Purdue Landscape Report: Pollarding is a tree pruning method in which the upper branches of a tree are cut back to the same points on a regular schedule, creating a framework of knobby growth points from which new shoots emerge. The practice has been used for centuries and is especially common in landscapes where trees must be kept at a controlled height or width. Pollarding is not the same as topping, which is generally considered harmful because it removes branches without a long-term management plan. Instead, pollarding is a deliberate, repeated technique that can shape a tree into a compact, manageable form.
One of the main advantages of pollarding is size control. In urban areas, along streets, and near buildings or utility lines, trees often need to fit within tight spaces. Pollarding can reduce conflicts with overhead wires, streetlights, sidewalks, and traffic while still allowing a tree to remain in place. It can also reduce shade, which may be useful in courtyards, parking areas, and other sites where too much canopy cover is a problem. Some trees also respond by producing dense, attractive new growth, which can give them a distinctive architectural look.
Pollarding may also extend the usable life of certain trees when it is started early and maintained properly. Because the tree is kept smaller and more compact, it may be less likely to fail under wind or storm stress than a large tree with heavy limbs. In some settings, the regular cutting of new shoots can even provide a source of small-diameter wood or fodder, which helps explain why pollarding developed historically as a practical land-management method.
That said, pollarding has real drawbacks. It must be done correctly and consistently; if a tree is pollarded at the wrong age, on the wrong species, or after long neglect, the result can be stress, decay, weak regrowth, or structural problems. Not all trees tolerate the practice well, and some may decline if pollarded too aggressively. Pollarding also creates a very artificial appearance, which some people dislike. A freshly pollarded tree can look bare or severe for a time, and the repeated cuts require ongoing maintenance.
Figure 1: New growth on pollarded tree. Photo credit: Ben McCallister
Figure 2: Pollarded street trees in Shibuya, Tokyo. Photo credit: Ben McCallister
Pollarding is most strongly associated with Europe, especially Britain, France, the Netherlands, Italy, and parts of Spain, where it has a long history in both rural and urban landscapes. Today, it is still widely seen in European cities and towns, particularly on street trees and in managed public spaces. It also appears in some parts of North America, but it remains much more culturally visible and historically rooted in Europe. In many places, it is valued both for its practical function and for the distinctive form it creates over time.
Used thoughtfully, pollarding is a useful tool rather than a universal solution. It works best when matched to the right species, the right site, and a long-term maintenance plan. For the right tree in the right place, it can be both functional and visually striking.
Danielle Howard stands in front of a field on fire from a prescribed burn.
Danielle Howard has been hired as an Extension prescribed fire specialist housed with the Department of Forestry and Natural Resources at Purdue
The prescribed fire specialist position, funded by the Sam Shine Foundation, aims to increase prescribed fire capacity in Indiana by coordinating, conducting, and leading prescribed fires and prescribed fire training and outreach statewide.
In this role, Howard also will support the formation of prescribed burn associations (PBAs) and the Indiana Prescribed Fire Council (INPFC). She will work closely with Indiana conservation partners to develop prescribed fire training and outreach that builds capacity and support for prescribed fire on public and private land in Indiana.
“Prescribed fire is key to maintaining healthy ecosystems in Indiana, and I’m very excited to be at the forefront of increasing its use across the state,” Howard said.
Co-PIs on the supporting grant titled “Building Capacity for Prescribed Fire in Indiana” are Extension wildlife specialists Jarred Brooke and Brian MacGowan, Extension forester Lenny Farlee, natural resources training specialist Jessica Outcalt and Dr. Zhao Ma.
Danielle Howard holds a drip torch while starting a prescribed burn.
Howard, who previously worked in FNR as the field coordinator for the Hardwood Ecosystem Experiment from 2020 to 2023, comes to her new role after spending the last three years as the central region ecologist for the Indiana Department of Natural Resources Division of Fish, Wildlife and Nature Preserves. In that role, she managed 71 state-dedicated nature preserves and multiple privately-owned conservation easements across 26 counties in central Indiana. She also planned, prepared and implemented prescribed fire, invasive species control measures, native plantings, forest stand management and other restoration activities. She also established and sampled research plots for post-fire vegetation monitoring in Brown County State Park.
Howard also has taught Applied Ecology as an adjunct professor at Indiana University since January 2025.
In her previous stint in FNR as part of the HEE project, Howard coordinated forest management research activities, including bird surveys, overstory plots, small mammal trapping and more, conducted by various universities and partners at sites in Morgan-Monroe and Yellowwood State Forests.
