Got Nature? Blog

Question: I am noticing pine trees dying in my neighbors’ yards and along the streets in Carmel and NE Indianapolis. The needles turn rust colored and fall within a couple weeks – leaving a bare tree. Some of these trees are mature but most are young. Should I be concerned? What should I do to protect my pine trees? What should I be looking for if it is a pest?

Answer: Many Indiana trees are dying from stress caused by the extreme weather we have had in the last few years. Urban Forestry Specialist Lindsey Purcell and Extension Consumer Horticulture Specialist Rosie Lerner discuss this in more detail in the Purdue Agriculture News article “Purdue experts: Tree deaths across Indiana may be related to weather stress.” There are also other potential causes of foliar discoloration and branch dieback in pine trees that are explained in the publication “Stress-related Conifer Dieback“.

If you’d like to investigate the issue further, a certified arborist​ can conduct a ground evaluation or you can examine the trees on your own using the Purdue Tree Doctor app.

Resources:
Purdue experts: Tree deaths across Indiana may be related to weather stress – Purdue Agriculture News
Stress-related Conifer Dieback – The Education Store, Purdue Extension Resource Center
Purdue Plant Doctor App – Purdue Botany and Plant Pathology and Extension Entomology
Needle cast in Colorado Blue Spruce, Purdue Landscape Report
Blue Spruce Update, Purdue Landscape Report
Why Spruce Trees Lose Their Needles, Purdue Extension
Blue Spruce Decline, Purdue Extension
Diseases Common in Blue Spruce, Purdue Extension
Tree Installation: Process and Practices, The Education Store, Purdue Extension resource center
Tree Planting and Urban Forestry Videos, Subscribe to our Purdue Extension-FNR YouTube Channel
Find an Arborist, International Society of Arboriculture

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

Electrical utility lines serve nearly every neighborhood, adding efficiency and luxury to every day of our lives.

Likewise, trees enhance our neighborhoods and bring beauty to our surroundings. Trees improve our air and water quality. They shade our homes, screen undesirable views, and help reduce noise along with many other ecosystem services.

We want both.

Purdue FNR Urban Forestry Specialist Lindsey Purcell addresses the conflicts that sometimes arise when trees and electrical lines must share space and ways to avoid them in his latest publication “Trees and Electric Lines“. Check out the publication to learn more about how to avoid boundary issues, safety concerns, power outages, and more while dealing with trees and electric lines.

Resources:
Trees and Electric Lines – The Education Store, Purdue Extension Resource Center
Tree Risk Management – The Education Store
Trees and Storms – The Education Store
Urban Forestry and Arboriculture – Purdue Forestry and Natural Resources
Power Friendly Trees – Indiana Department of Natural Resources

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

​This year’s Indiana Tree Climbing Competition has come to a close, with Purdue’s Casey Johnson finishing first place in the preliminary events and Jon Montgomery winning the Masters Challenge and going on to the international competition in San Antonio next spring.

Purdue’s public radio station highlighted the event in an article titled “A Different Kind of Athlete: Competitive Tree Climbers Compete In Indiana Championship“. From the article:

“What it does is mimics what you do in a work production standpoint, only in a competition environment,” says Lindsey Purcell, who teaches forestry at Purdue and serves as president of the Indiana Arborists Association. “I mean, I call them tree athletes. Instead of ‘triathletes’ I call them ‘tree athletes,’ because you not only have to understand the physiology and biology of the tree, but you also have to be athletic to get to work.”

To read more, check out WBAA’s article. For this year’s scores and more information on the competition, check out Indiana Arborist Association’s Tree Climbing Competition page.

Resources:
A Different Kind of Athlete: Competitive Tree Climbers Compete In Indiana Championship – WBAA
Tree Climbing Competition – Indiana Arborist Association
International Tree Climbing Championship – International Society of Arboriculture

Lindsey Purcell, Urban Forestry Specialist
Purdue Forestry & Natural Resources

​The cicadas are back. After Brood XXIII of the 13-year periodic cicadas emerged for a couple weeks this June, we had around a month of relative quiet as crickets, frogs, and other nighttime wildlife provided us with typical sounds of the summer.

