Thursday, July 2, 2009

and the story continues...

I could hear their chewing from across the yard. Granted, we have a small yard, but they are small animals, too. The chewing I heard was the female aspen or poplar borer beetle (Saperda calcarata) enlarging a hole in the bark of one of our quaking aspen (Populus tremuloides) to lay eggs of a new generation of long horn beetles. Over the last couple of weeks, the adult borer beetles have been mating in our yard, and the females have been laying eggs. One of our aspen, one we planted about nine-years ago is finally starting to succumb to the damage the borers are causing, and I am totally fine with this. Aspen are some of the most interesting and important trees in our yard, not because of the trees themselves but rather for the complex role they play in wildlife in our garden (read here).

Back to the dying aspen, ... I am actually looking forward to this aspen trunk dying (it is one of the largest trees in our yard) and becoming a standing snag (read here for more info). The diameter of this aspen is such that a black-capped chickadee or red-breasted nuthtacth could excavate a nest in its trunk, and there is already some progress to that end. As a result of the aspen borer life cycle, downy woodpeckers excavate the larvae in the late winter/ early spring when the larvae are close to the surface. The holes that the small woodpeckers create later become the beginnings of a cavity that chickadees and nuthatches will enlarge and excavate.
Even though this trunk is dying, this one has suckered and spread (a response to stress) and before long, a new aspen (or several will take its place). So by letting the borers do the work, we get several new aspen, a new snag, a lot of entertainment and wildlife habitat.

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