Purdue University - Extension - Forestry and Natural Resources
Got Nature? Blog
Many homeowners are finding their trees with dry and wilted leaves and no rain in sight. This publication describes how homeowners can deal with these drought-stressed trees, Drought? Don’t Forget the Trees!
Drought 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.
Trees in a weakened state from drought are more susceptible to pests, which can further weaken the tree, and even kill part or all of it. Although there is nothing we can do to prevent drought, it is important to know what can be done to reduce long-term effects of prolonged dry conditions.
Resources:
Water Your Trees, Video, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Trees in Times of Drought, Video, Purdue Agriculture
INPREPared, Purdue Extension
Drought Information, Indiana Department of Natural Resources
Tree Planting Part 1: Choosing a Tree video, Purdue Extension-FNR YouTube Channel
Lindsey Purcell, Chapter Executive Director
Indiana Arborist Association
Brown or black spots with yellowing are signs of anthracnose.
This time of year, many black walnut trees’ leaves may have black spots, turn yellow and begin to drop. This is commonly known as anthracnose, a fungal disease that causes trees to drop their leaves prematurely.
Anthracnose is worsened by wet weather, and some trees are more genetically susceptible to anthracnose than others. It is not fatal but can look like a serious problem. The absence of leaves can slow a tree’s growth and can reduce the nut crop, although by this time of year growth may have slowed or stopped for the season.
Anthracnose generally begins as small circular brown to black areas on the leaflets. Over the season those spots expand and cause leaf drop. There are a few other leaf spot diseases of black walnut, see the references below for descriptions of those diseases.
Although unsightly, there is no need for further action if you are growing timber and have anthracnose in a plantation or woods. It can be an issue if you are growing walnuts for a nut crop, and there are resources and spray products to help manage the fungus in those situations.
If you have individual landscaping trees and want to limit anthracnose spread there are few things you can do:
- Gather fallen leaves and compost or remove them from the site.
- Control weeds which could carry the fungus.
- Plant walnut trees where there is good air circulation.
- Keep the trees healthy and vigorous by managing soil fertility and thinning competition as needed.
Resources
Walnut Anthracnose, Walnut Notes, U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station
Indiana Walnut Council, Industry Representatives include 45 states and 3 foreign countries
Diseases in Hardwood Tree Plantings, The Education Store, Purdue Extension resource center
Study: Fungus Behind Deadly Disease in Walnut Trees Mutates Easily, Complicating Control, Purdue Agriculture News
Indiana Walnut Council
Diseases in Hardwood Tree Plantings, The Education Store, Purdue Extension resource center
Why are my walnut trees dropping their leaves?, Purdue Extension – Forestry & Natural Resources (FNR) Got Nature? Blog
Invasive Species Walnut Twig Beetle Detected in Indiana, Purdue Extension – FNR Got Nature? Blog
Intro to Trees of Indiana: Black Walnut, Purdue Extension – FNR Got Nature? Blog
Planting Hardwood Seedlings in the Central Hardwood Region, The Education Store
Regenerating Hardwoods in the Central Hardwood Region: Soils, The Education Store
Fertilizing, Pruning, and Thinning Hardwood Plantations, The Education Store
Resources and Assistance Available for Planting Hardwood Seedlings, The Education Store
Liz Jackson, Manager Walnut Council / IN Forestry Woodland Owners Association (IFWOA) & Engagement Specialist
Purdue University Department of Forestry and Natural Resources
Purdue Extension forester Lenny Farlee introduces you to the quaking or trembling aspen. This tree is found in northern Indiana and typically identifiable by whitish to grayish bark with dark spots where the branches come out.
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
Aspen, The Education Store, Purdue Extension resource center
Quaking Aspen, Purdue Fort Wayne
Investing in Indiana Woodlands, The Education Store
Investing in Indiana Woodlands, The Education Store
Tree Appraisal and the Value of Trees, The Education Store
Forest Improvement Handbook, The Education Store
ID That Tree, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources
On this edition of ID That Tree, Purdue Extension forester Lenny Farlee introduces you to the northern white cedar, a native conifer that is used for ornamental, windbreak and reforestation purposes. This evergreen has distinct scale like foliage which is soft to the touch. He shares how to distinguish it from the eastern red cedar.
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, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
ID That Tree: Eastern Red Cedar, Video
Thuja occidentalis, The Purdue Arboretum Explorer
Investing in Indiana Woodlands, The Education Store
Tree Appraisal and the Value of Trees, The Education Store
Forest Improvement Handbook, The Education Store
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources
Purdue Landscape Report: Have you noticed large, messy webs on trees? You may have seen a colony of fall webworms. These caterpillars hatch in mid-July but tend to become more noticeable as the summer progresses. They often eat branches bare of leaves but are they a threat to tree health?
What do they look like?
Fall webworms are small, fuzzy pale-yellow caterpillars (figure 1) that build large, conspicuous white webs in trees in the late summer (figure 2). Their webs stretch over tree branches and grow over the course of the summer. When disturbed, the caterpillars will violently thrash back and forth in a bid to ward off predators.
