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Twigs all over the lawn: squirrels, twig girdlers, or a tree shedding its own twigs
Why oaks drop small branches in summer and fall, how the cut end shows whether a squirrel, a beetle or the tree itself did it, and what to do with the twigs.
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What the end of the twig tells youThe tree shedding its own twigsDoes it harm the tree?What to do with the fallen twigs, and whenSend us the cut endCommon questionsSourcesLook at the end of a fallen twig, because the end names the cause, and most causes cost a grown oak nothing that matters. A cut as clean as a saw’s, around a small broken core, is the work of the twig girdler, a beetle that favors hickories and pecans. A slanting cut on a green, leafy twig is a squirrel’s. A smooth, slightly rounded end is the tree shedding its own twigs, called cladoptosis. Young trees can lose real growth, and a girdler’s fallen twigs hold its larvae, so gather those up and burn or chip them.
What the end of the twig tells you
The table sets each cause’s end beside its season and trees, in the order the twigs fall through the year.
| Cause | The end of the twig | When it falls | Usual trees |
|---|---|---|---|
| Periodical cicadas | Broken at or near a row of egg slits | June into fall of a brood year | Oaks, maples, apples, hickories |
| Twig pruner | Smooth wood in ragged bark, with an oval, sawdust-plugged hole | Late summer | Oaks most, also hickory and maple |
| Squirrels | One slanting cut, leaves still green, often acorns | Late summer to early fall | Oaks |
| Twig girdler | Smooth all around except a small broken core | Mid-August into October | Hickories, pecan, elm, persimmon, oaks |
| The tree itself | Smooth and slightly rounded | Mostly fall, some in summer with green leaves | Oaks, bald cypress, poplars, willows, maples |
The core the female girdler leaves snaps later, in wind or under the twig’s own weight. Her ring looks like a person’s work:
“The cuts are so neat and clean, and the fallen twigs are so uniform in size that the damage does not look like it was caused by any type of animal.” (Mississippi State University Extension Service, Twig Girdler, Vol. 7, No. 24)
The pruner works from inside. Its larva cuts outward through the wood but not the bark, and the twig hangs until the bark gives way.
Ohio State Extension calls a squirrel’s cut clean, and Iowa State Extension calls it ragged. Both find it slanting, on a twig whose leaves are still green.
The tree shedding its own twigs
Cladoptosis works like leaf fall. The tree grows an abscission layer across the base of the twig, and the layer shuts off water and sugar until the twig drops. Many oaks and bald cypresses do it every fall, and a tree sheds more as it ages.
There is evidence that the twigs dropped are the ones whose leaves pay their way least, short of light, water or nutrients. Drought, compacted soil and disease can add to the shedding. A sudden rise in shedding is worth a look at the tree’s water and roots.
Does it harm the tree?
Young trees are the ones at risk, because their leaders and side shoots are the size the girdler and the cicadas pick. The girdler takes twigs about as thick as a pencil, and cicadas lay in twigs a quarter to half an inch thick.
A girdler can take a sapling’s top and leave it deformed. Twig girdlers clip young mockernut, pignut and shellbark hickory.
In a brood year, periodical cicadas can cut into most of a small tree’s twigs, and a newly planted tree can die. Twig pruners favor stressed trees, and drought can draw them to young ones.
What to do with the fallen twigs, and when
The girdler’s and the pruner’s twigs hold their larvae, so gather those in fall and winter and burn, chip or bin them. The pruner’s adults can come out in spring and the girdler’s in late summer. Raking helps little beside a woodlot, where the beetles are many. A yard needs no spray:
“In non-agricultural settings, including urban backyards and forests where tree growth rate is not a concern, treatment for twig girdlers is unnecessary.” (UF/IFAS Extension, Twig Girdler: Oncideres spp.)
The rest, by cause:
- Cicada twigs. On a young tree, cut out twigs with egg slits within three weeks after the egg laying ends, before the eggs hatch and the nymphs drop to its roots. In a brood year, net a tree under 10 feet with half-inch mesh before the cicadas come out, and leave it on for 4 to 6 weeks.
- A lost leader. Prune a young hickory back to one leader in the dormant season, cutting just outside the branch collar.
- Twigs a squirrel cut or the tree shed. They need nothing but the rake.
Send us the cut end
If your twig matches no row, or a young tree has lost its top, write to us through the support page and say when the twigs began to fall. Blue Whale Trees replies by email, usually within a few days in season, and a close-up of the cut end and a photo of the whole tree can follow then.
