These files are R codes and data files used for calculating competition model parameters of tree species in tropical forest community. Paper Takashi S. Kohyama, Nanako Shigesada, Kokichi Kawasaki, Matthew D. Potts, Zamah S. Nur Hajar, Tetsuo I. Kohyama, and Douglas Sheil (2025) A simple competition model can predict rainforest tree diversity, species abundance and ecosystem functions, Journal of Ecology, 113, 842–855. DOI:10.1111/1365-2745.14485 Contents The provided dataset of tropical forest plot is a processed subset of the original dataset used in the model parameterisation for tree populations as demonstrated in our paper. Readers interested in using the original Pasoh 50-hectar plot data for purposes other than reviewing our analysis are advised to contact the Forest Research Institute Malaysia (FRIM) and the Center for Tropical Forest Science-Forest Global Earth Observatory (CTFS-Forest GEO), Smithsonian Tropical Research Institute. R codes employ 1-ha for subplot size and local species populations ≥ 10 trees per subplot for model parameter estimation (as baseline setting). One easily change subplot size and/or minimum tree density for local population selection. skt.r - Main R code for estimating species parameters and predicting a stable equilibrium solution in the competition model. functions.r - R code defining some functions for calculating turnover rates. data/pfr_sub_100by100.csv.gz - Processed subset of Pasoh 50-ha plot data, Peninsular Malaysia, for ca. 1990 and ca. 2000 censuses. species - species ID, integer subplot - subplot ID assigned by dividing the entire area into 100m x 100m, integer dbh1 - stem diameter (cm) in 1990, numeric dbh2 - stem diameter (cm) in 2000, numeric t - inter-census duration (year), numeric License The data files are licensed under the Creative Commons Attribution 4.0 International License, and the R codes are licensed under the MIT License.