Fog plays an important role in the plant water relations and the hydrology of forest ecosystems in various regions of the world where fog is frequent. Previous studies found that both evergreen trees and understory seedlings in the karst forest of Xishuangbanna used significant amount of fog water as their primary water sources in the dry season. However, there is still a lack of information on the fog water use by other functional groups, notably lianas and deciduous trees.
   Dr. FU Peili and his teachers of Xishuangbanna Tropical Botanical Garden (XTBG) used the stable isotope content of xylem water to compare the dry season water source partition between soil and fog water of lianas, evergreen trees, deciduous trees and understory seedlings in the Xishuangbanna karst forest, about 3 km from XTBG (21°55′39″ N, 101°15′46″ E) in southern Yunnan, China.
   They found that there were no significant differences for both soil gravimetric water content and soil volumetric water content among different depths in the dry season. The isotopic ratios of fog water were consistently higher than those of rainwater, soil water and xylem water samples. The xylem water isotopic ratios of all the studied plant species were closer to the average isotopic ratios of soil water than that of the fog water.
   The results showed that the lianas, evergreen trees, deciduous trees and understory seedlings in the Xishuangbanna karst forest used fog water for transpiration during the dry season. Lianas used more fog water than tree species. Deciduous trees could use more fog water than the evergreen trees at the beginning of dry season when they maintained leaves. Leaves of all the studied plant species had a potential to absorb fog water. All in all, the study showed that fog water was an important supplement for the dry season water use of plant species in the tropical karst forest of Xishuangbanna.
   The study entitled “Is fog an important water source for woody plants in an Asian tropical karst forest during dry season” has been published online in Ecohydrology.

Contact
FU Peili Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: fpl@xtbg.org.cn
Tel: 86 691 8713225