Previously, she acted as an intermittent bird biologist for the Indiana DNR, the whooping crane outreach program assistant in Indiana for the International Crane Foundation and as a farm bill wildlife biologist for Pheasants Forever/Quail Forever.
Howard is a type II certified wildland firefighter and has certifications in prescribed fire for managers, wildlife fire chainsaws (S-212), wildlife fire pumps (S-211) and a pesticide applicator’s license for core and forests.
Howard began her new role on May 18. She will be based remotely in Bloomington, Indiana.
Entomology Weekly Review: Purdue Forestry & Natural Resources (FNR) Extension would like to share a timely update from the Indiana Department of Natural Resources – Division of Entomology newsletter regarding a wood-boring insect that may be encountered in hardwood logs across the state. Will Drews, Entomology staff member located in south-central Indiana (Bloomington area), recently reported activity from one of the more common round-headed borer pests found in hardwood logs: the flat-faced longhorn beetle, Graphisurus fasciatus. Will shares in the Entomology Weekly Review how to identify the borer, their habitat and if we need to be concerned.
What to Look For On the wing recently is one of the more common round-headed borer pests I find in hardwood logs, and that is the flat-faced longhorn beetle without a common name: Graphisurus fasciatus (Photos 2 – 5). This longhorn beetle (in the family Cerambycidae) is quite large as far as longhorn beetles go, reaching up to 0.6 inches in length, and features two long antennae (aka “horns”) characteristic of most of its family (Photo 3).
Photo 2 – Flat-faced longhorn beetle (Graphisurus fasciatus) adult found on a black walnut (Juglans nigra) log during a recent phytosanitary inspection.
Photo 3 – Flat-faced longhorn beetle (Graphisurus fasciatus) adult female lateral view at 10X magnification. Note the long “horns” or antennae which are a little longer than the main body.
Photo 5 – Flat-faced longhorn beetle (Graphisurus fasciatus) adult female lateral view at 20x magnification. G. Fasciatus is parte of the flat-faced longhorn beetle subfamily (Lamiinae), which its membes are characterized by a long, usually flat face, shown here.
Host Trees and Habitat
As a larva, Graphisurus fasciatus feeds on a variety of hardwoods and is reported to feed on pine trees as well. I generally find G. fasciatus larvae feeding between
the bark and sapwood of black walnut (Juglans nigra), white oak (Quercus alba ) and red oak (Quercus rubra) logs (Photo 6).
Photo 6 – Flat-faced longhorn beetle (Graphisurus fasciatus) larva (below) and pupa (above) with signs of larval mines on a red oak (Queracus rubra) log.
Identification Tips There are several ways to differentiate this species from the less common but closely related Graphisurus despectus, but one of the surest ways is to examine the scutellum (aka the small shield-like plate at the top/between the elytra [wing covers]). In G. fasciatus, the scutellum has two small whitish patches of hair, not present on G. despectus (Photo 7). Another diagnostic characteristic of G. fasciatus is that it has elytra with emarginate (or notched) tips (Photo 8).
Photo 7 – Flat-faced longhorn beetle (Graphisurus fasciatus) adult female dorsal view at 20X magnification showing scutellum (cirecled in red). Note the two light/whitish patches of hair on the scutellum. This is one of the best ways to distinguish G. fasciatus from G. despectus.
Photo 8 – Flat-faced longhorn beetle (Graphisurus fasciatus) adult female dorsal view at 20X magnification showing its elongated ovipositor. the ovipositor of G. fasciatus is quite unusual and proturberant for a longhorn beetle species and makes the females closer to 0/75 inches in length counting it. Also present in this image is the emarginate (or notched) tips of the elytra. This is another distinguishing characteristic of G. fasciaturs.
Should You Be Concerned?
This species can be alarming by its noticeable size and relative abundance but is not necessarily a major pest of concern as it does not usually bore into the sapwood and cause defects to the wood.
Stay Informed
FNR Extension encourages landowners and natural resource professionals to remain observant when working with hardwood logs and report unusual insect activity when found.
Agricultural & Natural Resources (ANR) Newsletter: On May 5, Natural Resources professionals gathered at the Davis Purdue Agricultural Center (DPAC) in Farmland, Indiana, for a forestry and wildlife management training led by Purdue Forestry and Natural Resources’ Brian MacGowan, wildlife extension specialist and extension coordinator; Don Carlson, forester; Jarred Brooke, wildlife extension specialist; and Jessica Outcalt, natural resources training specialist. The program combined classroom updates with field-based learning focused on active land stewardship, habitat management and conservation planning.
