Xiaoyong Chen
Governors State University, Biology, Faculty Member
Thinning is a common silviculture technology in forestry, but there is considerable uncertainty about the changes of soil nutrients due to thinning practice in different aged forests. The influence of light thinning (reduction of 20% of... more
Thinning is a common silviculture technology in forestry, but there is considerable uncertainty about the changes of soil nutrients due to thinning practice in different aged forests. The influence of light thinning (reduction of 20% of stand density) on soil organic carbon (SOC) and other mineral elements (N, P, K, Cu, Fe, Zn, Mn and S), as well as soil pH and soil bulk density were investigated in 6-, 13-, and 23-year-old growth stands of Chinese fir forests in subtropical China. Six 10m ×10m plots (three thinning and three non-thinning plots) were set up in each aged forests. Soil samples were taken from different soil layers from these plots for nutrient analysis. Results showed that SOC increased 59.4, 48.9, and 62.0% in topsoil layer (0-30 cm) in 6, 13, and 23 year-old growth stands, respectively when compared to the control, and the content of N increased by 20.5, 44.6, and 54.1% corresponding after two year post-thinning. In the thinned forests, soil P slightly increased at ...
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Tropical savannas cover a quarter of the Australian landmass and the biome represents a significant potential carbon sink. However, these savannas are subject to frequent and extensive fire. Fire regimes are likely to affect the... more
Tropical savannas cover a quarter of the Australian landmass and the biome represents a significant potential carbon sink. However, these savannas are subject to frequent and extensive fire. Fire regimes are likely to affect the productivity and carbon sequestration potential of savannas, through effects on both biomass and carbon emissions. The carbon sequestration potential has been estimated for some savanna sites by quantifying carbon storage in biomass and soil pools, and the fluxes to these pools. Using different techniques, previous work in these savannas has indicated that net ecosystem productivity [NEP, net primary productivity (NPP) less heterotrophic respiration] was about –3 t C ha–1 y–1 (i.e. a carbon sink). However, the impacts of fire were not accounted for in these calculations. Estimates of NEP have been combined with remotely-sensed estimates of area burnt and associated emissions for an extensive area of mesic savanna in Arnhem Land, NT, Australia. Combining NEP ...
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Ecological stoichiometry plays important roles in understanding the nutrient constraints on tree growth and development, as well in maintaining ecosystem services in forests, yet the characteristics of carbon:nitrogen:phosphorous (C:N:P)... more
Ecological stoichiometry plays important roles in understanding the nutrient constraints on tree growth and development, as well in maintaining ecosystem services in forests, yet the characteristics of carbon:nitrogen:phosphorous (C:N:P) stoichiometry in forests under karst environment have not been sufficiently evaluated. In this study, concentration, distribution, stocks of Nitrogen (N) and Phosphorous (P), and ecological stoichiometry were studied in three common forest types: Masson pine natural forests (MPNF), Masson pine plantation forests (MPPF), and Slash pine plantation forests (SPPF) in a karst region of southwestern China. Results showed that N concentrations were higher in overstory than in understory and litter in the studied forests. However, P concentration was relatively low in overstory component of the forested ecosystems. Meanwhile, the N and P concentrations were higher in SPPF in the stem and litter, while these contents were higher in MPPF and MPNP in the overs...
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Agroforest systems have been widely recognized as an integrated approach to sustainable land use for addressing the climate change problem because of their greater potential to sequester atmospheric CO2 with multiple economic and... more
Agroforest systems have been widely recognized as an integrated approach to sustainable land use for addressing the climate change problem because of their greater potential to sequester atmospheric CO2 with multiple economic and ecological benefits. However, the nature and extent of the effects of an age-sequence of agroforestry systems on carbon (C) storage remain largely unknown. To reveal the influence of different aged poplar-crop systems on C stocks, we investigated the variation in biomass and C storage under four aged poplar-crop agroforest systems (3-, 9-, 13-, and 17-year-old) in the Henan province of China. The results showed that stand biomass increased with forest age, ranging from 26.9 to 121.6 t/ha in the corresponding four aged poplar-crop systems. The poplar tree biomass accounted for >80% of the total stand biomass in these poplar-crop agroforestry systems, except in the 3-year-old agroforestry system. The average stand productivity peaked in a 9-year-old poplar...
