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Huang F.Z.,CAS Institute of Botany | Huang F.Z.,Guangxi Youyiguan Forest Ecosystem Research Station | Ding T.,CAS Institute of Botany | Ding T.,Guangxi Youyiguan Forest Ecosystem Research Station | And 14 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

Based on the association classification of northern tropical karst seasonal rainforest in Nonggang plot, species diversity for all associations, trees, sub-trees, and shrub layers along an altitudinal gradient were evaluated using the indices of species richness, diversity, and evenness. The species diversity indices were significantly different among associations (P<0.01). The species diversity of various associations decreased in the following order: the Chionanthus ramiflorus, Vitex kwangsiensis, and Excentrodendron tonkinense association > the Clausena dunniana-Boniodendron minius-Excentrodendron tonkinense association > the Catunaregam spinosa-Vitex kwangsiensis-Excentrodendron tonkinense association > the Ardisia thyrsiflora-Sterculia monosperma-Saraca dives association > the Clerodendrum wallichii-Sterculia monosperma-Cychidendron guangxiensis association > the Walsura robusta-Cleistanthus sumatranus-Excentrodendron tonkinense association > the Aglaia odorata-Cleistanthus sumatranus-Excentrodendron tonkinense association > the Ficus hispida-Sterculia monosperm-Caryota obtusa association. The Patrick, Shannon, and Pielou indices indicated a "mid-altitude bulge" phenomenon below the middle slope (relative altitude < 76.3 m in the Nonggang plot); the species diversity of the associations located at middle altitudes was higher than those of associations at lower and higher altitudes. However, these indices increased as the relative altitude above the middle slope increased (i.e., when the relative altitude was greater than 76.3 m in the Nonggang plot). Species diversity indices for various layers decreased as follows: tree layer > sub-tree layer > shrub layer. This is similar to the pattern observed in tropical montane rain forests but contrary to that of subtropical karst evergreen broad-leaved forests. Differences in water and temperature reflect spatial habitat heterogeneity at various altitudes and influence the species diversity in northern tropical karst seasonal rainforests. The species diversity of trees was higher in relatively lower altitudes, which are characterized by beneficial water and temperature conditions. However, the observed species diversity of sub-trees and shrubs was higher for relatively higher altitudes characterized by harsh habitat conditions. Hence, sub-trees and shrubs are suitable for vegetation restoration in habitats for karst hills at high altitudes. © 2016, Ecological Society of China. All rights reserved.

Sun D.-J.,Guangxi University | Sun D.-J.,Chinese Academy of Forestry | Wen Y.-G.,Guangxi University | Wen Y.-G.,Guangxi Youyiguan Forest Ecosystem Research Station | And 8 more authors.
Forest Research | Year: 2015

The study was conducted in a Cunninghamia lanceolata stand under close-to-nature management, with three different thinning densities (75%, 55%, and 35%) and three repetitions, in the Experimental Center of Tropical Forestry, Pingxiang, Guangxi. Four broad-leaved species Castanopsis hystrix, Mytilaria laosensis, Castanopsis fissa and Machilus pingii were randomly inter-planted into the Cunninghamia lanceolata stand. The impact of close-to-nature management with different thinning densities on community composition, species diversity and growth status were studied. The results showed that after five years of the close-to-nature management, the number of species in tree layer, shrub layer and herb layer highly increased. The dominant species in shrub layer and herb layer varied before and after thinning operation, but they were mostly the same in different thinning intensities. In the shrub layer, there was no significant difference in diversity indexes between the thinning stands and the unthinned pure stands. In the herb layer, the diversity indexes in the thinning stands were higher than that of the unthinned pure stands, while the Simpson index and Pielous evenness index were significantly higher than the pure stand. The average DBH of Cunninghamia lanceolata was significantly increased with the thinning intensities, but no significant difference was found in tree height. The DBH and height of the broad-leaved trees grew as the thinning density increasing. Significant differences were found in the DBH and height of Castanopsis fissa and Castanopsis hystrix in different thinning intensities. Intolerant species such as Castanopsis fissa and Mytilaria laosensis, as well as neutral species Castanopsis hystrix were good for inter-planted in high thinning intensity during close-to-nature management in Cunninghamia lanceolata plantation, while the shade tolerant species like Machilus pingii performed better in medium thinning stands. ©, 2015, Chinese Academy of Forestry. All right reserved.

