Tree care glossary

Tree care terms describe what you see, what work involves and what to ask next. Use these definitions alongside an on-site assessment, not as a diagnosis.

By Help My Tree team

Updated 2026-10-25

Oak wilt

Oak wilt is a fungal disease that interferes with water movement inside an oak. Red oaks can decline quickly, while white oaks may develop symptoms more slowly.

In your yard: In a yard, leaves near the top may wilt, brown and fall while partly green. Drought can look similar, so leaf color alone does not establish the cause. Nearby oaks declining in a group are another reason to investigate.

What to do: Ask an arborist or extension diagnostic clinic about sampling promptly rather than assuming the tree only needs water. Avoid unnecessary wounds and do not move potentially infected firewood to another property.

Local note: St. Louis: MU Extension advises avoiding oak pruning from mid-March through mid-July. Memphis: Tennessee recommends avoiding March through July and describes oak wilt as not established across the state, not as absent everywhere.

Related terms: Bacterial leaf scorch, Dormant pruning.

Sources: extension.missouri.edu, www.tn.gov.

Hypoxylon canker

Hypoxylon canker is a fungal disease that develops in hardwood trees already under serious stress. It can kill weakened tissue and contribute to rapid decline, especially after drought.

In your yard: You may first notice small leaves and dying upper branches. Later, bark can fall away to reveal broad tan, brown or gray fungal patches rather than a small isolated leaf spot. A normal-looking patch of bark elsewhere does not establish that the affected trunk is sound.

What to do: Arrange an arborist assessment when bark loss and branch dieback appear together, particularly near a house or regularly used yard. Photograph the changes from a safe location. Do not treat fertilizer as a cure; investigate water stress and other underlying problems.

Local note: Memphis: Tennessee Forestry identifies this disease as a common contributor to oak decline after severe drought.

Related terms: Construction damage, Deep watering.

Sources: www.tn.gov.

Bacterial leaf scorch

Bacterial leaf scorch is an infection of a tree's water-carrying tissue. It persists from year to year and can gradually weaken affected branches.

In your yard: Leaves may develop brown margins separated from green tissue by a reddish or yellow band. Older leaves often show symptoms first, and hot, dry weather can make the damage more obvious. The pattern can resemble drought or other vascular diseases, so a photograph is not enough to confirm infection.

What to do: Record when browning begins and whether the same branches are affected each year. Ask an arborist or extension diagnostic clinic to distinguish infection from water or root problems before choosing a response. Water management can reduce stress but is not a cure.

Local note: Memphis: Tennessee Forestry's disease guidance states that there are no effective treatments for bacterial leaf scorch.

Related terms: Oak wilt, Deep watering.

Sources: www.tn.gov.

Emerald ash borer

Emerald ash borer is an invasive beetle whose larvae feed beneath the bark of ash trees. That feeding damages the tissues that move water and nutrients, and can kill the tree.

In your yard: Look for canopy decline, winding tunnels under loose bark or small D-shaped exit holes. These clues warrant identification, but not every declining tree is an ash or has this insect. Avoid peeling healthy bark to search for larvae.

What to do: Have a suspected ash assessed before waiting for it to die. The decision depends on tree condition and the risk to people and property, not simply its size. This glossary does not offer pesticide treatment.

Local note: St. Louis: the city's guidance separates publicly managed ash street trees from privately owned ash, so establish ownership before arranging work.

Related terms: Deadwood, Hazard tree.

Sources: mdc.mo.gov, Common Questions About Emerald Ash Borer Treatment and Removal.

Crape myrtle bark scale

Crape myrtle bark scale is a sap-feeding insect found on crape myrtle bark. Its sugary waste supports black sooty mold, which can make branches look coated in soot.

In your yard: Small white, felt-like patches often collect around branch forks or pruning wounds. A tree may flower less strongly without being dead, and the black coating is not itself proof of internal wood decay. Look closely from the ground rather than scraping or pressure-washing bark.

What to do: Ask an arborist or extension office to identify the pest and discuss appropriate management. Do not respond by topping the tree or adding fertilizer without a soil test. No pesticide application service is offered by this entry.

Local note: Memphis: University of Tennessee's West Tennessee guidance documents this pest in the region; it does not establish an infestation at your address.

Related terms: Crape murder, Plant health care.

Sources: taes.utk.edu.

Iron chlorosis

Iron chlorosis is leaf yellowing caused by too little usable iron reaching the plant. Iron may be present in soil but less available to a susceptible tree when the soil is alkaline.

In your yard: A pin oak with pale or yellow foliage is one familiar example. Yellow leaves alone cannot separate an iron problem from poor drainage, root injury or another nutrient issue. Compare the affected tree with its earlier appearance rather than with a different species.

What to do: Request a soil test and a diagnosis before adding iron or a general fertilizer. An arborist can consider soil pH alongside root condition and planting history. A fertilizer purchase should follow evidence of need, not simply a color change.

Local note: St. Louis area: Missouri guidance specifically flags pin oaks on alkaline urban soils, including sites containing limestone construction debris.

Related terms: Soil test, Deep root fertilization.

Sources: agebb.missouri.edu, Fertilizing Shade Trees | MU Extension, Fertilizing Trees in the Landscape - Franklin County Center | N.C. Cooperative Extension.

Anthracnose

Anthracnose is a group of fungal diseases that can spot or distort tree leaves. Different fungi affect different host trees, so the name does not identify one infection shared by every species.

In your yard: Young leaves may have irregular brown blotches, curling or early leaf drop during cool, wet weather. The damage can look alarming even when an established tree is likely to recover. Many affected trees produce replacement leaves after the weather changes.

What to do: Keep track of repeated severe defoliation rather than assuming a single damaged leaf requires treatment. Ask an arborist for identification if whole branches die or heavy leaf loss returns over several years. Avoid sprinklers that repeatedly wet foliage, and use a soil test before considering fertilizer. Most cases do not require chemical treatment.

