The study analyzed carbon isotope compositions of plant leaves in a mountainous area in Guizhou, China. They found that the average foliar δ13C was -28.14‰, lower than in other areas in China. Different plant species showed varying δ13C values, with Pterdium aquilinum var. latiusculum having higher values than others. Young leaves had higher δ13C values than mature ones. δ13C values increased with altitude.