The net primary productivity(NPP)of forest ecosystems plays a crucial role in regulating the terrestrial carbon cycle under global climate change.While the temporal effect driven by ecosystem processes on NPP variatio...The net primary productivity(NPP)of forest ecosystems plays a crucial role in regulating the terrestrial carbon cycle under global climate change.While the temporal effect driven by ecosystem processes on NPP variations is well-documented,spatial variations(from local to regional scales)remain inadequately understood.To evaluate the scale-dependent effects of productivity,predictions from the Biome-BGC model were compared with moderate-resolution imaging spectroradiometer(MODIS)and biometric NPP data in a large temperate forest region at both local and regional levels.Linear mixed-effect models and variance partitioning analysis were used to quantify the effects of environmental heterogeneity and trait variation on simulated NPP at varying spatial scales.Results show that NPP had considerable predictability at the local scale,with a coefficient of determination(R^(2))of 0.37,but this predictability declined significantly to 0.02 at the regional scale.Environmental heterogeneity and photosynthetic traits collectively explained 94.8%of the local variation in NPP,which decreased to 86.7%regionally due to the reduced common effects among these variables.Locally,the leaf area index(LAI)predominated(34.6%),while at regional scales,the stomatal conductance and maximum carboxylation rate were more influential(41.1%).Our study suggests that environmental heterogeneity drives the photosynthetic processes that mediate NPP variations across spatial scales.Incorporating heterogeneous local conditions and trait variations into analyses could enhance future research on the relationship between climate and carbon cycles at larger scales.展开更多
Tree growth synchrony serves as a valuable ecological indicator of forest resilience to climate stress and disturbances.However,our understanding of how increasing temperature affects tree growth synchrony during rapi...Tree growth synchrony serves as a valuable ecological indicator of forest resilience to climate stress and disturbances.However,our understanding of how increasing temperature affects tree growth synchrony during rapidly and slowly warming periods in ecosystems with varying climatic conditions remains limited.By using tree-ring data from temperate broadleaf(Fraxinus mandshurica,Phellodendron amurense,Quercus mongolica,and Juglans mandshurica)and Korean pine(Pinus koraiensis)mixed forests in northeast China,we investigated the effects of climate change,particularly warming,on the growth synchrony of five dominant temperate tree species across contrasting warm-dry and cool-wet climate conditions.Results show that temperature over water availability was the primary factor driving the growth and growth synchrony of the five species.Growth synchrony was significantly higher in warm-dry than in cool-wet areas,primarily due to more uniform climate conditions and higher climate sensitivity in the former.Rapid warming from the 1960s to the 1990s significantly enhanced tree growth synchrony in both areas,followed by a marked reversal as temperatures exceeded a certain threshold or warming slowed down,particularly in the warm-dry area.The growth synchrony variation patterns of the five species were highly consistent over time,although broadleaves exhibited higher synchrony than conifers,suggesting potential risks to forest resilience and stability under future climate change scenarios.Growing season temperatures and non-growing season temperatures and precipitation had a stronger positive effect on tree growth in the cool-wet area compared to the warm-dry area.High relative humidity hindered growth in the cool-wet area but enhanced it in the warm-dry area.Overall,our study highlights that the diversity and sensitivity of climate-growth relationships directly determine spatiotemporal growth synchrony.Temperature,along with water availability,shape long-term forest dynamics by affecting tree growth and synchrony.These results provide crucial insights for forest management practice to enhance structural diversity and resilience capacity against climate changeinduced synchrony shifts.展开更多
Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest eco...Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest ecosystems,the effects of prescribed burnings on soil microbial community structure are less studied.It is also unclear that how post-fire soil physiochemical properties changes affected soil microbial communities.Here,we studied the impacts of prescribed burning on soil microbiome in three typical temperate forests of northern China by collecting soil physicochemical and high-throughput sequencing for 16S rRNA and 18S rRNA was applied to analyze the diversity and community composition of soil microbes(bacteria and fungi).Compared with pre-fire condition,prescribed burning significantly decreased Chaol index and altered soil bacterial communities(P<0.05),whereas it had no significant effect on fungal diversity and community structure of the(P>0.05).Planctomycetes and Actinobacteria made the greatest contributions to the bacterial community dissimilarity between the pre-fire and post-fire conditions.The main variables influencing the post-fire soil microbial community structure are soil pH,available phosphorus,total nitrogen,and the ratio of soil total carbon to soil total nitrogen,which could account for 73.5% of the variation in the microbial community structure in these stands.Our findings demonstrated a great discrepancy in the responses of bacteria and fungi to prescribed burning.Prescribed burning altered the soil microbial structure by modifying the physicochemical properties.Our results pointed that it is essential to evaluate the impact of prescribed burnings on forest ecosystem functions.These findings provide an important baseline for assessing post-fire microbial recovery in the region and offer critical guidance for restoration efforts.展开更多
