Got Nature? Blog

In this edition of ID That Tree, Purdue Extension Forester Lenny Farlee introduces us to trumpet creeper, a native vine commonly found throughout Indiana. Often noticed climbing trees and other structures, this species plays a visible role in many woodland edges and disturbed sites. Student, landowner or even just simply curious about the plants you see climbing through trees and along roadsides, this video provides a quick and informational introduction to trumpet creeper in Indiana.

 

If you have any questions regarding wildlife, trees, forest management, wood products, natural resource planning or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

Resources:
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Fifty Common Trees of Indiana, Purdue Extension – FNR
Habitat University, Episode 12 – Exploring the challenges of Invasive Species, Habitat University-Natural Resource University
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Native Trees of the Midwest, Purdue University Press
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Find an Arborist, International Society of Arboriculture
Forest Improvement Handbook, The Education Store

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

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Join Purdue Extension forester Lenny Farlee in this episode of “A Woodland Management Moment” as he discusses the presence of black walnut within a pine plantation. This episode explores how hardwood species like black walnut can become established in planted pine stands and what that means for woodland management decisions. Watch the video to learn about opportunities, challenges and considerations for managing mixed-species woodlands over time.

 

A good resource to learn more is the Walnut Council website. Founded in 1970, the Walnut Council is an international association representing nearly 700 woodland owners, foresters, forest scientists, and wood-producing industry representatives in 45 states and three foreign countries. The purpose is to assist in the technical transfer of forest research to field applications, help build and maintain better markets for wood products and nut crops, and to promote sustainable forest management, conservation, reforestation, and utilization of American black walnut (Juglans nigra) and other high quality fine hardwoods.

If you have any questions regarding trees, forests, wildlife, wood products, or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

Resources:
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
The Nature of Oaks Webinar, Purdue Extension-FNR YouTube Channel, Shared from Indiana Forestry & Woodland Owners Association
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Native Trees of the Midwest, Purdue University Press
ID That Tree, Playlist, Purdue Extension – FNR YouTube Channel
Investing in Indiana Woodlands, The Education Store
Woodland Stewardship for Landowners Video Series, Playlist, Indiana Department of Natural Resources YouTube Channel
Ask an Expert: Tree Selection and Planting, Purdue Extension – FNR YouTube Channel
Forest Improvement Handbook, The Education Store
Find an Indiana Professional Forester, Indiana Forestry & Woodland Owners Association (IFWOA)
Purdue Arboretum Explorer

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

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Join Purdue Extension forester Lenny Farlee in this episode of “A Woodland Management Moment” as he highlights the breeding programs with the native Indiana tree Butternut. This episode introduces viewers to the once frequently found species and why there’s been a notable decline in its population. Watch the video to learn the reason behind butternut’s decline, how we have been trying to combat that with conservation efforts and details about how butternut grows.

 

If you have any questions regarding trees, forests, wildlife, wood products, or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

Resources:

ID That Tree: Butternut
Hardwoods of the Central Midwest: Butternut
Hardwood Lumber and Veneer Series: Butternut, The Education Store
Morton Arboretum: Butternut
Identification of Butternuts and Butternut Hybrids, The Education Store
Conservation and Management of Butternut Trees, The Education Store
The Plight of the Butternut
HTIRC Seed Propagation Protocol for Purdue and Hybrid Butternut
Purdue Arboretum Explorer
Butternut, Native Tree of Indiana River Walk, Purdue Fort Wayne
The Woody Plant Seed Manual, U.S. Forest Service
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Native Trees of the Midwest, Purdue University Press
ID That Tree, Playlist, Purdue Extension – FNR YouTube Channel
Investing in Indiana Woodlands, The Education Store
Woodland Stewardship for Landowners Video Series, Playlist, Indiana Department of Natural Resources YouTube Channel
Ask an Expert: Tree Selection and Planting, Purdue Extension – FNR YouTube Channel
Forest Improvement Handbook, The Education Store
Find an Indiana Professional Forester, Indiana Forestry & Woodland Owners Association (IFWOA)
Purdue Arboretum Explorer

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

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Purdue Landscape Report: It’s finally October, and we should be enjoying lovely fall temps and colors. While some of the trees are changing, it’s not necessarily due to the change in seasons. As I write this, the temperature is 84 F (29 C). I look out my window and see mostly green leaves with some colors from the short cold snap we had and some from heat and drought stress. Whether you are worried about the trees in your yard and community or not, there are some simple tasks that we can do to assist them as we await the cooler temperatures of Autumn.

