Urban Forestry News

Woodpecker damage is easy to spot during the winter

By Linda Williams, forest health specialist (Woodruff), Linda.Williams@wisconsin.gov, 715-356-5211 x232

Two elm trees with varying levels of bark stripping caused by woodpeckers feeding on larvae beneath the bark.

Two elm trees with varying levels of bark stripping caused by woodpeckers feeding on larvae beneath the bark. Photos: Linda Williams

Have you noticed any trees this winter with the bark partially or mostly removed? These trees can stand out dramatically during the winter. Woodpeckers remove outer layers of bark so that they can more easily punch their beaks through the remaining bark to get at the tasty, plump larvae underneath. The three most common trees that you’ll spot this damage on in Wisconsin are elm, tamarack, and ash. So, what’s going on?

On elm, there are three bark beetles of interest. One is a native beetle, and two are exotic species – the smaller European elm bark beetle and the banded elm bark beetle. Adult bark beetles chew their way under bark and lay eggs during the spring or summer. The eggs hatch, and larvae begin feeding in the tree layers under the bark. Going into winter, larvae are plump and delicious (if you’re a woodpecker), and it’s these juicy morsels for which the woodpeckers will strip the outer bark from the tree, sometimes starting at the ground and working all the way to the top. Elm trees will often appear a rich red or burgundy color when outer bark is removed. The U.S. Forest Service offers a document with additional information on elm bark beetles, as well as photos of each of them.

Close-up of tamarack bark, showing the larvae of Eastern bark beetle at the tip of my (broken) knife. Woodpeckers remove the outer bark to make it easier to access these tasty morsels.

Close-up of tamarack bark, showing the larvae of Eastern bark beetle at the tip of my (broken) knife. Woodpeckers remove the outer bark to make it easier to access these tasty morsels.

Tamarack trees (often referred to as larches) are attacked by a bark beetle as well. Eastern larch beetles attack stressed tamarack trees, although sometimes the stress is so minor that it’s not easily identifiable. The wet weather we had throughout the 2017 growing season definitely stressed some of tamaracks in Wisconsin; having roots in fully saturated soils for too long a period when the tree is actively growing can cause root mortality. Tamarack that have had the outer bark stripped off will appear dark red in color. More information on eastern larch beetle from the U.S. Forest Service can be found here.

Ash bark with pale areas where woodpeckers have removed outer layers of bark, as well as some small rough holes where the woodpeckers punched through bark and plucked out a nice plump EAB larvae.

Ash bark with pale areas where woodpeckers have removed outer layers of bark, as well as some small rough holes where the woodpeckers punched through bark and plucked out a nice plump EAB larvae.

Ash trees with the outer bark removed may be infested with either emerald ash borer or a native ash bark beetle. When woodpeckers remove outer bark of an ash tree, it makes the tree look very pale. Emerald ash borer populations build up to very high numbers as they move into new areas, which provides a great source of food for woodpeckers. A study published in 2012 showed that woodpecker numbers can increase due to the presence of EAB.

 

What about other woodpecker damage that you see on trees?

Pileated woodpeckers are large birds that can do a significant amount of damage to trees. The good news is that they tend to target trees that are dead or have a lot of decay in them. That’s not

to say that they won’t occasionally peck into a healthy tree, but the insects they prefer to feed on are more common in dead or severely stressed trees, or trees with a lot of decay in them. Pileated woodpeckers have tongues containing backward facing barbs that they can stick into an insect gallery to drag out the occupants for a meal. They can leave a pile of good-sized woodchips at the base of trees that they’re feeding in. The photo shows an example of the damage that they can do.

Sapsuckers are birds that drill orderly rows of holes through the bark of trees. The holes go through the bark to the cambial layer, causing the tree to “bleed” sap. Sapsuckers return to feed when the sap is flowing. Sapsuckers’ tongues have little hairs on them to help gather sap. Sapsuckers are migratory and may just pass through an area in the spring, but they will sometimes return to the same tree over multiple years, creating new rows of holes each year. Trees will attempt to grow over this damage, and are usually successful, although the damage to the bark may remain visible for many years. Loggers may note this damage when cutting logs; it is referred to as “bird peck”, and is considered a defect. Federal regulations prohibit people from killing sapsuckers, so control for yard trees is usually some manner of deterrent such as wrapping the main stem with hardware cloth or burlap, or using scare tactics in the tree.