Related terms: Bacterial leaf scorch, Plant health care.

Sources: extension.umn.edu.

Root rot

Root rot is decay or disease affecting a tree's roots, sometimes extending into the lower trunk. It can weaken both the tree's ability to take up water and its attachment to the ground.

In your yard: You might notice thinning foliage, dead upper branches or mushrooms at the base. Some root diseases have distinctive signs, such as Armillaria's white fungal sheets under bark, but a lawn mushroom alone does not identify the problem. Much of the affected wood may be hidden.

What to do: Have an arborist inspect suspected root decay near occupied areas, especially if the tree also leans or the ground moves. Do not assume that watering or feeding will restore weakened structural roots. Keep people away from an unstable tree while arranging an assessment.

Related terms: Root flare, Hazard tree.

Sources: extension.umn.edu, extension.psu.edu.

Heart rot

Heart rot is decay of the inner wood of a trunk or branch. A tree can still carry green leaves while that interior wood loses strength.

In your yard: A cavity, old wound or fungal shelf on the trunk may be a clue, but external appearance does not reveal the full extent of decay. Likewise, the absence of a visible mushroom does not prove that the inside is sound. The location of remaining sound wood matters as well as the size of an opening.

What to do: Ask an arborist to assess decay where a failure could reach people, buildings or parked vehicles. Do not drill into the trunk to investigate or treat a hollow as an automatic removal verdict. A risk assessment connects the defect to likely consequences and appropriate management.

Related terms: Root rot, Hazard tree.

Sources: extension.psu.edu, www.aces.edu.

Bagworms

Bagworms are caterpillars that feed on foliage while carrying protective silk cases covered with plant fragments. The bags can remain attached to branches after feeding has stopped.

In your yard: On arborvitae or juniper, they can resemble small hanging cones or ornaments. Heavy feeding leaves bare patches and may seriously damage evergreens. The presence of an old bag does not by itself tell you whether larvae are actively feeding today.

What to do: Inspect reachable branches and remove bags by hand on small plants when practical. Seek identification and management advice if bags are numerous, foliage is disappearing or the plant is too tall to inspect safely. Avoid climbing a ladder into dense branches to reach them.

Local note: St. Louis area: MU Extension describes bagworms as a Missouri landscape pest and notes that management timing depends on larval development.

Related terms: Deadwood, Plant health care.

Sources: extension.missouri.edu.

Root flare

The root flare is the widening at the base of a trunk where the main roots begin. It should remain visible rather than buried beneath a mound of soil or mulch.

In your yard: A tree that enters the ground like a straight fence post may have a buried flare. You may also see a flattened side of the trunk where a root presses against it, although not every buried flare has that problem. The top of a nursery root ball is not necessarily the correct soil level.

What to do: Gently pull loose mulch away from the trunk, but avoid digging into roots with a shovel. Ask an arborist to examine a deeply buried base or roots wrapped around the stem. Exposing the flare is a diagnostic step, not a guarantee of recovery.

Related terms: Girdling root, Mulch volcano.

Sources: henderson.ces.ncsu.edu, extension.umn.edu.

Dripline

The dripline is the ground-level outline of the outer edge of a tree's crown. It is a useful visual reference, not a boundary beyond which roots stop growing.

In your yard: Imagine tracing the tips of the outer branches onto the lawn. The resulting outline may be uneven where the tree grows beside a building or has lost branches. Roots may extend beyond that outline, so keeping a trench just outside it does not automatically protect the tree.

What to do: Use the dripline when discussing watering or construction plans, but ask an arborist to define a protection area before excavation. Keep equipment and stored materials away from vulnerable roots. For a newly planted tree, remember that the original root ball needs attention even before roots spread into the surrounding yard.

Related terms: Critical root zone, Deep watering.

Sources: extension.oregonstate.edu, extension.umn.edu.

Critical root zone

The critical root zone is an area around a tree set aside to protect roots needed for health and stability. Its appropriate size depends on the tree and the site, not only the visible trunk.

In your yard: On a construction site it should appear as a protected space, often with fencing, rather than an open parking spot under the branches. A tree can lose roots without immediate leaf symptoms, so a green crown does not prove recent excavation was harmless.

What to do: Have an arborist establish the protection area before trenching, grading or equipment access begins. Oregon State Extension recommends comparing trunk-based and dripline estimates and choosing the larger area. Keep storage and vehicle traffic outside the boundary, and seek advice before any work that would cross it.

Related terms: Dripline, Construction damage.

Sources: extension.oregonstate.edu.

Girdling root

A girdling root grows against or around a tree's stem or another root and restricts normal growth. As the trunk expands, that contact can interfere with movement of water and other materials.

In your yard: A flattened trunk base, a root crossing the flare or dieback on one side can prompt investigation. Some girdling roots are hidden under soil or deep mulch, so they are not always obvious from the lawn. Deep planting and excessive mulch can contribute to the problem.

What to do: Move loose mulch off the trunk, but do not cut a large crossing root yourself. An arborist should determine how much the root supports the tree and whether removal would cause additional injury. Soil removal for inspection can be useful; it does not mean every exposed root should be cut.

Related terms: Root flare, Air spading.

Sources: henderson.ces.ncsu.edu, extension.umn.edu.

Codominant stems

Codominant stems are two main stems of similar size that arise from the same junction. Their attachment can be a structural concern, particularly when bark is trapped between them.

In your yard: In a yard, the tree may fork into two trunks rather than continuing with one clear leader. The fork's shape, existing cracks and the weight carried by each side matter more than the label alone. Not every tree with two stems needs removal.

What to do: Have a young tree assessed for structural pruning before competing stems become large. For a mature fork over a patio or roof, ask an arborist to evaluate risk and whether pruning or supplemental support is appropriate. Installed support systems require later inspection; a cable is not a permanent substitute for checking the tree.

