A crown brace is, as the name suggests, designed to secure and stabilize unstable branches of the tree crown. This is usually done with the help of steel cables in combination with special spring systems to prevent jerky loads from occurring during storms.
The securing should not be completely rigid, as a little movement is good for the stable growth of the tree and the branches.
The crown should be secured especially where falling branches can be dangerous: on roads, pavements, public parks, tree houses, … The installation should in any case be carried out by qualified personnel (arborist, tree climber)!!