Mulching: One simple task to better prepare your trees for winter is to add a new layer of mulch, which benefits your trees in multiple ways. Adding a 2-3 inch thick layer of mulch will better maintain moisture levels and buffer extreme temperature changes in the soil and will add some organic matter too. Mulching to the drip line will benefit the tree the most, but in the case of larger trees it’s not always feasible. Try for at least a 3-foot radius from the trunk and make sure to leave a 2 inch or so gap between the trunk and the mulch. Remember, no volcano mulching.

Fertilizing: That mulch you just added will add some organic material to your soil as it slowly breaks down, but an autumn fertilization can benefit your trees too. Unlike trees in the forest that have a natural supply of nutrients from fallen leaves and twigs, trees around our homes are usually deprived as we rake and clean up our yards. Adding a slow-release fertilizer in the fall helps provide a nutrient boost over the winter, can promote root growth, and better prepare your tree for Spring.

Watering: Water is still an essential part of your tree care plan, but as temperatures drop and trees begin to head into dormancy they don’t need as much water as is required in the hit summer months. If you have irrigation systems in your yard start to drop the frequency of watering. You can water up until the first freeze, but make sure soils are just a little damp and not soaked. Evergreens in particular will benefit from slow deep watering 1-2 times a week until the soil freezes. Winter winds and temperatures can desiccate the needles without an adequate supply of water.

Pruning: Now is a good time to prune out any dead, damaged, or diseased limbs in your trees. If you have access to hand saws and pole saws or pruners, you can remove smaller branches or those closer to the ground. Make sure you are making proper pruning cuts though, and if there are large limbs, those at heights, or you are just unsure of how to make a good cut enlist the help of a professional arborist.

Trunk Damage: Sunscald or southwest damage occurs on young and/or thin barked trees in the winter. Wounds can occur between the south to southwest facing part of the trunk on sunny days in the winter as temperatures rise and suddenly drop. Over time these wounds can become quite large. Trees can also incur damage from deer during the rut. Bucks will scrape trees with their antlers, scraping off the bark and damaging the cambium. Both of these injuries can be reduced one younger trees by installing tree guards in the fall. Tree guards are plastic barriers you place around the main stem of the tree. I recommend using white corrugated drainage pipe that can be found at most home centers. You can make a cut lengthwise along the pipe for easy installation and make sure it has a large enough diameter to leave a space between it and the tree. Just remember to remove it come Spring.

Inspections: Visual inspections can be done year-round, but this time of the year it might be easier to see changes in your tree as leaves are falling and the canopy becomes more visible. From the ground up to the canopy, some of the things you’re looking for include fungal growth around the base of the tree, any sort of damage on the main stem or branches, premature leaf drop or color change, and branches that are dead, cracked, diseased, or seem weak. Any concerns you find are also great information to share with an ISA Certified arborist which can be found using the Trees Are Good website.

View the original article on the Purdue Landscape Report website: Help Your Trees Transition into Autumn.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
Re-mulch Your Trees, Purdue Landscape Report
Find an Arborist video, Trees are Good-International Society of Arboriculture (ISA)
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Moist soil and rotten roots makes it easy for trees to come crashing down – Fox 59 News
Expert: Some storm damage can be easily prevented – Fox 59
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
Tree Pruning Essentials, Publication & Video, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment – The Education Store
Trees and Electric Lines – The Education Store
Tree Defect Identification, The Education Store
Planting Your Tree, video, Purdue Extension
Tree Installation, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Subscribe – Purdue Extension-FNR YouTube Channel

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

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Purdue Landscape Report: Aspen, cottonwood, and poplar are all names for the fast-growing Populus tree species. Used widely for building materials, these trees are often located around ponds, riverbanks, and sloping areas toward water bodies (especially cottonwood). Cottonwood flowers produce little white tufted seeds that float through the air which a lot of people love (my kids included), unless it lands in their mouth. These beautiful trees are susceptible to a fungus that can cause significant damage under the right conditions: Marssonina (newer name is Drepanopeziza).