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Nitrogen (N) is often recognized as the primary limiting nutrient element for the growth and production of forests worldwide. Litterfall represents a significant pathway for returning nutrients from aboveground parts of trees to the soils... more
Nitrogen (N) is often recognized as the primary limiting nutrient element for the growth and production of forests worldwide. Litterfall represents a significant pathway for returning nutrients from aboveground parts of trees to the soils and plays an essential role in N availability in different forest ecosystems. This study explores the N transformation processes under litterfall manipulation treatments in a Masson pine pure forest (MPPF), and Masson pine and Camphor tree mixed forest (MCMF) stands in subtropical southern China. The litterfall manipulation included litterfall addition (LA), litterfall removal (LR), and litterfall control (LC) treatments. The project aimed to examine how litterfall inputs affect the soil N process in different forest types in the study region. Results showed that soil ammonium N (NH4+-N) and nitrate N (NO3−-N) content increased under LA treatment and decreased under LR treatment compared to LC treatment. LA treatment significantly increased soil to...
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Litterfall, directly and indirectly, affects the soil physicochemical properties, microbial activity, and diversity of soil fauna and flora by adding organic matter and nutrients to the soil. This study explores litterfall dynamics such... more
Litterfall, directly and indirectly, affects the soil physicochemical properties, microbial activity, and diversity of soil fauna and flora by adding organic matter and nutrients to the soil. This study explores litterfall dynamics such as litterfall production, litter decomposition rate, and associated nutrient return in three forest types, that is, camphor tree forest (CTF), Masson pine forest (MPF), and camphor tree and Masson pine mixed forest (CMF), in subtropical China. Results showed that CMF had the highest mean annual litterfall production (4.30 ± 0.22 t ha−1), which was significantly higher than that of MPF (3.41 ± 0.25 t ha−1) and CTF (3.26 ± 0.17 t ha−1). Leaf represented the major fraction of litterfall, constituting over 71% of the total litterfall mass in the three forest types. The contribution of branch litter was 16.3, 8.9, and 16.9%, and miscellaneous litter was 12.6, 18.9, and 11.1% in CTF, MPF, and CMF, respectively. The concentration of macronutrients ranked as...
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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 Ra and Rh components is a major challenge but necessary... more
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 Ra 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 CO2 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 µmol m–2 s–1, mean ± s.e.) was significantly lower than that from untrenched plots (1.22 ± 0.18 µmol m–2 s–1) (P < 0.001) during the study period. Compared with Ra, R...
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Through estimations of above-and belowground standing biomass, annual biomass increment, fine root production and turnover, litterfall, canopy respiration and total soil CO 2 efflux, a carbon balance on seasonal and yearly timescales is... more
Through estimations of above-and belowground standing biomass, annual biomass increment, fine root production and turnover, litterfall, canopy respiration and total soil CO 2 efflux, a carbon balance on seasonal and yearly timescales is developed for a Eucalypt openforest savanna in northern Australia. This carbon balance is compared to estimates of carbon fluxes derived from eddy covariance measurements conducted at the same site. The total carbon (C) stock of the savanna was 204€53 ton C ha 1 , with approximately 84% belowground and 16% above-ground. Soil organic carbon content (01 m) was 151€33 ton C ha 1 , accounting for about 74% of the total carbon content in the ecosystem. Vegetation biomass was 53€20 ton C ha 1 , 39% of which was found in the root component and 61% in aboveground components (trees, shrubs, grasses). Annual gross primary production was 20.8 ton C ha 1 , of which 27% occurred in above-ground components and 73% belowground components. Net primary production was 11 ton C ha 1 year 1 , of which 8.0 ton C ha 1 (73%) was contributed by below-ground net primary production and 3.0 ton C ha 1 (27%) by above-ground net primary production. Annual soil carbon efflux was 14.3 ton C ha 1 year 1. Approximately three-quarters of the carbon flux (above-ground, below-ground and total ecosystem) occur during the 5-6 months of the wet season. This savanna site is a carbon sink during the wet season, but becomes a weak source during the dry season. Annual net ecosystem production was 3.8 ton C ha 1 year 1 .
