COSA Tree Pruning when Fox squirrels nests are present

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Good afternoon all,

Our practices at the county are much in accord with the advice from Mr. Slattery at the City of Northglenn. For county trees, if the tree is in a location where it is not at risk of impacting a trail or public space if it fails, we will let the squirrels run wild so to speak and do what they will with the tree. Open space is as much for their habitat needs as for our enjoyment and the county doesn’t prune in open space for aesthetics, so if we lose a tree to squirrel infestation that is just the natural course of things. Snags make great habitat for various critters so we welcome the variety in our urban forests.

However, if the tree is in a parking lot or on the side of a trail so we HAVE to prune it for safety reasons, we will also try to wait to prune the tree at all until the family has moved on and the nest is vacated. If public safety necessitates immediate pruning, we will prune around the cavity that is occupied and removed as much dead wood and risk as possible without impacting the structural integrity of the nest. Should that not be enough to mitigate the risk, we would then discuss options with our wildlife and trails staff about mitigating risk to the public, such as by closing off the area below the tree until the family moves on and the hazard is removed or possibility relocating the squirrels should the limb where they are nesting prove to be too unstable and dangerous to wait on removing it.

Just one crew’s perspective on how to handle this problem. Hope this helps!

Take Care,

Cathy Thiltgen & Mary Tiernan

Boulder County Parks and Open Space Urban Forestry