| In this article,Pinus tabulaeformis populations with different number of mother trees(45/ha,75/ha,120/ha,195/ha)were maintained for 9 years after main cutting.We attemptted to describe the population stability of Pinus tabulaeformis Plantation after main cutting from the point of population structure and spatial pattern.Based on the difference of population stability of Pinus tabulaeformis plantation after main cutting and the difference of growth condition of individual regeneration after main cutting.This paper could provide reasonable suggestions for the next tending work of the forest farm,and provide scientific support and guidance for promoting natural regeneration of Pinus tabulaeformis.At the same time,it provided theoretical support for forest production and management in similar areas.The main conclusions are as follows:We found that the number of middle-aged Ⅰ-Ⅲ Pinus tabulaeformis individuals in four plots accounted for 88.57%,95.32%,97.61%and 96.63%of the total number ofPinus tabulaeformis individuals respectively.It was inferred that the population of Pinus tabulaeformis after main cutting was growing,which indicated that the whole population structure would maintain a relatively stable state for a long time.Pinus tabulaeformis in age class Ⅰ and Ⅱ in plot A,B,C and D were aggregated at the scale of 0-30m.Pinus tabulaeformis in age class Ⅳ-Ⅵ of plot A,plot B,plot C and plot D are aggregated.Individuals of internal age Ⅳ-Ⅵ of Pinus tabulaeformis tend to distribute randomly on the whole scale.Most age classes of Pinus tabulaeformis population in plot A and D showed negative correlation on a certain scale,which indicated that there was fierce competition among Pinus tabulaeformis individuals in plot A and D.Obviously,when the number of regenerated seedlings is too large to occupy the growth space of other Pinus tabulaeformis individuals,the negative correlation between age classes would be obvious.The positive correlation and independent relationship between different age classes in plot B and C all have no or positive correlation.When the number of trees was 75 or 120/ha,the competition pressure between individuals was low,and the spatial distribution of resources was reasonable.After the variance analysis of the number of regenerated seedlings and growth indices of Pinus tabulaeformis after main cutting of different reserved mother trees showed that the number of regenerated seedlings in plot D and C was significantly higher than that in sample plot A and B,and the growth indices of Pinus tabulaeformis in plot C after main cutting were significantly higher than those in other three sample plots.The Pinus tabulaeformis population in plot A,B,C and D were in progress.From the spatial pattern of Pinus tabulaeformis population,we can conclude that the negative correlation between different age classes of Pinus tabulaeformis population in plot A and D was obvious,and the structure of Pinus tabulaeformis population in plot B and C was bettter.From the point of view of the quantity and growth characteristics of the regenerated seedlings of Pinus tabulaeformis,the structural characteristics of the population and the spatial distribution pattern after the main cutting,it is suggested that the main cutting with 120/ha should be implemented for the Pinus tabulaeformis Plantation under the condition of shady slope and thick soil in the future,so as to ensure the smooth regeneration of the plantation of Pinus tabulaeformis in this area. |