There are three species of Marssonina that can infect Populus – different tree species may only be susceptible to one of the Marssonina species. The fungi cause the same kind of disease and develop similarly on the host. Marssonina can infect the leaves, stems and seeds of Populus, which can lead to large amounts of leaf loss during wet weather, girdled stems and dieback, and aborted seeds. Since seeds can carry the fungus, the seed will take it with it to where it lands and can become infected immediately after germinating. It is common to see high disease severity in the canopy, but unless there is significant leaf loss (up to 70% defoliation) it may not reduce plant vigor. Leaf lesions typically develop as small black to brown dots or flecks which expand in size as time goes one. As the disease progresses, large areas of the leaf will become necrotic, creating odd dead blotches, potentially killing the majority of the leaf blade.

The fungus produces asexual spores in a small black pustule on the upper surface of the leaf which will eventually burst and release the spores during humid weather early in the spring. Marssonina will continue to produce spores and cause disease the whole season, creating repeat infections on the same tree. Symptoms tend to start lower in the canopy and ascend up the tree as the season progresses. The spores are spread by water splash, so rainfall will help spread this fungus in the landscape.

For trees planted in native landscapes, this disease will likely be inevitable and may make the foliage look less than stellar. That being said, removing leaves that drop or at the end of fall will reduce total inoculum for future seasons and can reduce total disease long-term. Similarly, trees that are stressed will typically develop increased disease severity, so if you are seeing large amounts of leaf spots or leaf loss, I would recommend employing stress mitigation strategies to keep the tree happy and healthy (fertilizer, mulch, irrigation as needed, etc.). If a tree appears to develop significant disease every year and has reduced limb growth, you may consider removing the tree if you are concerned it may die early and replace with a resistant clone, as disease susceptibility can vary greatly between clones of the same species.

View the original article on the Purdue Landscape Report website: Marssonina leaf spot and blotch of Poplar.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
ID That Tree, Playlist, Purdue Extension – FNR YouTube Channel (Invasive White Mulberry, Siberian Elm, Tree of Heaven)
Eastern Cottonwood, Article, Purdue Fort Wayne
Find a Certified Arborist, Trees are Good-International Society of Arboriculture (ISA)
Video: Step by Step to Find an Arborist, Trees are Good-International Society of Arboriculture (ISA)
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
Tree Pruning Essentials, Publication & Video, The Education Store
Tree Defect Identification, The Education Store
Planting Your Tree, video, Purdue Extension
Tree Installation, The Education Store
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel (Against Invasives, Garlic Mustard, Autumn Olive)
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel (Common Buckthorn, Japanese Barberry)
Indiana Invasive Species Council
Indiana Department of Natural Resources: Invasive Species
Subscribe – Purdue Extension-FNR YouTube Channel

John Bonkowski, Lead Extension Administrator
Purdue Department of Botany and Plant Pathology

 

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Purdue University Landscape Report: Early fall is the time to begin preparing trees for the winter and get them off to a good start in the following spring. Preventative maintenance and some good cultural practices in autumn boost trees’ health and vigor during the winter and creates an encouraging growing environment in the spring. Here are 5 good tips for trees:

1. Scout for pruning issues.
   It’s advantageous to schedule pruning tasks after leaves have fallen. It’s much easier to see the branch structure of trees and deciduous shrubs in order to perform good selective cuts. Look for those non-beneficial plant parts and remove them. These include any dead, broken and crossing branches which can be removed. Also, search out and remove those epicormics sprouts in the canopy and basal sprouts emerging from around the trunk and root collar.  Refer to this pruning publication for more information.
   

