  Let T be a weighted tree with n numbered leaves and let D be its distance
matrix, so D(i,j) is the distance between the leaves i and j. If m is an
integer between 2 and n, we prove a tropical formula to compute the
m-dissimilarity map of T (i.e. the weights of the subtrees of T with m leaves),
given D. For m equal to 3, we present a tropical description of the set of
m-dissimilarity maps of trees. For m equal to 4, a partial result is given.
