Research And Evaluation Of Resource Use Efficiency Of Woody Plants In Yantai Coast

Coastal shelterbelt is a comprehensive system of sustainable development, a system withfunctions like protective conservation, ecosystem services and landscaping integreted.However, the present coastal shelterbelt in Yantai area of Shandong province are showingproblems with single tree species, aging and recession of the community, low-productivityand efficiency, fragile ecosystems, etc. At present, researches on coastal shelterbelt are mainlyfocusing on the adaptability of species to the environment, while the studies on the growthpotential and development of the different species under harsh conditions are relatively rare.For this reason, this research investigated the photosynthesis and transpiration, elementcontent, calorific value and other biological and chemical analysis in8woody plants: Tamarixchinensis, Pinus thunbergii, Juniperus chinensis cv kaizuka, Fraxinus chinensis Roxb.,Populus langfanggensis, Robinia hispida L., Robinia pseudoacacia and Amorpha fruticosaLinn in the ZhiFu Forest of Yantai. The results from the8species were compared andanalyzed according to their photosynthetic performance, resource use efficiency and biomasscosts. In addition, the comprehensive growth potential and resistance were calculated andevaluated with the method of membership function in order to provide reference for speciesselection of coastal shelterbelt construction.(1) The photosynthetic performance of different species: T.chinensis, P.thunbergii andP.langfanggensis are heliophiles that have higher light saturation point; F.chinensis andR.hispida can withstand less glare than other species, but these two species have low lightcompensation points and are suitable for moderately shaded environment; J.chinensis,R.pseudoacacia and A.fruticosa’s ability to tolerate high light and low light are between theabove two. Meanwhile, the respiration rate of T.chinensis and P.langfanggensis aresignificantly higher than of other species, which suggests a stronger ability to resist adverseenvironments.(2) The resource use efficiency: In the8species studied, light use efficiency of thescale and conifer leaved species (T.chinensis, P.thunbergii and J.chinensis) were lower thanthe broad-leaved species in the same area. P.langfanggensis and R.pseudoacacia showed thehighest light use ability, and J.chinensis showed the lowest. Especially, J.chinensis exhibited significantly lower ability than all other species. In general, water use efficiency of the scalesand conifer leaved species (T.chinensis, P.thunbergii and J.chinensis) were higher than thebroad-leaved species, but the difference between them was not significant. The photosyntheticnitrogen use efficiency of F.chinensis, A.fruticosa, R.pseudoacacia, R.hispida andP.langfanggensis were significantly higher than of T.chinensis, P.thunbergii and J.chinensis.It was apparent that the growth rate and productivity in5broad-leaves species weresignificantly higher than in the scales and conifer leaved species in the Yantai coastalenvironment. F.chinensis, R.hispida, P.langfanggensis and R.pseudoacacia etc. displayedhigh carbon use efficiency, indicating that they have a high growth potential. Contrarily, alow carbon use efficiency of J.chinensis might lead to a lower growth rate.(3) The calorific value and biomass construction costs: The ash calorific value (AFCV)were higher in A.fruticosa, R.pseudoacacia, R.hispida, P.thunbergii and J.chinensis,F.chinensis than in P.langfanggensis, with T.chinensis being the lowest in terms of AFCVamong the8species studied. From the perspective of the calorific value, it can be consideredthat R.hispida, A.fruticosa and R.pseudoacacia’s ability to adapt to the harsh environment ofthe coast is relatively low. This means that in order to adapt to the environment, they have toconsume more energy to synthesize the protective compounds. T.chinensis, F.chinensis andP.langfanggensis showed strong adaptability to adapt the coastal climate; while the ability ofP.thunbergii and J.chinensis can’t merely be judged by the calorific values in consideration ofthe high content of Resinous substances and lignin. Per unit area of leaf construction costs ofthe8species from low to high is: R.hispida, A.fruticosa, R.pseudoacacia, F.chinensis,P.langfanggensis, T.chinensis, P.thunbergii, J.chinensis, combined with specific leaf areaanalysis, it can be considered that the scales and conifer leaved species such as T.chinensis,J.chinensis and P.thunbergii have relatively low competitiveness and expansion, but theyhave long leaf life and strong ability to resist adverse environmental; R.hispida, A.fruticosaand R.pseudoacacia have higher growth potential, but life spans of their leaves were short, sothe resistance was low; F.chinensis and P. langfanggensis was between the above two in therank, both showed high growth potential, and a moderate resistance to adverse environment.To sum up, the rank of the growth potential in the8species in a descending order is:R.hispida, R.pseudoacacia, F.chinensis, A.fruticosa, P.langfanggensis, T.chinensis,P.thunbergii, J.chinensis; The resistance from high to low in the8species is: T.chinensis, J.chinensis, P.thunbergii, P.langfanggensis, A.fruticosa, R.pseudoacacia, F.chinensis,R.hispida,Overall, the growth potential showed negative correlation to the resistance. SinceP.thunbergii, P.langfanggensis, R.pseudoacacia, F.chinensis and R.hispida are repellent toeach other, T.chinensis, J.chinensis and A.fruticosa are shrubs, coastal shelterbelt of trees thefollowing organization would be optimal with T.chinensis being planted in the forefront as anoffshore plant, J.chinensis as the second layer, P.thunbergii as third layer, P.langfanggensisand R.pseudoacacia as the fourth layer, R.hispida is best planted in the rear of the shelterbeltA.fruticosa planting can be interspersed in the third layer and thereafter, in order to enhancethe resilience of the system.