   Newly-established trees benefit from fertilizer

2. Feeding for the future.
   Typically, tree roots have produce more root growth during the fall. Root systems are important as storage organs or banks to reserve energy for later. These stores of starch will become active energy on demand in the spring when shoot growth, leafing and flowering occur. Fertilization during this time will maintain soil nutrient levels and increase root production, promoting new growth in the spring. Newly, established trees and those younger trees are especially responsive to supplemental feeding. However, not all trees need or require fertilization. Refer to this publication on fertilization for more information.
   

   Mulch provides a blanket of protection

3. Complete cultural practices.
   It’s always beneficial to the tree to replenish mulch to give root systems an extra layer of protection against temperature extremes. This helps maintain the moisture levels in the soil during those drier winter months as well. Maintaining 2-3 inches of composted mulch over the root zone of the tree and landscape provides great protection. Also, it may be a good time to consider providing protective wraps on thin-barked or newly planted trees, if needed. Also, now is a good time for inspecting those existing wraps to be sure they are effective and not too tight around the trunk or harboring hidden pest issues.
   

   Good moisture levels going into the winter is critical for tree health

4. Water needed, still.
   The dry, cool air and low precipitation that can sometimes occur during fall and early winter can take a toll on trees. Provide supplemental irrigation with deep watering to prevent root damage and a good spring start. It is advisable to water only when temperatures will be above 40^o Water around mid-day so there is time to soak in before the freezing night temperatures. Applying approximately 5 gallons water per inch of tree diameter will be adequate for times when there is little to no rainfall going into winter.
5. Take inventory.
   This is a good time to assess your site for vacancies. Check your property for potential planting locations to install new trees next spring. Research during the winter allows plenty of time for good decision-making which includes proper species selection and suitable locations. Refer to the tree selection publication for more information.

There are many resources available to learn about proper tree care. If you are uncertain on how to maintain your trees or prefer professional services, it is important to reach out to an ISA Certified Arborist to help with the tree, within your landscape, especially the larger, mature trees. A Certified Arborist can proactively identify, analyze and evaluate your tree needs to maintain this important asset, your trees.

Resources:
Why Do Our Trees Go From Green Leaves to Different Colors?, Got Nature? Blog
Fifty Common Trees of Indiana
An Introduction to Trees of Indiana
The Nature of Teaching: Trees of the Midwest, The Education Store
Why Leaves Change Color, USDA Forest Service

Lindsey Purcell, Executive Director
Indiana Arborist Association

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With rainfall well below average, watering your trees is more important than ever. Indiana typically receives around 3.14 inches of rain in September, but as of 2025, only 1.31 inches have fallen—making this month even drier than last year. These conditions can lead to dry, wilted leaves and stress for trees across the state, especially during prolonged heat. To see how drought is affecting your area, visit the U.S. Drought Monitor for Indiana-specific maps.

In this video, Lindsey Purcell, Executive Director of the Indiana Arborist Association, explains why consistent watering is critical and shares practical tips to help your trees stay healthy through dry spells.

Extreme heat can have a major impact on tree health and survival. Water is the most limiting ecological resource for a tree, and without adequate moisture, decline and death are imminent. It reduces carbohydrate production, significantly lowering energy reserves and production of defense chemicals in the tree. Check out this publication titled Drought? Don’t Forget the Trees! to learn what to look for for any weakening issues including pests that like the dry conditions.

If you have any questions regarding wildlife, trees, forest management, wood products, natural resource planning or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

More Extreme Heat Resources:
Climate and Drought Maps, Purdue Indiana State Climate Office
Summer Tree Care, Purdue Landscape Report
Drought? Don’t Forget the Trees!, The Education Store, Purdue Extension resource center
Extreme Heat Including Fact Sheets, Purdue Extension – IN-PREPared
Extreme Heat – Resources, Extension Disaster Education Network (EDEN)
Drought Information​, Indiana Department of Natural Resources
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension YouTube Channel
Tree Selection for the “Un-natural” Environment, The Education Store
Tree Pruning Essentials Video, Purdue Extension YouTube Channel
Tree Defect Identification, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Surface Root Syndrome, The Education Store
Submit Sample, Purdue Plant & Pest Diagnostic Lab
Find an Arborist, Indiana Arborist Association

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

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Purdue Landscape Report: Tree care, in many cases, can be expensive if you require the assistance of an arborist for pruning or removals.  Extreme weather events, characterized by extensive rain and wind, can cause damage to the canopy or, in worst-case scenarios, lead to tree failure.  In cases of failures, weather is often the final push to already existing issues.  One cause that can lead to decay, decline, and failure if applied incorrectly can also extend the life of your tree with proper application.