Jarred Brooke provided an overview of prairie grass plantings, including seed mixes, establishment methods and species composition.
Don Carlson discussing the 2014 planting and the management goals involved at Herrmann Property.
During the field tour of DPAC and Herrmann Properties, participants explored topics including native warm-season grass management using prescribed fire, Sericea lespedeza control in native grass plantings, prairie restoration, young forest management, and oak forest management for multiple objectives. Don Carlson discussed the history and management goals of DPAC, emphasizing how tree spacing, mowing and the use of crop and nurse trees influence tree establishment and growth. Jarred Brooke highlighted challenges such as rabbit damage to young trees and invasive species management. Participants learned key wildlife habitat principles, including a practical guideline for quail habitat: If a baseball tossed into the grass rolls, the habitat structure is suitable for quail; if it does not roll, the vegetation is too dense. The day concluded with updates on the NR Training Hub, prescribed fire and evaluation efforts.
If you’re interested in bringing a program like this to your area, we’d love to hear from you, submit a request at fnrextension@purdue.edu.
Emily Kring, Extension Educator
Agriculture & Natural Resources, Purdue Extension Jay County
With storm season just around the corner, one topic of concern on many minds is damage to and from trees. Depending on the intensity of the storms and the condition of the trees, damage from high winds, heavy rainfall, and lightning can be quite severe. Cracked or broken branches, stem failure, and root failure are some of the main concerns, but also the risk and liability of damage to people and property.
If your tree is damaged, there are some steps to deal with the situation. First and foremost, consider the safety of yourself and others around you. Inspect the tree from a distance first looking for the following:
Heaving of the ground indicating potential root failure
Damage to limbs and/or the trunk of the tree
Hanging branches can fall to the ground resulting in injury or death
Be aware of utility and power lines. Trees can become charged by coming in contact with live wires. All utility lines should be considered energized and dangerous.
If you find your trees damaged from a storm hiring an International Society of Arboriculture (ISA) Certified Arborist to perform a risk assessment will help guide your decision of how to manage your tree. To find an arborist near you and verify credentials use the link at Find an Arborist, Trees are Good, International Society of Arboriculture (ISA). For more information, you can also view Trees and Storms: Understanding Damage, Risk and Recovery, an informational Got Nature? Blog article from Purdue Extension.
Purdue Landscape Report: Many of the leaf spot diseases we observe can cause premature leaf drop in affected plants, which can reduce plant vigor if the disease is severe enough and a large proportion of the canopy falls in one season. Elm trees are susceptible to a number of different anthracnose fungi, including Ophiognomoniaintermedia, Gloeosporium betulae, Cryptocline betularum, and Cylindrosporium sp. Cryptocline is the fungus that we encounter the most frequently on samples submitted to the lab for diagnosis.
Figure 1: Cryptocline leaf spot on Elm (photo by Paul Bachi, University of Kentucky Research and Education Center)
Figure 2: Cryptocline leaf spot on a young elm shrub. As the density of leaf spots increases, the leaf blade turns more yellow. (Photo from Purdue Landscape Report)
Figure 3: Mature Cryptocline lesions which are tan in color and have black fungal structures within (photo from Purdue Plant & Pest Diagnostic Laboratory)
Symptoms
Leaf spots may start as small, round chlorotic lesions that slowly expand over time (Figures 1 & 2). Eventually, a necrotic spot with a purple/black border and tan or white center will form (Figure 3). Lesions may begin to develop on a leaf vein and instead of being circular will follow the vein a little, creating a thin necrotic lesion (Figure 4). With increased leaf spot development, large areas of the leaf blade will turn yellow and eventually necrotic, before it falls from the tree (Figure 5). Leaf drop will typically occur in the lower canopy, areas where there is less air movement and higher humidity; however, epidemics occur during periods of we weather that can cause significant leaf drop. Leaf loss typically occurs in the summer (late July to mid-August).
