Resistant Clustering via Chopping Up Mutual Reachability Minimum Spanning Trees R package lumbermark version 0.9.0 Implements a fast and resistant divisive clustering algorithm which identifies a specified number of clusters: 'lumbermark' iteratively chops off sizeable limbs that are joined by protruding segments of a dataset's mutual reachability minimum spanning tree; see Gagolewski (2026) <https://lumbermark.gagolewski.com/>. The use of a mutual reachability distance pulls peripheral points farther away from each other. When combined with the 'deadwood' package, it can act as an outlier detector. The 'Python' version of 'lumbermark' is available via 'PyPI'. Software Imports: Rcpp, deadwood LinkingTo: Rcpp Suggests: datasets, Marek Gagolewski <marek@gagolewski.com> Comprehensive R Archive Network (CRAN) Marek Gagolewski [aut, cre, cph] (ORCID: <https://orcid.org/0000-0003-0637-6028>) AGPL-3 2026-03-16 application/tgz https://CRAN.R-project.org/package=lumbermark doi:10.32614/CRAN.package.lumbermark