Mulch is the double-edged sword that can promote healthy growth by maintaining soil moisture and temperature through extreme heat, cold, and drought, enrich the soil in the critical root zone, maintain a safety area from mechanical damage from lawn care tools, and add a nice aesthetic.

But it can also cause decay through excess moisture to the root flare, damage from pests like mice and insects that can live in mulch, expose the tree to pathogens, and promote unnecessary root growth and/or stem girdling roots that cut off nutrient supply between the root system and the rest of the tree.

The application is the same if it’s the first time mulching a tree or a re-application.  Add enough mulch so there is a 2–3-inch layer sloping away from the tree with at least a 3–5-foot radius around the stem (older, larger trees can benefit from larger mulch rings).  No volcano mulching, make sure you also have around a 1-2-inch gap between the stem and the start of the mulch ring.

If you are reapplying mulch, first rake the old mulch to even the layer and mix some into the soil if possible.  If your tree has already been mulched and has been volcano mulched, simply dig out the excess, exposing the root flare and creating that 1-2-inch gap between the stem and the mulch.

This simple act is relatively inexpensive, does not require a lot of time, and will help keep your tree healthy, extending its life.  If you notice any other issues with your trees, hiring an ISA Certified arborist is the next step in managing your trees’ health.  To find an arborist near you and verify credentials, use the link at Find an Arborist, Trees are Good, International Society of Arboriculture (ISA).

View the original article on the Purdue Landscape Report website: Simple Steps to Care for Your Tree: Mulching.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
Re-mulch Your Trees, Purdue Landscape Report
Find an Arborist video, Trees are Good-International Society of Arboriculture (ISA)
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Moist soil and rotten roots makes it easy for trees to come crashing down – Fox 59 News
Expert: Some storm damage can be easily prevented – Fox 59
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
Tree Pruning Essentials, Publication & Video, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment – The Education Store
Trees and Electric Lines – The Education Store
Tree Defect Identification, The Education Store
Planting Your Tree, video, Purdue Extension
Tree Installation, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Subscribe – Purdue Extension-FNR YouTube Channel

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

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Purdue Landscape Report: Recently, there has been an uptick in questions related to one of Indiana’s most notorious invasive pests: the emerald ash borer.  Homeowners, businesses, even professionals have asked if ash trees are still present in Indiana, and if the insect is still a threat to our ecosystem.  Emerald ash borer wreaked significant havoc among Indiana’s hardwoods, and a person could be forgiven for believing that there are no ash trees at all in our state, but this is simply not true.  Ash still survives in Indiana and can be found both as ornamental plantings and in untended woodlots; unfortunately, emerald ash borer is also still present and just as deadly to them as ever.  The question of protecting ash versus removal them is complex, but entomologists and tree specialists have learned from this insect’s invasion.

The emerald ash borer (Agrilus planipennis), a wood-boring insect native to Asia, is responsible for decimating ash (Fraxinus spp.) throughout the United States and elsewhere.  In Indiana, this insect’s presence was confirmed in 2004, though it had probably been in the state for some time before then.  Since its arrival, Hoosiers have been forced to watch as ash trees have rapidly declined and died due to the insect’s feeding and life cycle.  The insect lays its eggs in crevices in the bark of an ash that is 8 to 10 years old, and after hatching, the new larvae begin to bore through the tree’s cambium tissue. The tree relies on its cambium tissue to transport water and nutrients and supply cells for new growth.  Often, the only signs of the insect’s presence are a reduction in canopy coverage and D-shaped exit holes in the bark, indicating adult emergence.  As time goes on, however, the tree will continue to lose canopy, experience limb death, and often have large chunks of bark detach. Unprotected trees will typically die within 2 to 5 years of infestation.  Dead and dying ash trees represent a serious hazard to health and property as infestation will leave them extremely brittle. Brittle ash will often fall during weather events or even collapse over time as limbs fall off.

