Life in and around and ancient tree

As a tree ages parts might become damaged, slowly decay or hollow out. These natural processes help to protect and nourish the tree and develop valuable habitat features known as micro-habitats. These smaller discrete habitats are perfect for specialist species to colonise. Cracks and crevices, dead branches, hollow cavities, rot holes and loose bark are all important features. These changes help the tree to live longer and provide an ever-changing habitat rich in biodiversity.

An example of an ancient tree -  they display a wide, squat trunk, often with hollows and reduced growth in the crown

A tree doesn’t have to be of a grand old age either, a younger tree may be wounded or weakened, known as ‘veteranisation’, increasing its value for biodiversity and helping to fill the ecological gap caused by the loss of our ancient trees. Trees also continue to provide important micro-habitats after they die as well, in the form of fallen deadwood or standing dead trees.


Fungi and invertebrates are the most numerous organisms feasting on decaying wood, with around 2,000 invertebrate species in the UK alone. Fungi are the principle driver of wood decay in both living and dead trees. They come in a variety of forms, each providing a different opportunity for invertebrates to exploit. Key invertebrate groups include some of the most colourful beetles, flies, bees, wasps, sawflies and moths. The term saproxylic is used to describe insects that depend upon decaying wood for part of their life cycle.

Oak Polypore feasting on the heartwood of an oak tree. This fungi will slowly breakdown the wood forming a hollow - in important micro-habitat for other species (c) Vavrin_CC_BY_SA_3.0

Larvae of beetles such as the Stag beetle (Lucanus cervus) find nourishment from decaying wood with many species growing slowly over a number of years. Adults beetles tend to live long enough to find a mate and breed. During their short adult lives they may be found visiting sugary sources for food such as tree sap runs or Hawthorn flowers which are a key pollen and nectar source for many saproxylic insects.

Stag Beetle (c) Ben Andrew                                                                              Stag Beetle Larvae (c) Dr David Chesmore

Micro-habitats such as water-filled trees holes, also known as rot holes, are ideal places for some hoverfly species to lay their eggs. The larva of the Western wood-vase hoverfly (Myoleta potens), known as a rat-tailed maggot, feeds on leaf litter in rot holes until it pupates and emerges as an adult.

Western Wood-vase Hoverfly (c) Will George                                       Rot Hole in tree (C) Andy Godfrey

The Oak polypore (Buglossoporus quercinus) is an example of a bracket fungus which feeds on the heartwood of Oak trees which in turn, forms tree hollows releasing minerals to provide the tree with recycled nutrients to helping it to live longer. These cavities provide a safe space for nesting birds or potential roost sites for tree loving bats such as the Barbastelle bat (Barbastellus barbastellus) which will also breed and hibernate under loose, lifted bark or in natural cracks. Tree hollows become the perfect environment for invertebrates to feast on fungi leftovers. For example, the Violet click beetle (Limoniscus violaceus) dwells low within the hollows of Ash and Beech trees feeding on wood mould enriched with faeces and other remains which can take an astonishing 100 years to accumulate.

Let’s not forget there are plants that live on the surface of ancient and veteran trees such as mosses and lichens. The Knothole moss (Anacamptodon splachnoides) and Pox lichen (Pyrenula nitida) can be found on the smooth bark of ancient Beech trees where rainwater trickles down.

Knothole Moss (c) Steven Heathcote                                                         Pox Lichen

I have mentioned only but a few of some of our very rare and special wood-inhabiting species that thrive in and around an ancient tree. It really is fascinating woody world with great species richness. Next time you are passing an old tree why not stop and see if you can spot some of these features?


Ancient tree poster - download available!

Most people are unaware of the fascinating diversity of life that abounds ancient trees. They are home to some of our rarest wildlife; particularly those that rely upon decaying wood and aged bark. That is why we decided to partner up with illustrator Alexia Tucker to design a poster that celebrates life in and around an ancient tree!

The poster highlights some of the extraordinary wood dwelling species the project has been working to protect and the parts of a tree they make their home. This informative learning resource is available as an A3 download on our main Ancients of the Future page or by using the above link, so please print off and celebrate with us!


Hayley Herridge

Ancients of the Future - Outreach Officer


Would you like to help these incredible species? There are numerous ways in which you can:

  • Why not volunteer for Back from the Brink? Check out our events page for opportunities near you.
  • Help us to spread the word of this species, and the others we will be helping over the next 3 years, by sharing our message across our Twitter, Facebook, Instagram and YouTube pages. Follow us: @naturebftb.
  • Finally - help support the work we do across England by donating. Our impact will be greater with your help.