardless of changes to the quarantine rules.

The DNR and Department of Agriculture continue to discourage moving firewood. Moving firewood spreads other pests like gypsy moth, Dutch elm disease and oak wilt.

Where is the Cavalry?

While effective treatments are available for EAB, they are too expensive for large stands. Treatment must be started before significant thinning of the crown takes place. Most importantly, the treatments must be repeated every 2-3 years. Treating ash trees makes sense only in an urban or suburban setting to save a small number of exceptional specimen trees.

Until an effective biological control is available, such as a predatory wasp, there is little hope for Wisconsin ash trees. Woodland owners with significant ash stands should expect to harvest those trees in the very near future.

Making LEMONADE from Lemons

This is the time to plan for replacement of your ash trees. Think about your longterm management goals so that you can take advantage of this harvest to focus in on achieving your aims.

My land was oak savanna prior to settlement. Removal of dying ash trees will open the canopy allowing sunlight to once again reach the forest floor. My plan is to use this as an opportunity to restore that more open setting and focus on re-establishing oaks that were pushed out by more shade tolerant species like ash.

Think of this plague as a way to rewrite the story of your woodland. What do you want you land to look like in forty years? Take this opportunity to reset your dreams and create the woodland you want to leave your grandchildren.

Monday, 04 January 2021

This Week: January 4, 2021

Round-up of weekly news for Wisconsin landowners



Image of pileated woodpecker tearing bark off green ash tree.

Woodpeckers tear off bark looking for emerald ash borer larvae.

An elegy for ash trees

The Citizen, Auburn, NY
December31, 2020

Not until it began its extinction did I start to know Ash. Newly befriending the living in their last stages of vigor can be bittersweet; rich and previously unimagined relationships bloom as decline sets in and I wonder, how did I not know them sooner? What did I miss?

Help wildlife by planting native landscaping

Washara Argus
By News Staff on Wednesday, December 30, 2020

Now is the time to start planning native landscaping to help birds, pollinators and other wildlife next year.

Adding just a few native plants can not only help provide food and shelter for pollinators, birds and other wildlife but can increase your chances of watching wildlife. Rain gardens with specialized native wetland plants can also help handle storm water on a property and help keep lakes, rivers and groundwater clean.

Editorial: Plan now to help save monarch butterflies next summer

Let us take a break from early-winter cold to contemplate a summer wonder: the monarch butterfly. A seemingly delicate creature, practically weightless with gossamer-thin wings, it flits and floats like a leaf in the breeze.

Mammal Tracks on Wisconsin

Wisconsin DNR

The secretive ways of most mammals make them rare sights. Tracks are like an animal’s fingerprints in the wild.

Copyright 2021, Conservation Digest. All rights reserved.


August 2020

Wednesday, 12 August 2020

Kiss Your Ash Trees Goodby

Image or ash trees whose crowns are partially and fully defoliated by Emerald Ash Borer.

Nobody wants the crown layer of their woodland to look like this.

Wisconsin’s woodlands are changing. Emerald Ash Borer (EAB) is causing the greatest die-off of trees in the state since Dutch elm disease arrived in the 1960s. If you have ash trees on your property, you must learn to recognize EAB damage and quickly take action. In Wisconsin, that means black, green or white ash. Time is not your friend; indecision will remove any options. The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) has a website that shows where EAB is prevalent.

First, cruise your timber. Early detection is your best and only defense. Check out the Wisconsin DNR for website for woodlot owners. Treatment must be made to individual trees and completed before 1/3 if the crown is lost.


One of the best ways to identify emerald ash borer damage is through the “D” shaped holes emerging insects leave in the bark. Unfortunately, these holes are approximately 3/16 inch in diameter and may first appear rather high in the tree. The cream colored larvae living under the bark can be 1½ inches long. These are exit holes for the larvae that are emerging to morph into adults.

Most landowners will first spot the infestation by observing leaf loss in the crown. This crown thinning can easily be overlooked or written off as storm damage. By the time the damage is obvious, it is probably too late.

Image of green ash tree with significant bark blonding

Outer layers of bark begin to fall off an ash as EAB larvae eat their way through the sapwood.