Litter and root activities may alter the temperature sensitivity(Q_(10))of soil respiration.However,existing studies have not provided a comprehensive understanding of the effects of litter and root carbon inputs on t...Litter and root activities may alter the temperature sensitivity(Q_(10))of soil respiration.However,existing studies have not provided a comprehensive understanding of the effects of litter and root carbon inputs on the Q_(10)of soil respiration in different seasons.In this study,we used the trench method under in situ conditions to measure the total soil respiration(R_(total)),litter-removed soil respiration(R_(no-litter)),root-removed soil respiration(R_(no-root)),and the decomposition of soil organic matter(i.e.,both litter and root removal;R_(SOM))in different seasons of pioneer(Populus davidiana Dode)and climax(Quercus liaotungensis Mary)forests on the Loess Plateau,China.Soil temperature,soil moisture,litter biomass,fine root biomass,litter carbon,and root carbon were analyzed to obtain the drive mechanism of the Q_(10)of soil respiration in the two forests.The results showed that the Q_(10)of soil respiration exhibited seasonality,and the Q_(10)of soil respiration was higher in summer.The litter enhanced the Q_(10)of soil respiration considerably more than the root did.Soil temperature,soil moisture,fine root biomass,and litter carbon were the main factors used to predict the Q_(10)of different soil respiration components.These findings indicated that factors affecting the Q_(10)of soil respiration highly depended on soil temperature and soil moisture as well as related litter and root traits in the two forests,which can improve our understanding of soil carbon–climate feedback in global warming.The results of this study can provide reference for exploring soil respiration under temperate forest restoration.展开更多
Background: The large potential of the soil organic carbon(SOC) pool to sequester CO2from the atmosphere could greatly ameliorate the effect of future climate change. However, the quantity of carbon stored in terrestr...Background: The large potential of the soil organic carbon(SOC) pool to sequester CO2from the atmosphere could greatly ameliorate the effect of future climate change. However, the quantity of carbon stored in terrestrial soils largely depends upon the magnitude of SOC mineralization. SOC mineralization constitutes an important part of the carbon cycle, and is driven by many biophysical variables, such as temperature and moisture.Methods: Soil samples of a pine forest, an oak forest, and a pine and oak mixed forest were incubated for 387 days under conditions with six temperature settings(5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C) and three levels of soil moisture content(SMC, 30%, 60%, 90%). The instantaneous rate of mineralized SOC was periodically and automatically measured using a Li-Cor CO2analyzer. Based on the measured amount of mineralized SOC,carbon fractions were estimated separately via first-order kinetic one-and two-compartment models.Results: During the 387 day incubation experiment, accumulative mineralized carbon ranged from 22.89 mg carbon(C) ·g-1SOC at 30 °C and 30% SMC for the mixed forest to 109.20 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest. Mineralized recalcitrant carbon varied from 18.48 mg C·g-1SOC at 30 °C and 30% SMC for the mixed forest to 104.98 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest, and contributed at least 80% to total mineralized carbon.Conclusions: Based on the results of this experiment, the soil organic matter of the pure broadleaved forest is more vulnerable to soil microbial degradation in northern China; most of the amount of the mineralized SOC derived from the recalcitrant carbon pool. Labile carbon fraction constitutes on average 0.4% of SOC across the three forest types and was rapidly digested by soil microbes in the early incubation stage. SOC mineralization markedly increased with soil moisture content, and correlated parabolically to temperature with the highest value at 15 °C. No significant interaction was detected among these variables in the present study.展开更多
