An apparatus having corresponding methods and computer programs comprises a memory comprising a plurality of locations each to store a node for a binary tree comprising a plurality of the nodes; a classifier to search the tree, wherein the classifier requires one node processing interval to process one of the nodes; and a processor to modify the tree, wherein the processor (a) modifies a pointer that indicates a first one of the nodes to not indicate the first one of the nodes instead, wherein a second one of the nodes is a descendant of the first one of the nodes and is separated from the first one of the nodes by N pointers, (b) waits at least N+1 node processing intervals after (a), and (c) after (b), modifies a pointer that indicates the second one of the nodes to not indicate the second one of the nodes instead.