In this edition of ID That Tree, Purdue Extension forester Lenny Farlee takes us through the different characteristics of Hoptree, a relatively common shrub here in Indiana. This is a unique native plant with three-part leaves and hop-like seed pods. Also called Wafer Ash due to its distinctive wafer-shaped seeds, this shrub can often be confused with Poison Ivy or Bladdernut, so be sure to pay attention to key differences in the video. Features include trifoliate leaves and the temperate areas in which it grows.
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.
Purdue Agriculture News: As autumn settles in, we eagerly await the transformation of leaves into vibrant hues of red, orange and yellow. However, this year might tell a different story due to prolonged periods of hot weather. Ben McCallister, urban forestry specialist in Purdue University’s Department of Forestry and Natural Resources, sheds light on what to expect this fall.
The Impact of Weather on Fall Foliage Timing
“Right now, we’re seeing a mix of fall coming in and shifting temperatures, which is causing trees to respond. This back-and-forth hot weather is creating some color changes related to drought and stress. This can be expressed as brown color where leaves are starting to wilt and look a little crunchy from exposure to heat and drought stress,” McCallister explains.
While the typical color change occurs from mid-September to early November, it’s not unusual for leaves to remain green at this point in the season. McCallister suggests that while the hot weather “most likely won’t affect anything visually, it could influence fall foliage over time as climate change progresses.”
He anticipates a more pronounced display of fall colors extending through October, with some species showing their colors into November. Ultimately, the vibrancy and timing of these changes will depend on daily temperature fluctuations and the amount of sunlight trees receive.
The environment also plays a significant role in how trees respond. For instance, urban areas with more concrete and buildings create a “urban heat island” effect, which can delay color changes compared to more rural settings.
The Science Behind Color Transformation
The science of fall foliage is both fascinating and complex. McCallister explains that different tree species respond to autumn at varying times, with chlorophyll being a key player in this process.
“Changes in chlorophyll production leads to the color changes in leaves. Chlorophyll allows leaves to take up sunlight and convert it into energy, creating carbohydrates in the form of sugars – really anything that gives energy to the tree to help it grow, sustain itself and compartmentalize,” McCallister notes.
As temperatures cool and the sunlight diminishes, chlorophyll production declines, allowing the green hues of leaves to fade. This decline reveals carotenoids and anthocyanins – two chemicals essential to fall foliage. Carotenoids contribute to the yellow and orange shades, while anthocyanins produce reds and purples. As chlorophyll wanes, these vibrant colors emerge.
“It’s a very cool process,” McCallister adds. “Each color absorbs different spectrums of light, altering energy uptake and preparing trees for leaf drop and dormancy. As leaves in deciduous trees transition, trees store energy in their roots and wood so they can brave the winter.”
Viewing Fall Foliage
When it comes to enjoying fall foliage, McCallister emphasizes that Indiana offers many great viewing locations not far from Purdue’s campus.
Locally, Martell Forest, which is open to the public, is a great spot to check out the fall foliage and immerse yourself in the woods,” says McCallister.
What’s Next?
Leaf drop is likely to occur anytime from mid-October into December, although this process may take longer than usual due to the milder winters we’ve been experiencing. Similar to color changing, the timing of leaf drop varies by tree species and their growth patterns, as well as the overall weather conditions.
“For instance, ginkgo trees turn this brilliant yellow and have a cool reaction to leaf drop. Typically, all their leaves fall within a day or so, creating a carpet of yellow. In contrast, trees like maples and oaks, which have a mix of yellow, orange and red leaves, tend to hold onto their foliage a bit longer,” McCallister recalls.
It’s also important to note that while coniferous trees, like pines, spruces and furs, retain their needles year-round, some conifers like bald-cypress trees drop theirs. This sometimes causes confusion for homeowners who mistake these deciduous conifers for dying trees.
To provide the best care for your trees during these changing weather patterns, McCallister advises familiarizing yourself with different tree species. Resources like Google and dichotomous keys in forestry books can help with species identification and lead to tips for care. Regularly checking your trees’ health is essential year-round. Specialists in your local county Extension offices and ISA Certified Arborists can be valuable resources for proper tree management.
Question: We have a large 60+ foot mulberry tree in our backyard that is located by our pond. This is the first year I have seen these dark streaks on the bark of the tree. Should I have concerns?
Answer: From the photos, it looks like wet wood/slime flux is affecting your tree. It is a bacterial infection on trees and in most cases is not a serious issue, but unfortunately, there is nothing to be done about it. Many years ago they used to drill holes to try and allow gases and liquids drain from an area with the slime flux but through research and experience this practice is not recommended.
