Woodland owners

Got Buckthorn?

Article By: Jaqi Christopher, DNR Forest Invasive Plant Specialist, Rhinelander, Jacquelyn.Christopher@wisconsin.gov

Common buckthorn with green leaves and dark purple/black berries.

Common Buckthorn leaves with berries. Notice the prominent leaf veins and small thorns at the end of the branches.
Photo Credit: Wisconsin DNR

You can find buckthorn just about anywhere these days. It can sneak into the tidiest of gardens, as well as woodlots and forests. It aggressively outcompetes native plants and even tricks wildlife into spreading it to new areas. For example, birds are enticed to eat the berries, but buckthorn berries have a laxative effect, robbing birds of nutrition and ensuring the seeds are spread quickly across the landscape. 

There are two species of buckthorn in the state: common buckthorn and glossy buckthorn. The plants are similar in appearance and equally harmful to native ecosystems. Common buckthorn and glossy buckthorn grow to be 20-25 feet tall. Glossy buckthorn has round, glossy leaves with prominent leaf veins and a smooth margin, while common buckthorn has dull green leaves with small teeth on the margin. The branches of common buckthorn will have a small thorn at the tip of the twig. The bark is similar in both species, being rough and flakey. Native cherry and plum trees have similar bark, but buckthorn can be identified by leaf appearance andby cutting into the bark to expose the bright yellow and orange wood underneath.

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Take Action! Look For Gypsy Moth Egg Masses

Article By:  Bill McNee, DNR Forest Health Specialist, Oshkosh
bill.mcnee@wisconsin.gov or 920-360-0942

In 2021, gypsy moth populations increased for a second consecutive summer due to favorable weather conditions. Populations typically increase with an average or mild winter, below average spring precipitation and above average May through June temperatures.

Regional variation in weather can result in significant differences in populations. If weather conditions are favorable again in 2022, the most noticeable increase in caterpillar numbers would likely occur in southern counties, where conditions were driest during this past spring and summer.

Populations experience the fastest growth rate and are first noticed on:

  • Dry sites with sandy soil and abundant oak
  • Mowed lawns with preferred tree species (oak, crabapple, birch, etc.)
  • Large oaks (bur, in particular) with rough bark, especially on or adjacent to mowed lawns
Five small gypsy moth egg tan masses on a single tree branch in Walworth County.

Gypsy moth egg masses found in Walworth County in fall 2021.
Photo Credit: Gypsy moth egg masses KMSU

 

 

 

 

 

 

 

 

 

 

 

 

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Protect Oak Trees From Oak Wilt By Pruning After July, Not Before

By Don Kissinger, DNR Urban Forester, 715-348-5746 or Don.Kissinger@wisconsin.gov; Paul Cigan, DNR Forest Health Specialist, 715-416-4920 or Paul.Cigan@wisconsin.gov

The Wisconsin Department of Natural Resources (DNR) urban and forest health specialists recommend not pruning or cutting oaks from April through July to protect oak trees from the often fatal oak wilt disease.

The spring season often draws property owners outdoors to soak up rays of long-awaited sunlight, breathe in some fresh air and begin seasonal yard maintenance and cleanup projects. While spring is a time to dust off yard tools like rakes, shovels and weed clippers, when it comes to the health of oak trees, keeping those chainsaws and trimming tools a safe distance away will go a long way to ensure that your trees stay healthy for many more spring seasons to come.

Sap-feeding beetle on a diseased oak tree in Sawyer County.

Sap-feeding beetle on a diseased oak tree in Sawyer County.

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New emerald ash borer county detections: an update from DATCP and DNR

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), in partnership with the Wisconsin DNR, has detected emerald ash borer in four new counties (Dunn, Oconto, Pepin and Shawano). Please read this DATCP article for more information.

Adult emerald ash borer beetle.

Adult emerald ash borer beetle.

If you are a landowner and have questions about ash trees in your woodlot, contact your local DNR forester using the Forestry Assistance Locator.  

Gypsy moth populations rebound in 2020 – look for egg masses this fall

By Bill McNee, forest health specialist, Oshkosh, bill.mcnee@wisconsin.gov, 920-360-0942

The summer of 2020 saw a major rebound of the gypsy moth population after several years of weather conditions that were unfavorable for the non-native, defoliating pest. A mild winter and average summer temperatures/precipitation during the caterpillar stage were all favorable for a population increase.

Gypsy moth egg masses are tan-colored lumps about the size of a nickel or quarter.

Female moth laying eggs on tree trunk.

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Interactive HRD stump treatment guidelines available online

The HRD stump treatment guidelines are now available in an interactive format to make it easier to obtain stand-specific recommendations. You can find the link called “Interactive guidelines” on the right side bar under “Additional Resources” at the DNR HRD webpage. The user will be asked a series of questions and then a stand-specific recommendation will be provided at the end. The interactive guidelines incorporate Exceptions and Modifications described in the guidelines. Check it out!        

Report surviving elm in the forest

You can help keep native elm trees in the forests of Wisconsin! The US Forest Service continues to work on a project to identify Dutch elm disease (DED)-tolerant American elms native to Wisconsin forests. The goal of the project is to identify and propagate survivor American elms, especially from the colder hardiness zones 3-4, and develop a series of clone banks. Selections would eventually be screened for tolerance to DED. Ultimately, the goal is to make DED-tolerant American elm available for reforestation in northern areas, particularly as a component on sites currently forested by black ash.

If you live in hardiness zones 3 and 4, please look for evidence of surviving elms and report them to the US Forest Service.

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Educational HRD video now available

By Kyoko Scanlon, forest pathologist, Kyoko.Scanlon@wisconsin.gov, 608-235-7532

The Wisconsin DNR recently created a short video on Heterobasidion root disease (HRD) to compliment the updated guidelines that were released in 2019. The 5-minute educational video covers HRD biology, its significance as a tree disease, signs and symptoms, as well as preventative measures that landowners can take to reduce its introduction and spread. This is a great video for forestry professionals, landowners and the general public to learn more about HRD. Continue reading “Educational HRD video now available”

USDA seeks ash trees to battle EAB

Emerald ash borer (EAB) is an invasive insect from Asia that was first introduced into the United States in 2002. Since its discovery, EAB has caused the death and decline of tens of millions of ash trees. Today, the U.S. Department of Agriculture (USDA) is using ash trees against the pest to help preserve and protect the tree species. Staff in the USDA EAB biological control (biocontrol) program are asking Wisconsin landowners in Sheboygan, Fond du Lac and Door counties to help by donating infested ash trees for use in raising wasps that attack and kill EAB.

A square window of bark is removed from green ash to uncover EAB larvae underneath.

USDA staff cut a “bark window” in green ash to uncover signs of EAB.

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Upcoming forest health events

Learn more about forestry and forest health issues with these upcoming events in February and March! We link to conference brochures and webpages where you can find detailed information, including registration prices and deadlines where applicable. Continue reading “Upcoming forest health events”