Tree Cavities and Microhabitats

Small-scale specialised structures within living or dead trees, such as trunk hollows, rot holes, and loose bark, that provide important wildlife niches.

Tree Cavities and Microhabitats are small-scale, highly specialised structural features found on living, veteran, or dead trees that provide critical nesting, shelter, foraging, and overwintering niches for a massive proportion of forest wildlife. These localised features develop progressively as a tree ages and interacts with its environment, often initiated by mechanical storm damage, lightning strikes, woodpecker drilling, or localized fungal decay.

The most biologically significant microhabitats are deep tree cavities and rot holes, which offer highly insulated, secure nesting sites for hollow-nesting birds like owls and woodpeckers, as well as vital nursery and hibernation roosts for bats and arboreal mammals. Other essential tree microhabitats include water-filled trunk hollows (dendrotelmata) that support specialised aquatic insect larvae, deep sap runs that attract butterflies and hornets, peeling flaps of dead bark that shelter overwintering beetles, and thick cushions of epiphytic mosses and lichens.

A high density of tree microhabitats is a prime indicator of an old, structurally complex forest ecosystem, and preserving these features is a core objective of modern conservation-minded forestry.