Abstract: In order to understand the plant population growth status and community structure characteristics of natural deciduous broadleaved forests in Xiaolongshan region of western Qinling and to solve the selection issue of tree species in forest management, an investigation by the method of typical sampling was conducted on the deciduous broadleaved forest dominated by Quercus aliena var. acuteserrata from June to September 2009. The distributions of the tree species in this forest were investigated on small quadrat scale (10 m×10 m), the importance values of the tree species were calculated, and the interspecific associations among the 666 speciespairs of 37 tree species were quantitatively studied by 2×2 contingency table, variance ratio VR, Jaccard index, and χ² test. In the forest studied, Q. aliena var. acuteserrata had the highest importance value, while the others were the associated tree species. Overall, the 37 tree species showed positive associations, and the associations reached significant level. The χ² test showed there were 7 tree species pairs (1.05% of the total) presenting very significant association, 19 tree species pairs (2.85% of the total) presenting significant association, and 640 pairs (96.10% of the total) presenting no or insignificant association. In combining with the AC value, there were 5 pairs showing significant positive association, and 2 pairs showing significant negative association. The community was in a relatively stable stage of secondary succession. This study could provide guidance for the management of natural secondary forest and the selection of afforestation species.

Key words: Amygdalus communis, phenophase, meteorological conditions, correlation analysis, flowering forecast model.