title: Leaf phenological characters of main tree species in urban forest of Shenyang.
abstract: BACKGROUND
  Plant leaves, as the main photosynthetic organs and the high energy converters among primary producers in terrestrial ecosystems, have attracted significant research attention. Leaf lifespan is an adaptive characteristic formed by plants to obtain the maximum carbon in the long-term adaption process. It determines important functional and structural characteristics exhibited in the environmental adaptation of plants. However, the leaf lifespan and leaf characteristics of urban forests were not studied up to now.
  
  
  METHODS
  By using statistic, linear regression methods and correlation analysis, leaf phenological characters of main tree species in urban forest of Shenyang were observed for five years to obtain the leafing phenology (including leafing start time, end time, and duration), defoliating phenology (including defoliation start time, end time, and duration), and the leaf lifespan of the main tree species. Moreover, the relationships between temperature and leafing phenology, defoliating phenology, and leaf lifespan were analyzed.
  
  
  RESULTS
  The timing of leafing differed greatly among species. The early leafing species would have relatively early end of leafing; the longer it took to the end of leafing would have a later time of completed leafing. The timing of defoliation among different species varied significantly, the early defoliation species would have relatively longer duration of defoliation. If the mean temperature rise for 1°C in spring, the time of leafing would experience 5 days earlier in spring. If the mean temperature decline for 1°C, the time of defoliation would experience 3 days delay in autumn.
  
  
  CONCLUSIONS
  There is significant correlation between leaf longevity and the time of leafing and defoliation. According to correlation analysis and regression analysis, there is significant correlation between temperature and leafing and defoliation phenology. Early leafing species would have a longer life span and consequently have advantage on carbon accumulation compared with later defoliation species.
authors: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors: Sheng
authors: S
authors: Xu
authors: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors: Wenduo
authors: W
authors: Xu
authors: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors: Wei
authors: W
authors: Chen
authors: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors: Xingyuan
authors: X
authors: He
authors: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors: Yanqing
authors: Y
authors: Huang
authors: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors: Hua
authors: H
authors: Wen
mesh_terms: D000222:Adaptation, Physiological; D002244:Carbon / Q000378:metabolism; D002681:China; D002947:Cities; D016014:Linear Models; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D012621:Seasons; D013045:Species Specificity; D013696:Temperature; D013997:Time Factors; D014197:Trees / Q000254:growth & development / Q000378:metabolism / Q000502:physiology
chemical_list: D002244:Carbon