1. A machine-implemented method for performing a paging operation on a tree having a plurality of nodes, comprising: maintaining, in a machine-readable medium, for each node of said plurality of nodes of said tree, a preorder number and a subtree size, wherein the preorder number associated with a particular node of said tree identifies a position for said particular node in a depth-first search ordering of said plurality of nodes of said tree, and wherein the subtree size associated with said particular node identifies a count of all the nodes of a subtree rooted at said particular node; and in response to receiving a request to perform said paging operation on said plurality of nodes of said tree, determining a set of nodes that satisfy said paging operation using the preorder number and the subtree size of at least one node of said plurality of nodes of said tree.