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 receieve 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.
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
Lindesy 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
Photo credit: Dan Annarino
Hopefully no one is reading this after a catastrophic loss of their pond. This very wet summer has tested some ponds ability to hold and safely release excess water. I would like to quickly review the overflow structures ponds should have and also some management necessary to ensure the safety of ponds levees/dams.
For recreational ponds there should be one or perhaps two means of releasing water from the pond. Most of these ponds are built on sloping land in order to capture rainwater to fill the pond. In this case it is necessary to have an emergency spillway that will divert excess water, once the pond is full, away from the dam to prevent erosion and save the integrity of the structure. Usually they are just an earthen channel that runs around the end of the dam with an initial elevation 1-2 feet below the top of the dam. Water only runs through the spillway when the pond is full. An emergency spillway should have vegetation to prevent erosion but not to the extent that water is blocked from passing through efficiently.
A distinct advantage can be gained by having a drain structure installed through the dam when ponds are initially constructed. Drains such as this typically have a valve or swivel pipe which can regulate water level to whatever height the owner would like. With a wet summer such as we have had, the pond water level could be proactively lowered to save massive amounts of water passing through the spillway. Additionally you can remove stagnant low oxygen water from the bottom of the pond. If a drain structure is releasing water from the bottom of the pond it is a good idea to flush this valve 2-3 times per year to remove debris from around the structure which may plug it up if used infrequently. With these structures it is a good idea to use the 6/12 rule. Water levels are kept six inches below maximum in order to catch any rain water event without overflowing. Evaporation and seepage will reduce the level back down over time. The 12 refers to the level the inches below maximum where you would add well water if you have the capacity. Generally this is only used with aquaculture ponds.
Control structures to maintain water levels will ensure the integrity of your ponds dams and levees. By controlling the amount of water flushing through a pond, the owner can also manage the productivity of the pond ecosystem by releasing/maintaining nutrients in the pond.
Commercial Greenhouse and Nursery Production: Controlling Algae in Irrigation Ponds - The Education Store, Purdue Extension Resource Center
Indiana Ponds - The Education Store
Indiana Ponds Q&A - The Education Store
Management of Ponds, Wetlands, and Other Water Reservoirs to Minimize Mosquitoes - The Education Store
Indiana Pond Management - Indiana Department of Natural Resources (IDNR) - Fish & Pond Management
Ponds - Planning, Design, Construction - USDA Natural Resources Conservation Service (NRCS)
Bob Rode, Extension Aquaculture Specialist
Department of Forestry and Natural Resources, Purdue University
Trees continue to survive in spite of the many challenges they face in the urban environment. However, to grow from seedling to a mature tree in the urban forest, they need our help. They are the largest, oldest living organisms on the planet and can live long, healthy lives with some assistance. We often place trees in less-than-favorable growing locations that don't allow natural development and maturity and often require pruning to develop a durable structure, improve clearance, and maintain aesthetics.
Pruning has been called "one of the best, worst maintenance practices" performed on trees. The process creates wounds, which have a major impact on plant processes. Improper cutting on a tree causes severe damage or even death. To prune properly, it is important to understand both the proper techniques and how the tree responds to pruning.
In this publication, Urban Forestry Specialist Lindsey Purcell explores the techniques behind good pruning, from the planning process before planting to monitoring the tree's response after the pruning cuts. Check out Tree Pruning Essentials and make sure you are pruning your trees to maximize safety, aesthetics, and tree health!
Tree Pruning Essentials - Purdue Extension
Trees and Storms - Got Nature?
Tree Risk Management - The Education Store, Purdue Extension Resource Center
Pruning - Indiana Department of Natural Resources
Prune Your Trees - Indiana Department of Natural Resources
Lindsey Purcell, Urban Forestry Specialist
Department of Natural Resources, Purdue University
Photo credit: Tom Campbell
As boats enter and exit public bodies of water, they risk transfering aquatic plants, mussels, or invertebrates that attach themselves to the bottom of the boat. While this might seem pretty harmless at first, this spreading of aquatic species runs the risk of introducing invasive species into new environments.
Invasive species cause harm to local ecosystems by reproducing exponentially when they are outside of their usual habitat and the organisms that keep their populations in check. They can then cause great damage by feeding on local species and the food they depend on. Once an invasive species is detected, it is oftentimes very expensive and difficult to control. For example, around 1991, the U.S. and Canada spent an estimated $20 million per year to control invasive sea lampreys and restore the trout populations that were damaged by them. In Indiana alone, we spend around $800,000 a year to attempt to control the growth of Euarsian watermilfoil, another nuisance invasive species.
In an attempt to avoid more cases like this in the future, the Indiana Department of Natural Resources (INDNR) is looking for help. Volunteers can sign up to record information about boats and their potential aquatic hitchhikers entering and leaving lakes during times of heavy use. The DNR Division of Fish & Wildlife can take this data and use it for public outreach and planning species management.
