Guangxi Youyiguan Forest Ecosystem National Research Station

Pingxiang, China

Guangxi Youyiguan Forest Ecosystem National Research Station

Pingxiang, China
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You Y.,Guangxi University | You Y.,State Key Laboratory for Conservation and Utilization of Subtropical Agro bioresources | You Y.,Guangxi Youyiguan Forest Ecosystem National Research Station | Huang X.,Guangxi University | And 16 more authors.
Forest Ecology and Management | Year: 2017

Silvicultural practices are an important determinant of tree growth and stand structure. However, the potential advantages of long-term forest management, i.e., mixing valuable non-N2-fixing broadleaf tree species, such as Castanopsis hystrix Miq., with Masson pine (Pinus massoniana Lamb.) to increase stand growth and ecosystem carbon storage, remain poorly understood. In this study, we assessed tree growth, aboveground carbon accumulation, and belowground carbon sequestration in 26-year-old monocultures of C. hystrix (100C26), 26-year-old monocultures of P. massoniana (100P26), 50-year-old monocultures of P. massoniana (100P50), and even- and uneven-aged (50C26 + 50P26 and 50C26 + 50P50, respectively) mixed plantations. Carbon storage within the total ecosystem and in the tree and soil layers of 50C26 + 50P50 mixed plantations was significantly greater than values predicted based on the means of the 100C26 and 100P50 monoculture plantations (p <0.05). By contrast, differences within the shrub and litter layers were not significant, nor were the differences between observed and expected carbon storage values in the total ecosystem, except in the case of carbon stock in 50C26 + 50P26 mixed plantation soils. These results indicate that plantations of uneven-aged mixtures of P. massoniana and C. hystrix promote carbon sequestration via positive interactions. © 2017.


Guo Y.,CAS Institute of Botany | Guo Y.,Guangxi Youyiguan Forest Ecosystem National Research Station | Wang B.,CAS Institute of Botany | Wang B.,Guangxi Youyiguan Forest Ecosystem National Research Station | And 17 more authors.
Flora: Morphology, Distribution, Functional Ecology of Plants | Year: 2017

Aggregated patterns of tree species originate either from the physical forcing of habitat heterogeneity or from community processes. In both cases, spatial structuring plays a functional role in ecosystems. This study examines the spatial patterns of tree species, and discusses the degree to which variation in species distribution patterns depends on topographic variation. We first analyzed the spatial distribution patterns of tree species by using the univariate pair correlation function. We used redundancy analysis to identify the main structures explained by the measured topographic variables. Then, we used variation partitioning in combination with Moran's eigenvector maps and seven topographic variables to determine the relative importance of the effects of pure topographical, pure spatial, and spatially structured environmental processes on spatial patterns of tree species composition in a large-scale stem-mapping plot located in a diverse heterogeneous tropical karst seasonal rain forest of south China. Although aggregated distribution was the dominant pattern for tree species as we expected in this tropical karst forest, the degree of aggregation was lower than in other tropical or subtropical forests. Most species showed random patterns after controlling for habitat heterogeneity in a parametric heterogeneous Poisson process null model. The seven topographical variables explained about 16.7%, 31.0% and 47.2% of the total variance in species abundances by redundancy analysis for cell sizes of 10 m × 10 m, 20 m × 20 m and 50 m × 50 m, respectively. The pure spatial component was most important at the three spatial scales, which accounted for about one-third of total variance in species composition, while the spatially independent habitat contributed a negligible effect. This indicated that the overall evidence for topographic controls of the tropical tree species spatial pattern was strong, but the explanatory power of the topographic variables was negligible compared to the total variation of pure spatial processes, especially the broad-scale space. The results suggest that topographical and neutral progresses jointly contribute to the maintenance of species composition, and their relative importance varies with spatial scale in the Nonggang tropical karst seasonal rain forest. © 2017 Elsevier GmbH


Guo Y.,CAS Institute of Botany | Guo Y.,Guangxi Youyiguan Forest Ecosystem National Research Station | Li D.,CAS Institute of Botany | Li D.,Guangxi Youyiguan Forest Ecosystem National Research Station | And 10 more authors.
Biodiversity Science | Year: 2017

Litter fall is a significant component of forest ecosystems and has important ecological functions in material cycling and nutrient balance of forest ecosystems. In this study, we studied litter fall production, composition, spatial and temporal dynamics in a 15-ha northern tropical karst seasonal rainforest dynamics plot in Nonggang National Nature Reserve, Guangxi. We set up 90 litter fall traps, and collected litter fall weekly since May 2012. All litter fall in each trap was dried, classified and weighed. We used litter fall data from January 2013 to December 2014. The total annual litter production in 2013 and 2014 was 4,858.0 kg/ha and 4,928.8 kg/ha, respectively. Litter fall of leaves accounted for 85% while other components made up a small amount. Fruit litter fall was significantly higher in 2013. There were two litter fall peaks in each year, one in spring (March and April) and the other occurring in autumn to early winter (between August and November). The peak of fruit litter fall peak occurred in August. There were no significant inter-annual fluctuations in other litter fall components. The prevailing ecological factors of litter fall production were significantly different between 2013 and 2014. Litter fall production was significantly influenced by aspect and mean DBH(diameter at breast height). Composition and spatio-temporal dynamics of litter fall reflected material cycles affected by multiple biotic and abiotic factors. Our results provide basic information to reveal the unique characteristics of material circulation and energy flows in the geological background and geomorphology of karst. © 2017, Chinese Academy of Sciences. All rights reserved.

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