ABSTRACT Land-cover changes not only affect regional climates through alteration in surface energy and water balance, but also affect key ecological processes, such as carbon (C) cycling and sequestration in plant ecosystems. The object... more
ABSTRACT Land-cover changes not only affect regional climates through alteration in surface energy and water balance, but also affect key ecological processes, such as carbon (C) cycling and sequestration in plant ecosystems. The object of this study was to investigate the effects of land-cover changes on the distribution of soil organic carbon (SOC) contents under four plant community types (deciduous forests, pine forests, mixed pine-deciduous forests, and prairies) in northeastern Illinois, USA. Soil samples were collected from incremental soil depths (0–10, 10–20, 20–30, and 30–50 cm) under the studied plant communities. The results showed that SOC concentration decreased with increases of soil depth in the studied forests and prairies. No significant differences of SOC concentrations were found at the upper soil layers (0–10 cm) among the four plant types. However, SOC concentrations were statistically higher at the lower soil depth (30–40 cm) in prairies than in other three forest types. The SOC storage (0–40 cm soil depth) was reduced in an order prairies (250.6) > mixed pine-deciduous forests (240.7) > pine forests (190.1) > deciduous forests (163.4 Mg/ha). The characteristics of relative short life cycle, restively high turnover rate of roots, and large partition of photosynthetic production allocated to belowground were likely attributed to the higher accumulation of C in soils in tallgrass prairies than in forests. Our data indicated the conversion of native tallgrass prairies to pure forest plantations resulted in a considerable decline of SOC storage. Results suggest that land-cover changes have a significant impact on SOC storage and sequestration in plant ecosystems.
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In-stream large woody debris (LWD), defined as dead wood ≥ 10 cm in diameter and ≥ 1 m in length, has played multiple structural and functional roles in aquatic ecosystems. Despite the importance of LWD to fluvial ecosystems, few studies... more
In-stream large woody debris (LWD), defined as dead wood ≥ 10 cm in diameter and ≥ 1 m in length, has played multiple structural and functional roles in aquatic ecosystems. Despite the importance of LWD to fluvial ecosystems, few studies have been conducted in low-gradient Midwestern rivers and streams. In this study, the quantity and characteristics of LWD were investigated in the upper-, middleand down-stream sections along Thorn Creek located in Northeastern Illinois. The results showed that LWD abundance ranged from 18 to 58 pieces . 100 m-1, LWD volume ranged from 1.87 to 5.37 m3 . 100 m-2, and total LWD length ranged from 44.2 to 170.0 m per 100 m of stream length in the study sites. The quantity of woody pieces per 100 m of stream length was significantly higher in the downstream section than in both upperand middle-stream sections. Over 80% of LWD pieces were ≤ 20 cm in diameter and ≤ 4 m in length. Approximately 90% of wood pieces were in the medium and latter decomposition...
Fine roots and their turnover represent a dynamic aspect of below-ground biomass (BGB) and nutrient capital in forest ecosystems, and account for a significant fraction of net primary productivity (NPP) (Cuevas 1995, Vogt et al. 1990). On... more
Fine roots and their turnover represent a dynamic aspect of below-ground biomass (BGB) and nutrient capital in forest ecosystems, and account for a significant fraction of net primary productivity (NPP) (Cuevas 1995, Vogt et al. 1990). On a weight basis, coarse roots contribute more to total ecosystem biomass than fine roots, but they account for only a small portion of annual root production (Eamus et al. 2002). Despite the fact that fine roots may compose less than 2% of total ecosystem biomass, they may contribute up to 40% of total ecosystem production (Vogt et al. 1990). Therefore, estimates of root production, like estimates of root biomass, should differentiate between coarse- and fine-root production.