Related terms: Included bark, Structural pruning.

Sources: www.aces.edu, dnr.maryland.gov, dnr.maryland.gov.

Included bark

Included bark is bark trapped inside the junction between growing stems or branches. It can prevent a strong wood connection from forming at that attachment.

In your yard: A tight V-shaped fork or a dark seam between stems may suggest the condition. You cannot reliably judge the strength of a mature fork from its outline alone. Splitting, movement or a new crack makes the situation more urgent, particularly when the stems extend over an occupied space.

What to do: Ask an arborist to inspect a suspect junction and explain whether selective pruning, support or another response fits the tree. Do not wedge objects into the seam or try to tie large stems together yourself. Early structural pruning can help manage competing stems before their removal would leave large wounds.

Related terms: Codominant stems, Hazard tree.

Sources: www.aces.edu, dnr.maryland.gov.

Branch collar

The branch collar is the area of protective tissue around a branch's attachment to its parent stem. It is often visible as a swelling near the base of the branch.

In your yard: When a branch is removed, the final cut should preserve this attachment tissue rather than shave the trunk smooth. A large stub is not the answer either. Collars vary in appearance, and a narrow fork may not show the obvious ring that a homeowner expects.

What to do: For small, reachable branches, identify the collar before deciding where a cut belongs. Have an arborist handle large branches, unclear attachments or work requiring climbing. Ask that pruning specifications preserve the collar and bark ridge. An apparently tidy flush surface can be a larger injury than a correctly placed cut.

Related terms: Flush cut, Reduction cut.

Sources: dnr.maryland.gov, TreesAreGood Consumer Brochures Pruning Mature Trees.

Lean

A lean is a tree's departure from an upright position. A longstanding lean can be stable, but a new or rapidly increasing lean can signal loss of support.

In your yard: Compare the trunk with older photographs if they are available. A tree that has always grown toward open light is different from one that shifted after a storm. Visible changes around the base or fresh damage add concern, but you should not approach an unstable tree to inspect closely.

What to do: Keep people out of the possible fall area when the lean changes suddenly and arrange prompt professional assessment. Do not try to pull a mature tree upright or cut it down with a helper holding a rope. Leaning trees create special hazards during felling.

Related terms: Root rot, Hazard tree.

Sources: www.aces.edu, extension.missouri.edu.

Deadwood

Deadwood is wood in a tree that is no longer living, such as a dead branch or stem. It can occur on an otherwise living tree and does not automatically mean the whole tree is dying.

In your yard: A branch without leaves during the growing season may be dead, although seasonal differences and late leaf emergence need consideration. Broken hangers can remain caught in the crown after storms. Some species retain dead branches for a long time, which is not a promise that they will stay attached.

What to do: Have dead branches assessed when they extend over paths, play areas or roofs. An arborist can specify which branches need removal without stripping healthy growth from the tree. Keep away from hanging limbs and do not shake them loose.

Related terms: Crown, Hazard tree.

Sources: www.aces.edu, extension.psu.edu, dnr.maryland.gov.

Crown

The crown is the tree's branching, leaf-bearing portion above the main trunk. Its condition and shape help an arborist understand growth, storm damage and structural concerns.

In your yard: From the yard, compare the crown's outer outline with its interior branches. Sparse foliage, dead tips or a heavily one-sided shape may deserve attention, but the cause is not always the same. A crown can look green while the trunk or roots have serious defects.

What to do: Ask for a pruning objective rather than simply requesting that the crown be made smaller. After storm damage, have large broken branches and the remaining structure assessed before deciding to remove the tree. Keeping useful foliage matters for recovery, and cutting every remaining branch back to a stub is not restorative care.

Related terms: Crown reduction, Deadwood.

Sources: dnr.maryland.gov, www.aces.edu, extension.missouri.edu.

Crown reduction

Crown reduction selectively shortens branches to decrease a tree's height or spread. It uses suitable side branches to continue growth rather than leaving large, bare stubs.

In your yard: A properly planned reduction may create clearance beside a roof while preserving the tree's branching form. It is not the same as cutting a flat line across the top. Species, branch size and current condition affect how much reduction a tree can tolerate.

What to do: Ask an arborist to identify the clearance goal and the branches to be reduced before work begins. A request to make every tree much shorter may not be achievable without harmful cuts. If a tree repeatedly outgrows its space, discuss the long-term fit of the tree as well as the immediate pruning need.

Related terms: Reduction cut, Topping.

Sources: dnr.maryland.gov, www.treesaregood.org.

Crown raising

Crown raising removes selected lower branches to create vertical clearance. It changes the space beneath the crown rather than reducing the height of the whole tree.

In your yard: You may need clearance above a walkway, driveway or lawn work area. Removing too many lower limbs at once leaves a long bare trunk and sacrifices useful foliage. Large low branches also leave larger wounds than small branches managed earlier in the tree's life.

What to do: Ask an arborist to specify the clearance needed and the size of branches involved. Preserve enough live crown rather than stripping everything below an arbitrary height. A staged plan may be more appropriate for a young tree that still needs lower growth. Branches near electrical lines require utility coordination, not ordinary clearance pruning.

Related terms: Crown, Structural pruning.

Sources: dnr.maryland.gov.

Crown thinning

Crown thinning selectively removes live branches to reduce crown density. The remaining foliage should stay distributed through the crown rather than being left only at branch ends.

In your yard: A thinned tree should not resemble a set of bare poles carrying small tufts of leaves. That excessive interior stripping is called lion's tailing and can weaken branches. Thinning is also different from removing deadwood, which may be a more relevant task for a particular tree.

