Measurement of respiration amount of white birch(Betula platyphylla) population in the mountainousregion of Beijing

Measurement of forest community respiration is very important for clarifying the processes of mat-ter cycle in forest ecosystem. Measurement of respiration of white birch (Betula platyphylla) population inthe mountainous region of Beijing was reported herein and its results showed that the diameter frequency dis-tribution of the woody orgaris was fitted by a power equation and the respiration rates of the organs decreasedwith their increasing diameter. These formulae to calculate the total respiration amount of every organ for anindividual were introduced and those corresponding parameters were given. The quantitative relationship toestimate population respiration amount from three size was proposed. Using the ahave relationships, the an-nual respiration amount of white birch population was estimated to be 10. 8t CO_2/ha/a , of which stem , root ,branch and leaf were 1. 4 , 2. 0 , 2. 8 and 4. 7 tCO_2/ha/a, respectively.