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Research Interests: Carbon Dioxide, Carbon, Photosynthesis, Australia, Biology, and 15 moreEcology, Carbon Cycle, Eddy Covariance, Carbon Cycling, Carbon balance, Co, Oecologia, Ecosystem, Deciduous Forest, Pine Plantations, Carbon Sink, Leaf Phenology, gross Primary Production, net ecosystem production, and Dry Season
Intercropping is one of the most widely used agroforestry techniques, reducing the harmful impacts of external inputs such as fertilizers. It also controls soil erosion, increases soil nutrients availability, and reduces weed growth. In... more
Intercropping is one of the most widely used agroforestry techniques, reducing the harmful impacts of external inputs such as fertilizers. It also controls soil erosion, increases soil nutrients availability, and reduces weed growth. In this study, the intercropping of peanut (Arachishypogaea L.) was done with tea plants (Camellia oleifera), and it was compared with the mono-cropping of tea and peanut. Soil health and fertility were examined by analyzing the variability in soil enzymatic activity and soil nutrients availability at different soil depths (0–10 cm, 10–20 cm, 20–30 cm, and 30–40 cm). Results showed that the peanut–tea intercropping considerably impacted the soil organic carbon (SOC), soil nutrient availability, and soil enzymatic responses at different soil depths. The activity of protease, sucrase, and acid phosphatase was higher in intercropping, while the activity of urease and catalase was higher in peanut monoculture. In intercropping, total phosphorus (TP) was 14....
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Grazing affects nutrient cycling processes in grasslands, but little is known by researchers about effects on the nutrient stoichiometry of plant–soil–microbe systems. In this study, the influence of grazing intensity (0, 0.23, 0.34,... more
Grazing affects nutrient cycling processes in grasslands, but little is known by researchers about effects on the nutrient stoichiometry of plant–soil–microbe systems. In this study, the influence of grazing intensity (0, 0.23, 0.34, 0.46, 0.69, and 0.92 AU ha−1) on carbon (C), nitrogen (N) and phosphorus (P) and their stoichiometric ratios in plants, soil, and microbes was investigated in a Hulunber meadow steppe, Northeastern China. The C:N and C:P ratios of shoots decreased with grazing increased. Leaf N:P ratios <10 suggested that the plant communities under grazing were N-limited. Heavy grazing intensities increased the C:N and C:P ratios of microbial biomass, but grazing intensity had no significant effects on the stoichiometry of soil nutrients. The coupling relationship of C:N ratio in plant–soil–microbial systems was tightly significant compared to C:P ratio and N:P ratio according to the correlation results. The finding suggested grazing exacerbated the competition betw...
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Little information is available on horizontal precipitation in forest land in semi-humid climate regions. In this study, the quantity and duration of horizontal precipitation were investigated using the high precision weighing lysimeter... more
Little information is available on horizontal precipitation in forest land in semi-humid climate regions. In this study, the quantity and duration of horizontal precipitation were investigated using the high precision weighing lysimeter system in the mountainous areas of northern China during the experiment year 2011 and 2012. The purpose of this study was to better understand the formation mechanisms of horizontal precipitation in the semi-humid climate region. The results showed that hourly values of horizontal precipitation distributed between 0 and 0.1 mm, and that the one-night values distributed between 0.2 and 0.4 mm. The number of days with horizontal precipitation accounted for about 45% of the whole year. The average monthly amount of horizontal precipitation was 4.5 mm in the non-growing season, while it was a mere 1.6 mm in the growing season. The total amount of horizontal precipitation in the year was about 33 mm. Horizontal precipitation represented about 4.61% and 4....
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Antibiotic residues in the aquatic environment have become a global problem posing a serious threat to the environment and an inherent health risk to human beings. In this study, experiments were carried to investigate the use of carbon... more
Antibiotic residues in the aquatic environment have become a global problem posing a serious threat to the environment and an inherent health risk to human beings. In this study, experiments were carried to investigate the use of carbon material modified by liquid nitrogen treatment (CM1) and carbon material unmodified by liquid nitrogen treatment (CM2) as adsorbents for the removal of the antibiotic ampicillin from aqueous solutions. The properties of the CMs (CM1 and CM2) and the effects of variations of the key operating parameters on the removal process were examined, and kinetic, isothermal and thermodynamic experimental data were studied. The results showed that CM1 had larger specific surface area and pore size than CM2. The ampicillin adsorption was more effective on CM1 than that on CM2, and the maximum adsorption capacity of ampicillin onto CM1 and CM2 was 206.002 and 178.423 mg/g, respectively. The kinetic data revealed that the pesudo-second order model was more suitable...
