Arborist Q&A: Common Tree Problems Solved

Trees rarely fail overnight. They whisper first. Leaves yellow off-schedule, bark splits on the south side, a branch hangs lower after a windy night. If you learn to listen and act early, you can prevent most serious issues, from storm failures to pest explosions. I spend much of my week walking properties with homeowners, facilities managers, and HOAs, answering the same dozen questions in different settings. The details change with species and site, but the principles hold steady.

What follows is a field-tested Q&A that blends diagnostic cues, practical fixes, and the judgment calls a seasoned arborist makes on site. Whether you care for one shade tree in your backyard or a campus of 600 trees, you will find guidance you can use and clear signals for when to call a professional tree service.

How do I tell if my tree is actually in trouble or just stressed?

Healthy trees have range. They can shed a small branch, yellow a few interior leaves in late summer, or carry a modest aphid population without consequence. Trouble shows up as patterns and progressions. I look first at vigor: new shoot growth length, leaf size and density, coloration, and callus formation over old pruning cuts. Then I look for asymmetry. If one quadrant is thin while the rest looks normal, roots or soil conditions on that side deserve attention.

Time matters. A silver maple that drops a limb after a 60 mile per hour gust might be normal for the species. The same limb dropping on a windless morning signals internal decay, poor attachments, or both. Track changes over a few weeks. If canopy density declines, leaves scorch, or dieback marches down from the tips, act. A local tree service with ISA Certified Arborists can confirm what you are seeing and prioritize response.

My tree is losing leaves in mid-summer. Is that drought or disease?

Premature leaf drop has many culprits, but water balance leads the list. If soils have gone dry below the top 4 to 6 inches, especially after a heat spike, trees shed foliage to reduce demand. Drought stress often shows as marginal leaf scorch on broadleaf trees, with browning at the edges first. Fungal leaf diseases, by contrast, create discrete spots, blotches, or curling with distinct borders. On oaks with anthracnose, I often see tattered, distorted leaves early in the season, then partial drop that stops once weather dries.

One quick check: dig a narrow hole with a trowel near the drip line, 6 to 8 inches deep. Pinch the soil. If it crumbles like dry cake, water slowly and deeply. If it squeezes into a glossy ribbon, you are already wet enough, and root oxygen might be an issue. If leaves are spotted or curling, bring a sample to a reputable tree service company or your county extension office. They can confirm common pathogens without guesswork.

What is the right way to water a mature tree?

Most trees prefer slow, infrequent watering that wets the soil 12 to 18 inches deep. That depth covers the bulk of the fine absorbing roots. A mature oak or maple usually needs a long soak every 10 to 14 days during drought, rather than daily sprinkles. Irrigation bags help on new plantings, but they do not replace broader soil moisture for established trees.

Avoid spraying the trunk. Spread water from halfway between the trunk and the drip line out to a few feet beyond the canopy if space allows. Use a soaker hose, a hose-end sprinkler on low, or a portable emitter. As a rough guide, most medium to large trees benefit from 10 to 20 gallons per inch of trunk diameter per month during hot, dry periods, divided into one or two deep sessions. Adjust for soil texture. Sand drains fast, clay holds water longer. Always verify with that simple soil dig. Guessing leads to root rot on clay and drought stress on sand.

I see mushrooms at the base. Does that mean the tree is doomed?

Maybe, maybe not. Fruiting bodies at the base often indicate a decay fungus in the buttress roots or lower trunk. Armillaria and Ganoderma are common in many regions. Some fungi colonize dead wood without compromising living tissue right away, while others are more aggressive. The presence of conks or mushrooms tells you decay is present, not how much strength remains.

A trained arborist can use a mallet, probe, resistograph, or sonic tomography to assess the extent and location of decay. We also read the tree’s architecture. A tree can tolerate a surprising amount of central decay if the outer shell is thick and continuous, but decay in tension roots or at a critical buttress is a different story. I have recommended removal for a large willow with a massive Ganoderma conk and a hollow you could fit a hand into on the windward side, then monitored a similarly affected red oak that still had good shell wall and no lean. When mushrooms appear, schedule an inspection. This is not one to watch passively.

The bark is splitting on the south or west side. What caused that?

Southwest injury is common where cold, clear winter days are followed by rapid temperature drops at night. The sun warms the bark and cambium for a few hours, then a sudden freeze ruptures cells. On thin-barked species like young maples, cherries, and lindens, the damage presents as vertical cracks or elongated sunken patches. Summer sunscald looks similar on dark-barked trees recently exposed by pruning or construction.