The Purdue Landscape Report titled Slime Flux of Trees shares more about this disease:
Slime flux (also known as wet wood) is a dark, foul-smelling and unsightly seepage of sap from tree trunks. The disease is not usually a serious problem but the appearance can be alarming. Slime flux is caused by common surface-inhabiting bacteria or yeast fungi that enter the trunk through wounds associated with improper pruning, stem breakage, injections, cracks from freeze injury or weak limb crotches. The bacteria and yeast may live on sap nutrients within injured trees for many years without any outward evidence.
Symptoms
The main symptom is the appearance of the dark sap oozing on the trunk exterior which happens when gasses produced by growth of the bacteria and yeast cause the internal pressure of the sap to become high enough to force the sap out through cracks in the bark. The dark streaks usually turn light gray or white upon drying. Oozing sap may be frothy and white at the point of exit. Airborne bacteria, yeasts, and fungi often colonize the wet oozing material, which ferments and releases a foul odor. Slime flux may delay wound healing (callus formation).
Morning AgClips — Nestled within the cool, flowing waters of Indiana’s Blue River, the elusive hellbender thrives under big, flat rocks, seeking refuge from predators and finding the perfect conditions to lay their eggs. But in recent years, they have become increasingly difficult to find.
Morning AgClips interviews Purdue hellbender team for details regarding Farmers Helping Hellbenders Project, aimed at restoring Indiana’s endangered hellbender salamander population by improving water quality in the Blue River-Sinking watershed. Learn more about this initiative by hearing directly from the people involved, with the two overarching goals being about improving hellbender habitat and also enhancing local farming operations. Particularly, the project engages farmers in adopting sustainable practices as well, while strengthening conservation efforts for hellbenders.
Hellbenders used to have a much larger range, occurring in most of southeast Indiana’s tributaries to the Ohio River and in the Wabash River. Sadly, its population has dropped drastically due to modification of stream habitats including the accumulation of sediment, agricultural and industrial pollution, warming waters and the channelization of streams and rivers. Because of their decline, these endangered ancient amphibians, with their large, unique flat bodies, have become the focus of an ambitious conservation effort led by Purdue University.
“The significance of the hellbender and its conservation extends beyond the species itself,” Purdue Extension Wildlife Specialist, Nick Burgmeier explains. “Hellbenders are an indicator species; their presence reflects the health of the water quality. Historically common and a top predator in streams, their decline has ecological repercussions, particularly on crayfish populations, which can disrupt food webs.”
Purdue Landscape Report: August was National Check Your Tree Month, but this is something that every tree owner/manager should be doing year-round. As the last hot days of summer are finishing up and we look forward to cooler fall days, we can look to our trees for different signs of trouble.
Most people tend to look up at the canopy before anything else in trees. Check leaves for dieback, discoloration, stickiness or signs of chewing. Check branches and the main stem for damage like splits and breaks, peeling bark, tunneling patterns under the bark, oozing wet spots, or sawdust around the tree. These could be signs of issues in the root system, pathogens like bacteria or fungal organisms, insect problems, or structural damage.
This is not an exhaustive list and if you notice these or anything else that seems off, it could be time for a deeper dive into what might be wrong. If you know the species of your tree the Purdue Plant Doctor is a great tool to narrow down a diagnosis. You can also contact your local Extension office or an ISA Certified Arborist.
On a more positive side, you don’t have to be on the lookout for damage, decline, or signs of pathogens and pests. It is also a matter of enjoying the trees in your landscape. Take some time out of your day to sit in the shade especially as we transition from hot summer temperatures into the cooling of autumn. Revel in the color changes as chlorophyll production slows revealing the carotenoids (that give us yellows, oranges, and browns) and anthocyanin (that produces reds and purples). In winter, not only can you better see damage in the canopy hidden by leaves in the growing seasons, but also the structure and architecture of the canopies in different tree species and the differences in bark textures. And in Spring, new growth of leaves and flowers shows us Winter is nearing its end, bringing warmer days.
So check your trees throughout the year. But not only for potential issues and risk management but also for enjoyment. Trees offer us no many benefits and sometimes it takes a little reminder. If you do see any signs of decline or damage, again, be sure to contact your local Extension office or an ISA Certified Arborist.
Figure 1: Drought stress can cause decline and, in some cases, death in trees.
