Population Structure And Dynamic Characteristics Of Quercus Mongolica In Secondary Forest In Montane Region Of Eastern Liaoning Province,China

Based on the 1hm~2 monitoring sample plots of Quercus mongolica(QM)forest in montane region of eastern Liaoning province,this study explored the spatial pattern and association of different development stages of QM population,the spatial pattern of dominant tree species and their spatial association to QM seedlings,the factors affecting the survival and increase of QM seedlings,combined with the data of habitat and biological factors.According to the survey data of woody plants in 2018 and QM seedlings from 2019 to 2021,using the spatial point pattern analysis based on different null models,to provide a scientific basis for improving the regeneration and restoration of QM seedlings in this region.The main conclusions are as follows:The results of spatial pattern and spatial correlation of QM population at different developmental stages showed that the proportion of seedlings of QM in the sample plot is the largest.The seedling reserve is sufficient,the number of young trees is the least,and there is a bottleneck phenomenon.Affected by seed diffusion and habitat heterogeneity,QM seedlings,young trees and adult trees all showed the aggregated distribution pattern,and the aggregation intensity decreased with the increase of spatial scale,based on the complete spatial randomness null model.The young trees,adult trees and seedlings of QM showed a positive correlation in the whole research scale.Based on the heterogeneous Poisson process null model,the whole QM population showed uniform and random distribution.There was a negative correlation between adult trees and seedlings on a large scale,and no correlation between young trees and seedlings on the whole research scale.A total of 33 woody plants with DBH≥1cm were recorded during the investigation,and the diameter class distribution is an approximate inverse"J"curve.The spatial pattern of dominant tree species and their spatial association to QM seedlings showed that most of the eight dominant tree species showed aggregated distribution pattern on small scale and random distribution on large scale.After excluding habitat heterogeneity,except Acer pseudo-sieboldianum showed uniform distribution on a small scale,other dominant tree species showed random distribution on the whole research scale.Under CSR and HPP null models,the spatial association of dominant tree species relative to QM seedlings was mainly negative correlation and non-correlation,and this negative correlation was also reflected in the small scale.The results of influencing factors of survival and recruitment of QM seedlings showed that the habitat condition was the decisive factor for the survival and recruitment of QM seedlings,The survival of QM seedling was mainly affected by seedling height,light conditions and topographic factors.Which was significantly positive correlated with seedling height and canopy openness,and significantly negative correlated with altitude.The recruitment of QM seedlings was mainly affected by topographic factors and soil nutrients,which was significant positively correlated with slope,extremely significantly negative correlated with soil principal component 1(p H,Total nitrogen,Total phosphorus,Organic matter,Available nitrogen),and significantly negative correlated with altitude.