In the present work, the BETA function was used to adjust the tree circumference distribution, measured at 1.30m of the soil, in all forest types identified in the forest inventory of Rio Grande do Sul. The parameters of the function were estimated by the BETKLA program, in FORTRAN, according to ZOEHRER (1970). The BETA function underestimated the frequencies of CPAs at both ends of the distribution, in all forest types.
