Got Nature? Blog

Posted on August 14th, 2019 in Alert, Forestry, Forests and Street Trees, Land Use | No Comments »

One of the most dangerous pests to trees is a human, especially with equipment.  tree injury from equipmentInjuries to trees caused by a lawn mower or weed trimmer can seriously threaten a tree’s health.

Additionally, damage to the bark layer of trees causes a long-term liability by creating a wound which leads to a defect, becoming an unsafe tree.

The site of injury is usually the root flare area, where the tree meets the turf and gets in the path of the mower or trimmer.  The bark on a tree acts to protect a very important transport system called the cambium layer.

mower injury on tree

This is where specialized tubes are located which move nutrients and water between the roots and the leaves. Bark layers can vary in thickness on different tree species.  It can be more than an inch in thickness or less than 1/16 of an inch on young, smooth-barked trees such as maples and birch trees.  This isn’t much protection against string trimmers and mowing equipment, especially the young trees.

Any type of damage or removal of the bark and the transport system can result in long-term damage.  Damage, which extends completely around the base of the tree called girdling, will result in ultimate death in a short time.

weed eater injury on tree

Tree wounds are serious when it comes to tree health. The wounded area is an opportunity for other insects and diseases to enter the tree that causes further damage. Trees can be completely killed from an attack following injuries. Fungi becomes active on the wound surface, causing structural defects from the decay.  This weakens the tree or it eventually dies, creating a risk tree to people around it.

Newly planted, young trees need all the help we can provide to become established in the landscape and these trees are often the most commonly and seriously affected by maintenance equipment.  However, injury can be avoided easily and at very low cost with these suggestions.

  1. tree with mulch at baseThe removal of turf or prevention of grass and weeds from growing at the base of the tree are low-tech solutions to eliminate a serious problem. Spraying herbicides to eliminate vegetation around the base of the tree can decrease mowing maintenance costs. Be sure to use care when applying herbicides around trees.
  2. A 2-3” layer of mulch on the root zone of the tree provides an attractive and healthy environment for the tree to grow. Additionally, it provides a visual cue to keep equipment away from the tree.
  3. Also, trunk guards and similar devices can add an additional measure of protection for the tree. Using white, expanding tree guards can help improve the trees ability to withstand equipment contact, but also help to reduce winter injury.

Trees are a major asset to your property and important to our environment.  Protect our trees and preserve these valuable assets by staying away from tree trunks with any mowing or weed trimming equipment.  The damage lasts and it cannot be repaired and often results in losing your tree.

Purdue University Landscape Report Article

Resources
Corrective Pruning for Deciduous Trees, The Education Store – Purdue Extension resource center
What plants can I landscape with in areas that floods with hard rain?, Purdue Got Nature? Blog
Tree support systems, The Education Store
Tree Installation: Process and Practices, The Education Store

Lindsey Purcell, Urban Forest Specialist
Forestry and Natural Resources


Purdue Landscape Report: When was the last time you really looked at your trees?  It’s all too easy to just trees, grasslandsenjoy their cool shade and the sound of their leaves, but if you don’t know what to look for you could miss deadly diseases or dastardly demons lurking in their leaves and branches. A quick check can help you stop a problem before it kills your tree or your local forest!

National Tree Check Month is the perfect time to make sure your tree is in tip-top shape! Our checklist will help you spot early warning signs of native pests and pathogens and invasive pests like Asian longhorned beetlespotted lanternfly, and sudden oak death. You can stop invasive pests in their tracks by reporting them if you see them.

Is your tree healthy and normal?
Start by making sure you know the type of tree you have. Is it a deciduous tree like an oak or maple? Or is it an evergreen that like a spruce or a pine? Don’t worry about exactly what species it is. It’s enough for you to have a general sense of what the tree should look like when it’s healthy.

Check the leaves

  • Are the leaves yellow, red or brown?
  • Are they spotted or discolored?
  • Do the leaves look distorted or disfigured?
  • Is there a sticky liquid on the leaves?
  • Do the leaves appear wet, or give off a foul odor?
  • Are leaves missing?
  • Are parts of the leaves chewed?

