L o a d i n g
group
2.2 m3
at 3.5 m
48.2ºN
[knocked] tree
wood
excavating
rough
invertebrates
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
[knocked] tree
group
2.2 m3
at 3.5 m
48.2ºN
wood
excavating
rough
invertebrates
Austria
Vienna, Prater
48.2089°N, 16.4103°E
28/05/2025, 1:17pm
Provided by Paula Jana Peters and Wera Witek
During the survey, a fallen tree was found, likely damaged by a storm. Closer inspection revealed an ichneumon wasp (Ichneumonidae) active around the stump. Common in Austria’s forests, meadows, and dead wood, females use their long ovipositor to lay eggs in beetle or moth larvae. The young feed on the host, regulating insect populations. Despite their fearsome appearance, these wasps are harmless to humans and vital to ecosystems.
The found tree creates a varied microclimate: shaded cracks retain moisture, while exposed wood stays warm and dry. This attracts fungi and host insects such as beetle larvae, which in turn provide breeding sites for ichneumon wasps. Suspended above the ground, the trunk decomposes more slowly, offering long-lasting shelter and diverse niches for forest species.
This fallen, storm-damaged tree lied splintered and decaying in the prater park, offering ideal habitat for insects and fungi. Such dead wood attracts ichneumon wasps and other insects. While birds like woodpeckers feed on these insects, the wasps help regulate their populations, showing how dead trees sustain complex forest interactions.
The Green Prater in Viennas 2nd district is a diverse natural area with meadows, wetlands, and old floodplain forests. It provides habitat for numerous species, including birds, amphibians, reptiles, and mammals like deer, foxes, and squirrels. Its mix of water, trees, and open space makes it a vital refuge for urban wildlife and a peaceful escape for visitors.
The fallen tree is supported by the surrounding trees. After breaking, the trunk did not collapse fully to the ground but instead became wedged and suspended in the canopy, resting diagonally against neighboring trees and branches. This creates a kind of natural support structure, keeping the trunk elevated. Such suspended deadwood is ecologically valuable because it provides perches, shelter, and habitats for birds, insects, and fungi while decomposing more slowly than wood lying directly on the forest floor.
