Header picture deadwood
© Universität Münster
STOP 2
STOP 2

DEAD WOOD MEANS LIFE AND BIODIVERSITY

What we mean by “dead wood” is trees – either standing or lying on the ground – which have died. Dead wood results from several different causes: trees dying of old age, natural disasters such as forest fires or hurricanes, lightning, snow and ice, or other environmental impacts. As you saw at the veteran tree at Stop #1, dead wood is anything but dead. Even after a tree has died, it provides a habitat for beetles, mushrooms and birds, for example. This means that dead wood is an important part of a forest, providing a basis for the existence of many living things.

A habitat for insects

Many insects depend on dead wood in certain phases of decay and decomposition. Ants and butterflies find their habitat here, for example. Many of our species of wasps and bees also need old wood and dead wood for their survival. Wasps, for example, use wood as material for building their nests, and many bees live or hibernate in dead tree trunks.

Many types of beetle live on wood in various stages of decay. Here in this garden you can find the wasp beetle (Clytus arietis), the black-headed cardinal beetle (Pyrochroa coccinea) and the spotted longhorn (Rutpela maculate). Also, dead wood provides a winter home for a whole range of beetles – including many ladybirds, for example.

  • Wasp beetle

    Wasp beetle
    © Robert Matzke

    • Has a striking yellow and black colouring
    • Can attain a body length of between 7 and 14 millimetres – which is approximately the diameter of a one-cent coin
    • Belongs to the family of longhorn beetles (Cerambycidae)
    • It is the most commonly found member of its species in Central Europe
    • It gets the name “wasp beetle” – Predators find it difficult to tell the wasp beetle apart from real wasps and so they leave it alone
    • This sort of camouflage is called mimicry. This occurs in some creatures when they imitate others in order to deceive their enemies or to attract prey

  • Black-headed cardinal beetle

    Cardinal beetle
    © Robert Matzke

    • The wing covers and the pronotum are bright red, while the rest of the body is a deep black
    • It grows to a length of 14 to 18 millimetres
    • Has a broad, flat body
    • Can be found especially on blossoms and on dead wood
    • The fully-grown beetle feeds on tree sap, nectar and the honey dew of aphids (greenfly)
    • The larvae live off other insects and these insects’ larvae

  • Spotted longhorn

    Spotted longhorn
    © Robert Matzke

    • It is black with yellow wings which have black markings at the front and, towards the end of the body, broad black crosswise stripes. Its antennae are ringed black and yellow
    • It grows to a length of 14 to 20 millimetres
    • Can often be seen sitting on umbellifers
    • They feed on nectar, as well as on pollen and stamens
    • The larvae delve deep into old trees that are rotting
    • By rubbing its back legs against its wing covers, the beetle is able to produce chirping sounds

Drawing callus formation on a tree trunk
Callus formation on a tree trunk
© Robert Matzke

Injuries

Take a close look at the trunk of the copper beech. Do you notice anything strange? The so-called tree-wound tissue can be seen quite clearly. Any idea what might have occurred here? About 20 years ago, a thick branch was sawn off. During the healing process, the copper beech sealed off this wound on the outside by means of this callus, the wound tissue. This process to protect against infection is very similar to the way scabs are formed in humans.

  • WHAT'S THE ANSWER?

    1. Which animals and insects do you know of which use “mimicry”?

    2. How many species of animals and plants are dependent on dead wood for their habitat and as a source of food?

  • SOLVING

    1. Many living things camouflage themselves or imitate others in order to deceive their enemies or attract prey.
    Here are some examples:

    • The bush cricket looks like a leaf, which means it can make itself invisible to its enemies.
    • Frogfishes have a small piece of skin on their dorsal fin which wriggles back and forth, imitating a worm or a small fish. This enables the frogfish to attract prey towards its mouth when it then pounces extremely quickly.
    • With its black and yellow colouring, the harmless hoverfly looks like a wasp and is therefore avoided by predators.
    • Caterpillars and butterflies often have large markings on their wings which, from a distance, look like eyes. This deters birds, for example, which assume they’re seeing a different – and larger – animal.

    2. Over 6,000 species! These include around 1,200 beetles and 2,500 mushrooms.