Ming A.,Chinese Academy of Forestry | Ming A.,Guangxi Youyiguan Forest Ecosystem Research Station | Jia H.,Chinese Academy of Forestry | Jia H.,Guangxi Youyiguan Forest Ecosystem Research Station | And 3 more authors.
PLoS ONE | Year: 2014

More than 60% of the total area of tree plantations in China is in subtropical, and over 70% of subtropical plantations consist of pure stands of coniferous species. Because of the poor ecosystem services provided by pure coniferous plantations and the ecological instability of these stands, a movement is under way to promote indigenous broadleaf plantation cultivation as a promising alternative. However, little is known about the carbon (C) stocks in indigenous broadleaf plantations and their dependence on stand age. Thus, we studied above- and below-ground biomass and C stocks in a chronosequence of Mytilaria laosensis plantations in subtropical China; stands were 7, 10, 18, 23, 29 and 33 years old. Our assessments included tree, shrub, herb and litter layers. We used plot-level inventories and destructive tree sampling to determine vegetation C stocks. We also measured soil C stocks by analyses of soil profiles to 100 cm depth. C stocks in the tree layer dominated the above-ground ecosystem C pool across the chronosequence. C stocks increased with age from 7 to 29 years and plateaued thereafter due to a reduction in tree growth rates. Minor C stocks were found in the shrub and herb layers of all six plantations and their temporal fluctuations were relatively small. C stocks in the litter and soil layers increased with stand age. Total above-ground ecosystem C also increased with stand age. Most increases in C stocks in below-ground and total ecosystems were attributable to increases in soil C content and tree biomass. Therefore, considerations of C sequestration potential in indigenous broadleaf plantations must take stand age into account.

Hao J.,Chinese Academy of Forestry | Hao J.,Guangxi Youyiguan Forest Ecosystem Research Station | Mo H.-H.,Chinese Academy of Forestry | Mo H.-H.,Guangxi Youyiguan Forest Ecosystem Research Station | And 4 more authors.
Forest Research | Year: 2016

Objective: To study the decomposition dynamics of leaf litter and its relationship with soil chemical properties in two young plantation stands (monocultures of Betula alnoides and Eucalyptus urophylla × E. grandis) in subtropical China. Method: The decomposition processes of leaf litter were measured using mesh nylon bag method. Result: The decomposition coefficients of leaf litter of B. alnoides and E. urophylla × E. grandis were 0.96 a-1 and 0.88 a-1, respectively. During the 12-month decomposition, the organic carbon contents declined gradually in the two leaf litter. The total K and C/N ratio rapidly decrease at the early stage, and tended towards stability thereafter. The total N and total P in the two leaf litter increased gradually, whereas the N/P ratio increased at first and then decreased throughout the entire decomposition. In both early and late phase of decomposition, the dry mass loss of the leaf litter was correlated positively with the N contents (R=0.877 and 0.855, respectively), and a negative relation was observed with C/N ratio (R=-0.735 and-0.697, respectively). Compared with the E. urophylla × E. grandis stand, the B. alnoides had significantly higher contents of soil organic carbon (SOC), total N, total P, total K as well as higher N/P ratio in 0-10 and 10-20 cm soil depth. However, the litter decomposition had no significant effects on SOC, total K, pH, C/N ratio and N/P ratio in 20-30 cm soil depth. The correlation analysis revealed that the organic C of leaf litter was significantly related to SOC, total N, total P, total K and N/P ratio, whereas the total N of leaf litter was significantly related to soil total N, pH and C/N ratio. Conclusion: The nutrient contents of leaf litter were found to be significantly correlated with the soil nutrient condition. Compared with the E. urophylla × E. grandis, the nutrient contents of leaf litter were significantly higher in B. alnoides, and subsequently, faster decomposition rate of leaf litter resulted in higher soil nutrient contents. © 2016, Chinese Academy of Forestry. All right reserved.