Figure 4: Lesions of Cryptocline located on leaf veins, creating elongate necrotic lesions instead of the typical round lesions located elsewhere on the leaf. (Photo from Purdue Plant & Pest Diagnostic Laboratory)
Figure 5: Elm leaves which have turned yellow or necrotic and fallen prematurely from the tree. (Photo from Plant & Pest Diagnostic Laboratory)
Figure 6: Close up image of Cryptocline leaf spots with acervuli. (Photo by Paul Bachi, University of Kentucky Research and Education Center)
Life Cycle Cryptocline is only known to colonize the leaves, so it overwinters in fallen leaf tissue. In the spring, the fungus will produce ascospores which are carried in the wind to infect young elm leaves. Once initial lesions progress, black fungal structures (acervuli) will form in the necrotic tissue and being producing asexual spores (conidia) in a sticky substance, which can be spread via rain (Figure 6). The conidia act as a secondary infection cycle where it will infect foliage and create new leaf spots continuously throughout the growing season as long as the environmental conditions are conducive.
Management
Like other leaf spot pathogens that do not infect stems, removal of the foliage in the fall can reduce inoculum for the following year (though won’t eliminate the disease). Providing fertilizer (where needed) and water (hot and dry periods) will help mitigate some tree stress, as stress can predispose plants to increased disease severity. Fungicides are not normally recommended for mature trees as it is impractical to get coverage across the entire canopy, but could be practical in a nursery setting if symptoms are observed and leading to leaf drop. It is still early in the season, but the next few weeks are important to monitor for some disease issues that may explode later in the season.
For other information on management of foliar disease problems, please see the following link: Foliar Fungal Disease Management.
Join Purdue Extension forester Lenny Farlee in this episode of “A Woodland Management Moment” as he explores the considerations for growing high timber-quality black walnut on purpose. Learn about what black walnut requires to grow well, its visual characteristics and the timeline of this plant in openings. Watch the video to discover some of the management strategies you can use gradually develop these black walnut stems for timber markets.
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.
Spring is one of the best times to identify trees and shrubs in Indiana. As buds break and flowers emerge, many species reveal distinctive traits that make identification easier and more enjoyable. In this collection of ID That Tree videos, Purdue Extension Forester Lenny Farlee highlights a variety of native trees and shrubs from eye-catching flowering species to lesser-known woodland plants. Whether you’re a student, landowner or simply enjoy exploring the outdoors, these videos offer a quick and accessible way to build your tree identification skills this spring.
Explore the Spring Bloom Edition videos, starting with Umbrella Magnolia:
Continue building your identification skills with these additional ID That Tree: Spring Bloom Edition videos:
If you have any questions regarding wildlife, trees, forest management, wood products, natural resource planning or other natural resource topics, Purdue Extension – FNR is here to help. Visit our Ask an Expert webpage to connect with a Purdue Extension specialist.
Unhealthy trees can fail, causing potential damage to nearby homes
Trees provide many benefits for our homes, businesses and properties. If a tree is defective, however, it may become a hazard. It is important to understand that tree owners have a duty to inspect and maintain their trees. All property owners should take reasonable steps to protect themselves by involving a qualified consultant or certified arborist.
The primary responsibilities of the arborist are to assess the potential for tree failure, advise owners of the consequences of failure and recommend the proper measures to prevent and abate failures. In assessing and managing trees it is important to create a balance between the inherent risk a tree poses and the benefits provided by the tree. Risk tree management begins with these basic steps:
Reduce tree liabilities: The property owner or manager has an obligation to periodically inspect trees for unsafe conditions. Since all trees have risk associated with them, regular inspection compels the owner or manager to evaluate the amount of risk they are willing to assume. Tree risk assessment is an important part of a program to determine if a tree is structurally sound or has the potential for failure. Inspections show that the tree owner is actively managing their trees and could reduce the owner’s liability if a failure occurs.
Inspect regularly: Trees should be assessed through inspections by a qualified arborist, preferably an International Society of Arboriculture Certified Arborist. Further inspections should be conducted after major weather events. At a minimum, trees should be inspected every five years or according to the owner’s risk tolerance.
Document and maintain records: Every inspection should be recorded and kept on file for future reference. These records are important for several reasons. Past evaluations can show how a tree has changed in its health and structure over the years. Also, written assessments are beneficial in liability claims and court cases. These written evaluations could minimize liability if a failure occurs and a claim is filed against the tree owner.
Inspect trees for health conditions and defects during the tree risk assessment.
Develop a site policy and care plan: Every property manager should create and implement a policy for tree risk. This includes developing a standard of care, an inspection process and mitigation of property risk. Routine care and scheduled maintenance for all trees is essential.
