| This paper applies the theory of structured forest management to a study of Quercus variabilis secondary forests in the Feniu Mountain area of Western Henan.An analysis of community structure characteristics and stand structure characteristics in 25-,35-,55-and 85-year-old uneven-aged forests and 55-year-old even-aged forests(T1,T2 and T3)under different nursing measures,and based on the results of the analysis,recommendations are made for different management measures to optimize forest stands.This paper aims to comprehensively understand the current status of the secondary forest stands of Quercus variabilis and provide scientific basis and suggestions for its sustainable management.The main findings are as follows.(1)In the tree layer of uneven-aged forest,a total of 29 genera and 37 species of trees in 19 families,27 genera and 31 species of shrubs in 20 families,and 47 genera and 47 species of herbs in 28 families were surveyed.Of the four forest stands.The diversity of species in tree layer,shrubs layer and herbal layer increased with the age of the forest stands.(2)The diameter structure of the four stands of uneven-aged forest was inverted J-shaped;the q-values of uneven-aged forest ranged from 1.1 to 1.7.The older the age the smaller the q-value.Tree heights were not clearly differentiated except for 35-year-old stands with a bimodal distribution.The age of the stand decreases the proportion of accumulation of small-diameter dominant species..In uneven-aged forests,the number of species in each canopy increased with age,the density of lower stands increased,and the density of middle stands decreased.Diseased wood was present in all stands,while dead wood was present only in 55-and 85-year-old stands.Natural regeneration was all good in uneven-aged forest,with the highest number of Quercus variabilis regeneration plants.(3)The 25-,35-,and 55-year-old stands were randomly distributed and the 85-year-old stands were clustered;the average of the four stands' neighborhood comparison ranged from 0.478 to 0.516,and the average neighborhood comparison of the associated species were greater than the average neighborhood comparison of the dominant species;25-year-old forest stands had the lowest mingling and 85-year-old stands had the highest mingling.(4)A total of one species from one family and one genus in the tree layer,seven species from six families and seven genera in the shrub layer,and 27 species from 18 families and 27 genera in the herb layer of the even-aged forest were surveyed;the diversity in the shrub layer and herb layer was the lowest in sample plot T1.(5)Minimal stand density and maximum mean diameter at breast height in T1 sample plot of the even-aged forest,and the diameter distribution of the three sample plots were all single-peak normal distribution.The average tree height was highest in sample plot T1,and all three standard sites showed a single-peak asymmetrical mountainous height distribution.The proportion of medium-diameter wood accumulation was highest in sample plot T2 and T3,while the proportion of large-diameter wood accumulation was highest in sample plot T1.The canopies of the same age forest standards were all sigle layer structure.Natural regeneration was good in each sample plot,with the highest number of Quercus variabilis regeneration plants.(6)Sample plot T1 was randomly distributed,T2 were distributed in clusters,and T3 was evenly distributed.The neighborhood comparison in 3 sample plots ranged from 0.482 to 0.556,in which the forest differentiation was more pronounced in sample plot T1. |
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