COMMENT ON FUNCTION phylonode_depth(INT) IS 'returns as a FLOAT the
depth of the node with a particular phylonode_id - depth is defined as
the sum of distances from the node to the root';

COMMENT ON FUNCTION phylonode_height(INT) IS 'returns as a FLOAT the
height of the node with a particular phylonode_id - height is defined as
the maximum total distance from the node to the leaves';

