Northwest WI Forest Health

Eastern spruce dwarf mistletoe

Eastern spruce dwarf mistletoe (Arceuthobium pusillum), is a parasitic flowering plant that can be very damaging to black spruce, although it can also attack other spruces. Occasionally you’ll see it on other species growing amidst spruce such as tamarack, white pine, red pine, jack pine, or balsam fir. Continue reading “Eastern spruce dwarf mistletoe”

Forest tent caterpillar update

Forest tent caterpillars do not make web nests but may congregate and rest in groups on the bark.

Forest tent caterpillars do not make web nests but may congregate and rest in groups on the bark.

Caterpillars hatch from the eggs of a forest tent caterpillar egg mass.

Caterpillars hatch from the eggs of a forest tent caterpillar egg mass.

Forest tent caterpillars are hatching. Egg mass surveys were conducted in Iron, Ashland, Bayfield, Sawyer, Polk, Washburn, Douglas and Burnett counties, and no egg masses were observed. Surveys in Vilas, Oneida and Forest counties found very few egg masses.

Based on this information we expect low numbers and minimal defoliation again this year, but please let us know if you see forested areas with more significant defoliation.

Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.

 

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).

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.

Hail wounds on fine branches of white pine appear as dents with cracks in the bark. Those cracks will dry further as spring progresses and the cracked areas will increase slightly in size.

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.

Hail wounds on young aspen and the fine branches of mature aspen from the April 9-10 storm appear as scuffed bark (yellow arrows). These will callus over relatively quickly.

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. 

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.