New splits can often callus over if the tree is otherwise vigorous. Mulch properly, water during dry spells, and avoid further stress. On newly planted trees, trunk guards or light-colored tree wraps can moderate temperature swings during the first couple winters, but remove them for the growing season. Do not paint or seal the crack. Let the tree compartmentalize naturally. If the split coincides with a lean, dieback above, or fungal conks, the injury may be part of a larger structural problem that merits an arborist service visit.

Are the small holes on my ash or birch from borers?

Tiny D-shaped exit holes on ash are a hallmark of emerald ash borer in many states, accompanied by serpentine galleries under the bark and canopy thinning from the top down. Birch with bronze birch borer shows swelling and dieback on the upper crown and flattened, D-shaped exits on the trunk and larger branches. Peeling a small section of loose bark with a knife will often reveal the galleries. Fresh woodpecker activity with flaked bark can be another clue.

If you catch these borers early, systemic treatments may save the tree, especially if canopy loss is under 30 percent. Treatments are most cost-effective for high-value trees and require strict timing. Consult a professional tree service that offers plant health care. They can weigh the cost of treatments over a 2 to 3 year cycle against removal and replanting. For heavily infested trees, especially if they pose a target like a driveway or play area, removal is often the prudent call. Many municipalities also encourage replacing ash to diversify canopy species and reduce future risk.

The roots are circling the trunk. Is that fixable?

Girdling roots are common in trees grown in containers or planted too deep. Over years, a root wraps the trunk or crosses a main root, compressing and restricting vascular flow on that side. Above ground, you might see flattening of the trunk, reduced canopy on the affected side, or suckering at the base. Norway and red maples are frequent victims, but I have seen it on oaks, lindens, and honeylocust too.

Early detection helps. On young trees, root collar excavation with an air spade can expose the root flare and allow careful cutting of the offending root. On older trees, the decision becomes nuanced. Cutting a large girdling root can destabilize the tree or shock it if the root carries a significant portion of the load. When I evaluate, I consider trunk diameter at the cut, the proportion of girdling around the circumference, the tree’s lean, and site exposure. This is a classic case for a local tree service with experience in air excavation and structural pruning.

My tree leans. When is that unsafe?

Many trees lean from seedling days toward light, and they can be perfectly stable. What worries me is recent change. If a straight tree develops a fresh lean after a storm, or you see heaving soil and cracked ground on the side opposite the lean, roots may have failed. Combine that with saturated soils and wind, and you have a candidate for immediate emergency tree service.

So how much lean is too much? Angle alone is less important than movement and target. A 20 degree lean over an open field might be acceptable with monitoring. A 10 degree lean over a bedroom or sidewalk in a school campus usually triggers action. Look for other clues: bark cracks on the compression side, sudden canopy asymmetry, or exposed roots on the tension side. When in doubt, get an arborist on site quickly. We can deploy temporary mitigation like cabling or a reduction prune to reduce sail, but those measures have limits. No amount of hardware justifies ignoring a compromised root plate.

What does good pruning actually look like?

Good pruning aligns with tree biology. Cuts land outside the branch collar, not flush. The objective is to remove conflicts, reduce risk, and encourage strong structure, not to force a shape the species will never hold. I see two chronic mistakes: topping and lion-tailing. Topping, the removal of main leaders to stubs, triggers a flush of weakly attached sprouts, invites decay, and compounds risk. Lion-tailing strips interior branches and loads weight out at the tips, amplifying bending stress and wind throw.

For shade trees, structural pruning in the first 10 years after planting pays compounding dividends. Select a dominant leader, encourage well-spaced scaffold branches with good attachment angles, and subordinate competing stems with reduction cuts. On older trees, shift to cleaning out dead or diseased wood, addressing rubbing branches, and making selective reductions to reduce end weight. Frequency varies. A slow-growing oak might need a thoughtful visit every 3 to 5 years, while a fast-growing willow near a house might justify pruning more often. A professional tree service with ISA credentials can tailor a plan to species and site rather than selling a one-size-fits-all schedule.

My storm tore a big limb. Should I seal the wound?

Let the tree seal itself. Paints and sealants trap moisture and slow the natural compartmentalization process. The better approach is a clean cut back to a proper union, leaving the branch collar intact. If a tear is jagged and extends down the trunk, an arborist can smooth the edges without making the wound larger. After that, focus on aftercare: water during drought, maintain an organic mulch ring 2 to 4 inches deep and a few feet wide, and keep lawn equipment off the root zone. If the damage opened a cavity or exposed decay, a risk assessment can determine if a reduction pruning or, in some cases, removal is warranted. For commercial properties with high liability concerns, documentation from a commercial tree service after storms can be valuable.

Why are the leaves sticky and the patio black?

