The inhabitants of Sihlwald
Where rare beetles, ancient beeches and vanished lichens are at home
From the abraeus parvulus beetle to the ancient copper beech – if you look closely in the Sihlwald, you will discover a hidden coexistence. The wildness of the Sihlwald is quite unique in the Swiss Plateau.
The Sihlwald has been allowed to develop freely for 25 years and has since become a refuge for many species that can hardly find habitats elsewhere. These include those that remain hidden at first glance, but which make the Sihlwald so special.
Tiny little wonders
If you stroll through the Sihlwald, you will immediately notice the many fallen tree trunks and moss-covered stumps. What at first glance looks dilapidated turns out on closer inspection to be a valuable habitat full of tiny sensations. A prime example: the abraeus parvulus beetle. Just one millimeter in size, it lives in old, decaying tree ruins near ant nests. The beetle is a so-called primeval forest relict and only occurs in forests with a natural life cycle of old and dead trees. The fact that it was found in the Sihlwald in 2016 shows how valuable undisturbed forest development is.
Mushroom-covered beech trees serve as a habitat for the little ones
Another rarer inhabitant is the bolitophagus reticulatus beetle, which was only discovered in Sihlwald in June 2024 – a first for the canton of Zurich. It is also tiny, measuring just six to seven millimetres, and lives on the tinder fungus. This type of fungus only thrives where dead and weakened deciduous trees are not removed from the forest. Tinder fungi are mostly found on beech trees. There are many of these in the Sihlwald, which is a typical mixed beech forest. This type of forest used to characterise large parts of Central Europe. Some of the beech trees growing here are so-called giant trees and are several hundred years old.
The Sihlwald as a habitat for rare species
Mosses and lichens can also be found on bark and branches. Some of these are real rarities in the Sihlwald. The lichen Rinodina polyspora, for example, was long thought to be extinct throughout Switzerland until it was rediscovered in the Sihlwald. The pretty orthotrichum pulchellum moss and the bucklandiella heterosticha moss can also be found here; both of which are extremely rare.
The Sihlwald shows: If you leave a forest to its own devices, the result is not stagnation, but diversity. And in addition to the well-known inhabitants – foxes, owls and beech trees – many other, barely visible species also find a home here.
