A system includes determination of a first tree comprising a first hierarchy of nodes and a second tree comprising a second hierarchy of nodes, determination of first subtrees of the first tree which are identical to first subtrees of the second tree, generation of a first mapping between nodes of the first subtrees of the first tree and nodes of the first subtrees of the second tree, generation of a first feature vector for each of second subtrees of the first tree, insertion of the first feature vectors into an index structure, generation of a second feature vector for each of second subtrees of the second tree, and generation of a second mapping between nodes of second subtrees of the first tree and nodes of the second subtrees of the second tree based on the second feature vectors and the index structure.