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Yan W.-D.,Central South University of forestry and Technology | Yan W.-D.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | Xu W.-M.,Central South University of forestry and Technology | Chen X.-Y.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | And 8 more authors.
Pedosphere | Year: 2014

The flux of carbon dioxide (CO2) from soil surface presents an important component of carbon (C) cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better understand characteristics of soil CO2 flux (FCO2) in subtropical forests, soil FCO2 rates were quantified in five adjacent forest types (camphor tree forest, Masson pine forest, mixed camphor tree and Masson pine forest, Chinese sweet gum forest, and slash pine forest) at the Tianjiling National Park in Changsha, Hunan Province, in subtropical China, from January to December 2010. The influences of soil temperature (Tsoil), volumetric soil water content (θsoil), soil pH, soil organic carbon (SOC) and soil C/nitrogen (N) ratio on soil FCO2 rates were also investigated. The annual mean soil FCO2 rate varied with the forest types. The soil FCO2 rate was the highest in the camphor tree forest (3.53 ± 0.51 μmol m-2 s-1), followed by, in order, the mixed, Masson pine, Chinese sweet gum, and slash pine forests (1.53 ± 0.25 μmol m-2 s1). Soil FCO2 rates from the five forest types followed a similar seasonal pattern with the maximum values occurring in summer (July and August) and the minimum values during winter (December and January). Soil FCO2 rates were correlated to Tsoil and θsoil, but the relationships were only significant for Tsoil. No correlations were found between soil FCO2 rates and other selected soil properties, such as soil pH, SOC, and C/N ratio, in the examined forest types. Our results indicated that soil FCO2 rates were much higher in the evergreen broadleaved forest than coniferous forest under the same microclimatic environment in the study region. © 2014 Soil Science Society of China. Source


Li B.,Central South University of forestry and Technology | Fang X.,Central South University of forestry and Technology | Fang X.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | Li Y.,Central South University of forestry and Technology | And 9 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

Soil organic carbon (SOC) represents a large component of the global carbon cycle, and the SOC pool varies in forest ecosystems depending on species composition, growth stage and management practice. In order to accurately evaluate SOC distribution and dynamics in forests in Hunan Province of China, we reviewed, assembled and analyzed a comprehensive data package collected from (1) published estimates of SOC contents in various forested soil profiles (a total of 277 soil profiles in the province) in the past 15 years (from 2000 to 2014), (2) four times of forest inventory data from 1983 to 2009 in Hunan' s forests, (3) long-term field measurements in the Key National Observation Station of Central South University of Forestry and Technology in Huitong County, Hunan Province of China over the past 15 years (2000— 2014) and (4) field surveys of 59 soil profiles taken from ten typical forest types in the province during the period of 2008 to 2014. All forests in the province were classified into four categories of timber- forests, economic- forests, bamboo-forests and shrub-forests. The timber- forests were further divided into eight major forest types based on the species composition of the forest stands. The results showed that the arithmetic average of SOC contents ranged from 9.53 to 22.86 g/ kg in the four main forest categories, of which the shrub- forests had the highest SOC content. The differences of SOC mainly occurred in the 0—40 cm of soil layer among the studied forest groups. SOC density was in the range of 95.44—181.30 tC/ hm2 in the 0—80 cm soil layer, with an average of 137.15 tC/ hm2 in the examined forests. The differences of SOC density among the forest groups declined with the increase of soil depth, and the effect of forest types on variation of SOC density was gradually weakened with the increasing soil depth. From 1983 to 2009, SOC pool (0—80 cm soil depth) increases in Hunan' s timber- forests with a net increase of 414.86-106 tC and the area weighted average of SOC density increased 10.98 tC/ hm2 in the studied timber- forested soils (0—80 cm soil depth) as well. The difference of SOC pool gradually increased with aged stands of timber- forests, mainly occurring in Chinese fir (Cunninghamia lanceolata) forests, Masson Pine (Pinus massoniana) forests and broad- leaved forests. Among the forest types, natural forest accounted for a large percentage (>50%) of the total SOC storage in Hunan' s forests. But the proportion of SOC in plantation forests increased as the plantation areas gradually increased in the studied province. Economic- forests, shrub- forests and bamboo- forests made different contributions to the total SOC pool (0—80 cm soil depth) in Hunan' s forests, depending upon planting areas, cultivate systems and management practices. The changes in SOC pool in studied forests were closely associated with the alteration of forested area, convention of forest types and land use changes. These changes in terms of forested area and forest type were related to the formation and implementation of forestry policies in local, province and national levels. Our study suggested that human activities would influence SOC pool in forest ecosystems in regional scale through altering forested area and forest types. © 2015, Ecological Society of China. All rights reserved. Source