Zheng L.,Chinese Academy of Forestry | Zheng L.,Guangxi Youyiguan Forest Ecosystem Research Station | Cai D.-X.,Chinese Academy of Forestry | Cai D.-X.,Guangxi Youyiguan Forest Ecosystem Research Station | And 7 more authors.
Forest Research | Year: 2014

The allocation patterns of biomass in five plantations were studied by harvesting method and established allometric equations in subtropical area of south China. The results showed that the biomass of different species plantations were quite different in the same circumstances such as similar site conditions, age and management measures, showing that Mytilaria laosensis stand (404.95 t·hm-2) › Michelia macclurei stand (376.61 t·hm-2) › Pinus massoniana stand (239.94 t·hm-2) ›Castanopsis hystrix stand (231.01 t·hm-2) › Mesua ferrea stand (181.06 t·hm-2). The biomass spatial pattern dominated by tree layer, which accounted for 87.71%-97.86%, followed by the litter layer, accounting for 1.96%-10.90%, shrub and herb layers were the minimum, accounting for only 0.02%-1.09%. The organ biomass pattern of tree layer showed that proportion of stem biomass was the largest, followed by the root's or branch's, and then followed by the bark's, the lowest was the leaf's overall. The biomasses of shrub layer, herb layer, and floor litter among different stands were quite different. C. hystrix stand and P. massoniana stand had higher biomass of shrub layer, Mytilaria laosensis stand and Michelia macclurei stand were lower, Mesua ferrea stand was the lowest. The biomasses of herb layer and floor litter showed a similar law, that of P. massoniana stand was the highest, C. hystrix secondly, Mytilaria laosensis stand, Michelia macclurei stand and Mesua ferrea stand were lower.

Ming A.G.,Chinese Academy of Forestry | Ming A.G.,Guangxi Youyiguan Forest Ecosystem Research Station | Liu S.R.,Chinese Academy of Forestry | Nong Y.,Chinese Academy of Forestry | And 11 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

Enhancement of the carbon storage of plantation ecosystems by optimizing afforestation patterns has been extensively researched. In the present study, we investigated carbon storage and allocation in an 8-year-old Erythrophleum fordii stand (PE), a Castanopsis hystrix stand (PC), a Mytilaria laosensis stand (PM), and a mixed E. fordii × C. hystrix × M. laosensis stand (MECM) in subtropical China. We showed that the average carbon contents of different organs in E. fordii, C. hystrix, and M. laosensis ranged from 509.0 g/kg to 572.4 g/kg, 474.2 g/kg to 553.4 g/kg, and 512.8 g/kg to 556.3 g/kg, respectively. We determined significant differences in carbon contents among different organs of the same tree species. Within the same organs, the average carbon contents of different stands were ranked as follows: E. fordii (539.3 g/kg) > M. laosensis (532.7 g/kg) > C. hystrix (515.3 g/kg). In the shrub, herb, and litter layers, the highest carbon contents among the four stands occurred in PM, followed by MECM, PC, and PE. The carbon contents of the 0-10 cm, 10-30 cm, 30-50 cm, and 50-100 cm soil layers differed significantly among the four stands and were the highest in PM, followed by PC, MECM, and PE. The ecosystem carbon storages were ranked as PM (308.0 t/hm2) > MECM (182.8 t/hm2) > PC (180.2 t/hm2) > PE (135.2 t/hm2). We determined significant differences in average carbon contents within and among stands (P < 0.05), but no significant differences in the total ecosystem carbon storage between MECM and PE (P > 0.05). Our results indicate that the mode of afforestation can markedly influence the carbon storage and allocation of plantations. In mixed stands, C. hystrix and E. fordii will benefit from an increase in aboveground biomass carbon, but not from accumulation of soil carbon. On the other hand, in monoculture, M. laosensis will benefit from the sequestration of aboveground biomass carbon and from accumulation of soil carbon. Therefore, the afforestation mode for carbon sequestration forests should be selected according to the carbon accumulation characteristics of the representative tree species. © 2015, Ecological Society of China. All Rights Reserved.

