Amur cork tree (Phellodendron amurense) is a relatively new invasive plant found in at least four Wisconsin counties. It is classified as Prohibited under Wisconsin’s invasive species law, NR 40. The female cork tree cannot be possessed, transferred, transported or introduced in Wisconsin. We ask that you report this tree to DNR because it is invasive here and in other states and DNR is mounting control efforts before it becomes widespread. DNR works with property owners to achieve this by providing advice, tools and resource opportunities. Continue reading “Amur cork tree is an emerging threat to Wisconsin forests.”
Wind and hail damage caused by the April 9, 2017 storm
The National Weather Service local storm reports map shows hail was most commonly reported, with some tree damage, and one tornado (west of Wausau).
During the night of April 9-10, 2017 a strong line of storms moved through Wisconsin. Reports ranged from pea sized to tennis ball sized hail, with most stating quarter sized hail. Immediately following the hail, winds picked up and straight line winds took down trees in a number of areas around Oneida and Vilas Counties. The National Weather Service reports that there was a tornado touch down west of Wausau, and reports of tree damage showed up in the National Weather Service’s local storm reporting page.
Damage to trees from hail was most noticeable on the conifers which had needles knocked off, creating a green carpet below the trees. Fine twigs on white pines were damaged by the hail and some fine branch mortality may occur if the twigs were damaged badly enough. Damaged red pine may be more prone to getting diplodia where the twigs were wounded.
April 9 hail wounds on white pine branches (yellow arrows) appear small but will dry, and the bark will crack further as spring progresses. Some branch dieback may occur.
April 9 hail wounds on young aspen and the fine branches of mature aspen appear as scuffed bark (yellow arrows). These will callus over relatively quickly.
Small wounds on young aspen should callus over.
Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.
Herbicide damage to trees
Herbicide damage can resemble other tree problems such as branch dieback, foliage discoloration, and premature leaf or needle drop. Look for certain clues to help narrow down whether it is a weather related issue, insect or disease issue, or a potential herbicide issue.
Forest tent caterpillar egg mass surveys indicate low populations again
Newly hatched forest tent caterpillars with the egg mass they emerged from. Egg masses are laid in mid-summer and remain on the tree through the winter.
Low numbers of forest tent caterpillar egg masses were found recently during surveys in Vilas and Oneida Counties. Forest tent caterpillar is a native insect that has periodic outbreaks. Our last outbreak was from 1999-2002, and they typically have outbreaks every 10-15 years. Last year I noticed a few more caterpillars than the previous year, but there was no noticeable defoliation. So far egg mass surveys indicate another year of low populations, although there may be areas with locally higher populations. Forest tent caterpillar eggs will start hatching soon, timed to closely match the emergence of aspen leaves.
Eastern tent caterpillars hatch from eggs and immediately start to create a web nest. Young caterpillars are shown on a small nest.
Eastern tent caterpillars do not follow a typical outbreak pattern and tend to be present at some low level every year. They create web nests early in the spring, preferring black cherry trees, crabapple trees, or other stone fruits. When webs are small the caterpillars can be easily crushed or sprayed. As webs get bigger you may have to use a rake to pull them out of the tree. It is not necessary to prune the branch out of the tree. Doing so will actually cause more damage to the tree than the defoliation caused by the caterpillars, because trees can more easily send out additional leaves than grow a branch to replace one you prune out. Please do not burn nests out of the trees as this could start a wildfire.
Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.
Emerald ash borer new locations in Wisconsin
EAB quarantine and detections map. Counties shaded in tan are quarantined for EAB, green areas are townships and municipalities where EAB has actually been identified.
Emerald ash borer (Agrilus planipennis) continues to be found in new areas. Wisconsin continues to track EAB at the municipality or township level; quarantined counties are shown in tan and known infested areas are shown in green on the map.
If you know you have EAB, please contact us with that information so we can verify the infestation and update the maps. If your area:
- is not shaded in green on the map please contact DNR or
- is not shaded at all on the map please contact DATCP.
You can reach both agencies from the menu options when you call 1-800-462-2803.
New county quarantines
- none
New finds in counties already quarantined
- Adams/Columbia/Juneau/Sauk counties — city of Wisconsin Dells
- Brown County — village of Allouez
- Crawford County – town of Bridgeport
- Columbia County – town of Lowville
- Columbia/Dodge counties – village of Randolph
- Dane County – village of DeForest
- Green County – town of Monroe
- Jackson County — towns of Melrose and North Bend
- Jefferson County – towns of Aztalan, Farmington, Hebron, and Sumner
- La Crosse County – town of Shelby
- Monroe County – city of Sparta
- Rock County – towns of Clinton, Harmony, Johnstown, and Lima
- Sheboygan County – village of Kohler
- Trempealeau County — towns of Ettrick, Gale and Preston
Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.
Emerald ash borer trapping in 2017
The Wisconsin DNR forest health team is planning to trap for emerald ash borer (EAB) at 20 locations in 2017.
EAB trap locations in northwest Wisconsin in 2017.
EAB trap locations in northeast Wisconsin in 2017.
Traps will mostly be placed on state properties. A couple traps will be placed on county land where state properties are not in the local area. Traps are deployed close to 400 growing degree days so they are ready when EAB adults start emerging at approximately 450 degree days. In 2016, southern Wisconsin hit 450 degrees days (modified base 50°F) in late May.
Written by: Mike Hillstrom, forest health specialist, Wisconsin Dells (Michael.Hillstrom@Wisconsin.gov), 715-459-1371.
Emerald ash borer trapping by a few northern county forestry departments
Douglas, Oneida, and Sawyer County Forestry Departments will be trapping emerald ash borer on select sites across their properties this year. As needed, the DNR Forest Health Program and the Department of Agriculture, Trade and Consumer Protection (DATCP) will provide guidance to county forest departments that are responsible for purchasing, installing and monitoring their EAB purple prism traps.
Any new EAB detections will be tracked at the state level and may be used by forest managers to prioritize stand management based on EAB proximity, and by communities to inform the timing of ash management in community forests.
The abundance of ash forest resources and limited known distribution of EAB in the state’s north spurred interest by these counties to continue trapping.
Written by Paul Cigan, forest health specialist, Hayward (Paul.Cigan@Wisconsin.gov), 715-416-4920.
New staff members
Recently the Urban Forestry Program has filled three positions: West Central Urban Forestry Coordinator, Urban Forestry Grant Specialist, Urban Forest Assessment Specialist. The team is looking forward to the value and expertise these individuals will bring.
Celebrate Arbor Day
In 1854, J. Sterling Morton, a prominent newspaper editor and publisher, moved from Detroit to the area that is now Nebraska. He and other pioneers noticed a lack of trees, which were needed to act as windbreaks to stabilize the soil and to give shade from the sun. Morton planted many trees around his own home and encouraged others to do the same.
New Tree City USA designees
Congratulations to Wisconsin’s newest Tree City USA designees – Gays Mills, Milton, Mukwonago, and Stratford. The Tree City USA program, sponsored by the Arbor Day Foundation and administered in Wisconsin by the DNR, provides communities with a tangible goal and national recognition for their community forestry efforts.