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Contamination by heavy metals has become a serious environmental pollution issue today due to its potential threat to plant, wildlife, and human health. Photosynthesis, a process in which light energy is used to produce sugar and other... more
Contamination by heavy metals has become a serious environmental pollution issue today due to its potential threat to plant, wildlife, and human health. Photosynthesis, a process in which light energy is used to produce sugar and other organic compounds, is sensitive to heavy metals. In the present study, the response of photosynthetic process and carbon assimilation of Schima superba was investigated under cadmium (Cd) stress. Three Cd concentrations (0, 300, and 600 mg kg) were used designated as control (CK), low Cd (L), and high Cd treatment (L) of plants. Results showed that photosystem II (PSII) acceptor and donor side electron transport were more easily blocked in treatment compared to control, and L have more significant changes than L. A substantial decrease of 820 nm reflection curve absorption was observed both in L and L treatments. Special energy fluxes showed significant difference between the control group and the treated group, which indicated that low concentration ...
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With the increasing trend of converting monocultures into mixed forests, more and more studies have been carried out to investigate the admixing effects on tree growth and aboveground carbon storage. However, few studies have considered... more
With the increasing trend of converting monocultures into mixed forests, more and more studies have been carried out to investigate the admixing effects on tree growth and aboveground carbon storage. However, few studies have considered the impact of mixed forests on belowground carbon sequestration, particularly changes in soil carbon and nitrogen stocks as a forest grows. In this study, paired pure <i>Pinus massoniana</i> plantations, <i>Cinnamomum camphora</i> plantations and mixed <i>Pinus massoniana</i>–<i>Cinnamomum camphora</i> plantations at ages of 10, 24 and 45 years were selected to test whether the mixed plantations sequestrate more organic carbon (OC) and nitrogen (N) in soils and whether this admixing effect becomes more pronounced with stand ages. The results showed that tree species identification, composition and stand age significantly affected soil OC and N stocks. The soil OC and N stocks were the highest in mixed &...
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The stock, rates of sequestration and allocation of carbon were estimated for trees in 14 0.1-ha plots at Kapalga in Kakadu National Park, Northern Territory, using new allometric relationships of carbon stock to stem cross-sectional area... more
The stock, rates of sequestration and allocation of carbon were estimated for trees in 14 0.1-ha plots at Kapalga in Kakadu National Park, Northern Territory, using new allometric relationships of carbon stock to stem cross-sectional area and measured growth rates of trees. Carbon stocks of trees ranged from 12 to 58 t ha–1, with sequestration representing ~9% of the total stocks. More than half of the sequestered carbon is allocated to leaves and twigs and ~20% to wood. Only ~25% is retained in the live trees with leaf and twig fall accounting for 80%–84% of the total transfers to the environment. An alternative method of calculating sequestration rates from consideration of water use and carbon-isotope discrimination data had a close to 1 : 1 match with estimates from allometric relationships. We developed and applied algorithms to predict the impacts of fire on carbon stocks of live trees. This showed that the reduction in live carbon stocks caused by single fires increased with ...
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Savanna communities dominate the wet–dry tropical regions of the world and are an important community type in monsoonal northern Australia. As such they have a significant impact on the water and carbon balance of this region. Above the... more
Savanna communities dominate the wet–dry tropical regions of the world and are an important community type in monsoonal northern Australia. As such they have a significant impact on the water and carbon balance of this region. Above the 1200-mm isohyet, savanna’s are dominated by Eucalyptus miniata–E. tetrodonta open forests. We have described in detail the composition and structure as well as seasonal patterns of leaf area index and above-ground biomass in the E. miniata–E. tetrodonta open forests of the Gunn Point region near Darwin in the Northern Territory of Australia. In all, 29 tree species from four phenological guilds were recorded in these forests. Stand structure suggests that the forests were still recovering from the impacts of cyclone Tracy and subsequent frequent fires. Eucalyptus miniata and E. tetrodonta were significant contributors to overstorey leaf area index and standing biomass (>70%), and both leaf area index and biomass were strongly correlated to basal a...
