A method and system for compressing a tree with a plurality of nodes that each may be associated with a node identifier and a parent node identifier. The method may comprise for each node in the tree determining whether the current node is to be deleted, If the current node is to be deleted updating a list of deleted nodes such that the node identifier of the current node may be stored; a parameter representing a number of nodes currently having been deleted from the tree may be stored, such that the parameter is associated with the node identifier of the current node, and updating the node identifier and the parent node identifier of the current node as a function of the list of deleted nodes. Each node in the tree is visited only once.