Wood mould boxes
Old oaks with cavities have a rich fauna bound to them. It is inside the cavity and in the compost that is created in the bottom, called wood mould, that most species live. The wood mould is made of wood fragments and fungal mycelium but can also contain leaves and bird nest residues or residues from bats and other animals living in the cavities. In a lot of areas with oaks that are several hundred years old, where we can find rare beetles and other species living in the cavities, there is usually a big gap in age between the generation of really old oaks and the next generation oaks. It may also be a gap in distance between areas with old oaks which is threatening the survival for the species living in the cavities in such oaks.
Research has shown that it is possible to create artificial environments that work for a big part of the species bound to tree cavities. They are called wood mould boxes and look like big bird houses filled up 75 % with mainly saw dust and oak leaves, which partially are moisturized with water. The wood mould boxes have been placed in trees and are big enough to hold 70 and 200 liters. During this project a larger model will be built that can hold 1000 liters. The larger model will be placed on the ground next to a tree and anchored to the tree with elastic straps. Most of them will be built so that birds can be able to nest in the top part of the wood mould box and some will be built so that bats can nest in the top part.