Tian D.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | Tian D.,Central South University of forestry and Technology | Xiang W.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | Xiang W.,Central South University of forestry and Technology | And 12 more authors.
Forestry | Year: 2011

Since the 1970s, a long-term research project has been conducted to monitor the changes in primary productivity of Chinese fir plantation at Huitong Ecosystem Research Station, Hunan, China. Standing biomass and net primary productivity (NPP) of the plantation were investigated at four times (7, 11, 14 and 18 years old) in two successive rotations on the same site. The mean individual tree biomass and stand biomass in the second rotation were reduced by ∼18, 17, 7 and 3 per cent in 7-, 11-, 14- and 18-year-old stands, respectively, compared with the first rotation. In the first rotation, annual NPP was higher in the 7-, 11- and 14-year-old stands, but lower in the 18-year-old stands, compared with those in the second rotation. The proportion of biomass in stem, canopy (branch and leaf) and root was ∼80, 13 and 7 per cent and 64, 20 and 16 per cent at the later stages of the stand development (≥14-year old) in the first and second rotations, respectively. The results suggests that relative large dry matter found in root systems in the second rotation increases the capacity of Chinese fir to exploit the soil for nutrient and water resources, which facilitates tree growth and productivity. © Institute of Chartered Foresters, 2011. All rights reserved. Source


Tian D.,Central South University of forestry and Technology | Tian D.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | Wang G.,Central South University of forestry and Technology | Wang G.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | And 7 more authors.
Australian Journal of Botany | Year: 2011

Soil respiration (Rs) is overwhelmingly the sum of autotrophic respiration (Ra, root and rhizosphere) and heterotrophic respiration (Rh, microbes and soil fauna). Separating Rs into R a and Rh components is a major challenge but necessary for understanding the implications of environmental change on soil C cycling and sequestration. In this study, a trenching method was employed to partition Rs sources in Chinese fir plantations in Southern China. Soil CO 2 efflux (FCO2) rates were measured using an infrared gas analyser system with soil chambers at the trenched and untrenched (Control) plots from January 2007 to December 2008. Soil temperature (Tsoil) and soil water content (Wsoil) were also measured at the plots during the study period. The results showed that the mean soil FCO2 rate from trenched plots (0.88±0.12 Source


Yan W.,Central South University of forestry and Technology | Yan W.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | Deng X.,Central South University of forestry and Technology | Deng X.,National Engineering Laboratory for Applied Forest Ecological Technology in Southern China | And 7 more authors.
Hydrological Sciences Journal | Year: 2015

The dynamic properties of rainfall interception were investigated at three growth stages in Chinese fir plantations. The results showed that the annual interception ratio was significantly higher in mature stands than in young stands. For a storm event, interception rainfall amount increased with increasing rainfall, but interception ratio decreased. In contrast to dry season conditions, the interception amount was high in the wet seasons, while the interception ratio was low. The rates of change in interception ratio were extremely rapid in small rainfall events. There was little stemflow in Chinese fir forests due to the pyramid-shaped crowns and thick rough bark of the trees. The power model was suitable to describe the interception process for an individual rainfall event for stands of any age. Our results indicate that the interception process varied for stands of different ages in Chinese fir plantations due to contrasting canopy structures. © 2015 IAHS. Source

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