The trees of San Antonio, and what actually goes wrong with them.

• Small, leathery, oval leaves with smooth edges - not the lobed shape people picture when they hear oak.
• Trunk often leans and forks low; mature yard trees carry 50 to 60 feet of spread on a 40-foot height.
• Grows in mottes - clusters of trees whose roots have fused underground into one connected system.
• Drops its old leaves in February and March, then leafs out immediately. That is normal, not decline.

Oak wilt is the main threat, and in live oaks it travels underground through those fused roots, which is why an infection spreads outward as a widening circle rather than jumping around a property. Structurally, the low forks are the weak point: a heavy limb over a roof with a tight, included-bark union is a storm liability long before it fails.

Preventive propiconazole injection for high-value trees, trenching four to five feet deep to sever root grafts between a sick tree and its healthy neighbors, and structural pruning of heavy low limbs - done between July and January, never February through June.

• Lobes come to sharp points, unlike the rounded lobes of a post oak.
• Darker, more furrowed bark than a live oak; blackjack oak bark is notably blocky and near-black.
• Fully deciduous - bare in winter, which is the easiest way to separate it from a live oak at a glance.

Oak wilt kills a red oak fast, often in three to six weeks from first symptoms. It is also the species that starts new outbreaks: the fungus forms spore mats under the bark of a dead red oak, sap-feeding beetles feed on them and carry spores to fresh cuts on healthy oaks anywhere in the neighborhood.

A symptomatic red oak is a prompt removal, and the wood does not get stacked or shared - it is disposed of or sealed so it cannot form mats. This is the one case where speed genuinely matters rather than being a sales line.

• Thick, stiff leaves; the two middle lobes are wide and blunt, giving the cross shape.
• Slow-growing with a stout, often gnarled trunk.
• Common on older, undisturbed lots and at the edges of new development.

Root disturbance, more than anything else. A post oak will not tolerate grade change, trenching or compaction inside its drip line, and it often does not show the damage for two or three years - which is why a post oak dying next to a new build is such a common call.

Honest assessment first. If the root zone was cut through during construction the decline usually cannot be reversed, and the useful conversation is about hazard and removal rather than treatment.

• Compound leaves - one leaf is a whole row of leaflets on a stem.
• Gray, ridged bark that plates and flakes with age.
• Nuts in autumn. The Texas state tree, and old yard specimens can top 80 feet.

Not by snapping mid-span. A pecan drops whole limbs at the union, which means it can look full and healthy from the street while carrying three or four attachments that will let go in the next straight-line wind. Aphid honeydew making everything below sticky is cosmetic, not a health problem.

Selective reduction of over-extended limbs and inspection of the unions, not topping. Removals are rigging work because the wood is heavy and the drop zones on older lots are tight.

• Leaves under two inches, thick and rough on top, with toothed edges.
• Twigs often carry corky wings running along them.
• Narrow, upright habit; flowers and seeds in the fall rather than the spring.

Heavier and more brittle than it looks. Cedar elms shed limbs unpredictably in wind, and they carry that weight further out than the crown suggests.

Takes crown reduction well, though it calluses over differently from an oak and looks worse for a season before it looks better. Storm work on cedar elm is common and usually straightforward.

• Scale-like leaves pressed flat against the twig, not needles.
• Shreddy, fibrous bark in long strips.
• Rarely a single trunk - usually three to six stems fused at the base with bark trapped between them.
• The source of the December-to-February cedar fever pollen.

Structurally it rarely fails on its own. The problem is what it does to everything else: it crowds a lot, hides declining hardwoods from view, and it has to be cleared along a route before a trench line can go in, which is what makes oak wilt trenching expensive on a Hill Country property.

Clearing and thinning is a different job from hardwood removal - many small stems rather than one big one - and it is priced that way. Selective clearing that opens the canopy for the oaks is usually a better outcome than taking everything.

• Compound leaves with 3 to 5 broad leaflets, opposite each other on the twig.
• Gray, diamond-patterned bark.
• Often the largest tree on a mid-century subdivision lot, and often visibly hollow at the main unions.

Decay at the branch unions, usually hollowing from the center out. Arizona ash was planted for speed, not longevity, and a 55-year-old specimen is a storm call waiting to happen. It is the tree most likely to put a limb on a car.

Heavily represented in our storm cleanup. Removals are comparatively cheap because the wood is light and nobody rigs it delicately - but a large one over a house is still crane or bucket work.

• Deciduous conifer: the needles go rust-orange and drop in autumn, which alarms people every year.
• Fluted, buttressed trunk base; knees pushing up through the ground near water.
• Along Cibolo Creek, the Guadalupe and the San Antonio River basin.

Rarely fails structurally. What looks like alarming decline on a cypress is almost always a water problem - either drought pulling the creek down or a change in drainage upstream.

Usually the honest answer is that no work is needed. Deadwood removal over a patio or a path, and a conversation about watering.

• Tiny paired leaflets that cast almost no shade.
• Straight, sharp thorns at the leaf nodes.
• Long seed pods in summer. Leafs out late - the local saying is that mesquite does not leaf until the last frost has passed.

Splits at the base where the multiple stems meet. Common on thin caliche soil at the edges of the service area, and generally a low-value tree unless it is a specimen in a designed landscape.

Removal or clearing. The wood is worth asking about - mesquite has real value for smoking and milling.

• Hackberry: warty, bumpy gray bark - unmistakable once you have seen it - and asymmetric leaf bases.
• Ligustrum: glossy evergreen leaves, usually a fused clump of five or six trunks.
• Chinaberry: lacy compound leaves, lilac flowers in spring, hard yellow berries that persist.

Weak wood and bad structure from the start. A mature ligustrum clump can be six trunks fused at the base with a root mass wider than any one of them, which makes the stump work larger than the tree above suggests.

Removal, and the quote is driven by the root mass and access rather than the height. Regrowth from the stump is the norm if it is not ground out.

• Bradford pear: white spring flowers, tight upright branching, splits down the middle in wind.
• Chinese tallow: heart-shaped leaves, brilliant fall color, spreads aggressively.
• Crape myrtle: smooth mottled bark, summer flowers, usually multi-stemmed and small.

Structure, not disease. Bradford pear in particular is built from tight upright unions that split the tree in half in a storm, often at fifteen to twenty years old.

Removal and replacement advice. Crape myrtle work is mostly correcting bad past pruning rather than anything structural.