The Species Biodiversity Comparative Study Of Chinese Fir Forest Under Different Management

Biodiversity of plantation has always been a focus of research and issues by forest scientists home and abroad. Chinese fir was recommended as one of the most important growing timber tree species in southern China, for a long time, due to unreasonable business model, such as needles of pure forest and multi-generation serial phenomenon, which has brought a series of ecological problems. This aspect destroyed the biodiversity of plantations, soil degradation caused by soil, pests and diseases, such as flooding and erosion problems, on the other hand, it had restricted the sustainable development and the construction of South fir plantation timber.For this reason, over the years, our group research on Chinese fir plantation of biodiversity loss, severe damage to understory vegetation and other phenomena, to simulate natural fir plantation community, close to the natural transformation and regulation. At forest teaching farm in Nanping of Fujian Agriculture and Forestry University, natural evergreen broadleaf forest (control) and four different operating modes fir forest communities had been established. Which including old-growth Chinese fir forests, sprout forest of natural regeneration mode, second-generation Chinese fir plantation 1 in 1991 which formed by the tradition of controlled burning pattern and second-generation Chinese fir plantation 2 in 1993 which formed by non-burning mountain pattern.This study attempts to investigate the five communities by using of intensive field research methods positioned to respect the diversity of species, structural diversity and functional diversity systematic research within different communities. To reveal the specie diversity difference between different Chinese fir forest management model, restoration and reconstruction of degraded Chinese fir communities, and provide research and theoretical basis for the revolution of Chinese fir forest management model. The main research is as follows:(1) In the herbaceous layer, species distribution in the second generation Chinese fir plantation 1 community is uniform, the degree of complexity is higher and the amount of information contained well. Secondly, the order is:the second generation Chinese fir plantation 2, old-growth forests and sprout forests, in natural forests, the more uneven distribution of herbs, highlighting the status of the dominant species; in the shrub layer, species diversity index of natural forests and old-growth forests is similar and higher, while species diversity index of the sprout forest, the second-generation Chinese fir plantations 1 and the second-generation Chinese fir plantations 2 in the layer 2 is closer; in the tree layer, species diversity index is higher in sprout forest, followed by successively natural forests, old-growth forests, the second-generation Chinese fir plantationsl, while second-generation Chinese fir plantations 2 is lowest in tree layer. Judging from the whole community, Species diversity of natural forests, old-growth forests and sprout forest is much closer and higher than the second-generation Chinese Fir Plantation 1 and plantations(2) β diversity index of old-growth forests with natural forests is higher than the sprout forest with natural forests, difference between the β diversity index of second-generation Chinese Fir Plantation 1 with nature forests and plantations 2 with the natural is higher, and natural forests with the second-generation Chinese fir plantation 1 was higher than natural forests with the second-generation Chinese fir plantation 2.(3) From the point of view the whole community and the tree layer, functional diversity index of old fir forests, sprout forests and natural forests is higher than the second-generation Chinese fir plantation 1 and plantation 2; in the herbaceous layer, functional diversity index of the second-generation Chinese fir plantation 1 and second-generation Chinese Fir Plantation 2 were higher than old-growth fir forest, sprout forest and natural; but in the shrub layer, the variation of the different functions diversity index were inconsistent, which the order of FDQ index from high to Low was as follows:the second-generation Chinese fir plantation 2, natural forests, sprout forest, old-growth forests and the second-generation Chinese fir plantations 1, while order of FAD MFAD index was as follows:old-growth forests, the second-generation Chinese fir plantations 1, the second-generation Chinese fir plantations 2, natural forests and sprout trees.(4)The results of the regression analysis and correlation analysis between 5 species diversity index and 3 functional diversity shows that:Fit of the regression analysis on species diversity and functional diversity indices of different management model of Chinese fir forest were highly significantln addition to the correlation between Pielou evenness index and MFAD index show no significant, correlation analysis between other functional diversity index and richness index、Shannon-Winer index.、Simpson index、Pielou diversity index were significantly and positively correlated, correlation between the ecological dominance index and functional diversity indices showed highly significant negative correlation. This means correlation between functional diversity and species diversity is closely in general more.