Snags

Standing dead trees provide shelter and food for a variety of wildlife species. Snags occur naturally as trees die of old age or are struck by lightning, but snags can be created using a technique called girdling. I was interested in diversifying the habitat in the small woodlot behind my house and decided to create one. 
The first step was selecting a general location; for safety reasons, I didn't want it too close to my yard or the trail that runs along the back edge of my property. I also wanted to select an area that would benefit from an influx of sunlight to the trees and shrubs below resulting in greater understory complexity- an added benefit of creating a snag. Once the general area was defined it was time to select a tree. I decided the tree should be: a low value timber species, a low value mast-producer, irregular in form, relatively common, and relatively large. Generally, larger bole snags provide more benefits to wildlife and I would be unleashing more sunlight below if I selected a "big" tree.

The dominant species on the lot are red oak, black oak, American beech, and red maple. Given this list, the choice was easy, I selected a "big" red maple (~16" diameter) with an irregularly shaped based. Given the tree's compromised lower trunk and poorly drained soil below, it's likely this tree would fall or crack at some point in the next decade or two, which limiting my remorse...

Using a chainsaw, girdling a tree can be accomplished by making two parallel cuts into the trunk 2-3 inches deep, completely through the bark and cambium layer around the entire circumference. This severs the phloem and the tree is no longer able to transport sugars to the roots; it slowly dies and begins to decompose.

After making my cuts, I treated the wound with dressing to deter bugs and fungi that could spread to healthy trees, while not healing the wound itself. I plan to monitor this tree and the surrounding understory over time and will report back periodically with updates. It will be interesting to see when the first cavity excavators and foragers arrive, and if any songbirds nest amongst the shrubs below...