Luo D.,Chinese Academy of Forestry | Shi Z.M.,Chinese Academy of Forestry | Wang W.X.,Chinese Academy of Forestry | Liu S.R.,Chinese Academy of Forestry | And 6 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

Carbon sequestration in forest ecosystems is recognized as a key mechanism for mitigating the accumulation of atmospheric carbon dioxide. However, both forest carbon pools and sequestration vary according to tree species, age of the stand, soil types, climate, environmental disturbances, and management practices. Tree species composition and management practices are important tools for increasing carbon storage in forest ecosystems. Plantation is becoming a key component of the world’s forest resources and is playing an important role in sustainable forest management. Well-designed, multi-purpose plantations can reduce the pressure on natural forests and complement some ecological resources provided by natural forests in addition to mitigating climate change through direct carbon sequestration. Afforestation and reforestation are important measures for managing commercial forests in subtropical China. However, the large-scale development of monoculture plantations of coniferous species (e.g., Pinus massoniana and Cunninghamia lanceolata) and exotic species (Eucalyptus spp.) has caused a number of problems, such as the loss of biodiversity, degradation of soil fertility, reduction of ecosystem stability, and loss of ecological resources. Thus, some broad-leaved tree species with different functions (e.g., indigenous valuable broad-leaved species and nitrogen-fixing species) have been developed for restructuring the plantations. In this study, three young plantation stands (monoculture of Erythrophleum fordii, monoculture of P. massoniana and a mixed stand of the two species) were selected to study carbon and nitrogen storage in these ecosystems and their spatial distribution. The results showed that the total carbon storage of the mixed plantation stand was 137.75 t/ hm2, higher than that of monoculture stands of E. fordii (134.07 t/ hm2) and P. massoniana (131.10 t/ hm2). Nitrogen storage was highest in E. fordii (10.19 t/ hm2), followed by the mixed plantation (8.68 t/ hm2), and then P. massoniana stands (7.01 t/ hm2). The spatial distribution of carbon and nitrogen was identical in the three plantation stands, with the majority found in the 0—100 cm soil (occupying an average 81.49% and 96.91% of the total storage, respectively), followed by the above- ground biomass represented by the trees (17.52% and 2.69%, respectively), and the understory vegetation and litterfall. Soil organic carbon was mainly distributed in the top-soil, while soil nitrogen was irregularly distributed. Average organic carbon storage in 0—30 cm soil was 52.52 t/ hm2(47.99% of the total 0—100 cm soil storage). The mixed plantation stands showed a greater capacity for carbon storage in comparison to the other two monoculture stands. The above-/ underground ratio of carbon and nitrogen suggested that these three young plantation stands had a high potential for carbon and nitrogen sequestration. The results are significant in that they provide scientific references for tree species selection and plantation management to enhance productivity and carbon sequestration in subtropical China. © 2015 Ecological Society of China. All rights reserved.

Ming A.-G.,Chinese Academy of Forestry | Ming A.-G.,Guangxi Youyiguan Forest Ecosystem Research Station | Zheng L.,Chinese Academy of Forestry | Zheng L.,Guangxi Youyiguan Forest Ecosystem Research Station | And 4 more authors.
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2015

Based on the quadrat survey and actual biomass measurement in a 28-year-old Mesua ferrea plantation in Experimental Center of Tropical Forestry located at Pingxiang City of Guangxi Zhuang Autonomous Region, the carbon stock and its allocation characteristics were studied by the allometric method. The results showed that carbon contents in different organs of M. ferrea ranged between 452.4 and 524.5 g/kg, following the order of leaf > stem > branch > root > bark. Soil carbon content in the surface layer was the highest, and it reduced with the increase of soil depth. The biomass and carbon stock of tree layer in M. ferrea plantation were 165.8 and 79.3 t/hm2, and the allocation of biomass ranked as stem > branch > root > leaf > bark, the same as the allocation of the carbon stock in the tree layer. The biomass of M. ferrea plantation ecosystem was 173.5 t/hm2 and carbon stock 203.1 t/hm2, the biomass in the plantation was mainly distributed in the tree layer (95.6%), and the allocation of carbon stock in different components was soil layer (59.3%) > tree layer (39.0%) > ground layer (1.7%). The carbon content aboveground was greater than that underground in shrub layer and herb layer; however, the biomass and carbon stock aboveground were less than those underground. ©, 2015, Beijing Forestry University. All right reserved.