What to do: Ask an arborist what problem thinning would solve and which branches need removal. Do not assume that every dense-looking tree needs opening up each year. A written specification should identify the location and extent of pruning. Keep healthy foliage unless there is a clear reason to remove it, especially on a stressed tree.

Related terms: Crown, Structural pruning.

Sources: dnr.maryland.gov.

Structural pruning

Structural pruning guides the development of a tree's main branches and leaders. It reduces or removes selected growth to improve branch arrangement rather than simply changing the silhouette.

In your yard: On a young shade tree, the work may address competing upright stems, rubbing branches or poorly spaced future limbs. Small adjustments made early can avoid the need for large cuts later. The desired structure still depends on the species and the form appropriate for that tree.

What to do: Ask an arborist which branches should remain as the tree grows and which should be reduced gradually. Do not remove every lower branch to make a young tree resemble a mature one. For an older tree with a large split fork, request a risk assessment rather than assuming routine structural pruning can undo the defect.

Related terms: Codominant stems, Included bark.

Sources: dnr.maryland.gov, www.aces.edu.

Reduction cut

A reduction cut shortens a branch or stem back to a side branch capable of continuing its growth. It differs from a heading cut that ends at a bud or an undersized side branch.

In your yard: In the yard, the remaining branch should provide a continuing direction rather than leaving a conspicuous bare stub. The size of that side branch matters; merely finding a tiny twig next to the proposed cut does not make it a suitable endpoint.

What to do: Have an arborist select reduction points on large limbs or near buildings. Maryland's tree expert guide uses a side branch at least one-third the diameter of the removed portion as a guide. That proportion is not permission for unlimited cutting: tree condition and the amount of foliage removed still matter.

Related terms: Crown reduction, Heading cut.

Sources: dnr.maryland.gov.

Heading cut

A heading cut shortens a shoot or branch to a bud or a side branch too small to take over its leading role. It is not interchangeable with a reduction cut to a substantial lateral branch.

In your yard: On a shade tree, repeated heading can leave stubs followed by crowded shoots. Some specialized training systems and shrub pruning use heading deliberately, so the cut's name alone does not explain whether it fits the plant. The objective and follow-up care matter.

What to do: Ask an arborist why a proposed heading cut is appropriate before allowing major limbs to be shortened this way. Do not accept the claim that chopping every branch back is ordinary crown reduction. Large-tree size control should consider suitable reduction points, tree condition and alternatives to repeated harsh cutting.

Related terms: Reduction cut, Topping.

Sources: dnr.maryland.gov.

Flush cut

A flush cut removes a branch so close to the parent stem that it cuts into the branch collar. The smooth-looking surface sacrifices protective tissue around the attachment.

In your yard: Afterward, the wound may run along the trunk rather than remaining outside the collar. Homeowners sometimes mistake that neat appearance for better workmanship. Leaving an excessive stub is also undesirable, but the solution is a correctly placed cut, not shaving the branch base away.

What to do: Before pruning, locate the collar and bark ridge. Ask an arborist to handle a large limb or an attachment whose anatomy is unclear. If a flush cut already exists, do not enlarge it in an attempt to improve its shape. Have extensive wounds and any associated decay evaluated rather than applying a cosmetic repair.

Related terms: Branch collar, Structural pruning.

Sources: dnr.maryland.gov, TreesAreGood Consumer Brochures Pruning Mature Trees.

Topping

Topping is the indiscriminate cutting of major branches or leaders back to stubs. It is not proper crown reduction and can increase future failure risk.

In your yard: A topped tree often has an abruptly shortened outline and later develops clusters of new shoots near the cuts. Those shoots do not erase the large wounds or restore the original structure. Rapid regrowth can also leave the owner facing another round of work rather than a lasting size solution.

What to do: Do not request topping to make a tree safe before storms. Ask an arborist whether selective reduction can meet the clearance goal without major damage. If the tree was already topped, discuss a gradual restoration plan and its limitations. Removal is a separate decision, not the automatic answer to every previously topped tree.

Related terms: Crown reduction, Heading cut.

Sources: dnr.maryland.gov, www.treesaregood.org.

Crape murder

Crape murder is the informal name for severely topping a crape myrtle. It replaces the tree's natural branching with blunt cuts and often a mass of vigorous shoots.

In your yard: In a yard, you may see every main stem cut to the same height, followed by crowded regrowth. This is different from removing an occasional crossing branch or basal sucker. A crape myrtle does not have to be topped to produce flowers.

What to do: Choose a variety that fits the available space, and avoid treating annual harsh cutting as a requirement. Ask an arborist about corrective pruning if a mature plant has been repeatedly topped. If bark looks black or carries white scale patches, investigate that separate pest problem rather than cutting the entire crown off to improve appearance.

Related terms: Topping, Crape myrtle bark scale.

Sources: site.extension.uga.edu.

Dormant pruning

Dormant pruning is pruning performed while a deciduous tree is in its seasonal rest period. The timing can make branch structure easier to see and avoid some disease-transmission periods.

In your yard: A leafless crown lets you see competing stems and broken branches more clearly, but winter is not a reason to cut healthy growth without a goal. Species and the type of work still determine the appropriate timing. Immediate hazards need assessment even when a preferred routine pruning season has not arrived.

What to do: Ask an arborist to identify the tree and schedule nonurgent work accordingly. Do not postpone reporting a hanging branch simply because it is summer.

Local note: St. Louis: MU Extension recommends winter oak pruning and avoiding mid-March through mid-July. Memphis: Tennessee's oak wilt guidance advises avoiding oak pruning from March through July.

Related terms: Oak wilt, Structural pruning.

Sources: extension.missouri.edu, www.tn.gov, dnr.maryland.gov.

Mulch ring

A mulch ring is a broad, shallow layer of mulch over soil around a tree. It helps conserve moisture and protect the root area without burying the trunk.

