PATRISTICv1.0 is a java program that calculates patristic distances from large trees in a range of file formats and allows graphical and statistical interpretation of distance matrices calculated by other programs.
Reasonably fast method to compute the #patristic #distance between a pair of #species in a large tree http://blog.phytools.org/2015/10/new-reasonably-fast-method-to-compute.html