Is My Tree a Hazard? Signs to Watch

Most homeowners don’t call about a tree until something looks obviously wrong — but the trees most likely to cause real damage often look fine from a distance. Here are the six signs actually worth walking your yard to check for, and what each one means.

A leaning trunk that’s new or getting worse

A tree that has always leaned a certain way, gently, toward light or away from a prevailing wind, isn’t automatically a problem. What matters is change: a lean that’s new, that’s gotten more pronounced recently, or that’s paired with heaved or cracked soil on the opposite side of the lean (a sign the roots on that side are pulling loose rather than holding). If you have an old photo of your yard, it’s a genuinely useful way to check whether a lean has actually changed.

Root heave and soil cracking near the base

Root heave — roots visibly lifting and cracking a sidewalk, patio slab, or the soil surface close to the trunk — is common across the East Valley because much of the area sits on heavy clay or caliche soil that keeps roots shallower than they’d otherwise grow. Mesquite is a common local species where this shows up. It’s not just a hardscape nuisance: heaved roots near the base mean the tree’s actual underground anchoring is thinner than a full, healthy-looking canopy might suggest.

Fungal growth or mushrooms at the trunk base

Mushrooms or shelf-like fungal growth at the base of a trunk or at a major root flare is one of the more reliable physical signs of internal decay, since many of the fungi that produce visible growth are actively breaking down wood fiber inside the tree or its root system. This can be present well before a tree shows any visible canopy stress, which is part of why it’s worth checking the base directly rather than only looking up.

Large dead or hanging limbs

A dead limb still attached to an otherwise living tree — sometimes called a “widowmaker” — can fail with no warning at all, since dead wood doesn’t bend or telegraph stress the way live wood often does. Limbs that are already partially broken or hanging are an even more immediate concern, particularly over a driveway, walkway, patio, or anywhere people or vehicles regularly pass underneath.

Cracks, splits, or included bark at branch unions

A visible crack or split in the trunk, or in a major branch union, is a structural red flag regardless of how the rest of the tree looks. “Included bark” — where two branches or trunks grow so close together that bark gets pinched between them instead of forming a normal, strong union — is a related, less obvious pattern that tends to fail at that union under wind load.

Canopy dieback concentrated on one side

Thinning, browning, or bare branches concentrated on one side of an otherwise full canopy can point to root damage or soil compaction on that side, construction or trenching activity near the roots, or a spreading internal problem. Dieback spread evenly across the whole canopy is more often a watering, seasonal, or general-health issue — the lopsided pattern is the more specific hazard signal.

What to do if you spot one of these

None of these signs are a DIY diagnosis-and-fix situation — an arborist or tree service pro can look at the tree’s specific size, species, lean angle, and location relative to your house, driveway, and property line, and give you an actual read on urgency, not just a general warning. If you’ve spotted one of these signs, get a professional assessment rather than waiting to see whether it gets worse, especially heading into monsoon season when wind load tests exactly the kind of structural weakness these signs point to.