Photo credit: Aaron Doenges

Now, as the annual cicadas emerge with calls as loud as 100 decibels, the outdoors is noisy with insect calls once again. Annual cicadas are also known as dog-day cicadas due to their arrival coinciding with Sirius, the dog star, being visible at sunrise. They are green and black in color, in contrast to orange and black periodic cicadas. These insects spend 2-4 years in the ground feeding on sap from tree roots, but due to staggering emergence schedules, some of them come out every late summer.

​An interesting fact about dog-day cicadas is that they are one of folklore legend’s predictors of weather. There are several age-old observations that have been used to estimate weather over the years. For example, oak leaves reaching the size of a squirrel’s ear is known to be the perfect time to plant corn. A common one you are surely familiar with is Groundhog’s Day, February 2nd, when the sighting of clouds when a groundhog emerges from its hole predicts spring weather coming six weeks before it would be if the weather was sunny. Consider dog-day cicadas the anti-groundhog. The passed-down warning is that after the first call of the dog-day cicadas, there will be six weeks till frost. So enjoy the weather while you can! The cicadas are out, and if they are to be believed, cold weather is on the way.

To read more, check out Professor of Entomology Tom Turpin’s On Six Legs podcast “Cicada Weather Predictors“.

Resources
Cicada Weather Predictors – On Six Legs
Large Brood of Periodical Cicadas Return After Thirteen Years – Got Nature?
Annual Cicadas – Missouri Department of Conservation

Indiana has experienced extreme weather over the last couple of years. Extreme heat, draught, cold, winds, you name it, we’ve dealt with it. Most recently, through June and July, Indiana has experienced record-breaking rainfall and flooding. These weather conditions can make it difficult for our surroundings, but it can also cause a lot of stress on our trees.

Photo credit: Keith Robinson

Urban trees are more susceptible to weather-related injury because of their oftentimes compromised root systems. In forested areas, trees spread their roots out two to three times the length of the tree. This is important because roots are the tree’s way to receive oxygen from the soil. This provides for a healthy defense system, giving the tree advantages like the ability to draw in moisture during dry spells and secrete fungi- and insect-repelling chemicals. In urban areas, roads and construction oftentimes sever roots or restrict where they can go, leaving the trees in a vulnerable state.

Our vulnerable urban trees are especially likely to be harmed by weather-induced stress. Symptoms like browning of leaves, dying branches and early coloration in the fall are all signs that a tree’s health is declining.

Keep an eye on your trees, and if you are concerned, use the Purdue Tree Doctor app​ or submit a sample to the Purdue Plant and Pest Diagnostic Lab as you seek best practices to care and protect your trees.

Resources
Purdue Experts: Tree Deaths Across Indiana May be Related to Weather Stress, Purdue Agriculture News
Drought? Don’t forget the trees! The Education Store, Purdue Resource Center
Plan Today For Tomorrow’s Flood, The Education Store
Community & Urban Forestry, Indiana Department of Natural Resources
The Root of the Problem, Northern Woodlands

Purdue University Agriculture News

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

B. Rosie Lerner, Extension Consumer Horticulture Architecture
Department of Horticulture and Landscape Architecture, Purdue University​

​

Tree-of-heaven seedling

​Invasive plant species threaten many habitats including forests across Indiana. The introduced Asian tree-of-heaven (Ailanthus altissima) is one of these aggressive and troublesome invaders. Tree-of-heaven grows very quickly on a wide variety of sites from seed and sprouts and can rapidly out-compete native trees and shrubs. There are areas in Indiana forests already dominated by this unwelcome invader. Controlling large infestations of this tree can be very expensive and even dangerous. The sap and wet sawdust of this tree can trigger an allergic reaction in some people.

There is some hope on the horizon. Research work done by the U.S. Forest Service and universities in Pennsylvania and Ohio has identified a fungus that can kill tree-of-heaven and has minimal or no impact on surrounding plants. Verticillium nonalfalfae or Ailanthus verticillium wilt is a soil fungus that has been identified so far in Pennsylvania and Ohio that can rapidly kill large patches of tree-of-heaven. Tests with this naturally occurring soil fungus have shown it to be very effective at killing tree-of-heaven without having significant impacts on surrounding native plants.