Purdue Landscape Report: With recent rain storms across the state, watering may not be at the forefront of everyone’s minds. But as we head deeper into summer it is food to remember most of Indiana is in a state of abnormal dryness to moderate drought, continuing similar conditions from previous years. With that in mind, we should be thinking about the health of our trees (Fig. 1).
Understanding what drought is and its effects on trees can help to bolster care plans. Drought is an extended time with little to no precipitation and can slow growth, reducing photosynthesis, and depleting energy reserves trees need to survive dormancy in winter. Drought conditions can stress trees, making them susceptible to pests and diseases, reducing their ability to produce defensive chemicals, and in severe situations resulting in death (Fig. 2).
One simple task to protect your trees is watering. This is especially important in young and newly transplanted trees. A good industry guideline is the 5-plus-5 rule.
Figure 2a: Wilting in leaves and dieback in parts of the tree can indicate drought stress.
Figure 2b: Wilting in leaves and dieback in parts of the tree can indicate drought stress.
Apply 5 gallons of water plus 5 gallons for every diameter inch of the trunk. For example, a 4-inch tree would require about 25 gallons of water as needed. A good tactic to reduce water runoff from the hose is to take a large bucket and drill enough small holes to create a slow drip watering system. Also check moisture levels in your soil to see if conditions are dry, moist, or saturated.
Another way to maintain soil moisture is to mulch around the tree. Mulch rings should be at least 3 feet in diameter and 2-3 inches deep with a 2–3-inch space between the base of the trunk and the inner mulch ring. Mulching up to the trunk is called volcano mulching and causes issues like stem girdling root production and decay. Mulching reduces evaporation from the soil and helps maintain moderate soil temperatures. It also reduces competition with surrounding lawn and landscaping plants while protecting the trunk from mechanical damage caused by mowing and lawn care practices.
These little steps can go a long way to protect your trees, extending their life spans and your enjoyment with a healthy canopy. For a more detailed look at drought and trees, please have a look at the Purdue extension store here.
In this edition of ID That Tree, Purdue Extension forester Lenny Farlee takes us through the different characteristics of coniferous trees found here in Indiana, particularly their foliage and the features that pertain to them. Come along as we look through real examples of shape, scales, leaf and branches of various local trees. The featured species include Eastern red cedarwood, Northern white cedar, and more.
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.
In this edition of ID That Tree, Purdue Extension forester Lenny Farlee goes over leaf characteristics to look for when attempting to identify broadleaved deciduous trees in Indiana. He shares the features of both single and compound leaves while outlining the differences between tree leaves. He takes you through a thorough guide on analyzing the leaflets, leaves, stems and buds, while increasing your knowledge of your surroundings.
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.
Purdue Landscape Report: Recently a homeowner in Hamilton County posted on the Indiana Native Plant Society Facebook page with concerns about aphids, mites, and apple scab in her maple and oak trees. She asked for a second opinion and treatment options for these pests. I reached out to the homeowner and requested permission to collect samples from the trees. Let’s look at what I found (or didn’t find) and discuss when and if these issues should be treated.
Apple Scab on Maples?
First, we can eliminate the concern about apple scab because maple and oak trees are not hosts for this pathogen. Apple scab is caused by the fungus Venturia inaequalis, and hosts include apples, crabapples, hawthorn, mountain ash, firethorn, and loquat. There are other fungal diseases which cause leaf spotting in maples, such as Anthracnose, tar spot, and Phyllosticta leaf spot. To diagnosis these diseases, homeowners can submit a sample to the Purdue Plant & Pest Diagnostic Lab, or hire a certified arborist to assess the tree. However, all these diseases are primarily aesthetic issues. A healthy tree will not die from these pathogens and does not require treatment. You can find more information about maple diseases in this publication: Diseases in Hardwood Tree Plantings. You can also find a previous article on Tar Spot in Maple in the Purdue Landscape Report (Issue 18-12).
Fig. 1. Severe spider mite damage on maple leaves. (Photo: S. D. Frank, North Carolina State University)
Spider Mites
The next pest concern on these trees is spider mites. Out of the dozens of leaves I collected, I found only two immature mites on a couple of maple leaves I examined. This is a very small mite presence, and it is not recommended to treat for spider mites unless the populations threaten the health or appearance of the tree. Limiting pesticide usage will conserve the natural enemies, which are vital to keeping mite populations in check. In fact, improper pesticide applications can kill these important natural enemies and worsen mite infestations.
