| Based on the data of literature,material and sample plots survey,this paper made a multi-functional evaluation and management of evergreen broad-leaved secondary forest by qualitative and quantitative methods,model simulation,deductive deduction and long-term observation.According to the sample plots survey data,succession stage was divided,at the same time,the characteristics of stand structure in different succession stages were also analyzed.Furthermore,the socio-economic status of the study area was collected to obtain the multi-functional requirements of evergreen broad-leaved secondary forest,and the coupling mechanism model of forest structure and function was constructed.Moreover,the structure and function of evergreen broad-leaved secondary forest in different successional stages was evaluated and compared.The multi-functional management model of evergreen broad-leaved secondary forest was put forward,which was of great significance to the management of evergreen broad-leaved forest in this area,conducive to the reconstruction and restoration of regional evergreen broad-leaved forest,and the change from forest classification management to multi-functional management.It would also promote the forest three major benefits of society,economy,ecology to the greatest realization.The study draws the following main conclusions:(1)In this study,the qualitative and quantitative methods were used to as the main factor,to divide the plots into three successional stages.The successional pioneer stage:the stand volume?150 m3/hm2;transitional stage:150 m3/hm2<volume<300 m3/hm2;sub-top stage:volume>300 m3/hm2.(2)In this paper,the stand structure in different successional stages was analyzed,and the results showed that there was a significantly positive correlation in the pioneer stage community,the transitional stage community was non-significantly negative correlation,and the sub-top stage community had non-significantly negative correlation.The Weibull function could be used to fit the diameter distribution,and the proportion of mature forest and the proportion of large diameter forest were gradually increased.The volume proportion of small(6?18 cm),medium(20?32 cm),big(>34 cm)diameter class in pioneer stage was 5:3:2;The volume proportion of small(6?18 cm),medium(20?32 cm),big(>34 cm)diameter class in transition stage was 3:4:3;The volume proportion of small(6?18 cm),medium(20?32 cm),big(>34 cm)diameter class in sub-top stage was 2:3:5;The successional pioneer stage,the transition stage and the sub-top stage were all growth-type communities.The pioneer stage was 2-3 stand storey,the transition stage and the sub-top stage were all three forest storey.Tree spatial distribution pattern was reunion distribution in successional pioneer stage,and the transitional stage was the partial reunion distribution.The sub-top stage was close to random distribution.The number of stands in the three successional stages was close to each other,and the mingling degree increased with the progress of succession.The sub-top stage was extremely high mingling.The stands structure was restore while improving soil physical and chemical properties with succession proceeding.(3)The species diversity and natural regeneration status of tree,shrub and herb in different successional stages were compared and analyzed.The results showed that there were no significant differences in the four diversity indices of the different successional stages of the tree layer and herbage.There were significant differences in the Gleason index,the Shannon-Wiener index and the Simpson index in the different successional stages of the shrub layer,and there was no significant difference in the Pielou index.The diversity of shrub layer was the highest in the same succession stage,and there was significant difference with tree layer and herb layer.The diversity of tree layer was higher than that of herb layer.The natural regeneration density was basically able to meet the requirements of evergreen broad-leaved secondary forest.Based on the entropy method,the evaluation index system of evergreen broad-leaved secondary forest was constructed from three aspects:distribution status,growth status and age condition.The natural update status was better,and there was no significant difference in the comprehensive value of different successional stages.(4)The functional requirements of evergreen broad-leaved forest were studied,and the functional requirements of wood production,water conservation,soil and water conservation,species diversity protection and scenic recreation were determined.The average DBH(X1),the average tree height(X2),the volume(X3),stand density(X4),stand mingling degree(X5),soil porosity(X6),tree Shonnon-Wiener index(X7),shrub Shonnon-Wiener index(X8),herb Shonnon-Wiener index(X9),the natural regeneration comprehensive value(X10),shrub cover(X11),herbaceous cover(X12),stand age structure(X13),stand vertical structures(X14),a total of 14 structural factors,to construct a structural and functional coupling relationship model.F?=0.124X1+0.144X2+0.188X3+0.036X4+0.198X5+0.225X6+0.153X7+0.100X8+0.051X9+0.061X10+0.063X11-0.043X12+0.168X13+0.170X14The multi-functional values of pioneer successional stage,transition stage and sub-top stage were evaluated by using the coupling model of forest structure and function.The results showed that there were significant differences in the three successional stages,and the multi-functional value increased with succession proceeding.(5)The multi-functional management model of evergreen broad-leaved secondary forest was proposed,and the multi-functional management model of evergreen broad-leaved secondary forest was put forward.For the successional stages of evergreen broad-leaved secondary forest,the specific management target system was put forward,which provided the theoretical basis for the multi-functional management of evergreen broad-leaved secondary forest.(6)The non-linear model of the multi-functional forest of the dominant structural factors was established:F?;=0.30381n(V)-0.9422,the concept of forest multi-functional maturity was put forward.The results showed that the forest reached the multi-functional maturation when the community evolved to the top stage and the stock volume reached 500 m3/hm2. |
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