This naturally-occurring killer of tree-of-heaven could be an important tool in managing this invasive problem in Indiana. The quickest way to get started with natural bio-control of tree-of-heaven is to locate the fungus here in Indiana. Citizens and resource professionals can help us locate ailanthus verticillium wilt by identifying patches of tree-of-heaven that are being impacted by the fungus. This requires familiarity with the identification of both tree-of-heaven and the symptoms of the wilt disease on the tree.

Close-up of the “teeth” on the leaves of tree-of-heaven

Tree of Heaven has long, compound leaves resembling sumac or black walnut but possessing small notches or teeth at the base of the leaflets. The plant parts have a very unpleasant burnt nut odor when crushed or bruised. The bark is smooth and grey with light grey or white fissures running vertically in the bark. Twigs are very stout with a light tan spongy pith in the center.

Ailanthus wilt causes rapid death of the tree, often within one season, so look for patches of tree-of-heaven where most trees are showing wilting foliage or are already dead. The mortality will often be radiating out from a central group of dead or dying trees. Trees with wilt will have a yellow to yellow-brown discoloration of the wood directly beneath the bark. Healthy tree-of-heaven will have nearly white wood under the bark. The mortality will almost always be groups of trees, not scattered individuals. Several resources are included below to help you identify tree-of-heaven and ailanthus wilt.

If you encounter what you think is ailanthus wilt in Indiana, please contact:
Lenny Farlee, Hardwood Ecosystem Extension Specialist
Purdue Forestry and Natural Resources
Email: lfarlee@purdue.edu
Phone: 765-494-2153

Joanne Rebbeck, Plant Physiologist
USFS, Northern Research Station
Email: jrebbeck@fs.fed.us
Phone: 740-368-0054

Resources
Tree-of-heaven Images, Center for Invasive Species and Ecosystem Health
Scientists Using Fungi to Stop an Invader​, The Columbus Dispatch
Verticillium nonalfalfae, USDA Forest Service
Invasive Species, Purdue Extension​
The Education Store, Purdue Extension Resource Center (search “invasive”)

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

Photo credit: Colin Hutton

An often overlooked part of the ecosystem responsible for our food and environmental health are the pollinators. This group of animals move pollen from flower to flower, fertilizing seeds, fruits and vegetables. Pollinators include honey bees, native bees, moths, beetles, birds and bats, and they are struggling. 40% of honey bee colonies have been lost in the last year, and in the past two decades, over 90% of Monarch butterflies have disappeared.

After noticing this sharp decline, large efforts are starting to take place to restore the pollinator population. The Pollinator Partnership has created a Pollinator Week every year from June 15-21 where the pollinator’s importance is highlighted through local events. The White House has announced a National Strategy to Promote Pollinator Health in hopes to return the pollinator population to a sustainable level. In Norway, a connected network of honeybee habitats dubbed the Bee Highway was created. At the large scale, many initiatives are starting to form, but it is important to know that we can also be helpful on an individual level.

Our gardens and landscapes are the homes of many pollinators, providing the food, water and shelter that they need. When planting a garden or landscape, it is important to take this into consideration and follow a few simple guidelines. For an adequate food supply, aim for at least three flower species in bloom at a time. For shelter, pollinators can benefit from a break from the wind and sun provided by plants, fences and other structures. Finally, pesticides should be limited and used in a controlled way. Pick spray instead of dust-based pesticide. Try to use it only when necessary, follow all label directions and spray only in the early morning or at dusk when pollinators are less active. Keep these guidelines in mind, and your garden or landscape will be an attractive home for pollinators!

For more information, please check out the June column of Purdue Yard & Garden News.

Resources
Gardening for Pollinators, Purdue Yard & Garden News
News Columns & Podcasts, Purdue Agriculture
How to Minimize Pesticide Damage of Honey Bees, The Education Store
Honey Bees, Indiana Department of Natural Resources
Pollinator Partnership

B. Rosie Lerner
Extension Consumer Horticulturist, Purdue Extension