When do you know if the mite population is large enough to merit intervention? Check your trees for signs of heavy feeding damage, such as leaf stippling (Fig. 1), or dense webbing on the leaves. Mites can also be monitored by placing a sheet of paper (8.5×11”) beneath a branch and striking the limb. Chemical treatments should be considered when you count ≥24 mites per strike. You can find detailed management recommendations and a full list of pesticide options in this Purdue Extension publication: Spider Mites on Ornamentals.
Fig. 2: Adult painted maple aphids found on maple in Hamilton Co, Indiana. (Photo: Andrew Johnston, Purdue University).
Aphids
The aphids I found on the homeowner’s maple trees are Drepanaphis acerifoliae, or the painted maple aphid (Fig. 2). This species only feeds on maple trees, and is not a threat to the oak tree on this homeowner’s property. Painted maple aphid is a very common aphid in our region. I found only a few aphids on one of the maple trees I sampled, which is not enough to require treatment. In addition, one of the aphids was a “mummy”, or a carcass left behind from a parasitoid wasp. This indicates that natural enemies are already at work managing the aphid population. Aphids may rarely require chemical control if their numbers grow large enough to produce significant amounts of honeydew, which can result in sooty mold outbreaks.
Tussock Moth
The only insect I found on the oak tree was a white-marked tussock moth caterpillar, Orgyia leucostigma (Fig. 3). This is the likely culprit for the minor feeding damage I noticed. These are not significant pests and do not require treatment. Don’t touch them, though! The setae of this caterpillar are irritating and may cause allergic reactions.
Overall, the pests I found were minimal and non-threatening to the trees. It’s normal to find some insect pressure in the landscape. Knowing when and if to treat requires accurate diagnosis and monitoring of pest levels. Check out PurduePlantDoctor.com for an easy-to-use diagnostic aid and treatment recommendations.
The long lifespan of many trees, which could be centuries or even millennia in the case of a few species, is a source of awe and inspiration for many. The bark of trees can often tell some stories about their life and history, if we know how to interpret what we see. Here are a few examples you may run across in Indiana.
Is this tree sick? That may be a natural question to ask when looking at the striking difference in the bark pattern on this white oak. In fact, it is an infection, but not a harmful one to the survival of the tree. This is called smooth patch and is caused by a fungus that infects the outer bark of oak and some other tree species. There are several species of fungus that may cause this appearance, but the most common is Aleurodiscus oakesii. The fungus gradually decomposes the outer layers of bark, producing the flattened and smooth surfaces which contrast with the rough bark that is uninfected. If you look closely during moist periods, you may see the small cup-shaped fruiting bodies of the fungus on the bark. It is not a threat to the health or integrity of the tree as only the outer bark is impacted.
Figure 1 – Smooth patch on white oak. The normal bark pattern can be seen on the lower trunk.
Figure 2 – Smooth patch fungus, Aleurodiscus oakesii, fruiting body on white oak bark.
This isn’t the same species of tree, is it? Yes, it is! Bark pattern differences in some species may reflect the growth rate or relative vigor of the tree. These photos show black walnut bark from two very different growing sites. The blocky, alligator-hide bark pattern is often an indication of slow growth and may result from a tree growing on a very difficult site, like the dry hilltop where this tree is located, or severe competition from surrounding trees. The strongly interlacing ridges of the bark in the second photo are from a black walnut growing in a plantation on a creek bench with deep, moist and fertile soils, resulting in more vigorous growth.
Figure 3 – Black walnut with slow-growth bark pattern.
Figure 4 – Black walnut with vigorous growth bark pattern.
What happened here? The pattern in a horizontal line across these trees looks too perfect to be natural, but it was not produced by a human. This is the feeding activity of the yellow-bellied sapsucker, a species of woodpecker that migrates through Indiana. The sapsucker, true to its name, uses its sharp bill to create holes through the bark that ooze sap. The sapsucker feeds on the sap and may also feed on insects drawn to the sap. They tend to create straight lines of holes that leave this diagnostic pattern behind, even long after the birds have ceased their activity. This activity is usually not fatal to the tree, but does cause some damage to the wood beneath the bark, so trees that have been used by sapsuckers may have discolored spots or other blemishes in the wood revealed when processed for wood products.
Figure 5 and 6 – Yellow-bellied sapsucker feeding activity on sugar maple trees. These are older holes being covered by wood growth.
Humans also may leave a history of our presence on trees. This American beech tree in a recreation area has recorded the comings and goings of visitors, with some apparent editing as well! I do not endorse this activity as it can be harmful to the tree by introducing avenues for decay and disease, and is generally prohibited on public property. Instead, enjoy reading the nature stories found in bark.
Figure 7 – American beech bark defaced by carving.
