Abstract: The concept of nutrient use efficiency (NUE) plays an important role in the study of nutrient cycling. To reveal the nutrient use strategy, NUE of several trees in Tiantong National Forest Park were studied in this paper, focusing on the difference of the NUEbetween different life forms. The result showed that there was a significant positive correlation between NUE_N and NUE_P in evergreen broad leaved species, but not in deciduous species. Meanwhile, all plants have a positive correlation between NUE_N and NUE_P . In addition, there was an obvious difference in NUE_N among different life forms, conifer species> evengreen broad leaved species > deciduous species. Finally, the authors agreed that plants had the highest NUE when their habitat's productivity was the lowest. It indicated that these plants can use available nutrients effectively to produce more biomass when there is a deficiency in nutrient availability.

Key words: Cinnamic acids, Allelopathy, Photosynthetic rate, Cucumis sativus, Transpiration rate, Root activity