Check the trunk and branches

  • Are there holes or splits in the trunk or branches?
  • Is the bark peeling from a tree that shouldn’t shed its bark?
  • Are there tunnels or unusual patterns under the bark?
  • Is there sawdust on or under the tree?
  • Is there sap oozing down the tree?
  • Does the sap have a bad odor?
  • Do sticky drops fall on you when you stand under the tree? You might have spotted lanternfly. Please report it right away!

Now what? If you answered YES to any of the questions above, there’s a good chance something is wrong. To decide if and how you should treat or report the problem, you’ll need to have a tentative diagnosis. Luckily, there are many ways to get one!

Know the tree species? Use the Purdue Tree Doctor to get a diagnosis and a recommendation on whether treating or reporting is needed.  This app allows you to flip through photos of problem plagued leaves, branches and trunks to help you rapidly identify the problem.  If you have an invasive pest, it will guide you how to report it.

Don’t know the tree species and still need help? Reach out to local experts. We’re happy to help!

Confused but think something is TERRIBLY WRONG?  Contact Purdue’s Exotic Forest Pest Educatorreport online, or call 1-866-NOEXOTIC.

Resources:
Trees and Storms, The Education Store, Purdue Extension Resource Center
Why Is My Tree Dying?, The Education Store
Caring for storm-damaged trees/How to Acidify Soil in the Yard, In the Grow, Purdue Extension
Tree Risk Management, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment, The Education Store
Tree Installation: Process and Practices,  The Education Store
Tree Planting Part 1 & Tree Planting Part 2, videos, The Education Store

Cliff Sadof, Professor & Coordinator of Extension
Purdue University, Department of Entomology

Elizabeth Barnes, Exotic Forest Pest Educator
Purdue University, Department of Entomology


man standing in tall grass

A “weedy” field like this may seem unsightly to some, but to wildlife, it provides invaluable food and cover. Just by leaving this field unmowed, you can improve habitat on your farm.

man mowing tall grass

Mowing just to clean up the farm, or Recreational Mowing Syndrome (RMS), eliminates habitat for countless wildlife species.

Do you have a sudden urge to jump in the tractor and mow your fields, field borders or road ditches?
You might have RMS.

Do you enjoy spending your weekend in the cab of the tractor with a mower in tow in search of places to mow across your property?
You might have RMS.

Do you get queasy at the sight of a “weedy” unkempt field?
You might have RMS.

What is RMS you ask? RMS stands for Recreational Mowing Syndrome, a condition that afflicts many rural landowners during the summer months. And if you answered yes to any or all of the questions above, then you have RMS.

What is it?
RMS is the sudden urge many landowners get to ‘clean’ up their property by mowing the ideal fields, field borders, and road ditches around the farm during the summer months. While a mowed field may look attractive in the eyes of a landowner, in the eyes of wildlife, this is a serious problem.

These prime mowing spots provide habitat for a suite of birds, mammals, herpetofuana, and pollinating insects that inhabit our rural landscapes. Many of these species are actively nesting or raising young in these areas during peak mowing season – April through September. And the weeds coming up in these fields like common milkweed, tall ironweed, common ragweed, and many others provide food and cover for wildlife.

How to treat it?
The easiest way to treat RMS is by going cold-turkey – park the tractor for the summer. If you are not ready to give up mowing all together, then restrict your mowing to just the lanes around the fields, instead of the whole field. If you are ready to give up mowing, but still want to enjoy time in the tractor, try these options.

Instead of hooking up the mower, hook up the sprayer and go control some invasive species on the property, like bush honeysuckle, autumn olive, or sericea lespedeza. Or try hooking up the disk and disking around the field to prepare firebreaks for a late summer or fall prescribed fire.

You can still spend time on the tractor during the summer months without eliminating wildlife habitat through mowing. In fact, you can improve it!

