Dead, alive, upright, on the floor, or underwater, tree hollows are essential habitats.

However, since it takes them around 100 years of growth, maturation, and decay to form and just a few hours for them to vanish, we have a responsibility to preserve those we have and replace those we’ve lost. 

As Arborist Michael Sullings put it, “The industry needs to start recognizing the habitat value of trees, rather than simply assessing safety against amenity. Sure, our urban trees need to be safe, and sometimes they cannot be rendered so without removing their amenity to humans. However, trees with zero amenity to humans can still have massive amenity to wildlife.” 

Thankfully, we have methods to address the issue. Nesting boxes can be added, and expert arborists can even hollow into existing trees. Different species prefer different hollow shapes and sizes, and this can be very specific. The frequency, season, and species that use a hollow depend on its depth, insulation, size, and shape of the entrance, as well as its position. Diversity is key.

We have some work to do!