While emerald ash borer did significant damage to ash tree populations in Indiana, they did not destroy the population entirely.  While virtually all untreated trees will eventually become infested, saplings with a trunk diameter of ½ to 1 inch will remain untouched, allowing annual replacement of trees to continue.  Since the initial invasion killed so many trees, the borer’s populations have been proportionally reduced as well due to a lack of a food source.  This combination of factors has created a cycle of growth and infestation that allows both populations to survive, but at significantly lower levels as compared to the period of the initial infestation.  Unfortunately, this also means that emerald ash borer is now a permanent fixture in the hardwood ecosystem in Indiana.

While many may believe ash trees are a total loss, there are still options to protect ash tree and even rescue ash that have already been infested.  The first step in this process is to determine the extent of damage in a given tree.  As the cambium tissue is consume by ash borer larvae, the tree will experience a steady loss of canopy and limb death.  The proportion of lost canopy makes a great indicator for treatment viability.  For example, a tree that has only lost 10% of its canopy will normally respond well to treatment.  As more canopy is lost, recovery is more challenging, until the tree has lost %30 of canopy coverage.  After that point, there is very little chance that a rescue treatment will be successful, and removal will most likely be necessary.  It is also important to remember that limb death may occur; these limbs will not recover and will need to be removed to avoid any potential hazards.

There are several insecticides with varying ranges of efficacy that can be used to manage emerald ash borer.  These include imidacloprid, dinotefuran, azadirachtin, and emamectin benzoate. Several studies have been conducted to find the best combination of chemical and application type, such as the difference between using a soil drench compared to a trunk injection. While all of the above chemicals can be effective against the insect, the combination of emamectin benzoate applied through a trunk injection offers the best, longest lasting protection from infestation.  This combination has a durable effect lasting for two years under dense infestations.  However, the reduction in emerald ash borer populations have spread the distribution of the insect thinner, and longer intervals between treatments are possible.  A ten-year study conducted by Purdue University demonstrated that treating trees once every three years provided sufficient protection from the beetles, while also showing that 4 to 5 years after last treatment coincided with an increase in damage to the trees.  This same study also found that by six years post-treatment, the trees would decline to the point of making removal a necessity.  This research concluded that increasing time between intervals after three years increased the risk of catastrophic damage due to emerald ash borer activity, thus the recommendation for three-year intervals.

Ultimately, many will see this as a financial issue: the cost of treatment over time against the cost of removal to avoid potential damages.  The above study estimated the cost of treating a single tree with an emamectin benzoate injection at $300 per treatment. Since treatment only needs to happen once every three years, the cost per year per tree would be $100, approximately.  Tree removal was estimated between $1800 and $3600, depending on tree location and other factors.  Also consider replacement costs if you wanted to continue to grow ash in that area, and how long the tree would need to grow to match the size of the tree you just replaced.  Additionally, add in any treatment costs to make sure it survives infestation.  When looked at from this angle, maintaining regular treatment on rescuable trees would appear to be the most cost-effective route for managing ash.  Any treatment plan should be discussed with a professional, such as a certified arborist.