Plants diversity and phenological pattern of the trees were monitored in a montane wet temperate forest （shola） in the Kukkal Forest, Palni hills of the southern Western Ghats, India. Twelve random plots were select...Plants diversity and phenological pattern of the trees were monitored in a montane wet temperate forest （shola） in the Kukkal Forest, Palni hills of the southern Western Ghats, India. Twelve random plots were selected for sampling the vegetation. For phenological studies, twenty-three fleshy fruit trees were identified in the study area and 10 individuals of each species were selected to record the phenological events fortnightly between April 2002 and April 2004. The phenological events were divided into vegetative and reproductive phases. A total of 2279 individuals were inventoried which belong to 83 species, 68 genera and 40 families. About 30% of the species were endemic to the Western Ghats. The most dominant species （〉 1 cm dbh） was Psychotria nilgiriensis var. astephana （Rubiaceae）, which accounted for 12% of the total sampled individuals. Lauraceae was the dominant family accounting for 20% of the individuals. Fruiting peak occurred in July 2003 and least in June 2002. During the peak period, fruits of 85 individuals of six species were observed. Syzygium tamilnadensis, Ilex wightiana and Beilschmiedia wightii fruited only once during the two years of study. The number of fruiting species showed no correlation with rainfall （r = 0.26, p = 0.2）, while a correlation was found with fruit abundance （r = 0.40, p 〈 0.05）. The results indicate that the montane wet temperate forest is unique in their diversity and a conspicuous display in phenology.展开更多
Fruiting phenology, assessed by seed fall, in five warm- and cool-temperate forests on Yakushima Island, southern Japan, was studied for two years in one 50 m × 50 m plot and for four years in four 100 m ×50...Fruiting phenology, assessed by seed fall, in five warm- and cool-temperate forests on Yakushima Island, southern Japan, was studied for two years in one 50 m × 50 m plot and for four years in four 100 m ×50 m plots. The elevation of the plots ranged between 170 and 1200 m a.s.l. Seed fall phenology showed annual periodicity in all five plots. This was clear when assessed by the number of species but became less clear when assessed by the biomass of seed litter. Community-level annual periodicity was based on the prevalence of population-level annual periodicity and interspecific synchronization of the fruiting peak from autumn to winter. Fleshy fruits had peaks of seed fall in a wider range of months than non-fleshy fruits, since it is sometimes beneficial to bear fruit outside the community-level fruiting peaks in order to avoid interspecific competition for animal seed dispersers. No consistent effect of climatic factors on seed fall phenology was detected.展开更多
Quantification of fruit fall is the only way to compare fruit food availability among different studies. This study aims to reveal the general characteristics of fruit fall in temperate forests, which should offer ind...Quantification of fruit fall is the only way to compare fruit food availability among different studies. This study aims to reveal the general characteristics of fruit fall in temperate forests, which should offer indispensable information for using fruit fall data as food availability for frugivores. Fruit fall in three warm-temperate and two cool-temperate forests on Yakushima, an island in southwestern Japan, were studied for two years in one cool-temperate plot of 50 m × 50 m in size and for four years in other plots of 100 m × 50 m in size. The elevations of the plots ranged 170-1200 m a.s.1. Fruit fall was highest in the lowland forests （599 and 564 DW kg·ha^-1·year^-1 and lowest in the mid-elevation forest （198 DW kg·ha^-1·year^-1）. Fleshy fruits and food-fruits for Japanese macaques constituted 3-37% and 4-87% of the total fruit fall, respectively. When only fleshy-fruit fall was compared, it was higher in the western lowland forest （222 DW kg.ha^-1.year^-1） than in any other forests （9-66 DW kg-ha^-1.year^-1）. The pulp of fleshy fruits, presumably the edible parts for frugivores, was only 1.1-12.7% of the total fi ait fall. The edible parts for Japanese macaques constituted 3-54% of the fruit fall, showing a high value where acorns are abundant. Half of the fruit-fall biomass consisted of only one or two non- fleshy-fruited species, which are usually dominant in many other temperate forests, such as Quercus and conifers. These variations agreed with the variations in occurrence of frugivorous （such as Japanese macaques）.展开更多
Temperate forests exert significant biogeophysical influences on local and regional climates through modulating the energy and moisture exchanges between the land surface and the atmosphere,thereby serving as crucial ...Temperate forests exert significant biogeophysical influences on local and regional climates through modulating the energy and moisture exchanges between the land surface and the atmosphere,thereby serving as crucial barriers with significant buffering impacts on the productivity of adjacent agricultural ecosystems.However,the extent and underlying mechanisms of these biogeophysical and buffering effects of temperate forest barriers remains insufficiently understood.In this study,we integrated the dynamic crop model Noah-MP-Crop with the Weather Research and Forecasting(WRF)model to investigate the biogeophysical climate regulation of temperate forests and its buffering effects on crop yields in adjacent agricultural lands across Northeast China.Our findings revealed that temperate forest barriers induced significant local climate effects by cooling air and surface temperatures and reducing wind speeds within forested areas during the growing season,while also regulating non-local climate,particularly