| Most of the artificial forests in the central and southern region of Shandong province belong to pure stands with the same age.However,the forest productivity in ecology and economic are generally too lower to meet the production needs due to the defective cultivation measures and unscientific management system for the large-scale afforestation.In this study,Platycladus orientalis plantation in Shandong province was selected as the researching object based on the model of sustainable forest management.The management theory of near-natural forest was applied to propose the corresponding forest processing measures according to the phased characteristics of stands growth and development.Hence,the sustainable forest tending plans in the60-year-old P.orientalis plantation were established based on the mentioned findings.And the effects of forest managements in oriental arborvitae were evaluated after the tending operation.And the main results were as follows:1.According to the succession process of forest community and the multi-purpose forest management objectives,the management theoretical model of the P.orientalis plantation was constructed.The corresponding forest planting schemes were put forward in accordance with the characteristics of stands growth and development in different succession stages.(1)According to the management theory of near-natural forest,for the middle aged stand with good forest form and in the stage of quality selection,the target tree management technology system is adopted.The target diameter and the number of target trees are determined according to site conditions and various forest management measures are implemented with the target tree as the center to promote the succession of stands to the continuous forest stage.(2)For the new afforestation that has not been closed,the soil should be loosened and the grass cut and irrigation should be carried out timely to ensure the survival rate and preservation rate of afforestation and promote the growth of young trees.(3)For the young forests that have not yet entered the quality selection stage,it is advisable to release and cleaning cuttings measures at the right time.Aiming to promote the growth of standing trees and improve the stand population structure by the reasonably stands adjusting in structure and composition.(4)For single-layer overripe forests formed by long-term unreasonable management,asexual reproduction should be carried out to promote natural seed regeneration artificially under crown cultivated processing.The aims of the tending measures are to promote the formation of the stratified structure at different ages and to facilitate the transformation of heterogeneous stratified forest to the continuous.2.The near-natural forest management theory and target tree operation system are carried out by taking 60-year-old of P.orientalis plantation in Shanting forest station located at Zaozhuang city for an example.The forest in the near future and long-term forestry plans are designed on the basis of optimum diagnosis tree analysis and target tending managements.Also,the effects of the cultivated measures for P.are evaluated.And the main findings are as the following:(1)The multifunctional forest management plan with target tree cultivation as the core is formulated.It is determined that the cultivation period of target trees is120-150 years,the target DBH is 40 cm,and the number of target trees is 150-180 in per hectare.On average,the number of the interfering trees is 17 and trees,and the thinning intensity is 11%.The target trees and other reserved trees were pruned.The total investment is 18,800 RNB in per hectare.(2)The implementation of the forest management plan has obviously improved the stand structure and the growth environment of the trees,aiming to promote the trees growth.In the second year of stand tending,the average diameter at breast height of the stands is 14.23 cm,which is 6.83%higher than that of the control.The average height of the stand is 7.90 m,that is 4.64%higher than that of the control.The average height of the live branch was 3.80 m,which is 21.02%higher than that of the control.The average crown is 12.39 m~2,that is 7.37%higher than that of the control.The unit area of the stand is 69.02 m~3,and it is 1.05%higher than that of the control.(3)The plant diversity in the forest changes greatly after stand tending.There are8 species of shrubs from 8 families and 9 species from 8 families in the tending stand and 1 species less in the tending stand than in the control stand.There are10 species of herbaceous plants in the tending stand and 12 species in the control stand.3 species of Oxalis corniculata,Liriope spicata and Rubia cordifolia are added to the tending stand,and 5 species of Digitaria Sanguinalis,Themeda japonica,Oplismenus annulatifolius,Solanum nigrum and Bidens pilosa were reduced;The Pielou evenness index,Simpson diversity index,Shannon-weiner diversity index and Gleason richness index of undergrowth herbage in tending stand are 0.9659,0.9011,2.4002 and 1.8759,and the control stands are 0.9681,0.8750,2.1272 and 1.4069,respectively.(4)The pH value of soil is more neutral in tending stand.The soil conductivity,moisture content,total porosity,bulk density and volume moisture content of the tending forest are 98.40 k?/cm,12.056%,14.30%,1.04 g/cm~3 and 0.60771,respectively.The tending stand increased by 0.95%,-6.64%,-3.18%,0.04%and-5.22%,respectively.The activities of catalase,urease,neutral phosphatase,sucrase in the soil of tending stand are 2.32mg/g,1.88mg/g,1.85mg/g,147.96mg/g,compared with the control standard,the increase is of-13.43%,21.29%,-13.95%,15.48%,respectively. |
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