Mathematica software for modeling long-term tree growth curves indirectly, when tree ages are unknown

The Mathematica notebook "Long-term growth curves of trees with unknown ages (Ricker Nov 2025).nb" carries out all calculations that are developed in the article "Modeling long-term tree growth curves indirectly with piecewise linear regression and explaining factors, when tree ages are unknown", by Ricker et al. (2025) in "Environmental and Ecological Statistics". The two Excel files are two different input files. Please see the instruction file for details of how to use the notebook. For just inspecting the code, without the Mathematica software, the notebook and output files are provided as PDF files.