Sticky leaves and a black film often point to sap-sucking insects that excrete honeydew, which then grows sooty mold. Aphids, scale, and whiteflies are typical culprits. I often find scale on magnolias, maples, and euonymus, and aphids congregate on the tender new growth of many species. The good news: sooty mold itself is superficial. The concern is the feeding insects that weaken the tree over time.

Before spraying anything, identify the pest and its life stage. Many scale species are vulnerable only during crawler stages. Beneficial insects and horticultural oils can be effective and gentle when timed correctly. On larger shade trees, systemic treatments may be appropriate, applied by a tree care service with the proper equipment and licensing. Cultural steps matter too: reduce excess nitrogen that fuels aphid booms, water deeply rather than frequently, and avoid overpruning that stimulates succulent regrowth.

The trunk has a cavity. Do I need to fill it?

Not anymore. Filling cavities with concrete was standard decades ago, and those fills often created new problems by adding rigid mass where the tree needed flexibility. Today, we manage cavities by reducing risk and allowing the tree to compartmentalize. A cavity alone is not a removal sentence. The questions are: how much sound wood remains around it, where is the cavity relative to key unions, and what are the targets below?

I have managed a red oak with a sizable trunk cavity for 12 years by combining thoughtful reduction pruning to lower wind load and annual inspections that included sounding and occasional drilling to confirm shell thickness. In contrast, a cottonwood with a large cavity at the base, a fresh lean, and pedestrian traffic nearby needed removal before the next storm cycle. If you can fit a fist into a basal cavity, call a professional tree service for an evaluation. We can quantify risk rather than relying on internet photos.

Should I mulch up to the trunk?

No. Mulch is best used as a wide, shallow donut, not a volcano. Piled mulch against the trunk traps moisture, encourages decay, and invites rodents. Spread a 2 to 4 inch layer out to the drip line if possible, keeping a hand’s width clear around the trunk. Wood chips are excellent. They moderate soil temperature, conserve moisture, and feed soil biology as they break down. On commercial sites, I sometimes specify coarser chips in high foot traffic zones to stay in place longer. If you inherit a mulch volcano, pull it back and check for girdling roots or basal decay.

How deep should a tree be planted?

Set the root flare at or slightly above finished grade. That flare, where the trunk transitions to buttress roots, should be visible. Planting too deep suffocates roots and invites decay at the base. In many balled and burlapped trees, soil is heaped over the flare in the nursery. I routinely remove 2 to 4 inches of excess material at planting. For container-grown trees, untangle or cut circling roots before backfilling. In clay soils, raise the planting slightly, then feather soil out to grade to prevent a sump effect. Water in as you backfill to eliminate air pockets, and stake only if necessary, removing supports after one growing season.

Can I top my tree to keep it small?

Topping is never the answer for size management. It creates structurally weak regrowth and accelerates maintenance cycles. If a tree is the wrong species for the location, consider phased removal and replacement with a species that fits. If the tree must remain, reduction pruning can lower and spread weight without brutal cuts, though it requires skill and an eye for tree architecture. For flowering trees and hedges, controlled heading cuts within the outer canopy can be appropriate, but that is different from topping a shade tree’s main leaders. A professional tree service can outline realistic options and likely outcomes so you are not surprised two years later when a thicket of sprouts returns.

When is cabling or bracing a good idea?

Cabling and bracing are support systems, not cures. I recommend cabling when a tree has co-dominant stems with included bark, especially in species prone to splitting like Bradford pear or mature silver maple, and when the tree has high value and acceptable overall health. Modern systems use high-strength, flexible cables installed high in the canopy to limit movement during storms. Steel rods can reinforce cracked unions in specific cases.

Support hardware demands inspections every 1 to 3 years, and it adds cost over time. It also comes with practical limits. If decay is advanced, roots are compromised, or targets are unforgiving, hardware is a poor substitute for prudent removal. I have removed cables more than once because they were installed without addressing the underlying load. If someone suggests cabling without discussing canopy reduction or crown cleaning in the same breath, ask more questions or get a second opinion from another arborist service.

What does an arborist look for during a risk assessment?

A good assessment blends biology with physics. I read root flare conditions, soil moisture and texture, buttress root integrity, trunk defects, union quality, decay indicators, canopy balance, prevailing wind exposure, and targets. I use tools when they help answer a specific question. A resistograph can map shell thickness around a suspect cavity, while a drone can inspect high unions on large trees safely. Most of the time, a thorough visual assessment and sounding can narrow risk categories. Documentation matters for commercial tree service clients, who often need clear, prioritized work orders and timelines.

How often should my trees be inspected?

