Statewide Forest Health

Effects Of Winter Take Toll On Trees

Posted on by akabelowsky
A group of planted white pine saplings with varying amounts of brown needles caused by winter desiccation.

Minor to moderate damage to white pine needles caused by winter desiccation. Photo: Wisconsin DNR

 

By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg

michael.hillstrom@wisconsin.gov

Winter damage is one of the most commonly reported tree issues in early spring. The damage may be minor, such as off-color needles that are quickly replaced, but could be as severe as partial- or whole-tree mortality.

Winter desiccation occurs when conifers begin photosynthesizing on warm, windy days in late winter or early spring. Conifers may dry out in these conditions if they use their stored water and cannot replace it because the ground is still frozen.

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USDA Seeks Donations Of Infested Ash Trees

Posted on by akabelowsky

By Kyle Loughlin, Field Team Lead, USDA-APHIS
kyle.m.loughlin@usda.govor 734-732-0025

A window cut into a tree’s bark shows signs of emerald ash borer infestation.

USDA staff cut a ‘bark window’ in green ash to uncover signs of emerald ash borer. Photo: US Department of Agriculture

The U.S. Department of Agriculture (USDA) is asking Wisconsin landowners for help in the battle against emerald ash borer (EAB).

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.

The USDA is asking Wisconsin landowners to donate live ash trees infested with EAB to support USDA’s biological control program. The staff will use the wood to rear EAB’s natural enemies, which will then be released in Wisconsin and 31 other EAB-infested states and Washington, D.C.

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Oak Harvesting During A Cold Spring

Posted on by akabelowsky

By Kyoko Scanlon, DNR Forest Pathologist, Kyoko.Scanlon@wisconsin.gov or 608-235-7532

Oak trees in a snow-covered field

The colder weather in spring 2023 might delay the DNR’s recommendations to avoid trimming or cutting from April through July. Photo: Wisconsin DNR

It’s April, but in much of Wisconsin the weather doesn’t seem to have gotten the message.

You may be wondering if the oak harvesting restriction that started on April 1 (south of the tension zone) and will start on April 15 (north of the tension zone) might be pushed back due to unusually cold temperatures.

Even with unusually cold springs, we remain consistent with the same general messages: “Stop pruning in April” and “Avoid harvesting in April (south of the tension zone).” We do this for the following reasons:

  • It is difficult to spread the word in a timely manner about when to begin the restrictions. Often when spring comes late, it arrives suddenly; in those cases, before we know it, we’ve entered the high-risk period.
  • We want to be consistent in stressing the messages of the existing oak harvesting guidelines, so that the public is aware of them.

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Make Plans To Control Spongy Moth Before The Eggs Hatch

Posted on by patricialindquist

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

Spongy moth (formerly known as gypsy moth) egg masses typically begin to hatch in April as temperatures warm. Each mass that hatches may produce up to 1,000 leaf-eating caterpillars.

Now is a great time to inspect your trees for egg masses and treat or remove any masses within reach. Wisconsin weather has been favorable for this pest over the last three years and populations have grown.

Photo of three spongy moth egg masses on the underside of a pine branch in Walworth County.

Three spongy moth egg masses on the underside of a pine branch in Walworth County. Photo: Bill McNee, Wisconsin DNR.

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Treat Your Valuable Ash Trees Against Emerald Ash Borer This Spring

Posted on by patricialindquist

By Bill McNee, Forest Health Specialist, Oshkosh, Bill.McNee@wisconsin.gov or 920-360-0942

Property owners with healthy, valuable ash trees are encouraged to treat them with insecticide this spring to protect against emerald ash borer (EAB). The pest is currently the most damaging threat to trees in Wisconsin, killing more than 99% of the ash trees it infests.

Woodpecker damage during the winter is often the first sign that an ash tree is infested. The birds remove pieces of bark while feeding on EAB larvae inside the tree. Insecticide treatment of infested ash trees is more likely to be successful if the trees have low or moderate levels of woodpecker damage.

Now is a good time to consider insecticide protection, because the treatments are typically done between mid-April and mid-May. Ash (in the genus Fraxinus) is the only type of tree that needs protection against EAB. Mountain ash and prickly ash do not need protection because the insect does not attack them.

Ash tree branch in West Allis has been damaged by woodpeckers. Sections of bark are missing, exposing the tree’s light brown wood.

This ash tree branch in West Allis has been damaged by woodpeckers feeding on EAB larvae beneath the bark.
Photo: Bill McNee, Wisconsin DNR.

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Fighting Invasive Plants

Posted on by grace.hershberg

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.

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Climate Impacts On Forest Insects

Posted on by grace.hershberg

Climate change may impact forest insects in a variety of ways that will likely put stress on the forest. Warmer temperatures, altered precipitation patterns, more frequent extreme weather events and longer growing seasons are a few consequences of climate change that may shape the effects of insects in future forests. A changing climate may impact insects as:

  • Warmer temperatures accelerate larval development and increase insect populations.
  • Extended growing seasons allow for more generations of insects each year.
  • Altered leaf chemistry modifies insect host plant preferences.
  • Extreme weather events damage and stress forests, resulting in attacks by native and non-native insects.
  • Warmer temperatures allow insects to expand their range and occupy new areas.

Many examples of insects responding to climate change have already been documented. Two examples are:

1) Mountain pine beetle expanding its geographic range in the western U.S. and infesting a new host tree species during the most recent outbreak; and

2) Eastern larch beetle having an additional generation each year that has resulted in an unprecedented 20-year outbreak in Minnesota. Continue reading “Climate Impacts On Forest Insects” →

Statewide Forest Action Plan Strategies

Posted on by grace.hershberg

Forest health experts from federal and state government, tribes and universities worked together to create the two goals and numerous strategies featured in the forest health chapter of Wisconsin’s 2020-2030 Statewide Forest Action Plan. Many goals and strategies in other chapters are also relevant to forest health efforts.

These goals are high-level statements about the desired future conditions of Wisconsin forests. The forest health chapter goals are:

  1. Forested land and ecosystem functions are maximized, while losses due to forest health threats are minimized
  2. Forest health threats are identified and managed in a fashion that is adaptive and responsive to multiple values

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Forest Health In The Statewide Forest Action Plan

Posted on by grace.hershberg

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” →

Acorn Weevils Make Acorns Float

Posted on by brenna.denamur

Article By: Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665

Have you seen small round holes in acorns? These holes are a sign of acorn weevil damage that can occur in all Wisconsin oak species.

In a pile of brown and tan acorns, two have small round pencil-tip sized holes caused by acorn weevil larvae burrowing out from the inside.

Two acorns show exit holes of acorn weevils. / Photo Credit: Wisconsin DNR

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