In your yard: In a yard, the ring should look flatter and wider than a mound, with an open space at the base. Grass beneath a young tree can compete with roots, and keeping mowing equipment away also reduces opportunities for trunk injury. More mulch is not automatically better.

What to do: Check the existing depth before adding another layer, and keep the flare visible. Ask an arborist about buried bark or roots growing into old mulch piles rather than covering them again.

Local note: Memphis: Tennessee Smart Yards recommends a 2 to 3 inch mulch layer with at least 2 inches of space at trunk bases.

Related terms: Mulch volcano, Root flare.

Sources: Manage Soils and Mulch | Tennessee Smart Yards, extension.umn.edu.

Mulch volcano

A mulch volcano is a pile of mulch heaped against a tree's trunk. It buries the flare and can create conditions that harm roots and lower-stem tissue.

In your yard: The base may look like a cone with the trunk emerging from its top. Repeated annual additions can hide the original soil level and encourage roots to grow in the mulch rather than outward. A neatly edged mound can still be damaging.

What to do: Pull loose mulch back from the bark and avoid adding more until you understand the existing depth. If soil is piled high or substantial roots have developed in the mound, ask an arborist to assess the base before digging or cutting.

Local note: Memphis: Tennessee Smart Yards calls for shallow mulch kept away from trunk bases, not mounds stacked against them.

Related terms: Mulch ring, Girdling root.

Sources: extension.umn.edu, henderson.ces.ncsu.edu, Manage Soils and Mulch | Tennessee Smart Yards.

Soil compaction

Soil compaction occurs when pressure squeezes soil particles together and reduces the spaces between them. That can limit the movement of air and water needed by tree roots.

In your yard: A parking area beneath a tree, a worn access path or equipment tracks may indicate repeated pressure. Poor growth can follow later, so the crown may not show the injury immediately. Compaction can coexist with root cutting or buried soil levels, making a single visible symptom hard to interpret.

What to do: Prevent additional traffic and storage over the root area. Ask an arborist to evaluate the soil before choosing a treatment; fertilizer does not reverse physical damage. Air excavation may be useful in selected situations, but protecting the area from repeated pressure remains part of the solution.

Related terms: Construction damage, Air spading.

Sources: extension.oregonstate.edu, tcimag.tcia.org.

Air spading

Air spading uses a specialized compressed-air tool to move soil around roots. It can expose a buried root collar or help investigate compacted soil without ordinary shovel excavation.

In your yard: During the work, roots become visible as soil is displaced, and the surrounding area can become dusty or messy. The tool helps reveal a problem; it does not by itself prove that every exposed root needs cutting or that the tree will recover. Professional technique and root protection still matter.

What to do: Ask an arborist what the excavation is intended to diagnose or improve and how the area will be finished afterward. Do not confuse this method with drilling fertilizer holes. Any nutrient addition should follow a soil test, and air work is not a reason to prescribe fertilizer automatically.

Related terms: Root flare, Soil compaction.

Sources: tcimag.tcia.org, henderson.ces.ncsu.edu, The Influence of Soil Decompaction and Amendments on Soil Quality | Arboriculture & Urban Forestry.

Deep root fertilization

Deep root fertilization is the placement of fertilizer beneath the soil surface near a tree's roots. It is an application method, not evidence that the tree needs nutrients.

In your yard: In a yard, the work may involve injections or holes distributed through the root area. A tree with yellow leaves or weak growth may instead have drainage problems, damaged roots or unsuitable planting depth. Fertilizer cannot repair those conditions.

What to do: Start with a soil test and a diagnosis of the tree's symptoms. Many landscape trees need no supplemental fertilizer. Ask why subsurface placement is being proposed: Nebraska Extension reports that surface-applied nitrogen is as effective as nitrogen placed below the surface. This definition explains the term without offering fertilizer application or assuming that a recurring treatment is justified.

Related terms: Soil test, Soil compaction.

Sources: extensionpubs.unl.edu, Fertilizing Shade Trees | MU Extension, Fertilizing Trees in the Landscape - Franklin County Center | N.C. Cooperative Extension.

Plant health care

Plant health care is an approach that monitors a tree and its growing conditions before choosing care. It connects observations over time with specific actions rather than treating every tree on the same schedule.

In your yard: In a yard, useful observations include changes in foliage, root-zone conditions and recent construction. Photos and written notes help distinguish a new problem from a longstanding feature. A healthy-looking crown still does not rule out a structural defect at the base.

What to do: Ask an arborist to explain the suspected cause, the proposed response and what improvement would be monitored. Watering or mulch adjustments may be more relevant than a product. Use a soil test before nutrient additions, and recognize that many trees need no fertilizer. A care plan is not a promise to prevent every future problem.

Related terms: Soil test, Establishment care.

Sources: Fertilizing Trees in the Landscape - Franklin County Center | N.C. Cooperative Extension, extension.umn.edu, extension.psu.edu, extensionpubs.unl.edu.

Soil test

A soil test is a laboratory analysis of a soil sample for properties such as pH and selected nutrients. It helps guide amendments but does not by itself diagnose every cause of tree decline.

In your yard: The useful result is a report connected to the sampled location, not simply a statement that the yard was tested. Soil near construction fill may differ from soil elsewhere, and a sample does not reveal every girdling root or drainage problem. The tree's symptoms still need interpretation.

What to do: Follow the laboratory's sampling directions and identify the tree or planting area accurately. Ask an arborist to connect any recommendation to the report before adding fertilizer. Many trees need no feeding, and a nutrient application cannot fix deep planting, root injury or compacted soil.

Related terms: Iron chlorosis, Deep root fertilization.

Sources: Fertilizing Trees in the Landscape - Franklin County Center | N.C. Cooperative Extension, Fertilizing Shade Trees | MU Extension, extensionpubs.unl.edu.

Deep watering

Deep watering applies water slowly enough to soak into the active root area rather than only wetting the surface. It does not mean leaving a hose running until the soil stays saturated.