Common questions
What is cladoptosis?
Cladoptosis is a tree shedding its own twigs through a layer of cells at their base, the way it sheds leaves. Oaks, bald cypress, poplars, willows and maples do it, mostly in fall.
Why is my oak tree dropping small branches?
Usually a squirrel, a twig-cutting beetle or the oak itself is the cause, and the end of the twig tells which. Only a young oak loses much, to a twig girdler or to periodical cicadas.
Why are squirrels chewing off oak branches?
No published study explains it, but the clipped twigs often carry acorns, which points to squirrels harvesting nuts from the tips. The clipping peaks in late summer and early fall.
What does twig girdler damage look like?
Pencil-thick twigs drop from mid-August into fall, each chewed smooth all around except a small broken core. The larva is inside, so gather the twigs and burn, chip or bin them before next August.
Sources
- Twig Girdler/Twig Pruner: Virginia Cooperative Extension (Eric Day and Theresa Dellinger, ENTO-374NP, reviewed 2025): the girdler’s straight cut around a small center core that breaks later, the pruner’s larva cutting outward through the wood but not the bark, the smooth inner cut in ragged bark with an oval, sawdust-plugged hole, the pruner on oak most of all, when each adult comes out, and raking up the twigs to burn or chip them.
- Twig Girdler, Vol. 7, No. 24: Mississippi State University Extension Service, Bug’s Eye View (Blake Layton, 2021): pencil-sized twigs cut straight and clean around a toothpick-sized center, girdled twigs falling to their own weight or wind, hickory, pecan and elm as the favored hosts, little harm to large trees and more to young ones, and the quotation on how neat the cuts are.
- Twig Girdler: Oncideres spp.: UF/IFAS Extension, Featured Creatures EENY-817 (Miranda Barnes and Jiri Hulcr, 2025): cleanly whittled ends with a jagged break to one side, hickories and pecans as the usual hosts with persimmon, elm and oak among the others, and the quotation that yards need no treatment.
- Twig Girdlers and Dropped Twigs: Iowa State University Extension and Outreach (Donald Lewis, 2007): adults out from mid-August to early October and again the next summer, twigs falling to wind or their own weight, young trees deformed, the pruner’s ragged broken end, the squirrel’s diagonal, ragged cut on green-leaved twigs, sanitation of limited value beside woodland, and sprays that do not work in a home landscape.
- Twig Pruner: NC State Extension (James Baker, reviewed 2025): larvae cutting outward through the wood but not the bark, the oval hole plugged with frass, the pruner’s hosts from oak to hickory and maple, fallen branches destroyed or sent to a landfill, and stressed and drought-struck young trees drawing the beetles.
- Tips on Oak Tips: Ohio State University Extension, BYGL (Joe Boggs, 2021): three causes of fallen oak tips, squirrels clipping oak twigs with green leaves and acorns in a clean cut at the slant of their incisors, mostly in late summer and early fall, with no published study of why and little real damage, and cicada-damaged oak twigs detaching and still dropping in October.
- Periodical Cicadas in Kentucky: University of Kentucky Entomology (D. W. Johnson, L. H. Townsend and Ric Bessin, revised 2026): twigs breaking at the egg slits and hanging brown, harm to the structure of small trees and not large ones, eggs in quarter- to half-inch twigs of oak, hickory and apple, activity from late April through June, and cutting out slit twigs on young trees within three weeks of the egg laying.
- Periodical Cicada: Penn State Extension (Greg Hoover and Michael Skvarla, 2021): slits in a straight row up to 2 to 3 inches long, oaks, maples and apples preferred, large healthy trees unharmed, small trees whose branches are mostly the size cicadas choose, newly planted trees at most risk, eggs hatching and nymphs dropping to the roots, and netting trees under 10 feet with half-inch mesh for 4 to 6 weeks.
- Cladoptosis: An interesting phenomenon: Texas Plant Disease Diagnostic Lab, Texas A&M AgriLife Extension (2013): shedding through an abscission layer at the branch base, the trees that do it yearly in fall, more with age, the evidence on weak or poorly supplied foliage, drought, compaction and disease as stresses, the smooth, slightly rounded end, and cladoptosis as seldom a cause for concern.
- Plant Health Clinic Newsletter, Issue 17: University of Arkansas Cooperative Extension Service (Sherrie Smith, 2017): oak branches shed in the growing season with green leaves, the abscission layer shutting off water and sugars, and foliage short of light, water or nutrients.