Next time you look at your window and see a “weedy” field, don’t cringe and give into the urge to mow it. Instead, just smile and listen to all the quail whistling, songbirds singing, and bees buzzing in the habitat you improved by not mowing.

Resources
Renovating native warm-season grass stands for wildlife: A Land Manager’s Guide, The Education Store, Purdue Extension Resource Center
Effective Firebreaks for Safe Use of Prescribed Fire, Got Nature?, Purdue Extension – FNR
Sericea Lespedeza: Plague on the Prairie, Got Nature?, Purdue Extension – FNR

Jarred Brooke, Wildlife Extension Specialist
Purdue Forestry and Natural Resources


Storm damage, trees downSafety first! Stay clear and look for dangerous hanging limbs, broken branches and other failures before beginning cleanup or inspections. Keep others clear of the areas beneath and around damaged trees. Be alert for power lines that could be involved with damaged trees. All utility lines should be considered energized and dangerous.

Lindsey Purcell, Purdue urban forestry specialist, shares, “in my experience, during storm cleanup, many tree owners are faced with the decision of what to do with their trees relative to restoration or removal”.  There are several types of tree damage that occur from violent weather. Each has its own specific assessment considerations. All parts of the tree should be inspected during a post-storm assessment. This requires the expertise of trained, professional arborists to assist with the decision making regarding the best course of action. Unfortunately, there are those who take advantage of the situation and overcharge or provide poor advice when it comes to the best decision on their trees. Don’t make any hasty decisions and be sure you are hiring an International Society of Arboriculture (ISA) Certified Arborist, ask for references and proof of insurance in the process.

View publication Trees and Storms located in The Education Store, Purdue Extension’s resource center, for more information.

Resources:
Trees and Storms – The Education Store, Purdue Education Resource Center
Caring for storm-damaged trees/How to Acidify Soil in the Yard – In the Grow, Purdue Extension
Moist soil and rotten roots makes it easy for trees to come crashing down – Fox 59 News
Why Is My Tree Dying? – The Education Store
Tree Risk Management – The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment – The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


Dying oak leaves, phytophthora ramorum-Sudden Oak DeathSudden oak death, as the name suggests, is a disease that is capable of rapidly killing certain species of oaks.  It was first identified in California, in 1995. Two years earlier it was identified in Germany and the Netherlands, killing rhododendron. Because the pathogen originally infected and killed tanoaks, an undesirable, understory scrub tree, it generated little interest until other, more desirable oaks species began dying.  However, by this point, the disease was well established and eradication no longer an option, with millions of oak trees killed by the disease.  Currently, over 120 hosts in addition to oaks have been identified, and more continue to be added to this list.  What is most unusual about sudden oak death is the severity of disease symptoms coupled with the broad host range of the pathogen. This leads to difficulty in diagnosing and managing this disease.

What causes this disease?
The pathogen that causes SOD is Phytophthora ramorum (pronounced Fī-toff-thor-ă  ră-mor-ǔm).  This pathogen belongs to a group of organisms in the Kingdom Chromista, and has characteristics similar to fungi, plants and animals.  It spreads throughout the plant by hyphal threads (like fungi), produces spores (like fungi) that have flagella and swim through water (like animals), but its cell wall is made up of cellulose (like plants). When conditions dry up, Phytophthora can produce thick walled sexual spores called oospores, or asexual chlamydospores. Because P. ramorum is not a ‘true’ fungus, many fungicides labeled for control of other fungal diseases are not effective against it.

With such a broad range of plant hosts, it is important to stress that P. ramorum affects different species in different ways. Identification must be confirmed in the laboratory and cannot be identified on field symptoms alone. Many common landscape shrubs are also infected by other endemic Phytophthora species, and symptoms look similar. Boring insects and other root rots may be mistaken for this disease. For this reason, all Phytophthora infections should be screened by the Purdue Plant and Pest Diagnostic Laboratory.