Fig1. A colony of fall webworm caterpillars feeding on a leaf. Note that the web covers the leaves they are currently eating. Photo by Judy Gallagher.
Fig2. Trees will often have multiple fall webworm webs on them. This photo shows a typical number of webs for a large tree. Notice that the webs tend to be on the ends of branches and that the leaf damage is concentrated close to each web. Photo by Ken Gibson.
What kind of damage do they cause?
Fall webworms eat the leaves of many species of deciduous trees and bushes. This damage occurs late in the summer shortly before the trees normally drop their leaves for fall. Therefore, fall webworms very rarely do serious damage to trees. In most cases the trees will grow their leaves back the following spring. On rare occasions, a tree that is already highly stressed may be further weakened by fall webworm damage. However, most trees, even heavily infested trees, are minimally affected and show no signs of damage the following spring.
Do they need to be managed?
Fall webworm damage generally looks much worse than it is. In general, trees only need to be managed for fall webworm if the owner is concerned about aesthetics. In that case, the easiest means of management is pulling the web off the tree by hand and putting it in a bucket of soapy water or freezing it. Some people may be sensitive to the caterpillars’ hairs so gloves should be worn to prevent contact.
In cases where the webs are too high up to be reached, they can be managed through insecticides. Further instructions can be found here.
Cover image by Photo by msumuh on Flickr.
Resources
Fall Webworm Bulletin, Purdue Extension -Entomology
Which Web is Which, Purdue Landscape Report
Will My Trees Recover After Losing Their Leaves?, Purdue Landscape Report
Safe Caterpillar Control, Purdue Landscape Report
Mimosa Webworm, The Education Store, Purdue Extension resource center
Sod Webworms, Turf Science at Purdue University
Bagworm caterpillars are out feeding, be ready to spray your trees, Purdue Extension – Forestry and Natural Resources
Elizabeth Barnes, Exotic Forest Pest Educator
Purdue University Department of Entomology
Join Kara Salazar, Assistant Program Leader and Extension Specialist for Sustainable Communities, and Sarah Hanson, Ag & Natural Resources Educator for Purdue Extension in Johnson County, as they introduce you to the world of rainscaping and rain gardens.
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
Rainscaping Education Program, Purdue University
Master Gardeners Program
Ask An Expert, Playlist, Purdue Extension – Forestry and Natural Resources Youtube channel
Rainscaping, Playlist
Rain Gardens Go with the Flow, Indiana Yard and Garden, Purdue Horticulture
Rainscaping Education Program Highlighted in NOAA Annual Report, Got Nature? Post, Purdue Extension
What is Rainscaping? Purdue Rainscaping Education Program Video, Purdue Extension
Q&A About Drainage Water Recycling for the Midwest, The Education Store, Purdue Extension resource center
Become a Purdue Master Gardener, The Education Store
Kara Salazar, Assistant Program Leader and Extension Specialist for Sustainable Communities
Department of Forestry and Natural Resources
Sarah Hanson, Ag & Natural Resources Educator
Purdue Extension for Johnson County
Meet the Hackberry. Purdue Extension forester Lenny Farlee introduces you to this native tree with single toothed leaves, an uphill/downhill shaped base of the leaves and a gray, ashy bark with warty/bumpy areas with smooth spots in between.
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, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
Hackberry/Sugarberry, The Education Store, Purdue Extension resource center
Investing in Indiana Woodlands, The Education Store
Tree Appraisal and the Value of Trees, The Education Store
Forest Improvement Handbook, The Education Store
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources
In this edition of ID That Tree, Purdue Extension forester Lenny Farlee introduces you to the Eastern White Pine, Indiana’s only native five-needle pine. This species, which can grow to 150 feet tall, grows a ring of branches as it ages. Learn more inside.
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, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
White Pine and Salt Tolerance, The Education Store, Purdue Extension resource center
Tree Diseases: White Pine Decline in Indiana, The Education Store
Investing in Indiana Woodlands, The Education Store
Tree Appraisal and the Value of Trees, The Education Store
Forest Improvement Handbook, The Education Store
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources
Purdue Extension forester Lenny Farlee introduces you to one of Indiana’s most common trees, the sugar maple. This species, which is often used to produce maple syrup, is easily identifiable by its five-lobed leaves, opposite leaf and branch arrangement, and ability to thrive in the understory.
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
The Story Behind a Sugar Maple Scar, Purdue Extension
Sugar Maple, The Purdue Arboretum
Hard or Sugar Maple, The Education Store, Purdue Extension resource center
Investing in Indiana Woodlands, The Education Store
Tree Appraisal and the Value of Trees, The Education Store
Forest Improvement Handbook, The Education Store
ID That Tree, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources
Purdue Extension forester Lenny Farlee tells you where to find and how to identify a species that clings to many of our trees, poison ivy. Protect yourself from the itch by recognizing this species before it is a problem.
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
Poison Ivy, Purdue Landscape Report
Poison Ivy, Purdue Extension
Poison Ivy, The Education Store, Purdue Extension resource center
Investing in Indiana Woodlands, The Education Store
Tree Appraisal and the Value of Trees, The Education Store
Forest Improvement Handbook, The Education Store
ID That Tree, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources
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