Windsor is oak country. Valley oaks, blue oaks and Oregon white oaks were here long before the subdivisions, and many neighborhoods were built around them, so it's common to find an oak older than any house on the street growing in a backyard that's only a few decades old. That's a gift, but it comes with care. Old oaks don't like new lawns, sprinklers or trenches under them. Since 2023, Windsor has also been dealing with a newer threat, the Mediterranean oak borer, a tiny beetle that attacks those same three oak species. Toward the town's rural edges, larger lots bring their own mix of oaks, firs and overgrown brush.
Most Windsor jobs we do involve oaks, either keeping a healthy one in good shape or deciding what to do with one in decline. If yours looks off, start with a tree health care visit. If the tree is past saving, see how we handle big takedowns on our tree removal page. With oaks this size, we also look at what's around the trunk: a lawn, a patio or a new irrigation line within the canopy can be the real reason a tree is struggling, and fixing it costs far less than losing the tree. Call for a free estimate.
The Mediterranean Oak Borer in Windsor
The Mediterranean oak borer was confirmed in Windsor in August 2023 by UC Cooperative Extension, on Conde Lane. The Town removed infested trees, then treated hundreds of heritage oaks on public land with insecticide injections in the spring of 2024. The beetle attacks valley oak, blue oak and Oregon white oak, boring into the trunk and carrying a fungus that blocks the tree's water flow. On your own oaks, watch for tiny round holes in the bark, fine pale boring dust collecting at the base or in bark cracks, and sections of the crown that suddenly turn brown in summer. A tree with an active infestation can decline quickly, and dead infested wood can spread beetles to neighboring oaks. If you see the signs, get the tree looked at before cutting or moving any wood. Treatment works best on trees caught early, while most of the canopy is still green, so waiting a season to see what happens usually narrows your options. Homeowners just north in Healdsburg should keep an eye out too.
Windsor's Protected Trees
Windsor's tree preservation ordinance protects native species. Its list centers on native oaks, plus California buckeye and California bay, and those are protected anywhere in town. Removing one requires a permit from the Town, and cutting a protected tree without one can bring penalties. Trees that aren't on the protected list can generally be removed without a permit. The ordinance has been updated over the years, most recently in 2024, so before any removal we look up what applies to your lot today and tell you what the application needs. Pruning a protected oak also deserves care. Heavy cuts and work in the wrong season can stress a tree that's already fighting drought or beetles. If you're just over the line in unincorporated county land or up toward Santa Rosa, different rules apply.
Common Questions
The first signs are small, perfectly round holes in the bark of a valley, blue or Oregon white oak, often with light-colored boring dust below them or piled at the base. As the infestation grows, parts of the canopy wilt and turn brown, sometimes over a single summer. The beetle has been confirmed in Windsor since 2023. If you see these signs, have the tree checked and don't move the wood off the property until you know what you're dealing with.
Yes. Windsor's tree ordinance protects its native oaks, along with California buckeye and California bay, and removing one requires a permit from the Town. Trees not on the protected list generally don't. Because the rules have been updated over time, it's worth checking with the Town or asking us to before any protected tree is removed or heavily pruned.