(5) In the vertical direction, the community structure of old-growth forests are more complex, followed by natural forests, sprout forests, the second-generation Chinese fir plantation 1 and the second-generation Chinese fir plantation 2; but on the level of heterogeneity index, the order from high-to-low was as follows:natural forests> sprout forests> old-growth forests> the second-generation Chinese fir plantation 2> the second-generation Chinese fir plantation 1.(6) The trend of species-area curve draw according to the nest plot methods and quadratic combinations method of woody plants in the community is more consistent, the number of species in each sample increased with the increasing area. The initial increase in the sampling area, the number of species showed a rapid growth trend, followed by a slower growth then finally stabilized. In addition, viewing the species-area the curve of two kinds of methods, range 1000-1200m2 can be used as Minimum sampling area in old-growth Chinese fir community. (7) This paper select three kinds of mathematical models S= b+αInAb和S= αA/(1+bA) which fitted well for the species-area curve of old-growth Chinese fir community and can be used to describe the relationship between species and area of old-growth Chinese fir community,(8) In the increasing of initial sampling area, the species number of tree and shrub layer showed a rapid growth, then entered a slower growth phase, and finally stabilized, but the trends of the species- area curve of tree and shrub layer had some differences. In addition,700-900m2 can be a minimum sampling area of the tree layer,1200-1300m2 as a minimum sampling area in shrub layer. Viewing the fitting results from different mathematical models, the model of S= b+αA fitted a higher species-area curve relationships of tree layer (R2> 0.87), however, the model of S= b+αInA and S= αAb fitted a highe species-area curve relationship of the shrub layer (R2> 0.81).(9)The effect of nest plot methods and quadratic combinations method to increased scale of way on shrubs layer, trees layer and community of FIR ageing forest is almost the same, are in the early of scale increases, there is a big effect of scale changes on Shannon-Winer index, ecological advantage degrees and Simpson, and effect on Pielou uniform degrees index was smaller, with the increasing of sampling scale, 4 species diversity index are tends to stable. Among them, the minimum size for the Shannon-Winer index was between 625 to 900m2, the minimum size for ecological advantages and Simpson index was between 200 to 400m2 and Pielou evenness index was between 1200 to 1400m2.Viewing the scale influence of different levels of the plant species diversity, the minimum size for shrubs, trees and Shannon-Winer index was between 700 to 900m2, the minimum size for shrubs, trees and community ecological dominance and Simpson index was between 200 to 400m2, then the minimum size of shrubs, trees and Pielou evenness index of the community was between the 1200 to 1500m2. (10) When the scale was 15m × 15m, Shannon-wiener index, ecological dominance, Simpson index and Pielou evenness index of the shrub layer and community did not show significant differences with other smaller scale, and the coefficient of variation was low, indicating that in this scale condition, the four indices can describe the diversity of shrub layer and communities; viewing the tree layer, when the scale was 30m × 30m, coefficient of variation of Shannon-wiener index, ecological dominance, Simpson index and Pielou evenness index were minimum, indicating that the estimated species diversity index on this scale is more accurate.(11) In shrub layer, richness index respectively with natural soil moisture content, organic matter and total phosphorus was highly significantly correlated, but was significantly correlated with total nitrogen content; Shannon-Winer index respectively with natural soil moisture content, organic matter and total nitrogen content was highly significantly correlated, but was significantly correlated with total phosphorus; In tree layer, richness index, Shannon-Winer index and Pielou evenness index respectively with soil available potassium content was a significant positive correlation; For the communities, richness index respectively with the natural soil moisture content, organic matter and total phosphorus was highly significantly correlated,but was significantly correlated with total nitrogen content; Shannon-Winer index respectively with the natural soil moisture content, organic matter, total nitrogen and soil available potassium was a significant positive correlation, but showed a significant negative correlation with the total phosphorus.(12) According to principal component analysis, by using of various communities at different levels of species diversity, functional diversity and structural diversity, to make a comprehensive evaluation of different Chinese fir forest management models and natural forest communities. Evaluation results show that:Comprehensive Evaluation of plant diversity in old-growth forests was the highest, followed by the order of natural forest, sprout forest, second-generation Chinese Fir Plantation 2 and second-generation Chinese fir plantations 1. This shows that old-growth forests and sprout Chinese fir forest communities which built to simulate the natural had better plant diversity, rich understory vegetation diversity, more complex structure and high functional diversity, the two mode forests can be used as a useful reference in governance of plantation biodiversity decreased aspects in the future.