Those interested are highly encouraged to sign up on INDNR's Volunteer Program page.
Aquatic Invasive Species (AIS) - Indiana Department of Natural Resources
DNR seeks help gathering info on spread of aquatic species - WSBT22
Indiana Invasive Species Council - Purdue Entomology Extension
Invasive Plants - Purdue Agriculture Weed Science
The Education Store, Purdue Extension Resource Center (place "invasive as keyword in search field)
Indiana Department of Natural Resources
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 US 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 so far been identified 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 verticullium wilt by identifying patches of tree-of-heaven that are being impacted by the fungus. This requires familiarity with ID 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
Joanne Rebbeck, Plant Physiologist
USFS, Northern Research Station
Ailanthus Verticillium Wilt Photoguide - United States Department of Agriculture
Tree-of-heaven Images - Center for Invasive Species and Ecosystem Health
Scientists using fungi to stop an invader - The Columbus Dispatch
Ailanthus and Verticillium nonalfalfae Research - USDA Forest Service
Invasive Species - Purdue Extension
The Education Store, Purdue Extension Resource Center (place "invasive" as keyword is search field)
Lenny Farlee, Hardwood Ecosystem Extension Specialist
Department of Forestry & Natural Resources, Purdue University
We all know that trees help to improve our air quality. Absorbing toxins, reducing CO2 levels, and providing shade are well-known benefits of trees, and many initiatives are in place to increase urban forested areas. However, there is an interesting fact to consider. According to the U.S. EPA, the average American spends 90% of their time indoors, where those benefits of outdoor trees aren't nearly as impacting. In fact, indoor pollutants are estimated to be two to five times higher indoor than outdoors, and account for several billion dollars of health costs nationally. Indoor air needs to be cleaned too. This is the problem Purdue's BioWall team hopes to solve.
The project began in 2009 as part of a fully self-sustainable house called the INhome. In 2011, INhome competed against 20 other teams in the United States Department of Energy's Solar Decathlon and scored second place, largely due to it's most distinguishable feature, the BioWall. The BioWall was integrated into the return duct of INhome's air conditioning system, filtering the air inside the home through the roots of goldon pothos and other species of ivy that are known to have a strong effect on air quality.
Today, the BioWall team is in the process of testing out an updated version of the BioWall. Prototype designs are being tested to improve the air cleaning qualities as well as the lifespan of the plants. Bypass tubes are being implemented to lessen the amount of air passing over the plants' roots, allowing them to dry out slower and live longer. Eventually, the team would like to put out a consumer version in the next few years for about $2,000. It's a lofty goal, but the team believes they can succeed and bring affordable and self-sustaining indoor air cleanliness to homes around the world.
For more information, check out the BioWall team's website.
BioWall - Purdue University
Office of University Sustainability - Purdue University
Purdue Biowall hopes to boost air quality - WLFI
Questions About Your Community: Indoor Air - United States Environmental Protection Agency
William Hutzel, Professor of Mechanical Engineering Technology
With all of the recent rain we have had throughout the state, I have received several inquiries about effects on wildlife and what we can expect. While some flooding is natural in low areas and wildlife are adapted to respond, extreme flooding can impact wildlife. Flood waters can wash away nests or drown developing or very young animals for those living in low-lying areas. For example, heavy spring rains can reduce nest success of wild turkeys in flood plain areas.
In many cases, wildlife will adapt by simply moving to higher ground. I recently received an email from a Purdue Extension Educator. She was contacted by a homeowner about a possible increase in garter snake populations. According to her email, the homeowner never saw garter snakes in years past until this year. In fact they were now showing up in neighborhood homes. Certainly our environment changes over time and wildlife can and do respond to these changes. However, this recent change was likely due to a response of snakes moving to drier ground. This and other similar displacement of wildlife is usually temporary.
What can we do about this? I’m afraid not much for our currently flooded friends. However, in the long-term, times like this reinforce the need to create and enhance quality wildlife habitat. Providing wildlife with quality habitat that contains the necessary food, cover and water resources gives them a fighting chance to deal with issues that inevitably arise. In addition, wetlands that landowners build and restore on their properties not only enhance wildlife habitat, but also help retain flood waters and recharge groundwater supplies.
If some unwanted wildlife has overstayed their welcome around your home, check out my article on trapping nuisance wildlife. If you think you have found a sick or injured animal, you can find a list of licensed Wild Animal Rehabilitators in your area on the DNR Division of Fish and Wildlife's website. In Indiana, wildlife rehabilitators have necessary state and federal permits to house and care for sick or injured wild animals.
Preventing Wildlife Damage – Do You Need a Permit?, The Education Store, Purdue Extension
The Basics of Managing Wildlife on Agricultural Lands, The Education Store, Purdue Extension
Brian J. MacGowan, Extension Wildlife Specialist
Department of Forestry & Natural Resources, Purdue University