Read the original article posted in the Purdue Landscape Report April 2025 Newsletter: Revisiting Ash Tree Protection.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
New Hope for Fighting Ash Borer, Got Nature? Purdue Extension-FNR
Invasive Pest Species: Tools for Staging and Managing EAB in the Urban Forest, Got Nature?
Emerald Ash Borer, Purdue Extension-Entomology
Emerald Ash Borer Tools & Resources – Purdue Extension Entomology
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension YouTube Channel
Tree Planting Part 2: Planting a Tree, Purdue Extension – Forestry and Natural Resources YouTube Channel
Indiana Invasive Plant List, Indiana Invasive Species Council, Purdue Entomology
Landscape Report Shares Importance of Soil Testing, Purdue FNR Extension
Find an Arborist website, Trees are Good, International Society of Arboriculture (ISA)
Tree Risk Management – Got Nature? Blog, Purdue Extension – FNR
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Native Trees of the Midwest, Purdue University Press
Professional Forester, Indiana Forestry Woodland Owners Association
Forest Improvement Handbook, The Education Store

Bob Bruner, Exotic Forest Pest Educator
Purdue Entomology

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Purdue Landscape Report: These three maples have somewhat similar-looking leaves. On the surface, you may think this is simply an academic exercise. But if you care about invasive plants and local ecology, this distinction is an important one.

Norway maple is an invasive tree species, while sugar and black maples are native tree species (sometimes called hard maples). Sugar and black maples are even more beloved for their gift of delicious sugary sap that can be made into maple syrup and similar products. They also make great shade trees. Note that there are other native and non-native maple species.

One way to distinguish between Norway (Acer platanoides), sugar (Acer saccharum), and black (Acer nigrum) maples is to count the number of lobes on the leaves. Lobes are large areas of the leaf that stick out, like an ear lobe, although that is not the clearest analogy. Norway maples typically have 5-7 lobes (commonly 7), sugar maples typically have 5, and black maples typically have 3-5. Black maple’s bottom two lobes are so much less prominent than sugar maple that it often looks like 3 main lobes. Additionally, black maple leaves droop on the sides, almost like they are starting to wilt from lack of water.

Another way to distinguish Norway maples from native maples (sugar and black) is to look at the winged seeds, called samaras. Children may call these “helicopters,” as they twirl on their way to the ground. The Norway maple has paired samaras arranged like a handlebar mustache. Sugar and black maple samara pairs look more like a Fu Manchu mustache, pointing downward rather than the near horizontal arrangement of Norway maple samaras.

A third way to distinguish Norway maples from native maples is to snap off the long leaf stem (petiole). Norway maples have a milky latex sap that exudes if you squeeze or pinch a petiole, while native maples have clear sap.

There are a few other identification nuances between these species. For example, black maples have stipules (leaf-like growths) at the base of their petioles (absent on sugar maple). They also have pubescence or hairiness on the underside of the leaves. Norway maple has hairs in the axils of leaf veins. Norway maple’s leaves are generally broader than long. Other differences may be seen in the bark, twigs, buds, and fall coloring.

Although Norway maple is an invasive species, it has been a long-time landscaping favorite of homeowners, especially cultivars like ‘Crimson King’ that retain their deep red color all year. This attribute has made Norway maple a popular choice because few other options exist to offer that color feature for the landscape. Other varieties or cultivars exhibit the normal green leaf color. Native to northern Europe, the tree was introduced in America in the late 1700s. George Washington reportedly purchased two trees in 1792 to plant at Mount Vernon.

For full article: Distinguishing Between Norway, Sugar, and Black Maples, Purdue Landscape Report.

Resources:
ReportINvasive, Purdue College of Agriculture
What are Invasive Species and Why Should I Care?, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Large Spots on Maple Leaves that Look Like Tar, Purdue Extension News
Find an Arborist, International Society of Arboriculture
Fifty Common Trees of Indiana
An Introduction to Trees of Indiana
Native Trees of the Midwest, The Education Store
Shrubs and Woody Vines of Indiana and the Midwest, The Education Store
Tree Installation: Process and Practices, The Education Store
Planting Your Tree Part 1: Choosing Your Tree, Video, Purdue Extension – Forestry & Natural Resource (FNR) YouTube Channel
Investing in Indiana Woodlands, The Education Store
Forest Improvement Handbook, The Education Store
ID That Tree, Purdue Extension-FNR YouTube playlist
Purdue Plant and Pest Diagnostic Laboratory

John E. Woodmansee, Extension Educator – Agriculture and Natural Resources (ANR)
Purdue Extension – Whitely County

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