What are the symptoms of SOD?
To understand this disease, it is important to recognize that there are two categories of hosts: bark canker hosts and foliar hosts. Further complicating this is the fact that oaks are divided into three subgroups, and only the red oak group are susceptible to this pathogen. Of our 17 oak species in Indiana, half are potentially, or known to be susceptible, and include black, blackjack, cherrybark, Northern pin, pin, red, scarlet, and Shumard oaks. Diagnostic symptoms of infected red oaks include oozing sap and red-brown cankers that often leading to death.

Our concern right now is on ‘the other’ hosts. Despite its name, sudden oak death primarily spreads through foliar hosts that are sold throughout the United States. Foliar hosts include rhododendrons, azalea, viburnum, lilac, and periwinkle (Vinca minor).

These hosts (and many others) are infected via the leaves and small branches. These infections rarely cause death, and can be mistaken for sunscald, twig canker, and dieback caused by other pathogens, including native Phytophthora species. Although symptoms from these infections are not severe, and are rarely fatal, the infections produce enormous numbers of spores that can infect neighboring, susceptible oaks—and other plant species. For this reason, we are asking people to examine any rhododendrons (or other co-mingled hosts like azalea, viburnum and lilac) purchased this spring from Walmart and Rural King, while the disease may still be controlled and the pathogen contained. Although this disease doesn’t look like much on rhododendron or lilac, its ability to spread to oaks and kill them is what makes it so devastating. These shrubs play a key role in the spread of P. ramorum, acting as a breeding ground for spores (inoculum) that can spread through water, wind-driven rain, plant material, or human activity. Oaks are considered terminal hosts, since the pathogen does not readily spread from intact bark cankers; they become infected only when exposed to spores produced on the leaves and twigs of neighboring plants.

For full article and photos view: Purdue Landscape Report

Other resources:
Sudden Oak Death: a million trees gone and counting, North Central Pest Management Center
Sudden Oak Death, California Oak Mortality Task Force
Sudden Oak Death, Indiana Department of Natural Resources
White Oak, The Education Store, Purdue Extension resource center
Planting Forest Trees and Shrubs in Indiana, The Education Store
Successful Oak and Hickory Regeneration, The Hardwood Ecosystem Experiment: 2006-2016, The Education Store
Find a Certified Arborist, International Society of Arboriculture

Janna Beckerman, Professor
Purdue Botany and Plant Pathology


Question: I have noticed that a lot of very mature (> 80 ft) sycamore trees look ill. They don’t seem to have as many leaves, or as large as they usually get and some have already turned brown and died. There are at least 2 in my 5 acres of woods and have noticed the same with other sycamores while driving from Mooresville to Indianapolis. Is there a certain blight/cancker/pest that is damaging sycamores this year?

Answer: I have also noticed that many sycamores appear relatively bare and may have brown or wilted leaves on the stems and littering the ground around the trees. The culprit is sycamore anthracnose, a fungal disease that causes damage and death of leaves as well as stem cankers. Sycamore anthracnose symptoms can be severe when we have cool, moist spring weather at the time of bud-break and leaf emergence , but healthy trees generally recover and put on new leaf area once the environmental conditions that favor the disease change to the warmer, drier conditions of late spring and summer.

Normally, the best management practices for sycamore anthracnose are patience and maintaining good tree health. The disease cycle is dependent on cool, moist spring weather, so it will run its course by late spring or summer when the average temperatures rise. Trees that are repeatedly defoliated could be reduced in vigor and be more susceptible to other problems, so steps to promote good tree health can be used as a preventative measure.

Resources:
Fertilizing Woody Plants – The Education Store, Purdue Extension Resource Center
Diseases of Landscape Plants (leaf diseases) – The Education Store
Sycamore – The Education Store
Hardwood Lumber and Veneer Series – The Education Store
Anthracnose of Shade Trees – Purdue Plant and Pest Diagnostic Laboratory
Purdue Plant Doctor App- Purdue Extension

Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources


This looks to be shaping up as a tough winter for us and our trees. Lots of snow and ice are predicted for the Hoosier state and this can be a challenge for our trees and shrubs.

