Monoculture rubber plantations and primary tropical forests are highly variable in physiological traits related to the water balance. Therefore, the change in canopy temperature in relation to the responses of the two communities to expected climate change might also be variable.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) evaluated canopy temperature in a rubber plantation and tropical rainforest in Xishuangbanna, southwestern China. An infrared temperature sensor was installed at each site to measure canopy temperature.
The results showed constant difference between the two forests, with the rubber plantation having a higher (canopy temperature – air temperature) than the tropical forest throughout the whole year. The greater heating of canopy leaves in rubber plantation is likely the result of general low canopy stomatal conductance, leading to low transpirative cooling.
Plants under soil water deficit decrease stomatal conductance, thereby reducing transpiration and increasing leaf temperature.
The reduction in transpiration in the dominant canopy trees during the dry season (with high evaporative demand) could partly explain the increase of canopy to air temperature difference.
The study entitled “Comparison of infrared canopy temperature in a rubber plantation and tropical rain forest” has been published online in International Journal of Biometeorology.
ZHANG Yiping Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China