Mitigate tree risk: Tree owners should make every effort to reduce risk with proper pruning and health care practices. Consider all options before deciding on removal. If possible, move or remove the “target” (see definition in “Tree Risk Assessment” section). Install structural support systems where feasible. Modify site conditions to improve the environment around the tree. Risk mitigation requires a process of logical options focusing on protecting the target and preserving the tree.
Schedule tree work: While evaluating trees for risk, the inspector should note any tree maintenance needs. The inspection can determine the timing and priority of work needed. The work should be prioritized first for safety and then for tree health. Consider potential risk, activities around the tree, level of acceptable risk and the needs of the client.
Create good tree planting strategies: Identify planting needs and locations that become available as trees are removed or destroyed. Improving the health and safety of the landscape requires an understanding of management principles, such as species selection and diversity. Also consider the impact of site infrastructure, including utilities, streets and sidewalks, and choose the right tree for the right place. Select trees known to thrive under local conditions and sustainable as long-term investments in the property
Tree Risk Assessment
For a tree to be considered hazardous it must be defective either in some part or as a whole, with risk for failure and a target that is threatened. Trees are declared hazards if assessments have been completed and mitigation is required to prevent a failure from causing damage affecting the target. To understand the implications of this concept, tree owners need to know some common terms of tree risk management.
Identify potential targets for tree failure.
A target is people, property or activities that could be injured, damaged or disrupted by a tree failure. Tree owners must carefully assess the area around homes, playgrounds, sidewalks and parking areas. Is the target static, moveable or mobile? Consider whether people can be kept away or separated from the target area. Also, assess the target’s value and potential. Review the target zone, which is the area where the tree or a branch is likely to strike when it falls, to determine consequences of the tree’s failure. The target zone should include the areas inside a circle around the tree, which is at least as wide as the total tree height.
Risk is the combination of the likelihood of a tree failure event and the severity of the possible consequences of that event. Every tree has the potential to fail; however, only a small number of failures actually cause injury or damage. It is impossible to maintain trees free of risk. Some level of risk must be accepted by the owner.
Hazard is a likely source of harm and is identified as the tree part or parts which will affect the target zone. For example, an entire tree or a single branch could be determined as a hazard. Hazards are identified during tree assessments, and tree owners are required to take steps to minimize the risk of damage from failure.
Individual tree characteristics must be considered when conducting evaluations for defects and failure potential. Evaluations should take a systematic approach, assessing the potential for tree failure, understanding the impact of such failures and outlining a plan of action to prevent and mitigate these failures. Tree owners should fully understand the site factors and characteristics of the tree species. There are several contingencies that influence tree failure potential and risk. These include soil type and saturation, wind exposure, pest damage, poor growing conditions and poor pruning practices such as topping.
Among the characteristics to consider when conducting tree risk evaluations are:
Defects — severity and location. Decay, cankers, cracks and other positive indicators of weakness in the roots, stems and branches may need immediate attention if a target is present.
Species characteristics. Some tree species possess weaker wood, a susceptibility to decay, poor growth habits and potential for pests. They could be more likely to fail after wounding because of poor ability to wall off internal decay or health issues.
Canopy size, shape and weight distribution. This is especially true in situations where a tree is exposed to windy conditions, is leaning or has a poor stem-to-canopy ratio.
Crown architecture. Poor branching and similar characteristics can create high-risk situations in strong winds and other weather conditions.
Plant health and vigor. This determines how a tree can overcome wounding or pest infestations.
The overall size of the defective part. A predetermined rating system, which outlines critical thresholds, should be considered and incorporated into the tree’s risk management plan.
Tree Inspections
Assessments should include a thorough examination of each section of the tree. A systematic approach using standardized evaluation methods aids the process. Review the canopy (crown), branches and root zone to check for signs of failure. These include:
Dead, diseased, dying or broken branches.
Thinning or poor canopy health.
An unstable branching pattern, overextended or weakly attached branches, or cracks in the stems.
Cracks or decayed areas in the main trunk.
Exposed or decayed roots, heaving of the soil, fungus growth or cracks in the soil around the root plate.
Recurrent inspections to determine tree health and condition are critical for successful risk management programs. Trees in active-use areas should be inspected annually for defects and conditions leading to failure. Inspections are necessary after storms to ensure excessive loads have not exceeded the strength of the tree and its parts. Also, be sure to note trees with a history of failures or those with problematic structure, for more frequent monitoring and inspection. A good database and archive of tree evaluations is a critical strategy in the overall risk management plan.