Orderly rows of holes created by yellow-bellied sapsuckers. These birds will revisit these holes that they drill and lick the sap that flows from them.

Orderly rows of holes created by yellow-bellied sapsuckers. These birds will revisit these holes that they drill and lick the sap that flows from them.

Damage from pileated woodpeckers can be quite extensive. A single woodpecker can create this level of damage in a few days, or it may work at a tree throughout the season. Note the pile of large woodchips at the base of the tree.

Damage from pileated woodpeckers can be quite extensive. A single woodpecker can create this level of damage in a few days, or it may work at a tree throughout the season. Note the pile of large woodchips at the base of the tree.

New! Statewide quarantine for emerald ash borer

by Jodie Ellis, Forest Health Team, communications specialist, Jodie.Ellis@wisconsin.gov, 608-266-2172

 An emerald ash borer adult.

An emerald ash borer adult.
Photo: Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org

A statewide quarantine of the invasive insect emerald ash borer (EAB) will go into effect on March 30, 2018. Previously, individual counties were quarantined when EAB was confirmed within each’s borders. Since EAB has been found in 48 of 72 Wisconsin counties, officials have determined that statewide regulation of the devastating ash tree pest is warranted.

Movement of ash wood, untreated ash products and hardwood firewood of any type to areas outside of Wisconsin will continue to be regulated by USDA’s Animal and Plant Health Inspection Service, Plant Protection and Quarantine. (APHIS PPQ).

Within the state, Wisconsin businesses and members of the public will be able to freely move ash wood, ash products, and hardwood firewood to or from any Wisconsin county. Firewood restrictions will remain in effect on state and federal lands.

Items affected by the statewide EAB quarantine include ash wood with bark attached, larger ash wood chips, and hardwood firewood of any kind. County-by-county quarantines for gypsy moth, another invasive forest pest, remain in effect.

The move to a statewide quarantine does not mean that the state has given up on managing EAB; it is simply a shift in strategy as EAB continues its slow spread through the state. The Wisconsin DNR will continue releasing tiny, stingless wasps -natural enemies of EAB – at appropriate sites, which it has done since 2011. The DNR also continues participation in silvicultural trials in which different ash management strategies are being tested.

Most importantly, campers, tourists, and other members of the public are strongly encouraged to continue taking care when moving firewood within the state. “The actions taken by the Wisconsin public during the last few years have significantly slowed the spread of emerald ash borer and other invasive forest pests in the state,” said Wisconsin DNR EAB program manager Andrea Diss-Torrance. “We can continue to protect the numerous areas within our state that are not yet infested – including those in our own backyards – from tree-killing pests and diseases by following precautions.” Public members should continue to obtain firewood near campgrounds or cabins where they intend to burn it, or buy firewood that bears the DATCP-certified mark, meaning it has been properly seasoned or heat-treated to kill pests.

Emerald ash borer is native to China and probably entered the United States on packing material, showing up first in Michigan in 2002. It was first found in eastern Wisconsin in 2008.

For further information on EAB in Wisconsin, visit https://dnr.wi.gov/, using key words “emerald ash borer”.

Arbor Day: Show your appreciation

“When we see land as a community to which we belong, we may begin to use it with love and respect.” Aldo Leopold spoke these words many years ago, but they still ring true today. We all belong to a community, built around the people and the places we love and feel connected to, including trees and the land. Trees help shape communities and create sentimental landmarks that connect people and places. Consider the large elm that may hold a family tire swing, or the oak that made the perfect place for a secret club house, perhaps it’s under a crabapple tree that a couple shared their first kiss, trees becomes fixtures in our lives, bookmarks for the moments we relish.

