Invasive plants are a major threat to Wisconsin’s forests, highlighted in the forest health chapter of Wisconsin’s Forest Action Plan. Invasive plants limit tree regeneration, reduce plant diversity and increase management costs. Recent Forest Inventory and Analysis data from the USDA Forest Service found that more than half of forest sites surveyed in Wisconsin had two or more invasive plant species. Forest landowners should learn to recognize common invasive plants like buckthorns, honeysuckles and garlic mustard. Mobile applications are a handy tool for landowners to learn to identify the plant species in their woods (e.g., PlantNet, iNaturalist) and report invasives (e.g., EDDMapS). For information about the regulated invasive plants in Wisconsin visit the Wisconsin Department of Natural Resources’ (DNR) Terrestrial Invasive Species page.
Invasive plant
Forest Health In The Statewide Forest Action Plan
The forest health chapter of Wisconsin’s 2020-2030 Statewide Forest Action Plan, completed in June 2020, highlights the impacts of insects, diseases, invasive plants and worms in Wisconsin’s forests.
Forest health experts from government agencies, universities and tribes worked together to evaluate these current impacts. They then developed goals and strategies to help the forestry community refine how it will invest state, federal and partner resources to address major forest health management and landscape priorities over the next ten years.
Forest health is a critical component of the plan because native and non-native pests increase tree mortality to a level that negatively affects forest stocking levels, clean water, wildlife habitat and raw material for wood products. This causes economic losses and undesirable management outcomes. Continue reading “Forest Health In The Statewide Forest Action Plan”
Got Buckthorn?
Article By: Jaqi Christopher, DNR Forest Invasive Plant Specialist, Rhinelander, Jacquelyn.Christopher@wisconsin.gov
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.
Oriental Bittersweet: A Bitter Beauty!
Article By: Jaqi Christopher, Invasive plant specialist & Mary Bartkowiak, Invasive plant coordinator
Just as the leaves begin to shift from summer green to the fall shades of gold, orange, red and bronze, the fruits of Oriental bittersweet explode on the scene with their very own show-stopping colors of bright gold and red.
The sight of these vines full of colorful berries may tempt the casual observer to take these berry-filled branches home to use as fall decorations or to plant in their own garden. This, however, would be a mistake, as this striking plant is a serious threat to native ecosystems. Oriental bittersweet is a restricted species under Wisconsin’s Invasive Species Rule NR40. This makes it illegal to transport, transfer or introduce Oriental bittersweet statewide.
Oriental bittersweet is an aggressive-growing woody vine that invades forests, woodlands, fields and hedgerows. The vines twine up trees, smother the crown and girdle trunks with their thick woody stems. In fact, the sheer weight of the vine can cause tree crowns to break and collapse and whole trees to uproot. Additionally, large mats of bittersweet can shade out native plants.
Oriental bittersweet vine girdles tree trunks. Photo Credit: Minnesota Department of Agriculture
Oriental bittersweet vine girdles tree trunks. Photo Credit: University of Illinois’ Chris Evans
Invasive Plant Management Factsheets
Tree-of-Heaven. Photo credit: Richard Gardner, Bugwood.org
The Renz Lab at the University of Wisconsin-Madison Division of Extension has created a series of factsheets discussing the identification and control of many common invasive plant species problematic to natural areas.
Mechanical, cultural and chemical control methods are discussed in detail, including the effectiveness of the control method and appropriate rates and timings of chemical control applications.
Wild Cucumber Will Catch Your Attention
Plants that are pokey, viney or spread quickly across the landscape sometimes seem alarming when you discover them in your backyard or woods or when they’re spotted along the highway. Wild cucumber has all these characteristics but is not as ominous as it seems.
