This function provides a table with a discretized description of the main stem (= segments of branching order 0) with diameter information for different heights (= Stem taper table). In the 90s, there was a program for the Silicon Graphics workstation called GROBOL (growth of boles engine), which could display and analyze the stem using this table (I am only mentioning this here because this software pops up in the sources occasionally, but don't bother searching for it).