Continue reading “Arbor Day: Show your appreciation”

Canopy cover assessed for all Wisconsin municipalities and urban areas

By Dan Buckler, Urban Forest Assessment Specialist, DNR

Whether you see urban trees as art, infrastructure or the lungs of your community, they are important assets in our state. And recently released tree canopy data from the DNR’s Urban Forestry program shows exactly where those trees and other woody vegetation exist in the state’s municipalities and urban areas. Continue reading “Canopy cover assessed for all Wisconsin municipalities and urban areas”

A Glimpse into New Berlin’s Tree Canopy

By Dan Buckler, Urban Forestry Assessment Specialist, DNR

The Urban Forestry program’s recently released Urban Tree Canopy data shows the extent of tree and shrub cover across every Wisconsin municipality and urban area. The City of New Berlin in southeast Wisconsin offers a glimpse into the kind of information you could derive from the canopy data. Continue reading “A Glimpse into New Berlin’s Tree Canopy”

Community Tree Management Institute: Building on a solid foundation

By Olivia Witthun, Urban Forestry Coordinator

CTMI students learningThe second of three sessions for Wisconsin’s Community Tree Management Institute (CTMI) was held February 6-7, 2018 in Green Lake. Through hands-on training and exercises, twenty-six students from across the state learned how to identify community forestry management needs and get the work done. Topics included: inventories, management plans, urban and community forestry operations (planting, pruning and removal), natural areas, tree biology, hardscape conflicts, soils, risk tree management and tree emergencies. Instructors for session II included: municipal forestry staff, university staff, consultants and DNR staff. The variety of instructors, their perspectives and interactive components are meant to appeal to all learning styles. Continue reading “Community Tree Management Institute: Building on a solid foundation”

2018 WAA/DNR Conference was an immense success

WAA exhibit hallThe 2018 WAA/DNR Annual Conference was held February 18-20 in Green Bay, Wisconsin. This year there was a record attendance of 857 people. Those in attendance were from the private industry, business owners, municipal staff, and state employees. Again, this year there were several different tracks attendants could attend: general sessions, climbers corner, introductory, business and utility. Across these tracks many topics were covered, from insects and pests to climbing and building an arboriculture business. This three-day conference also hosted many different exhibitors from the industry to provide attendees with up-to-date technology, equipment and practices to improve their work. Continue reading “2018 WAA/DNR Conference was an immense success”

New Wisconsin Wildcard available on beech bark disease

Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov, 715-356-5211 x232.

A new Wisconsin Wildcard is available on beech bark disease (BBD).  Wisconsin Wildcards are pocket-sized, collectible informational pieces available at Wisconsin state parks. The BBD Wildcard may be viewed at https://p.widencdn.net/clz4yw/Beech-bark-disease-wildcard and ordered by emailing a request to Forestry.Webmail@wisconsin.gov (ask for publication no. FR-218x).

Beech bark disease will eventually become a problem wherever beech is found.  The native range of American beech (Fagus grandifolia) extends into the eastern third of Wisconsin. BBD is the result of a relationship between exotic scale insects and a Neonectria fungus. The disease was first identified in Wisconsin in 2009. Currently, the only known area of the state which has experienced mortality from BBD is Door County. 

Front and back of the new beech bark disease Wisconsin Wildcard.

Front and back of the new beech bark disease Wisconsin Wildcard.

The scale insects feed by inserting their mouthparts through the bark on the trunk and branches and sucking the sap from the tree. The fungus, which “hitchhikes” on the scale insects’ bodies, enters the tree through those wounds.  The tiny scale insects secrete a white waxy protective covering; when scale populations explode and there are millions of scales on a tree, the tree can appear white from a distance, making it resemble a birch tree. As the fungus enters the tree at numerous points and dead spots under the bark (called cankers) form, the tree becomes weakened, leading to a risk of “beech snap.”  Beech snap can occur unexpectedly when the tree still has a full canopy of leaves remaining.  Beech snap can create huge problems for park and campground managers who are trying to keep guests safe; there is no way to predict when a tree is going to fail from BBD.    

Hundreds of tiny scale insects (covered in white fluff) are present on this small area of beech bark.   

Hundreds of tiny scale insects (covered in white fluff) are present on this small area of beech bark. Photo: Linda Williams

Eventually, the insects and disease take their toll and the beech trees decline and die.  Any age of beech tree can be infested, so in stands with significant beech mortality, regenerating trees will become infested as well as mature ones.  The good news is that three to five percent of American beech trees are resistant to BBD.  Michigan has identified and propagated such trees for a number of years, and have established a seed orchard of resistant trees.  BBD is not yet as established in Wisconsin, but already we’ve been able to identify a couple of resistant trees in the area where BBD has killed many trees. 

For more info on beech bark disease, visit Wisconsin DNR’s webpage on BBD.