In your yard: A brief lawn sprinkler cycle may wet grass while missing a newly planted tree's root ball. Conversely, a low area can stay wet even when the surface looks dry. Root-ball moisture and drainage are more useful checks than a fixed routine copied from another yard.

What to do: Water slowly and adjust to soil conditions and rainfall. Ask an arborist about persistent wilting despite wet soil, or about watering a large stressed tree whose roots extend well beyond the trunk. Newly planted trees need regular attention while roots establish, with the watered area expanding as they grow.

Related terms: Establishment care, Mulch ring.

Sources: extension.umn.edu, Fertilizing Trees in the Landscape - Franklin County Center | N.C. Cooperative Extension.

Construction damage

Construction damage is injury to a tree from building or site work around it. It includes root loss, soil compaction, grade changes and direct wounds to the trunk or branches.

In your yard: A trench beside a healthy-looking tree can sever roots that are not visible from above. Stored fill, parked machinery or a new driveway can also change the root environment. Symptoms may appear later, so surviving the construction period does not prove the tree escaped injury.

What to do: Bring an arborist into the plan before digging, not only after leaves decline. Establish a protected root area and keep storage and traffic outside it. If work has already damaged roots or changed the soil level, request an assessment of both tree health and stability before assuming extra water or fertilizer will solve it.

Related terms: Critical root zone, Soil compaction.

Sources: extension.oregonstate.edu, www.aces.edu.

Establishment care

Establishment care is the attention a newly planted tree needs while roots grow into the surrounding soil. It focuses on moisture, planting conditions and protection rather than treating the tree as fully established immediately.

In your yard: A small root ball can dry out while the nearby lawn still looks green. Mulch touching the trunk, deep planting or damage from mowing can create problems even when watering is regular. The time needed for establishment varies with tree size and site conditions.

What to do: Check root-ball moisture and water consistently without keeping the soil saturated. Maintain a shallow mulch layer away from the flare and expand watering as roots spread. Ask an arborist about persistent wilting, settling soil or a buried flare. Do not assume a large fertilizer dose will accelerate recovery from poor planting.

Related terms: Deep watering, Mulch ring.

Sources: extension.umn.edu, extension.oregonstate.edu.

Sectional removal

Sectional removal takes a tree down in separate pieces rather than dropping the whole tree at once. Pieces may be lowered with ropes or handled by equipment when there is limited room below.

In your yard: In a tight yard, a roof, fence or neighboring tree may make whole-tree felling unsuitable. The crew needs a plan for where each piece goes and how workers and bystanders stay clear. Taking smaller pieces does not remove the hazards of weakened wood or overhead wires.

What to do: Ask an arborist to explain the removal method and access needs in the written scope. Keep children and pets out of the work area, and do not assist by holding ropes. Confirm separately whether the scope includes the stump and removal of resulting debris.

Related terms: Rigging, Felling.

Sources: dnr.maryland.gov, www.osha.gov, extension.missouri.edu.

Rigging

Rigging uses ropes and related equipment to control tree pieces during cutting and lowering. It is different from simply allowing a severed branch to fall freely.

In your yard: You may see a limb held above a roof and guided toward a designated landing area. The anchor, the piece's weight and the forces created during movement all matter. A rope around a branch is not enough to show that the system is safe or appropriately designed.

What to do: Leave rigging to trained tree workers and stay outside their work zone. Ask the arborist how nearby structures and people will be protected, especially where there is little open ground. Do not tie a tree to a vehicle as a substitute for a professional removal plan, and never stand under a suspended piece.

Related terms: Sectional removal, Crane removal.

Sources: dnr.maryland.gov, www.osha.gov.

Crane removal

Crane removal uses a crane to lift and move cut tree sections. It is a method for handling tree material, not a guarantee that every difficult tree requires a crane.

In your yard: A crane may reach material that cannot safely be dropped into the yard, but it also needs suitable access and setup space. Nearby power lines and the condition of the tree affect planning. A crane and a bucket truck serve different purposes even when both appear on one job.

What to do: Ask an arborist why the crane is proposed and how the site will be managed. Keep people away from suspended loads and do not enter the operating area to watch. The work plan should address access and property protection without promising that heavy equipment can never disturb the site.

Related terms: Rigging, Bucket truck.

Sources: www.osha.gov.

Bucket truck

A bucket truck is a vehicle-mounted aerial lift that positions a worker above the ground. It provides access to branches but does not automatically make any tree or electrical situation safe.

In your yard: You may see a worker in a raised platform instead of climbing the tree. Access, reach and site conditions determine whether the truck can be used. The presence of a bucket is not proof that the crew is qualified to work near energized lines.

What to do: Ask the arborist how workers will reach the tree and where equipment will stand. Keep clear of the operating area and falling material. Do not ask an ordinary tree crew to handle a branch touching a wire.

Local note: Memphis: MLGW directs residents not to attempt tree work near power lines and to contact the utility about interference.

Related terms: Crane removal, Line clearance.

Sources: www.osha.gov, www.mlgw.com.

Stump grinding

Stump grinding uses a machine to break the visible stump and some nearby wood into chips below ground level. It does not remove the entire root system from the yard.

In your yard: Afterward, a mixture of wood shavings and soil may remain in a depression. That material is not the same as a finished bed of topsoil ready for planting. Grinding depth and the treatment of large surface roots need to be specified for the intended use.

What to do: Ask an arborist or stump contractor what area will be ground and whether chips will be removed and the hole filled. Identify buried utilities before work starts, and discuss nearby private irrigation or lighting lines. If you want to replant, plan for suitable soil rather than placing a new root ball into loose grindings.

Related terms: Stump excavation, Haul-off.

Sources: How to Remove Tree Stumps | Yard and Garden, Memphis Light, Gas and Water - Residential Overview.