Wild cucumber (Echinocystis lobata) is a vine native across the U.S. and found throughout Wisconsin. It has maple-like star-shaped leaves and has pale greenish-white flowers from July through September. A single plant is self-fertile but can also be pollinated by bees, wasps and flies. It produces a pod-like fruit with spikes resembling a cucumber which is unsafe to eat. Each pod produces four seeds that fall to the ground when the pod is ripe. The pods may persist into the winter and become thin brown shells.
Star-shaped leaves, pale flowers, and cucumber fruit of wild cucumber. Photo: Bugwood
Giant Hogweed: Rare But Harmful
By Bernie Williams, DNR Invasive Plant Specialist. Bernadette.Williams@wisconsin.gov or 608-444-6948.
Giant hogweed is a non-native, invasive plant that has gradually gained a foothold in the northeastern U.S. Once popular for its massive size and white umbrella-like flowers, it was introduced as an ornamental as early as 1917. Now known for its harmful blisters, it is recognized as a public health hazard and controlled wherever possible.
Characteristic purple blotches and white hairs on green stem of giant hogweed. Photo credit: Herkulesstaude_Fritz Geller-Grimm
Wisconsin DNR 2020 Forest Health Annual Report
By Elly Voigt, DNR Forest Lab Technician and Communications Specialist, Eleanor.Voigt@wisconsin.gov
The Wisconsin Department of Natural Resources’ Forest Health team recently completed the 2020 Forest Health Annual Report. The report summarizes impacts from pests, diseases and weather on the health of Wisconsin’s forests. Highlights from 2020 include:
• An update on emerald ash borer in Wisconsin, including newly confirmed counties
• New township detections of oak wilt
• Flooding and tornado damage
• Summary of state nursery studies
For access to the report, visit the link here.
Nominations Open For “Invader Crusader” Awards
By Tara Bergeson, DNR invasive species team leader, 608-264-6043, Tara.Bergeson@wisconsin.gov
Nominations are being accepted through March 23, 2020 for “Invader Crusaders.” These awards go to individuals, groups and organizations who made outstanding contributions in 2019 to prevent, control or eradicate invasive species that harm Wisconsin’s native wildlife and wetlands, forests, prairies, lakes and rivers.
The Wisconsin Invasive Species Council is seeking nominations for exemplary efforts at addressing issues surrounding terrestrial and aquatic invasive plants and animals. The awards will be presented in both volunteer and professional categories.
To submit a nomination, download and fill out a nomination form available on the Wisconsin Invasive Species Council’s Invader Crusader webpage. Email the completed form to invasive.species@wisconsin.gov by March 23.
A panel of Wisconsin Invasive Species Council members will review the nomination materials and select the award winners. All nominators and winners will be notified by mid-May 2020.
Recipients of the awards will be recognized at an awards ceremony on June 11 at Olbrich Botanical Gardens in Madison.
Invasive species are nonnative plants and animals that cause great ecological, environmental or economic harm, and some can even affect human health. Once an invasive species becomes established in an area, it can be difficult to control. The most important action Wisconsinites should take is to avoid moving invasive species or the materials that might harbor them to new places.
To learn more about what you can do to stop the spread of invasive species, visit the DNR invasive species webpage.
2019 Forest Health Annual Report now available
Forest health annual report now available for 2019.
The Forest Health Annual Report summarizes notable impacts for that year of pests, diseases and weather on the health of Wisconsin’s forests. The report is a collaborative product created by DNR forest health specialists from around the state. It outlines the damage and spread of both native and invasive pests and diseases during that year and puts these into context of observations from previous years. Management programs and their results are also described. Highlights from the 2019 annual report include:
- Dramatically increased decline and mortality from emerald ash borer in southern WI
- New county and township detections of oak wilt
- Precipitation record and major storm damage
- Summary of state nursery studies on Diplodia sapinea, galls on jack pine seedlings, and testing new fumigants to replace methyl bromide
This year’s annual report is available on the DNR forest health homepage. Previous annual reports, including historical reports dating back to 1951, are archived and available upon request. Contact your local forest health specialist if you’d like digital copies of any archived annual reports.