Abstract: Clarifying the photosynthetic transpiration characteristics of the main landscape tree species in small towns, as well as their capacity in carbon fixation, oxygen release, cooling and humidifying can provide scientific basis for rational allocation of landscape tree species and the quantification of their ecological and environmental benefits. We measured photosynthetic characteristics of 19 main landscape tree species in the public spaces of Zhongyuan HuaduFragrant Town of Yingzhou District, Balihe Tourist Town of Yingshang County, and Maji Hair Art Town of Taihe County in Fuyang City along the Huaihe River in Anhui Province by LI-6400XT portable photosynthesis system, and analyzed their carbon sequestration and oxygen release as well as cooling and humidifying efficiency. The results showed that: (1) Except for Photinia serratifolia and Camellia japonica, carbon sequestration, oxygen release and cooling and humidifying capacities per unit leaf area of all the tree species in each season were in the order of summer > spring > autumn. (2) Carbon sequestration and humidifying of tree species were significantly correlated with net photosynthetic rate, transpiration rate, and stomatal conductance. (3) From the perspective of the photosynthesis and transpiration efficiency, we evaluated carbon fixation, oxygen release, humidifying and cooling capabilities of the tree species with the principal component analysis. They followed the order of Platanus acerifolia > Rosa chinensis > Hibiscus syriacus > Salix babylonica > Prunus cerasifera > Malus halliana  > Cinnamomum camphora  > Pyracantha fortuneana > Celtis sinensis > Viburnum odoratissimum > P. serratifolia > Chimonanthus praecox > Cerasus serrulata > Osmanthus fragrans > Buxus megistophylla > Magnolia grandiflora > Michelia denudata > Ginkgo biloba > C. japonica. Therefore, in the disposition of landscape tree species in small towns along the Huaihe River in Anhui Province, the tree species with higher ability of carbon fixation, oxygen release and humidifying and cooling can be selected. The preferred arbor species are P. acerifolia, S. babylonica, P. cerasifera andC. camphora, and the shrub species are R. chinensis, H. syriacus, M. halliana, P. fortuneana and V. odoratissimum.

Key words: regions along Huaihe River in Anhui Province, landscape tree species, carbon sequestration and oxygen release, cooling and humidification.