Dynamics Of Forest Succession And Restoration Strategies For Degraded Spruce-fir Forest In Changbai Mountain

The forest is the surface biological communities,which is composed of the trees for the main body; the forest of nature growth is the geographical landscape on the earth's surface in the long-term development of nature history(The Editorial Board of〈Chinese forest〉,1997).The forest is the main body of terrestrial ecosystems,which is the survival and development foundation of humanity and many kinds of biology.The forest also has complex structure and function,it is not only providing massive woody forest products and non forest product,having the value of history,culture,aesthetics,leisure, and so on,but also playing an vital and irreplaceable role in the aspect of guaranteeing the conditions of agriculture-stock production,maintaining the biodiversity,protecting the ecological environment, reducing the natural disaster,regulating the global carbon balance and biogeochemical cycle,and so on. Therefore,the conservation and sustainable management of forest resources are the focus of attention and study.The study area is located at the Jingouling experimental forest farm,Wangqing forestry bureau, Jilin province,situated on the middle lower hill region of Changbai Mountain in northeast China.Based on the theory and technology related to vegetation ecology,quantitative ecology,forest management, the author combination of the sample-plot survey and the statistical method,the degraded spruce-fir forest was quantified at different secondary succession stages,analysis the interspecific association of main tree populations in the different succession stages,and also studied the spatial distribution pattern, stand diameter structure,growth and mortality of size-class model,growth process and succession trends.In the end,the stand structure regulation and restoration strategies was proposed.The study may be helpful to the research of secondary forest management,and to the secondary forest restoration,the construction of ecological environment in China.The study has mainly obtained the following research results:(1)Division the succession stages is one of the most important part in the research of vegetation restoration.Based on spatial-temporal method,the author established a degraded spruce-fir secondary succession forest series plots to analysis the spatial pattern,regeneration and succession process.All trees at least 5 cm in diameter at breast height were mapped and identified to species.Based on the interspecific association,main component analysis and fisher optimum split method,the degraded spruce-fir forest was quantified at different secondary successional stages,which is in Changbai Mountain,northeast China.We found that:during the secondary forest succession,Betula platyphylla and Populus ussuriensis were the declining species;Pinus koraiensis,Abies nephrolepis and Picea jazoensis are the progressive species;and Betulla costata,Larix gmelini,Tilia mandshuricum,Acer mono,Ulmus propinqua.Fraxinus,Maackia amurensis and Phellodendron are the transient species. The succession process was divided into five stages:the first and second stages are polar-birch secondary communities of different recovery,and the dominant species are Betula platyphylla,Populus ussuriensis,Tilia mandshuricum and Acer mono;the third stage is the polar-birch and spruce-fir mixed forests;the forth stage is the spruce-fir overcut forest;the last stage is the virgin forest,which is spruce-fir and broadleaved mixed forests.Analysis of quantitative division of secondary successional stages in degraded spruce-fir forest is benefit to the management and restoration of the secondary forest.(2)A series of techniques,including analysis of variance,x² test and interspecies association coefficient,were used to analyze interspecies association of dominant species both in polar-birch secondary forests and in spruce-fir forest.The results showed that the mean variance of the 12 principal arbor species in polar-birch secondary forests is 0.932,closes to 1,and has no significant correlation; but in spruce-fir mixed forest,it shows positive correlation,this indicated that the stage is relatively stable that adapts the environmental condition,and the positive correlation of the whole community is strengthening along with the progression of succession.The end-result of competition will lead the pioneer tree contains B.platyhylla and P davidiana,they are declining species,will be replaced by the zonal climax species in the future.The overall correlation between multi-species reflects the general trends between various species in community.The passage further explains that the community in the transitional stages will changed from the polar-birch secondary forests to spruce-fir mixed forest.(3)Based on spatial-temporal method,the author established a degraded spruce-fir secondary succession forest series plots to analysis the spatial pattern,regeneration and succession process.All trees at least 5 cm in diameter at breast height were mapped and identified to species.In this study,the spatial patterns and spatial associations of pioneer species,climax species and other species among different succession stages were analyzed by a point pattern analysis method,which was the Ripley's K(t)and K₁₂(t)statistic.We found that in the secondary process from polar-birch forest,spruce-fir forest and spruce-fir mixed forest,all of the species showed clumps to randomly distribution.Pioneer species such as Betula platyphylla and Populus davidiana are changed from aggregated to randomly at all spatial scale.The other species showed clumps at small scale but randomly at large scale.Climax species showed in the middle of the upper and lower broken line,and tends to rectangular distribution at scale lager than 12 m.During the secondary succession,interspecies of pioneer species and climax species was changed from negative to positive association,and shared the environment resources in the end.The polar-birch forest vs other species showed negative association at all scale,but significantly at 15 m.Climax and other species association showed positive at all scale,and spruce and fir species were continuously regenerating population.So,qualify the intra- and interspecies spatial associations of varied with species,spatial characteristics of the forest structure are closely related to spatial scales. Analysis of spatial pattern of intra- and interspecies of polar-birch secondary succession is benefit to the management and restoration of the secondary forest. (4)The forest structure has the important reference significance regarding the forest managers.In the paper,Neighborhood pattern,comparison and distribution of mingling are used to analysis the process of spatial structure succession in polar-birch secondary forests in Changbai Mountain from 1989 to 2005.The result shows that the stand is in mild accumulation distribution in 2005,while in random distribution in 1989,and the gap between various trees diameter disparity is reducing gradually,and the stand already has been from moderate mixed degrees to a mixed intensity.Along with the secondary succession,pioneer tree species such as the Betula platyphyll,Populus davidiana and Xylosma racemosum are gradually withdraw from the community,but the pioneer species such as Picea jezoensis and Pinus koraiensis become dominant,By using the spatial pattern method to study the structural change in the process of the secondary forest succession,it also reflects the succession process,and it is very useful to guiding management and structural adjustment.At last,it will be speed up the forest to the top stage development.(5)Based on observation data of these plots,the Weibull function and Negative exponential diameter distribution function,were developed to model diameter frequency distributions.Results show that Weibull function and Negative exponential function are suitable models for modeling uneven-aged secondary forests.And the study calculates the q factor,which is characterized by a constant ratio in the number of trees between successive size classes,that is between 1.26～1.49.(6)Based on the 4 permanent observation plots in the spruce-fir mixed forests in over-cutting forest area of Changbai Mountain,northeast China,and the data material was continuous observed for 12 years from 1978 to 1990,the latest observation was in 2008.In the paper,we are using the diameter and periodic annual increment data of main coniferous species,that is Pinus koraiensis,Abies nephrolepic and Picea koraiensis,to establish the transition probability,and predicted the average increment of diameter grade.From the testing data in 1990 years,the testing results indicate that the practical application error is small and the precision is high of probabilistic model.At the same time,the author analysis the mortality distribution in each species among 12 years from 1978 to 1990,results show that Weibull function is suitable for tree mortality model in uneven-aged spruce-fir mixed forests.(7)The study discusses two aspects.In one hand,according to the data of the analytic trees,which is the species of Betula platyphylla Suk and Populus davidiana Dode,the author fits the Richards equation using the diameter at breast height,tree height and volume of the growth equation,and compiles the forms of the growth process.In the other hand,based on the standard of arbor species diameter grade,the author makes the statistic of the number and proportion in every grade,and the succession trend is analyzed.The results showed that the pioneer tree contains Betula platyphylla Suk and Populus davidiana Dode,they are declining species,but Pinus koraiensis Sieb.et Zucc,Abies Mill and Picea asperata Mast are occupying the major advantages,they are the zonal climax species in the future,and the other species changes of is small.