Stump excavation

Stump excavation digs out a stump and associated roots rather than grinding wood in place. It generally creates a larger disturbed area than grinding the stump below the surface.

In your yard: In a yard, excavation leaves a hole that needs an agreed plan for backfill and restoration. Large roots can extend toward other trees, structures or buried services. A small visible stump therefore does not describe the full below-ground job.

What to do: Ask whether complete excavation is necessary for the proposed use or whether grinding would meet the goal. Have utilities located before digging and discuss nearby roots with an arborist. Do not pull a stump with an improvised chain attached to a vehicle; a slipping or broken chain can injure people. Specify who removes the wood and restores the hole.

Related terms: Stump grinding, Construction damage.

Sources: How to Remove Tree Stumps | Yard and Garden, Memphis Light, Gas and Water - Residential Overview.

Chipper

A chipper is a machine that reduces branches and other suitable woody material into small pieces. Its feed mechanism and cutting parts create serious hazards even when the equipment looks routine.

In your yard: On a tree job, branches may be fed into the machine and chips directed into a truck. The work area can be noisy, and material may move suddenly. Homeowners should not interpret a pause in feeding as an invitation to approach or help.

What to do: Stay outside the crew's work zone and let trained workers handle material. Ask whether chips will be hauled away or left in a specifically agreed location. If you use appropriate wood chips around trees, spread a shallow layer and keep it away from the trunk rather than building a mulch mound.

Related terms: Haul-off, Mulch ring.

Sources: www.osha.gov, Manage Soils and Mulch | Tennessee Smart Yards.

Haul-off

Haul-off means taking agreed tree debris away from the property after work. It does not necessarily include every log, stump grinding or piece of material unless the written scope says so.

In your yard: A removal job can leave different materials: large wood, chipped branches and stump shavings need not be handled the same way. A clean-looking lawn is also different from filling a stump hole or restoring damaged turf. Clarify the finish you expect before comparing proposals.

What to do: Ask the arborist or contractor to specify what leaves the site and what remains. Do not assume public or utility crews collect debris from privately arranged work.

Local note: Memphis: MLGW distinguishes routine trimming cleanup from storm-related work, so confirm who is responsible rather than relying on a general expectation of utility pickup.

Related terms: Chipper, Stump grinding.

Sources: How to Remove Tree Stumps | Yard and Garden, www.mlgw.com.

Felling

Felling is cutting a standing tree so that it falls to the ground. It differs from dismantling a tree in pieces while controlling each section separately.

In your yard: An open-looking lawn may still contain obstacles, neighboring trees or overhead lines that make a full-tree drop unsuitable. Lean, dead limbs and damaged wood can affect what happens as the tree moves. A tree caught in another tree is especially dangerous, not a partly completed job to walk beneath.

What to do: Have an arborist plan removal where a tree could reach buildings, people or utilities. Do not treat this definition as a cutting tutorial or try to pull a leaning tree into place with a helper.

Local note: Memphis: MLGW says residents should not attempt tree work when power lines are near the work area.

Related terms: Sectional removal, Lean.

Sources: extension.missouri.edu, www.mlgw.com.

Hazard tree

A hazard tree is a tree with a condition that could lead to harmful failure where people or property may be affected. The concern depends on both the defect and what could be struck.

In your yard: A large dead limb over a busy patio presents a different situation from deadwood in an unused woodland. Green leaves do not prove structural safety, and a hollow does not automatically establish that removal is required. The location and likely consequences need assessment.

What to do: Keep away from obvious hanging branches or a suddenly shifting tree, and arrange prompt professional evaluation. Ask an arborist to explain the defect, the affected area and options for reducing risk. Sometimes moving a target or removing a particular branch is appropriate; sometimes removal is needed. No assessment can promise zero future risk.

Related terms: Lean, Deadwood.

Sources: www.aces.edu, extension.psu.edu.

ISA Certified Arborist

An ISA Certified Arborist is an individual who has met the International Society of Arboriculture's eligibility requirements and passed its certification examination. The credential belongs to that person, not automatically to their employer or every worker on a crew.

In your yard: When someone visits your yard, a company logo or a reference to certified staff does not identify who will assess your tree. Certification demonstrates a level of arboricultural knowledge; it is not a guarantee of a particular result or proof of insurance.

What to do: Ask for the person's name and credential details, and verify the current credential through ISA. For a structural concern, also ask about tree risk assessment experience and relevant qualifications. Keep the written scope and insurance checks separate from the credential check, since they answer different questions.

Related terms: TRAQ, Certificate of insurance.

Sources: www.isa-arbor.com, extension.missouri.edu.

TRAQ

TRAQ stands for the ISA Tree Risk Assessment Qualification. It is a qualification in assessing tree risk, not another name for ISA Certified Arborist certification.

In your yard: At a yard visit, a risk assessment considers the tree's condition along with what people or property could be affected. The assessment level and access limitations matter: a limited visual inspection is not the same as an advanced investigation. A credential alone does not tell you which inspection was performed.

What to do: Ask the assessor to identify their current qualifications, the scope of the inspection and the recommended response. Request written findings when deciding how to manage a suspect tree. TRAQ supports a systematic approach to risk; it does not certify a tree as permanently safe or mean every assessed tree must be removed.

Related terms: ISA Certified Arborist, Hazard tree.

Sources: isarmc.org, www.aces.edu.

TCIA Accreditation

TCIA Accreditation is a third-party business verification program administered by the Tree Care Industry Association. It evaluates a tree care company against program standards rather than certifying an individual arborist.

In your yard: On an estimate, the words TCIA member and TCIA accredited are not interchangeable. Membership alone is not evidence that a company has completed accreditation. Likewise, a worker's individual ISA credential does not establish the company's accreditation status.

