On the structure and patterns of major tree species populations of secondary forests in the montane regions of eastern Liaoning Province

In order to research the main tree species populations of major communities (Quercus stand, hard-broadleaved stand, Populus-Betula stand and the complex stand) of secondary forests in the montane regions of eastern Liaoning Province (MRELP), this paper examined the structure and patterns of the four communities by applying the methods of class size substituting for age size, and the spatial difference substituting for temporal change, respectively.The patterns were analyzed by using three independent methods, ie variance to mean ratio (S²/x), which was tested by t value, the patchness index (M^*/x) and the expanding index (I_δ).Additionally, the clumped or random extents of patterns were analyzed by using the method of the negative binomial parameter (K).The results could be summarized as follows:1) tree species of Q.mongolica, Fraxinus mandshurica, Juglans mandshurica, B.costata and P.davidiana were intermittent populations, which lacked of seedling or sapling or both of them.Among the above, Q.mongolica, F.mandshurica and J.mandshurica were attributed to growing type, while B.costata and P.davidiana were classified into senescent type.However, Acer mono, Tilia amurensis and Ulmus japonica could be attributed to growing and stable population with a reversed J-shaped size structure;2) in MRELP, the patterns of major tree species populations were different, eg B.costata and P.davidiana populations were random in Populus-Betula forest community, while the other populations were clumped;3) among the major tree species populations, the patterns of class size of major populations showed the rule that the seedling and sapling classes were clumped but the middle and the big tree classes were random or uniform.It was found that the patterns of major species populations changed with the time during their development period, the clumped intensity of different populations was gradually reduced from the seedling or sapling to big trees, and the populations were diffusing;4) the formation of the structure and patterns of major tree species populations of secondary forests in MRELP was influenced by the results from long-term interaction between biological features and natural environment as well as their succession period.