Plant functional trait diversity and structural diversity co-underpin ecosystem multifunctionality in subtropical forests

Tree species diversity is assumed to be an important component in managing forest ecosystems because of effects on multiple functions or ecosystem multifunctionality.However,the importance of tree diversity in determining multifunctionality in structurally complex subtropical forests relative to other regulators(e.g.,soil microbial diversity,stand structure,and environmental conditions)remains uncertain.In this study,effects of aboveground(species richness and functional and structural diversity)and belowground(bacterial and fungal diversity)biodiversity,functional composition(community-weighted means of species traits),stand structure(diameter at breast height and stand density),and soil factors(pH and bulk density)on multifunctionality(including biomass production,carbon stock,and nutrient cycling)were examined along a tree diversity gradient in subtropical forests.The community-weighted mean of tree maximum height was the best predictor of ecosystem multifunctionality.Functional diversity explained a higher proportion of the variation in multifunctionality than that of species richness and fungal diversity.Stand structure-played an important role in modulating the effects of tree diversity on multifunctionality.The work highlights that species composition and maximizing forest structural complexity are effective strategies to increase forest multifunctionality while also conserving biodiversity in the management of multifunctional forests under global environmental changes.

Management Models and Development Strategies of the Farmers’ Professional Cooperatives in the Western Poor Counties and Regions of China: A Case Study of Long’an County,Guangxi

In the new era,an important task is how farmers’professional cooperatives to better adapt to new development environment and effectively solve the problems that"who will cultivate land"and"who does agriculture depend on"in the future.In this paper,model and development direction of farmers’professional cooperatives in Long’an County of Guangxi are analyzed and studied based on realistic development background of Guangxi.

Evaluation of Hepatic Cystic Echinococcosis’ CT image in Xinjiang Uygur Autonomous Region based on Kolmogorov Complexity Model

Designing and developing computer-assisted image processing techniques to help doctors improve their diagnosis has received considerable interests over the past years. In this paper, we used the kolmogorov complexity model to analyze the CT images of the healthy liver and multiple daughter hydatid cysts. Before the complexity characteristic calculating, the image preprocessing methods had been used for image standardization. From the kolmogorov complexity model, complexity characteristic were calculated in order to quantify the complexity, between healthy liver and multiple daughter hydatid cysts. Then we use statistical method to analyze the complexity characteristic of those two types of images. Our preliminary results show that the complexity characteristic has statistically significant (p<0.05) to analyze these two types CT images, between the healthy liver and the multiple daughter hydatid cysts. Furthermore, the result leads us to the conclusion that the kolmogorov complexity model could use for analyze the hydatid disease and will also extend the analysis the other lesions of liver.

Nutrient enrichment driven by canopy rainfall redistribution:Mechanism,quantification,and pattern

Vegetation canopies intercept and redistribute rainfall into throughfall and stemflow,which transfer substantial amounts of elements into the soil,influencing soil microbial community,plant survival,and plant community succession.Despite advancements in ecohydrological research,the implication of nutrient enrichment resulting from this redistribution of rainfall by canopies remains largely unexplored.To address this gap,we conducted a systematic review of 1020 papers published between 2000 and 2022,gathering data on nutrient concentration and enrichment for critical ions(including K^(+),Na^(+),Ca^(2+),Mg^(2+),NH_(4)^(+),Cl^(-),NO_(3)^(-)and SO_(4)^(2-))from the Web of Science and Chinese Knowledge Infrastructure databases.We aimed to synthesize the mechanisms,quantify the enrichments,and identify global patterns of nutrient enrichment in stemflow and throughfall across climate zones,and vegetation types and ecosystems.The results of this study indicate that stemflow exhibits,on average,2.1times greater ion concentration(6.13 mg L^(-1))compared to throughfall.In particular,among the investigated ions,SO_(4)^(2-)(12.45and 6.32 mg L^(-1))for stemflow and throughfall,respectively,and Cl^(-)(9.21 and 4.81 mg L^(-1))exhibit the highest concentrations in both rainfall redistribution components,while K^(+)(13.7 and 5.8)and Mg^(2+)(5.6 and 2.8)have the highest enrichment factors.Across climate zones,throughfall and stemflow show the lowest ion concentrations but the highest enrichment factors in extremely humid regions.Along the temperature gradient,ion concentrations are the highest in cold climates with no clear patterns observed for enrichment factors with increasing temperature.In addition,shrubs,conifers,mixed forests,and artificial ecosystems demonstrate enrichment factors 1.1 to 3.0 times greater than those of trees,broad-leaved plants,pure forests,and natural ecosystems.These findings emphasize the need for increased attentions to artificial ecosystems,such as urban and agricultural ecosystems,which often received limited research focus,especially regarding shrubs and conifers exhibiting stronger nutrients enrichment capabilities.Future investigations should integrate soil moisture analysis to better understand the impact of rainfall redistribution on the nutrient enrichment processes,patterns,and nutrient balance in global terrestrial ecosystems.

