Progressive Tree Service

Japanese beetle season runs late June through August in the Chicago area, and in a bad year, the defoliation they cause on certain tree species is significant enough to warrant intervention rather than just watching.

Feeding pattern: they skeletonize leaves — eating the tissue between the veins, leaving the vein structure intact. The lacy, brownish result is distinctive. Top host species: lindens, crabapples, purple-leaf plum, roses, certain ornamental cherries. Oaks and most maples typically aren't heavily affected.

For most established trees: one season of moderate defoliation is manageable. An established linden can lose 30–40% of leaf area and recover fully. The situation escalates when:
— Heavy defoliation happens over consecutive seasons
— Defoliation compounds existing drought or disease stress
— The affected tree is young or has limited energy reserves

Active management options:
— Systemic soil-applied insecticides (dinotefuran or imidacloprid) provide control but work best as preventive treatments before peak feeding — not reactive treatments once the beetles are already present and feeding heavily
— Trunk injection acts faster but costs more
— Manual removal is effective on small trees

Beetle traps: research consistently shows they attract more beetles to your yard than they catch. Skip them.

For trees where defoliation is compounding other stressors, a professional assessment determines whether systemic treatment is cost-effective this season.

The most dangerous assumption in tree care: full leaves = healthy tree. A tree can hold a full, green canopy while carrying a serious structural defect, active root disease, or significant internal wood decay — sometimes until the year it fails.

Signs that are genuinely concerning:

Crown dieback progressing top-down. When the upper crown is failing and lower branches are still green, that pattern points to a vascular problem — root disease, girdling root, vascular wilt. The top of the crown is the last part of the water delivery system to be served. It fails first when the system is compromised.

Fruiting bodies (mushrooms, shelf fungi) at the base or on roots. These are the visible signal of wood decay that started years ago and has been advancing internally. The outside of the tree may look structurally sound. The inside may not be.

Cracks at major branch unions or along the trunk. Structural defects under load. They don't heal themselves, and they worsen.

Signs that are typically cosmetic:

Leaf spots and tar spot on maples. Looks alarming. Largely benign in established trees.

Some early leaf drop in summer. Not all early drop is a crisis — heat, drought, and common fungal infections cause it in otherwise healthy trees.

Surface root visibility. Not a health problem in most cases. A structural concern only if damage or soil change has compromised the root zone.

Knowing the difference prevents two bad outcomes: removing a healthy tree unnecessarily, and delaying action on one that actually needs it.

Trimming and pruning get used interchangeably in almost every homeowner conversation about trees — but they're different practices with different goals. Knowing the distinction helps you get better work done on your trees.

Tree trimming is primarily a size and clearance service. You're managing where the tree grows: cutting back branches that are hitting the house, overhanging the neighbor's property, encroaching on power lines, or blocking a driveway. The driver is external — a boundary or clearance requirement. The objective is controlling the tree's footprint.

Tree pruning is about the internal structure and long-term health of the tree. The cuts are made to: remove deadwood and diseased material, correct structural issues like co-dominant stems and included bark unions, reduce competing branches, and improve airflow and light through the crown. A properly pruned tree often doesn't look much smaller — it looks cleaner, more open, and structurally better defined.

Timing differences: trimming follows clearance needs and can happen throughout the season (with species-specific exceptions like oaks). Structural pruning follows guidelines tied to species biology and disease risk windows.

In practice, most residential jobs combine both — clearance work on problem branches plus deadwood removal and structural correction on the same visit. An ISA-certified arborist identifies what your specific tree needs rather than defaulting to a service name.

If you've been told your trees need "trimming," it's worth asking whether structural pruning is also warranted — and what the difference looks like for your specific trees.

July 4th weekend: outdoor gatherings, yard time, the statistical peak of summer storm activity in Chicago. Most people think about fireworks safety. The trees overhead get skipped.

Hazards worth checking before your guests arrive:

Hidden deadwood. Full summer canopy conceals interior dead branches. They didn't go anywhere — you just can't see them from the ground anymore. Wind or a storm drops them where people are standing.

Over-extended lateral limbs. The big horizontal branches on mature oaks and maples grow longer every season, and the leverage on the branch union increases with them. These are the limbs that fail silently under a wind load — no prior visible warning, just a major branch on the ground.

Added load from activities. Ropes, hammocks, kids climbing — these add live load to limbs that may be at their structural limit. The tree doesn't announce when it's reached that limit.

Before the weekend starts, spend five minutes looking up in the spaces your guests will be using. Dead branches, limbs at odd angles, cracks or splits at major unions. These are fast to spot once you know what to look for.

For anything that concerns you: (847) 530-1533. Emergency response available. Serving Niles, Evanston, and the North Shore.

Fungal disease is the most common tree health problem in North Shore yards — and the one most often misidentified or addressed too late.

Four fungal conditions worth knowing:

Anthracnose — affects oaks, maples, sycamores. Brown lesions along leaf veins, cupped or distorted leaves, premature drop. Common in wet springs. Established trees usually tolerate it, but chronic infections accumulate over seasons and weaken overall defense capacity.

Verticillium wilt — targets maples and many ornamental species. Starts in one branch or section, progresses unevenly. Cut into an affected branch and you'll see dark streaking in the sapwood — the fingerprint of vascular colonization. No cure; management supports health and slows spread.

Ganoderma root rot — the shelf mushrooms at the base of a tree that look decorative and aren't. By the time those conks are visible, extensive internal wood decay has already occurred. Ganoderma-infected trees need a structural risk assessment — you can't evaluate the interior from the outside.

Fusarium cankers — sunken, discolored patches on the trunk or scaffold branches with sap or resin around the margin. Active cankers kill the cambium layer within their boundary. The affected tissue dies back to the canker edge.

These are all manageable with early identification. Missed until they've advanced into structural wood or through the full vascular system — much harder to address and potentially irreversible.

A disease management assessment is the right first step when you see anything that doesn't look right.