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Below-ground biomass of a Eucalyptus savanna forest was estimated following trenching to depths of 2 m around 16 mature trees in a tropical savanna of north Australia. Correlations among below-ground and various components of above-ground... more
Below-ground biomass of a Eucalyptus savanna forest was estimated following trenching to depths of 2 m around 16 mature trees in a tropical savanna of north Australia. Correlations among below-ground and various components of above-ground biomass were also investigated. In addition, root morphology was investigated by fractal analyses and a determination of an index of shallow-rootedness was undertaken. Total root biomass was 38.4 t ha–1, including 1 t ha–1 of fine roots. About 77–90&amp;amp;amp;amp;amp;amp;amp;percnt; of total root biomass was found in the upper 0.5 m of soil. While fine-root biomass density was approximately constant (0.1 kg m–3) in the top soil, irrespective of distance from a tree stem, coarse-root biomass showed large variation with distance from the tree stem. Significant positive correlations among total root biomass, total above-ground biomass, diameter at breast height, leaf biomass and leaf area were obtained. It is likely that total root biomass can be reasonably accurately estimated from aboveground biomass and fine-root biomass from tree leaf area. We present equations that allow the prediction of belowground biomass from above-ground measures of tree size. Root morphology of two evergreen and two deciduous species was compared by the use of three parameters. These were the fractal dimension (d), which describes root system complexity; a proportionality factor (&amp;amp;amp;amp;amp;amp;amp;alpha;), which is the ratio of the cross-sectional area before and after branching; and two indices of shallow-rootedness (ISR). Roots were found to be amenable to fractal analyses. The proportionality factor was independent of root diameter (Dr) at any branching level in all tree species examined, indicating that branching patterns were similar across all root sizes. The fractal dimension (d) ranged from 1.15 to 1.36, indicating a relatively simple root structure. Mean d was significantly different between E. tetrodonta (evergreen) and T. ferdinandiana (deciduous); however, no significant differences were found among other pairs of species. Terminalia ferdinandiana had the highest ISR, while Planchonia careya (deciduous) had the lowest. In addition, differences in ISR between P. careya and the other three species were significant, but not significant among E. miniata, E. tetrodonta and T. ferdinandiana. There were clear relationships among above-ground tree stem diameter at breast height, stem base diameter, and horizontal and vertical proximal root diameter. By the use of mean values of and stem diameter, we estimated the total crosssectional area of root and root diameter-class distribution for each species studied.
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Below-ground biomass of a Eucalyptus savanna forest was estimated following trenching to depths of 2 m around 16 mature trees in a tropical savanna of north Australia. Correlations among below-ground and various components of above-ground... more
Below-ground biomass of a Eucalyptus savanna forest was estimated following trenching to depths of 2 m around 16 mature trees in a tropical savanna of north Australia. Correlations among below-ground and various components of above-ground biomass were also investigated. In addition, root morphology was investigated by fractal analyses and a determination of an index of shallow-rootedness was undertaken. Total root biomass was 38.4 t ha–1, including 1 t ha–1 of fine roots. About 77–90&amp;amp;amp;amp;amp;amp;amp;percnt; of total root biomass was found in the upper 0.5 m of soil. While fine-root biomass density was approximately constant (0.1 kg m–3) in the top soil, irrespective of distance from a tree stem, coarse-root biomass showed large variation with distance from the tree stem. Significant positive correlations among total root biomass, total above-ground biomass, diameter at breast height, leaf biomass and leaf area were obtained. It is likely that total root biomass can be reasonably accurately estimated from aboveground biomass and fine-root biomass from tree leaf area. We present equations that allow the prediction of belowground biomass from above-ground measures of tree size. Root morphology of two evergreen and two deciduous species was compared by the use of three parameters. These were the fractal dimension (d), which describes root system complexity; a proportionality factor (&amp;amp;amp;amp;amp;amp;amp;alpha;), which is the ratio of the cross-sectional area before and after branching; and two indices of shallow-rootedness (ISR). Roots were found to be amenable to fractal analyses. The proportionality factor was independent of root diameter (Dr) at any branching level in all tree species examined, indicating that branching patterns were similar across all root sizes. The fractal dimension (d) ranged from 1.15 to 1.36, indicating a relatively simple root structure. Mean d was significantly different between E. tetrodonta (evergreen) and T. ferdinandiana (deciduous); however, no significant differences were found among other pairs of species. Terminalia ferdinandiana had the highest ISR, while Planchonia careya (deciduous) had the lowest. In addition, differences in ISR between P. careya and the other three species were significant, but not significant among E. miniata, E. tetrodonta and T. ferdinandiana. There were clear relationships among above-ground tree stem diameter at breast height, stem base diameter, and horizontal and vertical proximal root diameter. By the use of mean values of and stem diameter, we estimated the total crosssectional area of root and root diameter-class distribution for each species studied.