After a heavy snowfall, protect your trees and property with these simple tips:

Heavy limbs

Limbs bending from ice loading.

Ice on Trees

Ice accretion on hawthorn branches.

Do not shake limbs to try to remove snow or ice.
When you find your trees are bending or drooping as a result of ice or snow accumulation, your first instinct is probably to shake the branches or knock the weight off with a broom or something similar. This may cause worse damage or actually cause the branch to snap off. Stop right there! Healthy tree branches are flexible, so knocking off the accumulation of snow or ice accretion may cause them to “snap” back, potentially damaging their food and water transport system. The results of the damage may not be evident until next spring.

Trees that tend to suffer the worst damage as a result of snow and ice are upright evergreens, like arborvitae and juniper, and clump trees, like birch. And, when it comes to ice, age does not make a tree stronger; younger trees are better at actually overcoming damage in ice storms.

Hire a Professional.

Snow on Trees

Snow weighing down spruce branches.

Safely remove broken limbs.
Broken and hanging branches can be a threat to people and property. If a limb breaks off from the weight of ice or snow and remains in the tree canopy, have it removed and the remaining stub properly pruned to the branch collar as soon as weather allows. The tree will recover better when properly pruned. For undamaged limbs bending under the weight of ice or snow, don’t prune as a means of correcting the situation. Be patient. It takes time for wood fibers in the limbs to return to its natural position.

Always be mindful of walking or parking under branches loaded down by snow or ice as they may snap and fall, causing injury or damage. If a limb breaks and becomes entangled in power lines, notify your utility company immediately. Never approach a downed power line or a branch touching a utility line.

If there is substantial damage to your tree, have an arborist examine damaged branches and limbs for signs of weakness and injury for reparations. It is best to always hire an ISA Certified Arborist. To find an arborist in your area, visit the website, www.treesaregood.org

How can you help prevent ice damage to trees? Proper pruning is one way. Particularly important is the removal of poor branch attachments and weak branch structure in the tree, prior to winter. For more information on pruning, download the publication, Tree Pruning Essentials.

Full article published in the Purdue Landscape Report.

Resources
Avoid Deadly Risk of Dying Ash Trees with Timely Tree Removal, Got Nature? Purdue Extension-FNR
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 Cost Calculator – Purdue Extension Entomology
Corrective Pruning for Deciduous Trees, The Education Store, Extension Publications

Lindsey Purcell, Urban Forestry Specialist
Purdue Forestry and Natural Resources


GroundhogGroundhogs are good at many things, said Brian MacGowan, Purdue University Extension wildlife specialist and Forestry and Natural Resources Extension coordinator, but predicting the weather definitely isn’t one of them.

The lore surrounding Groundhog Day originated in Germany where people used the reactions of badgers and hedgehogs to gauge weather patterns. When the tradition eventually migrated to America, Jarred Brooke, Extension wildlife specialist, said hedgehogs, which can be found throughout the United States, became the mammalian forecaster of choice.

“They’re crafty little critters,” McGowan explains, “which is why they’re found in so many different places. They’re habitat generalists and can live in open woodlands, grasslands, what have you.”

While MacGowan and Brooke agreed groundhogs don’t have a great track-record of weather prediction, other facts make groundhogs one of the more interesting members of the squirrel-family.

For full article see: Groundhogs can’t predict the weather but they do poop underground.

Resources:
Selecting a Nuisance Wildlife Control Professional – The Education Store, Purdue Extension Resource Center
Preventing Wildlife Damage – Do You Need a Permit? – The Education Store
The Basics of Managing Wildlife on Agricultural Lands – The Education Store
Nuisance Wildlife – Indiana Department of Natural Resources
Dealing with nuisance geese this spring – Got Nature?
Animal Damage Management: Woodchucks, The Education Store

Brian MacGowan, Wildlife Extension Specialist
Purdue University, Forestry and Natural Resources

Jarred Brooke, Wildlife Extension Specialist
Purdue University, Forestry and Natural Resources


Emerald ash borer (EAB), the most destructive forest pest to enter North America has left hundreds of millions of dead ash trees in its wake.  Although this pest has been found throughout our state, many of Indiana’s ash trees are still alive, or dead and still standing.  Ash trees killed by emerald ash borer, become extremely brittle and break easily as they decline. Branches can fall on people and property in snowstorms, with a light breeze, or even on a calm clear day. Danger could be hanging over your head in the street, in the forest, and even in your backyard.