Ming A.G.,Chinese Academy of Forestry | Ming A.G.,Guangxi Youyiguan Forest Ecosystem Research Station | Liu S.R.,Chinese Academy of Forestry | Mo H.H.,Chinese Academy of Forestry | And 11 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

The focus has been on afforestation and re-afforestation as new methods for improving carbon sequestration, byoptimizing the mode of afforestation and adjusting the forest tree species composition. Carbon content and storage of differentcomponents, including tree, shrub, herb, litter, and soil layers and their allocations of a 26-year-old Castanopsis hystrix(PCH), Cunninghamia lanceolata (PCL), and mixed C. hystrix ×C. lanceolata (MCC) stands in subtropical China werestudied using quadrat sampling combined with biomass measurements. The results showed that the average carbon content ofdifferent organs in C. lanceolata and C. hystrix were 492.1—545.7 g/ kg and 486.7—524.1 g/ kg, respectively. Significantdifferences were found among different organs in the same tree species(P<0.05). The average carbon content of C. hystrix(539.3 g/ kg)was higher than C. lanceolata. Carbon content of the ground cover was PCH>MCC>PCL. Soil content in 0—100 cm showed significant differences among the three stands, which was ranked as PCL>MCC>PCH(P <0.05). Thecarbon storage in the total ecosystem was ranked as PCL(169.49 t/ hm2)> MCC(141.18 t/ hm2)> PCH(129.20t/hm2.Significant differences were found among different components in the same stand, and among different stands of the samecomponents (P<0.05). Afforestation significantly affected the carbon storage and allocation in plantations, and the mixedstand benefited from increased carbon biomass and soil carbon for C. hystrix; while monoculture stand benefited from thebiomass and soil carbon for C. lanceolata Therefore, we should select the afforestation mode based on the carbonacumination characteristics of tree species regarding carbon sequestration forests, because mixed stands do not always fixmore carbon compared with pure forests. © 2015, Ecological Society of China. All rights reserved.

Ming A.-G.,Chinese Academy of Forestry | Ming A.-G.,Guangxi Youyiguan Forest Ecosystem Research Station | Jia H.-Y.,Chinese Academy of Forestry | Jia H.-Y.,Guangxi Youyiguan Forest Ecosystem Research Station | And 10 more authors.
Chinese Journal of Applied Ecology | Year: 2014

Carbon storage and its allocation of 7-, 29- and 32-year-old Erythrophleum fordii plantation ecosystems in Guangxi were studied on the basis of biomass survey. The results showed that the carbon contents in different organs of E. fordii, ranging from 509.0 to 572.4 g·kg-1, were in the order of stem > branch > root > bark > leaf. No significant differences in carbon content were observed among the shrub, herb and litter layers of the E. fordii plantations with different ages. Carbon content in the soil layer (0-100 cm) decreased with increasing the soil depth, but increased with increasing the stand age. The carbon storage of the arbor layer was 21.8, 100.0 and 121.6 t·hm-2 for 7-, 29- and 32-year-old stands, respectively, and the order of carbon storage allocation in different organs was same as the order of carbon content. The 7-, 29-and 32-year-old E. fordii plantation ecosystems stored carbon at 132.6, 220.2 and 242.6 t·hm-2, respectively. The arbor layer and soil layer were the main carbon pools, accounting for more than 97% of carbon storage in the ecosystem. Carbon storage allocation increased in arbor layer but decreased in soil layer with increasing the stand age. The influence of stand age on carbon storage allocation in shrub, herb and litter layers did not show a obvious regular pattern.

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