Bark blonding takes place when the bark of an infested tree shards to shed the outer layer of its bark. The tree is essentially dead at this point. Blonding occurs because the sapwood below the bark is dead and outer layers of bark are drying out and stuffing off. 

Image of debarked ash trunk with EAB tunnels

Peal away the bark of an infested ash tree and you will find tunnels in the sapwood created by the EAB lava.

The EAB lays it eggs under the bark. When the eggs hatch, they spend two years developing in the cambium layer of the ash tree. They eat the sapwood, burrowing tunnels are they feed. The tunnels interrupt nutrient flow. Eventually, limbs and even the trunk die as tunnels completely cut the supply of sugars and water.

What’s Next?

If tree you want to save is less than 47″ around at chest height, you may be able to treat it yourself. You can apply a liquid soil drench homeowner product for about $20-35/year. An arborist should treat larger trees or those with special circumstances. Their treatments involve directly injecting trees under the bark. Those treatments typically cost several hundred dollars and must be repeated every 2-3 years.

Recent research suggests that EAB density moves through a forest like a wave (Sadof, 2017). Chemical treatment is most effective when begun early and should be continued for approximately ten years after initial infestation. At that point most neighboring trees have already died and the great mass of EAB have moved on to greener pastures (forests).

The cost or removing dead ash trees start at $1,000 and more, depending on size and location. Your only choice, if you have too many trees to treat, may be to conduct a timber harvest.

More Informaiton

The Emerald Ash Borer Information Network has the latest information about he pest and how to control it.


Sadof, Clifford S., Hughes, Gabriel P., Witte, Adam R., Peterson, Donnie J., and Ginzel, Matthew D. Tools for Staging and Managing Emerald Ash Borer in the Urban Forest, Arborculture & Urban Forestry, 43(1): 15-26. 2017.



November 2018

Thursday, 15 November 2018

Why Are Invasives So Bad?

photo of Phragmites also called common reed grass.

Phragmites creates stands so dense that wildlife cannot move though it.

For the past year, I have been fielding questions about conservation, biology and invasive species on the forum Quora. It gives me a chance to hear the questions and concerns that people have and give back to the community. Questions I think Conservation Digest readers might be interested in have found their way into the FAQ section of this website.

This question appeared last week. Below is my response. After reading it, I hope you see what motivated me to create the website and write this blog.

Invasive garlic mustard, honeysuckle and buckthorn have all but wiped out spring wildflowers from the woodlands of southern Wisconsin. Japanese knotweed crowds out everything along stream banks where it becomes established. Wild parsnip causes serious chemical burns when the sap gets onto the skin. Cattails take over wetlands reducing open water for waterfowl and displacing the native sedge, reeds and wetland wildflowers. Phragmites (common reed) creates such dense stands that waterfowl cannot use the wetland.

Those four sentences capture a small portion of the problems caused by invasive plants that plague natural areas in Wisconsin. They only begin to scratch the surface of the issues created by invasive species.

Check out our new webpage About Invasive Species to learn more about the problem and how to prevent new invaders from getting a foothold in Wisconsin.

Tuesday, 13 November 2018

About Invasive Species

photo of Phragmites also called common reed grass.

Phragmites creates stands so dense that wildlife cannot move though it.

It can be really confusing when people talk about invasive species. What exactly are they and why should I care? These questions are especially important for landowners because invasive plants, and to a lesser extent invasive animals, can cause real and lasting damage. Because many of them have been around for years, a property owner may not even know they these unwanted guests or why they pose a problem.

Picture of common buckthorn leaves

Common buckthorn branch. Photo credit: University of Georgia.

Problem Plants

Invasive garlic mustard, honeysuckle and buckthorn have all but wiped out spring wildflowers from the woodlands of southern Wisconsin. Japanese knotweed crowds out everything along stream banks where it becomes established. Wild parsnip causes serious chemical burns when the sap gets onto the skin. Cattails take over wetlands reducing open water for waterfowl and displacing the native sedge, reeds and wetland wildflowers. Phragmites (common reed) creates such dense stands that waterfowl cannot use the wetland.

