International Collaboration Reveals Nitrogen Fixation in Forest Canopy

09/10/ 2010

Epiphytes are plants growing on tree trunks and branches.  They can capture more light by standing high in forest canopy than growing low on ground.  They can easily obtain water from the moist environment.  However, their growth is most limited by the lacking of nutrients.  Dr. Xiaoming Zou, professor of the Institute for Tropical Ecosystem Studies, collaborated with a research team in the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences.  They studied nitrogen fixation by epiphytic plants in a subtropical moist forest of China.  They reported that epiphytes, together with microorganisms, have the capacity to fix atmospheric nitrogen for themselves and for other trees in the forest.


Epiphytic plants are abundant in the subtropical mountainous cloud forest of the Ailao Mountains in the Yunnan Province, southwestern China. Dr Zou’s team reported that nitrogen-fixing potentials of canopy epiphytes in this forest increased greatly from dry season to wet season and from sub-canopy to top-canopy layers. Epiphytic nitrogen-fixing potentials for the subtropical cloud forest in the Ailao Mountains ranged between 0.027 and 2.24 kg ha−1 year−1. These findings suggest a new nitrogen source for the subtropical forest ecosystem, thus can have profound impact on the studies of nitrogen cycling.


  1. Han, B., X. M. Zou, J. J. Kong, H. D. Gong, Z. Yu, T. Cao, L. Q. Sha.  In press.  Nitrogen fixation of epiphytic plants enwrapping trees in Ailao Mountain cloud forests, Yunnan, China.  Protoplazma, DOI 10.1007/s00709-010-0150-8.