espiration amount of Quercus liaotutungensis, a dominant species in Q. liaotungensis com-munity located in Beijing,was studied in the present paper. The method and technigue ofmeasuring the respiration rate of organs of trees by using a CO_2 gas analyzer were noted insome details,and two basic formulae for woody organs,diameter frequency distribution func-tion and the relation of the respiration rate to its diameter, were given. Baded on these twoformulae, the authors built an equation for the calculation ...