Tree Comparisons

Seeing gene trees within species trees, where one tree is within another
annotating nodes with 'events', gene duplications, etc
two trees, mapping nodes in one onto nodes in another
visualizing tree space, including sampled and non-sampled trees
Tree set viz as a means of communicating uncertainty of trees provided by iPlant
Tree set viz + recognition of clusters + viz comparison between clusters (a la Tree Juxtaposer)
Co-evolution and tanglegrams - can we use some sort of matrix representation for this with the trees on x and y axes
GMap, Geographic maps of tree sets

Can we minimally compute (and display) a consensus tree for a set of large input trees

challenges of scale - what if you have thousands of input trees?