Long Island’s trees are dealing with pests and diseases that weren’t here a generation ago. Three of them account for a large share of the dead and dying trees homeowners call about. Here’s how to recognize each, where it’s hitting, and how to decide between treating and removing.
Southern pine beetle: pitch pines in the Pine Barrens and South Fork
What it is: a tiny bark beetle (about the size of a grain of rice) that attacks pines in mass, girdling them from the inside. It was first confirmed on Long Island in 2014, and NYSDEC reports it has since killed hundreds of thousands of trees here. Pitch pine, the signature tree of the Central Pine Barrens, is its main target.
Where: the Pine Barrens hamlets of Brookhaven (Manorville, Ridge, Middle Island, Yaphank), Riverhead, and the South Fork, with scattered hits across central Suffolk.
Signs:
- Needles fading from green to yellow to red-brown across the whole crown, often fast
- Pitch tubes: small, popcorn-like blobs of resin on the bark
- S-shaped galleries under loose bark
- Clusters of dying pines together (the beetles attack in groups)
Treat or remove? Once a pine is infested, it’s dying. There’s no saving it. Beetle-killed pines dry out fast and drop limbs or snap in wind, so dead pines near houses, driveways and wires should come down promptly. Removing infested trees quickly can also help protect neighbors’ pines. Report suspected new infestations to NYSDEC.
Beech leaf disease: North Shore beeches
What it is: a disease linked to a microscopic nematode (Litylenchus crenatae mccannii) that damages leaf buds. It was first found in New York in 2018 and reached Nassau and Suffolk in 2019. It affects American and European beech, including the big copper and weeping beeches on many North Shore properties.
Where: everywhere beech grows, but especially noticeable on estate properties in North Hempstead (Manhasset, Port Washington, Roslyn), Oyster Bay’s Gold Coast villages and Huntington.
Signs:
- Dark bands between the leaf veins, easiest to see looking up at leaves against the sky
- Leaves that are thick, leathery, crinkled or curled
- A thinning canopy and fewer buds each year
- Eventually, dieback and death, usually over several years in mature trees
Treat or remove? Some arborists offer treatments that can slow the disease in trees that are still in good shape, so early is the time to ask. Once a large beech has lost much of its canopy, the wood becomes brittle, and it becomes a hazard tree, especially over a house or driveway. At that point removal is usually safer and cheaper than waiting.
Oak wilt: red oaks (pin, red, black, scarlet)
What it is: a fungal disease that blocks an oak’s water-conducting tissue. Trees in the red oak group can die within weeks to about six months. It spreads two ways: sap beetles carry spores to fresh wounds, and the fungus travels underground through grafted roots between neighboring oaks.
Where on Long Island: oak wilt was found in the past in the Towns of Islip, Southold and Riverhead. NYSDEC now lists those Suffolk sites as inactive after years without new detections. But red and pin oaks are everywhere here, from Levittown streets to North Shore woods, and vigilance matters.
Signs:
- Leaves that wilt and turn bronze or brown from the tip and edges inward, in summer
- Rapid leaf drop, sometimes of green leaves, from the top of the crown down
- A red oak that looks fine in June and dying by August
Treat or remove? An oak suspected of oak wilt should be reported to NYSDEC and tested before anyone cuts it. Infected trees need special handling: root-graft disruption, and careful disposal of wood so beetles can’t spread spores. Never move firewood from a suspect oak.
Prevention for everyone: NYSDEC advises not pruning or wounding oaks from March through September, when spore mats and beetles are active. If an oak gets wounded then (storm, mower, construction), seal the wound right away with water-based spray paint or wound dressing.
Quick ID table
| Southern pine beetle | Beech leaf disease | Oak wilt | |
|---|---|---|---|
| Trees | Pitch pine (other pines) | American & European beech | Red oak group |
| Where on LI | Pine Barrens, South Fork, central Suffolk | Island-wide, very visible on the North Shore | Past sites in Islip, Southold, Riverhead |
| Key sign | Red-brown crown, pitch tubes | Dark banding between leaf veins | Summer wilting and leaf browning from tips |
| Speed | Weeks to months | Years | Weeks to months |
| Save it? | No, once infested | Sometimes, if caught early | Get it tested; special handling required |
When removal is the right call
Across all three, the decision usually comes down to:
- Is it dead or mostly dead? Dead wood gets more brittle every season, and removal gets riskier and pricier. Beetle-killed pines and badly declined beeches are the classic cases.
- What would it hit? A declining tree 40 feet from anything can wait. The same tree over a bedroom can’t.
- Is it a source for neighbors? Infested pines and oak wilt trees can spread the problem.
- What does the town require? Many Long Island towns ease permit rules for dead or hazardous trees, but often want an ISA Certified Arborist letter and photos (Huntington does, for example). Check permits by town.
Removal of a dead or diseased tree usually costs more than a healthy one of the same size, because crews can’t safely climb brittle wood and may need a bucket truck or crane. See the Long Island tree removal cost guide for ranges.
Need it done? See tree removal on Long Island. Local rules: North Hempstead, Oyster Bay, Huntington, Islip, Brookhaven.
