Balance metric (in the case of a binary tree), which measures the sum across all internal nodes of one over the maximum depth of all attached tips to that node. Although also defined on non-binary trees, the treestats package only provides code for binary trees.
b1(phy, normalization = "none")
B1 statistic
phylo object or ltable
"none" or "tips", in which case the resulting statistic is divided by the number of tips in the tree, as a crude way of normalization.
K.-T. Shao and R. R. Sokal. Tree Balance. Systematic Zoology, 39(3):266, 1990. doi: 10.2307/2992186.