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In this study, a colorimetric method is proposed based on the peroxidase-like activity of Fe 3 O 4 magnetic nanoparticles for screening metal ion inhibitors for glucose oxidase activity. First, the glucose oxidase was typically used as a... more
In this study, a colorimetric method is proposed based on the peroxidase-like activity of Fe 3 O 4 magnetic nanoparticles for screening metal ion inhibitors for glucose oxidase activity. First, the glucose oxidase was typically used as a specific enzyme to catalyze the oxidation of b-D-glucose resulting in the generation of hydrogen peroxide. Next, having an inherent peroxidase-like activity, Fe 3 O 4 magnetic nanoparticles were adopted as the catalyst. Then, the generated H 2 O 2 was capable of participating in the oxidation of 3,3 0 ,5,5 0-tetramethylbenzidine to yield a blue colored product. Based on the above results, an in vitro screen model of metal ion inhibitors of glucose oxidase was thus established. Metal ions including Ca 2+ , Pb 2+ , Mn 2+ , Ag + , Al 3+ , Cu 2+ , Mg 2+ and Zn 2+ have been tested. Herein, towards the glucose oxidase activity, Ca 2+ , Pb 2+ , Mg 2+ and Mn 2+ showed no effect while Al 3+ and Zn 2+ displayed a slight activation, while of Ag + and Cu 2+ expressed a strong inhibition. The further detection of Ag + and Cu 2+ manifested that their IC 50 were 0.662 mmol L À1 and 12.619 mmol L À1 , respectively. The entire detection process could be accomplished within 15 min. This assay is economical, time-saving and highly-effective with definitely significant reference for the screening of metal ions as glucose oxidase inhibitors.
Research Interests: Carbon Dioxide, Carbon, Photosynthesis, Australia, Ecology, and 22 moreCarbon Cycle, Seasonality, Eddy Covariance, ROOT, Carbon Cycling, Carbon balance, Soil Carbon, Plant Roots, Seasonal variation, Oecologia, Water Use, Ecosystem, Total Organic Carbon, Soil Organic Carbon, Savannah, Primary productivity, Seasons, Tropical Climate, Deciduous Forest, Carbon Sink, gross Primary Production, and Plant Leaves
Research Interests: Remote Sensing, Hydrology, Multidisciplinary, Eddy Covariance, Evapotranspiration, and 15 moreWater Table, Landsat TM, Leaf Area Index, Water Loss, Complex terrain, Optical Remote Sensing, Water Resource, Indexation, Subsurface Flow, Black Spruce, Soil Water, Distributed Hydrological Model, Unsaturated Zone, Growing Season, and temporal variation
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Based on the biomass studies of a typical evergreen broad-leaved forest stand and a typical Chinese fir plantation stand in a subtropical region, the differences and patterns of biomass accumulation, biomass distribution, productive... more
Based on the biomass studies of a typical evergreen broad-leaved forest stand and a typical Chinese fir plantation stand in a subtropical region, the differences and patterns of biomass accumulation, biomass distribution, productive structure, productivity and litter ...