The two-parameter lognormal distribution was derived theoretically and proposed as a simple mathematical model to describe the diameter frequency distributions and height ones in even-aged stands. The model was applied to 24 observed diameter frequency distributions and 22 observed height ones. The agreement between the observed and the expected frequencies was tested by the chi-square test. The model achieved a good fit to the diameter and the height frequency distributions except 2 cases out of 24 in the diameter and 4 cases out of 22 in the height. The two-parameter lognormal distribution is very simple,but it may be useful for analyzing the eyen-aged stands.