Hydrologic balance, net primary productivity and water use efficiency of the introduced exotic Eucalyptus grandis × Eucalyptus urophylla plantation in south-western China

Aims Land cover changes can disrupt water balance and alter the partitioning of precipitation into surface runoff,evapotranspiration and groundwater recharge.The widely planted Eucalyptus trees in south-western China have the potential to bring about hydrologic impacts.Our research aims to elucidate the hydrologic balance characteristics of the introduced exotic Eucalyptus grandis×Eucalyptus urophylla plantation and to assess whether its high productivity results from high water use efficiency(WUE)or large water consumption.Methods A 400-m^(2) experimental plot was established in an E.grandis×E.urophylla plantation in south-western China.Water balance components,including stand transpiration(T_(r)),evapotranspiration(E_(t))and runoff(R)were obtained as follows:T_(r) was estimated based on sap flow measurements,E_(t) was estimated as the average of surface transpiration and evaporation weighted by the fractional green vegetation cover using a modeling approach,and R was collected using the installed metal frame.Net primary productivity(NPP)was obtained from allometric equation and annual diameter at breast height(DBH)increment determination.Important Findings Annual E_(t) and T_(r) were 430±31 and 239±17 mm,respectively.Annual T_(r) accounts for 56±8%of total evapotranspiration on average.WUE(NPP/T_(r))of the E.grandis×E.urophylla was estimated to be 3.3–3.9 mmol·mol^(−1).Based on the comparative analysis of T_(r) and WUE,E.grandis×E.urophylla had a high productivity due to its high WUE without exhibiting prodigal water use.Meteorological factors including vapor pressure deficit and global solar radiation(R_(s))were key factors regulating E_(t) and T_(r) in our research site.Annual surface runoff,E_(t) and canopy interception occupied 7%,27–30%and 16%of total precipitation,while the remaining 46–50%of precipitation was used for sustaining groundwater recharge and altering soil water storage.The higher runoff coefficient(7.1%)indicated the weaker capability of E.grandis×E.urophylla to reserve water resource than natural forests and less disturbed plantations.The planting and protection of understory vegetation may decrease the surface runoff and exert beneficial effects on water conservation capacity of Eucalyptus plantation.

Efficient bright γ-ray vortex emission from a laser-illuminated light-fan-in-channel target

X/γ-rays have many potential applications in laboratory astrophysics and particle physics.Although several methods have been proposed for generating electron,positron,and X/γ-photon beams with angular momentum(AM),the generation of ultra-intense brilliant γ-rays is still challenging.Here,we present an all-optical scheme to generate a high-energy γ-photon beam with large beam angular momentum(BAM),small divergence,and high brilliance.In the first stage,a circularly polarized laser pulse with intensity of 10^(22) W/cm^(2) irradiates a micro-channel target,drags out electrons from the channel wall,and accelerates them to high energies via the longitudinal electric fields.During the process,the laser transfers its spin angular momentum(SAM)to the electrons’orbital angular momentum(OAM).In the second stage,the drive pulse is reflected by the attached fan-foil and a vortex laser pulse is thus formed.In the third stage,the energetic electrons collide head-on with the reflected vortex pulse and transfer their AM to the γ-photons via nonlinear Compton scattering.Three-dimensional particle-in-cell simulations show that the peak brilliance of the γ-ray beam is∼10^(22) photons·s^(-1)·mm^(-2)·mrad^(-2) per 0.1% bandwidth at 1 MeV with a peak instantaneous power of 25 TW and averaged BAM of 10^(6)h/photon.The AM conversion efficiency from laser to the γ-photons is unprecedentedly 0.67%.

Laser chirp controlled relativistic few-cycle mid-infrared pulse generation

Relativistic few-cycle mid-infrared(mid-IR)pulses are unique tools for strong-field physics and ultrafast science,but are difficult to generate with traditional nonlinear optical methods.Here,we propose a scheme to generate such pulses with high efficiency via plasma-based frequency modulation with a negatively chirped laser pulse(NCLP).The NCLP is rapidly compressed longitudinally due to dispersion and plasma etching,and its central frequency is downshifted via photon deceleration due to the enhanced laser intensity and plasma density modulations.Simulation results show that few-cycle mid-IR pulses with the maximum center wavelength of 7.9µm and pulse intensity of a_(MIR)=2.9 can be generated under a proper chirp parameter.Further,the maximum energy conversion efficiency can approach 5.0%.Such a relativistic mid-IR source is promising for a wide range of applications.

Water transport of native and exotic tree species in relation to xylem anatomical characteristics in low subtropical China

Aims Exotic fast-growing tree species have been commonly planted as pioneer species to facilitate ecological restoration in South China.Their growth and resource utilization behavior related to intrinsic physiology and structural properties have profound influences on forest ecosystem.However,the contrastive research focusing on water utilization features along with xylem anatomical properties between native and exotic species is scarce in South China.The objective of this study is to investigate the sapwood anatomical characteristics and water utilization conditions of native and exotic fast-growing species,and to elucidate the relationship between sap-flux density and conduit features.Methods We measured sap-flux density,conduit length,diameter and density of four native species(Schima superba,Michelia mac-clurei,Castanopsis hystrix and Castanopsis fissa)and four exotic species(Eucalyptus citriodora,Eucalyptus urophylla×grandis,Acacia auriculaeformis and Acacia mangium).Sap flux density was measured based on the Granier’s thermal dissipation probe method.The whole-tree water transport was quantified by mul-tiplying sap-flux density by sapwood area.The measurements of conduit characteristics were conducted by using segregation and slice method.Important Findings Sapwood area increased with the growing diameter at breast height(DBH)as a power function.Native species had a larger water-conducting tissue area than exotic species at the same DBH value when trees grew to a size with a certain value of DBH.The con-duit diameter of exotic species was significantly larger than that of native species.Conversely,native species,such as S.superba and M.macclurei,had longer conduit length and higher conduit den-sity than other tree species.Based on a physiological interpretation of the measured conduit characteristics,native tree species devel-oped a safe water transport system while exotic fast-growing tree species come into being an efficient system instead.Water trans-port increased with the growing DBH as a power function,and the exponent for native species(1.60)was higher than that for exotic species(1.22).Under the combined impact of sap-flux density and sapwood area,native species presented a larger water transport at a larger DBH value,indicating that growth advantage of exotic fast-growing species might weaken as DBH increased.