I’ve put an R package on my Github which has functions for a load of different competition indices designed for forest tree-tree competition, which I’ve harvested from the academic literature. A lot of these competition indices come from older papers, as times have moved on and this isn’t such a popular field of research anymore, but with more and more emphasis being put on long-term forest plot monitoring infrastructure to track biodiversity, productivity, and reaction to climate change, I think it might be time for a revival. In the package repository you can find the package manual and a vignette which describes the behaviour of some of the indices.