For 2026, the Latvian Fund for Nature (LDF) has designated tree hollows as its habitat of the year, bringing attention to these vital, often overlooked, components of forest ecosystems.
The Importance of Tree Hollows
Tree hollows serve multiple functions for a wide range of species. They provide shelter, nesting sites, feeding areas, and storage spaces for birds, mammals, insects, and fungi.
A Home for Many
These hollows are most often created by woodpeckers over a period of about three weeks in the spring – typically March and April – though they can also form through natural decay or mechanical damage. Once created, they become valuable real estate, often occupied by a succession of creatures.
Larger hollows, those with a diameter of 10 centimeters or more, are frequently inhabited by tawny owls, woodpeckers, and wood pigeons. Smaller hollows provide homes for birds like house sparrows, titmice, and the pygmy owl. Dormice, squirrels, and voles also utilize hollows, often storing food within them.
Focus on Old Growth
The LDF’s designation highlights the importance of preserving old trees, as hollows are more likely to develop in larger, thicker, and older specimens. The organization aims to draw attention to the need to protect natural structures within forests and cultural landscapes.
As ornithologist and LDF board member Jānis Ķuze noted, “A tree hollow is not just a hole in a tree – it is a very important element of nature. Hollows are like homes that their owners pass on to tenants who come and go.”
Frequently Asked Questions
What creates most tree hollows?
Most tree cavities are hollowed out by woodpeckers in the spring, usually in March and April.
What other creatures besides birds use tree hollows?
Tree hollows are home to mammals like dormice, squirrels, and voles, as well as invertebrate species.
Can hollows form without woodpeckers?
Less commonly, hollows can be caused by mechanical damage, such as a broken branch, and subsequent decay.
If the number of old trees continues to decline, it is likely that species reliant on tree hollows will face increasing pressure on their populations. Conservation efforts focused on preserving existing old-growth forests and promoting the natural regeneration of trees could become increasingly important. Further research into the specific needs of species dependent on tree hollows may also be undertaken.
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