Study on Intraspecific and Interspecific Competition of Mixed Plantation of Cyclocarya paliurua (Batal.) Ilinsk and Chinese fir

Using Hegyi′s competition index model of single tree,the intraspecific and interspecific competition intensity is quantitatively analyzed.The result shows: the intraspecific ,interspecific,entire stands competition intensity of objective tree Cyclocarya paliurua (Batal.)Ilinsk decreases with increase in diameter class and the intraspecific competition intensity is more intensive than interspecific competition intensity; The relation between competion intensity and individul size of objective tree in diameter class closely follow equation CI=AD~\{-B\}.When diameter size of objective tree≥26 cm,change of competition intensity is feeble.The study provides quantitative index for cultivation of mixed plantation.