关键词: 四川大头茶, 年轮, 气候, 滤波, 功率谱, 周期, 氮素运转, 氮素分配, 甜瓜, 氮素吸收利用率

Abstract: With the methods of correlation analysis, stepwise regression, digital filtering and power spectrum, the dynamics of tree ring growth of Gordonia acuminata in Mt. Jinyun was analysed. After the genetic factors of tree growth were filtered by mathematical model, the chronological tables of Qinglongzhai and Xinglufeng were constructed, which showed a significant positive correlation with the precipitation in Chongqing. The mathematical model between tree ring growth and climatic elements was Y=-2.19+0.00747J₁+0.00612J₂+0.00140J₃+0.00384J₄+0.00371J₅+0.00731T₁+0.0564T₅. The power spectrum density was not evenly distributed with wave number,and the power spectrum cycle of tree ring width variation revealsed that the precipitation wave cycle of tree growth environment was about 2, 11～12 and 22 years. The construction and analysis of the chronological table of tree ring was one of the important ways to study the dynamics of ecosystem and the historical change of its environment.

Key words: Gordonia acuminata, Tree ring, Climate, Filter, Power spectrum, Cycle, nitrogen distribution, melon, nitrogen utilization rate, nitrogen transfer