Those four sentences capture a small portion of the problems caused by invasive plants that plague natural areas in Wisconsin. They only begin to scratch the surface of the issues created by invasive species.

Staying with plants for a moment, think about how many millions of dollars farmers and ranchers spend every year controlling weeds. They pass along those costs to us in the price of our food. Pesticide drift causes both economic and health threats to farm workers and neighbors. Chemical residues are a problem for consumers.

Picture of zebra mussels.

Zebra mussels colony. Photo credit: USDA

Not Just Weeds

Moving past invasive plants, Zebra mussels cause millions of dollars of damage to power plant systems while reducing the electricity they can generate. Those same invasive mollusks consume the available food for native insects and shell fish causing the base of the food chain to collapse. The lakes they invade turn into water deserts.

Those who grew up in Wisconsin before 1975 will remember the curse of alewife. They are a small invasive fish whose populations exploded in the 1960s. Alewife consumed all the small fish and insects that form the bottom of the food chain. That effectively destroyed the commercial lake trout fishery in Lake Michigan. Fish biologists fought over how to control them and settled on introducing Coho salmon to the great lakes. While coho reduced the alewife and created a new game fishery, native lake trout stocks have not recovered as hoped.

Emerald ash borer (EAB) is an invasive beetle that is destroying  Wisconsin’s green ash trees. Homeowners, public works departments and park managers planted millions of green ash trees over the past half century. That makes them one of the most popular trees on the urban Wisconsin landscape. Whole neighborhoods to lost their terrace trees to EAB. Many parks have gaping holes in their shade canopies.

The emerald ash borer is also wiping out the native black ash, which Native American tribes in Wisconsin call basket wood. Ho Chunk woven wood baskets are purchased by collectors around the world. The loss of black ash means an important cultural and economic resource disappears from the state.

Long History

Invasive species are nothing new. Farmers introduced sheep to northern Wisconsin during World War II. Sheep brought with them a liver fluke that nearly wiped out the white tailed deer population in those counties. Dutch elm disease swept through Wisconsin in the 1960s doing away with a large percentage of our native elm trees. Recently, the pest has returned to attack many of those trees it missed the first time, as well as their offspring.

As long as people get on planes and ships, moving around the world and bringing living stuff with them, the threat for bad things happening will be there. Sometimes invaders are introduced on purpose because the they pose is not understood. Other times pest species sneak in as weed seed in grain, or insect eggs in pallets.

Picture of Asian longhorn beetle on human finger.

Asian longhorn beetle. Photo credit: USDA

Solutions Are Simple But Difficult

There is a way to stop them from becoming a serious problem. The key is early detection and eradication. In 1998, Asian longhorn beetles were discovered on the north side of Chicago. This is a pest that kills maples and other trees in genus Acer. The black and white beetle spreads with amazing speed. The beetles were traced back to pallets that arrived from China that were delivered to a local hardware distributor. Local officials jumped into action and in what was seen by some as over reaction, cut down 1,500 in northeastern Illinois. This quick response stopped the invasion in its tracks, so that by 2003 there were no new infestations.

Be Part of the Solution

You can help. Check out the Wisconsin DNR invasive species website and learn how you can identify them. Report suspicious plants or pests to the DNR using their reporting website. Citizen science is becoming popular in the state. The Wisconsin Early Detection Network is a program of the UW Extension Weed Science program. It encourages landowners to actively get involved in locating and reporting new invaders. The DNR will eradicate prohibited species preventing major problems.

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May 2017

Monday, 15 May 2017

Emerald Ash Borer: Landowner Workshop

Want to know how to tell whether your ash trees are being attacked by the Emerald Ash Borer? What do you do to protect your ash trees? What can be done with wood from ash trees that cannot be saved? All these questions and more will be answered at a special workshop, “Save your ash trees!” hosted by the Golden Sands Resource Conservation and Development Council.

The workshop will happen on Saturday June 3, 2017 from 9:30am to 3:30pm at the Mosquito Hill Nature Center, N3880 Rogers Rd, New London, WI. Registration is $15 and includes lunch. Seating is limited and the event will run rain or shine so dress for the weather!

Contact Amy Thorstenson (715) 343-6215 for more information or download and return their registration form.