The estimation of phylogenetic trees for individual genes or multi-locus datasets is a basic part of considerable biological research. In order to enable large trees to be computed, Disjoint Tree Mergers (DTMs) have been developed; these methods operate by dividing the input sequence dataset into disjoint sets, constructing trees on each subset, and then combining the subset trees (using auxiliary information) into a tree on the full dataset. In this talk I will survey the techniques used in DTMs, and evaluate the impact of using DTMs for use with maximum likelihood gene tree estimation and species tree estimation using methods, such as ASTRAL, that address incomplete lineage sorting.