Why does emerald ash borer make ash trees so brittle?

EAB damaged tree

Large ash limbs that have broken off in the upper canopy.

Unlike elms, oaks, and maples, ash trees use a thin ring of conducting tissue to supply water from the roots to the entire tree.  Emerald ash borer grubs will damage these functional water pipes as they chew just beneath the bark inside trunks and branches. This causes the tree to dry quickly and the structural wood to become prone to cracking. Internal breaks in the structural wood that bear the weight of the tree are often hidden from view by tree bark. As such, limbs can break and fall at any point along the branch at any time. It is not uncommon to have sizable limbs snap 30 feet off the ground on a calm day.

The threat of falling limbs is not limited to just dead ash. A comparative study of ash trees conducted in Ohio shows that structural integrity of ash trees can begin to decline even when trees are mostly green and have two thirds of the canopy still intact.

What should I do to protect myself from falling ash trees and limbs?

EAB tree thinning with percents.

If your tree has lost less than 30% of its canopy hire a professional to protect the tree.

If the tree has lost more than 30% of the canopy, make plans to remove it.  Delaying removal allows the tree to become more brittle and the problem more dangerous.  Remember, EAB causes progressively more injury to ash trees as time goes on.  The dead parts never come back to life.

If you have been treating your tree continue to do so.

How should I remove the tree?

To minimize risk of harm, hire a trained professional who has experience removing emerald ash borer damaged trees. The International Society of Arboriculture maintains a directory of Certified Arborists and their credentials. They can help find an arborist near you.  Always get bids from more than one contractor. Be sure your contractor is insured and bonded in case of an accident. Professionals are happy to share this information.

Some homeowners might be hesitant to remove dead ash trees because they provide valuable habitat for a range of woodland animals and mushrooms. However, we do not recommend keeping them standing unless you can guarantee that no people, domesticated animals, or property will ever be in their path if they fall. If you have a dead tree that can’t be felled right away or ever, stay away from it until after it has fallen.

Article courtesy of the Landscape Report.

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 Cost Calculator – Purdue Extension Entomology

Lindsey Purcell, Urban Forestry Specialist
Purdue Forestry and Natural Resources

Elizabeth Barnes, Exotic Forest Pest Educator
Purdue Entomology

Cliff Sadof, Professor, Ornamental, Pest Management
Purdue Entomology Extension Coordinator


How do I remedy poor branching? Is my tree at risk of splitting, and how can pruning prevent that? Corrective pruning has many implications for tree structure, health, and longevity. Developing a strong, central branch structure in a deciduous tree is critical for preventing structural failure caused by storms, wind, and ice. This 8-page publication explains the problems resulting from a co-dominant stem structure and addresses pruning strategies for correcting poor structure.

To view this full publication please go to Corrective Pruning for Deciduous Trees located in The Education Store, Purdue Extension’s resource center.

Resources
Preparations to Prevent Southwest Tree Injury, Got Nature? Blog
When do you stake a tree?, Got Nature? Blog
Top 5 List for Tree Selection and Planting, Got Nature? Blog
Tree Selection for the “Un-natural” Environment, The Education Store, Purdue Extension
Tree Support Systems, The Education Store, Purdue Extension
Tree Installation: Process and Practices, The Education Store, Purdue Extension
Planting Your Tree Part 1: Choosing Your Tree, video, The Education Store, Purdue Extension

Lindsey Purcell, Urban Forestry Specialist
Purdue Forestry and Natural Resources


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