Annually is a good baseline for most properties, with additional checks after major storms or construction activity. New plantings need closer attention during the first two seasons while roots establish. Fast growers near structures benefit from inspection every one to two years. Older landmark trees deserve a regular relationship with a trustworthy local tree service. Conditions change. A disease that was absent five years ago might now be common. A neighbor’s removal can change wind exposure. The best time to find a problem is before it becomes a failure.

What should I expect from a professional tree service?

Look for ISA Certified Arborists on staff, proof of insurance, and clear, written proposals that specify pruning objectives and methods, not just “trim tree.” A reputable tree service company will ask about your goals, identify priority risks, and outline options with costs and timelines. For residential tree service, that might mean a two-visit plan to spread budget and minimize impact. For commercial tree service on campuses or retail centers, expect inventory-based plans, risk ratings, and traffic control measures. Emergency tree service capability matters in storm-prone regions. You want a partner who can pivot from routine care to safe, efficient removals with the right equipment and crew size.

What is the single best thing I can do for long-term tree health?

Protect the root zone. Most problems we treat above ground start below. Maintain a wide mulch ring, keep heavy equipment and repeated parking off the drip line, avoid trenching through roots, and water deeply during extended drought. During construction, fence off root zones and plan utilities around trees rather than through them. I have watched a mature oak thrive next to a new addition because the builder respected a 15-foot no-go zone, then seen a similar oak fade over three years after a contractor compacted wet soil with repeated skid steer passes. The difference was not fertilizer, it was respect for roots.

When does a tree need removal?

Asking this early saves regret. A tree needs removal when the risk of failure exceeds your tolerance and mitigation is not practical, when decay or disease has advanced beyond recovery, or when infrastructure conflicts cannot be resolved. I weigh target value, defect severity, remaining life expectancy, and the client’s goals. Sometimes the right answer is a phased plan: reduce crown now to lower risk, plant a successor this fall, remove the old tree in two to three years when the replacement has established. This approach is especially useful for street trees that anchor a landscape. Removal is not failure. It is part of responsible tree care.

Quick checks you can do before calling an arborist

• Scratch test a small twig to confirm it is green and moist beneath the bark. Brittle and brown suggests dieback.
• Dig 6 to 8 inches near the drip line to check moisture before watering or blaming drought.
• Look up and out, not just at the trunk. Dead branch tips and thinning in the upper crown often tell the real story.
• Photograph problem areas from the same angle every two weeks. Patterns help diagnosis and tracking.
• Note targets under the tree: patios, driveways, playsets. Risk is about what might be hit as much as defect severity.

The value of local knowledge

Trees speak the language of place. The same species grows differently on a breezy ridge than in a sheltered courtyard. A regional drought one year and a saturated spring the next change disease pressure and pest cycles. A local tree service brings that context. We see which cultivars shrug off late frosts, which neighborhoods harbor oak wilt, and which soil pockets hold water long after rain. For properties with many trees, especially those open to the public, that context shapes decisions about planting, pruning intervals, and budget priorities.

On one municipal site with 300 maples, we adjusted pruning timing to avoid peak flight for a local borer, added wood chip mulch around high-traffic specimen trees, and worked with facilities to redirect a routine irrigation spray that soaked trunks nightly. Failures dropped, vigor rose, and so did public compliments. That is not luck. It is site-specific care.

When to pick up the phone

Call sooner rather than later when you see mushrooms at the base, fresh leans with soil cracks, large dead limbs over targets, sudden canopy thinning, or signs of borers in susceptible species. If a storm drops a limb that leaves a large wound or exposes included bark, an emergency tree service can stabilize the situation safely. For everything else, schedule a routine assessment and create a simple plan. Good tree care is rarely a one-off event. It is a steady rhythm of monitoring, timely pruning, and respect for roots.

If you are choosing a partner, ask about their approach to risk assessment, whether they offer both residential tree service and commercial tree service if you manage mixed properties, and how they handle services for trees that go beyond chainsaws and trucks, such as soil improvement, plant health care, and preservation during construction. A professional tree service should talk as comfortably about soil compaction and species selection as they do about cranes and chippers.

Final thought from the field

Trees are long-term companions. They shade our homes, soften our skylines, and hold stories under their bark. Most problems give a warning if you know how to read it. Learn the basics, keep an eye on patterns, and lean on experienced arborists for the calls that carry risk. With that mix, you will solve the common problems, avoid the preventable losses, and keep the canopy above you healthy and safe for years to come.

If you need help interpreting what you see, or if you want a tailored tree care service plan for your property, reach out to a reputable tree services provider in your area. A short walk under the canopy with someone who knows what to look for can save you years of frustration and keep your trees doing what they do best: growing, quietly, in the right direction.