What to do: Ask for the exact status being claimed and verify it with TCIA rather than inferring it from a logo. Continue to check the written work scope and current insurance before hiring. This glossary defines the accreditation program; it does not claim that Help My Tree or its crews are accredited, and it does not turn a membership statement into that claim.

Sources: treecareindustryassociation.org, www.isa-arbor.com, treecaretips.org.

Certificate of insurance

A certificate of insurance is a document summarizing stated insurance policies and coverage information. It is evidence to check, not a substitute for the policy or a guarantee that every possible loss is covered.

In your yard: Before tree work in your yard, the certificate should match the business you are hiring and the planned work dates. Liability coverage and workers' compensation address different risks and may appear on separate certificates. An old copy left in a sales folder is not enough to establish current coverage.

What to do: Request current documentation and verify it with the listed agent or insurer. Ask about work-specific coverage questions before signing, rather than after damage occurs. Hiring an arborist with a credential does not eliminate this separate insurance check or establish what a policy covers.

Related terms: ISA Certified Arborist, Storm chaser.

Sources: treecaretips.org, extension.missouri.edu.

Line clearance

Line clearance is tree work performed to maintain separation from electrical facilities. It requires electrical-hazard planning and appropriate worker qualifications, not just ordinary pruning equipment.

In your yard: A branch may be near a wire even when it appears safely separated from the trunk. Tools, falling pieces and the tree itself can create an electrical hazard. Do not try to identify a line's voltage or safety by its appearance from the yard.

What to do: Contact the utility about branches near or touching lines and keep people away. An arborist planning nearby work should coordinate the electrical hazards rather than ask you to clear them first.

Local note: Memphis: MLGW warns residents not to attempt tree work near power lines and directs reports of tree interference to its Customer Care Center.

Related terms: Bucket truck, Street tree.

Sources: www.mlgw.com, www.osha.gov.

Right-of-way tree

A right-of-way tree is a tree growing within land reserved for public travel or related public use. Its location may place tree work under public authority even when the adjoining yard is privately owned.

In your yard: The grass strip near a curb is a common example, but the boundary is not established by mowing responsibility or appearance alone. A tree near the street may be public or private depending on the actual right-of-way. Do not infer ownership solely from where a sidewalk runs.

What to do: Confirm the boundary and responsible agency before hiring an arborist to prune or remove it. Private permission does not replace required municipal authorization.

Local note: St. Louis: the Forestry Division describes street trees as trees on public rights-of-way and manages their planting, maintenance and removal under city ordinance.

Related terms: Street tree, Tree permit.

Sources: Common Questions About Emerald Ash Borer Treatment and Removal, www.stlouis-mo.gov, www.stlouis-mo.gov.

Street tree

A street tree is a tree along a street, often within the public right-of-way. The everyday label describes its setting, while local rules determine who can authorize work on it.

In your yard: You may see one between the curb and sidewalk or in a sidewalk opening. A large crown may extend into a private yard even when the trunk is publicly managed. Conversely, a private tree can stand close to the road without becoming city property.

What to do: Check ownership and municipal requirements before arranging pruning or removal. An arborist's advice about the tree does not itself grant permission to work on public land.

Local note: St. Louis: the city's Forestry Division maintains right-of-way trees, and its tree maintenance permit page covers authorization for work such as pruning, removal and treatment of city trees.

Related terms: Right-of-way tree, Tree permit.

Sources: Common Questions About Emerald Ash Borer Treatment and Removal, www.stlouis-mo.gov.

Tree permit

A tree permit is written authorization from the responsible public authority for specified tree work. Whether one is required depends on location, ownership and the rules applying to that tree.

In your yard: In a yard, the permit question may arise before removal, pruning or work affecting a protected area. Being the property owner does not automatically answer it. Nor does a contractor's estimate establish that municipal approval has been obtained.

What to do: Identify the exact jurisdiction and ask the responsible department about the proposed work before scheduling it. An arborist can help document condition, but the authority determines permission.

Local note: St. Louis city has a permit process for work on city trees. Nearby Ladue has separate removal rules that can apply to private trees; do not treat a St. Louis mailing address as one uniform jurisdiction.

Related terms: Protected tree, Right-of-way tree.

Sources: www.stlouis-mo.gov, www.cityofladue-mo.gov.

Protected tree

A protected tree is a tree covered by a particular law, ordinance or approved protection requirement. The label does not have one universal size threshold or identical meaning in every community.

In your yard: A private yard tree may qualify because of its size, location or designation. Trees in a stream buffer or development plan may be treated differently from ordinary landscape trees. A tree that looks unhealthy is not automatically exempt from documentation requirements.

What to do: Ask the local authority which rule applies and what evidence is needed before work begins. Have an arborist document tree condition when that is relevant to an application or exemption.

Local note: Ladue: its tree ordinance addresses private-tree removal and requires a written determination by a certified tree professional for the stated dead-or-dying exemption. Other jurisdictions must be checked separately.

Related terms: Tree permit, Critical root zone.

Sources: www.cityofladue-mo.gov, shelbycountytn.gov.

Storm chaser

In tree work, storm chaser is an informal label for someone seeking jobs in an area after storm damage. Traveling to a disaster area is not by itself proof of either competence or dishonesty.

In your yard: After a storm, a visitor may offer immediate removal while you are worried about a damaged tree. Some visiting arborists provide legitimate recovery help; others pressure owners into unnecessary work. A business card or chainsaw does not settle that distinction.

What to do: Check identity, current insurance and a written scope before hiring, and avoid decisions driven only by urgency from a salesperson. For a hanging limb or unstable tree, keep people away while arranging qualified assessment. MU Extension recommends checking credentials and insurance rather than assuming every out-of-town worker is unqualified or every local offer is trustworthy.

Related terms: Certificate of insurance, Hazard tree.

Sources: extension.missouri.edu, treecaretips.org.