by altering regional precipitation patterns,2 m water vapor mixing ratio(Q2),and soil moisture,predominantly in adjacent cropland areas.Furthermore,these forest barriers were found to modulate climate extremes,through affecting maximum temperature and wind speed on a local scale,as well as both maximum and minimum Q2 in non-local croplands.Our study also observed that temperate forest barriers,through biogeophysical climate regulation,enhanced GPP,NPP,and grain yields across most cropland areas.This productivity boost was especially pronounced,with yield increases up to 20%in certain regions during the extreme drought conditions of 2017,underscoring the critical role of temperate forest barriers in sustaining and enhancing crop yields under severe climatic stress.Our findings underscore the significant buffering effects of temperate forest barriers on regional agricultural production,having important implications for climate adaptation strategies aimed at bolstering agricultural resilience in the face of increasing climate variability and extremes.展开更多
Numerous efforts have been made to characterize forest carbon （C） cycles and stocks in various ecosystems. However, long-term observation on each component of the forest C cycle is still lacking. We measured C stock...Numerous efforts have been made to characterize forest carbon （C） cycles and stocks in various ecosystems. However, long-term observation on each component of the forest C cycle is still lacking. We measured C stocks and fluxes in three per- manent temperate forest plots （birch, oak and pine forest） during 2011-2014, and calculated the changes of the components of the C cycle related to the measurements during 1992-1994 at Mr. Dongling, Beijing, China. Forest net primary production in birch, oak, and pine plots was 5.32, 4.53, and 6.73 Mg C ha-1 a-1, respectively. Corresponding net ecosystem production was 0.12, 0.43, and 3.53 Mg C ha-1 a-1. The C stocks and fluxes in 2011-2014 were significantly larger than those in 1992-1994 in which the biomass C densities in birch, oak, and pine plots increased from 50.0, 37.7, and 54.0 Mg C ha-1 in 1994 to 101.5, 77.3, and 110.9 Mg C ha a in 2014; soil organic C densities increased from 207.0, 239.1, and 231.7 Mg C ha-1 to 214.8, 241.7, and 238.4 Mg C ha-l; and soil heterotrophic respiration increased from 2.78, 3.49, and 1.81 Mg C ha-1 a-1 to 5.20, 4.10, and 3.20 Mg C ha-1 a-l. These results suggest that the mountainous temperate forest ecosystems in Beijing have served as a carbon sink in the last two decades. These observations of C stocks and fluxes provided field-based data for a long-term study of C cycling in temperate forest ecosystems.展开更多
Aims Species assembly is shaped by the interactions among ecological and evolutionary processes.By integrating the niche conservatism and evolutionary history,the tropical niche conservatism hypoth-esis(TCH)has clarif...Aims Species assembly is shaped by the interactions among ecological and evolutionary processes.By integrating the niche conservatism and evolutionary history,the tropical niche conservatism hypoth-esis(TCH)has clarified species latitudinal diversity gradient at large scales.One of the TCH’s central predictions,though lack-ing empirical evidence,implies that positive relationship between clade age and temperature along the altitudinal gradient should also be observed.Thus,we aim to test this prediction using a data set derived from forest communities of Mt.Taibai,central China.Methods We systematically established 49 plots(20 m×30 m)along the north slope on Mt.Taibai,China.We calculated the mean family age(MFA)and its corresponding standardized values through rarefi-cation and standardization,for woody and herbaceous angiosperm assemblages in each community respectively.Generalized linear models with Akaike weight and correlation analysis was used to evaluate the relationships between MFA with seven environmental predictors.Important Findings For both woody and herbaceous assemblages,the standardized MFA showed significant decreasing tendencies along the eleva-tional gradient and positive associations with minimum temperature(measured as mean temperature of the coldest month).Additionally,minimum temperature is the dominant predictor compared with the others in the regression models.These findings are generally con-sistent with the age-related predictions of the TCH,but are contrary to the results of related studies conducted in tropical regions.展开更多
A total of 900 soil samples were collected from five habitats,including primary coniferous broad-leaved mixed forests,secondary coniferous broad-leaved mixed forests,secondary broad-leaved forests,secondary shrub fore...A total of 900 soil samples were collected from five habitats,including primary coniferous broad-leaved mixed forests,secondary coniferous broad-leaved mixed forests,secondary broad-leaved forests,secondary shrub forests,and cutover lands in spring,summer,and autumn to quantify responses of soil Collembolans(springtails)to the restoration of vegetation of temperate coniferous and broad-leaved mixed forests.The results reveal that the taxonomic composition of Collembolans varied in the different stages of vegetation restoration.Seasonal variations were in regard to their abundance and richness.High similarities existed in Collembola communities at different stages of vegetation restoration,and distribution patterns of Collembola taxa displayed an evenness throughout all habitats.Soil Collembolans tended to gather on litter layers and soil surface;the highest abundance was found in the upper 5 cm soil layer during the initial stages of vegetation recovery.Tomocerus,Proisotoma,and Folsomia genera responded positively to the restoration of vegetation.However,responses of Ceratophysella and Parisotoma genera were negative.In addition,the Onychiuridae family did not respond to the vegetation restoration process.It was concluded that restoration of vegetative cover can increase the abundance of soil Collembolans,but different genera respond differently.展开更多
Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management...Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management and research.Our study aims to develop basal area growth models for tree species cohorts.The analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,Mexico.First,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster analyses.Then,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site quality.The principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the community.The generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak cohort.The developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.展开更多
Root tips are the main components of absorptive fine roots,but their seasonal dynamics and relationship to environmental factors remain unclear due to the difficulties in methodology.In this study,we explored the temp...Root tips are the main components of absorptive fine roots,but their seasonal dynamics and relationship to environmental factors remain unclear due to the difficulties in methodology.In this study,we explored the temporal patterns of root-tip production and mortality in monoculture plantations of five temperate tree species at a common site in northeastern China,and identified the general environmental controls on such processes.We made monthly in-situ assessments of root tip length(RTL)production and mortality in two hardwood and three coniferous species with a minirhizotron(MR)method during the growing seasons of 2008 and 2009.Air temperature,rainfall,soil temperature and water content at 10 cm depth were determined concurrently.RTL production in all species exhibited consistent peaks in summer(June–August)in two growing seasons.RTL mortality showed substantial interannual and interspecific variability,with peaks in autumn and winter in 2008,but various patterns in 2009.RTL production positively correlated with monthly soil and air temperature across all species,and with monthly rainfall in three coniferous species.However,there was no significant correlation between RTL production and soil water content.By contrast,RTL mortality was weakly related to environmental factors,showing positive correlations with soil temperature in Korean spruce,and with rainfall in Korean pine and Korean spruce.Our findings suggest that the seasonal patterns of RTL production are convergent across the five temperate tree species due to the overlapped distribution of heat and rainfall,which can conduce roots to maximizing the acquisition of nutrient resources in the soil.展开更多
Increasing human activity is altering the struc-ture of forests,which affects the composition of communi-ties,including birds.However,little is known about the key forest structure variables that determine the richnes...Increasing human activity is altering the struc-ture of forests,which affects the composition of communi-ties,including birds.However,little is known about the key forest structure variables that determine the richness of bird communities in European temperate oak forests.We,there-fore,aimed to identify key variables in these habitats that could contribute to the design of management strategies for forest conservation by surveying 11 oak-dominated forest sites throughout the mid-mountain range of Hungary at 86 survey points to reveal the role of different compositional and structural variables for forest stands that influence the breeding bird assemblages in the forests at the functional group and individual species levels.Based on decision tree modelling,our results showed that the density of trees larger than 30 cm DBH was an overall important variable,indi-cating that large-diameter trees were essential to provide diverse bird communities.The total abundance of birds,the foliage-gleaners,primary and secondary cavity nest-ers,residents,and five specific bird species were related to the density of high trunk diameter trees.The abundance of shrub nesters was negatively influenced by a high density of trees over 10 cm DBH.The density of the shrub layer positively affected total bird abundance and the abundance of foliage gleaners,secondary cavity nesters and residents.Analysis of the co-dominant tree species showed that the presence of linden,beech,and hornbeam was important in influencing the abundance of various bird species,e.g.,Eur-asian Treecreeper(Certhia familiaris),Marsh Tit(Poecile palustris)and Wood Warbler(Phylloscopus sibilatrix).Our results indicated that large trees,high tree diversity,and dense shrub layer were essential for forest bird communities and are critical targets for protection to maintain diverse and abundant bird communities in oak-dominated forest habitats.展开更多
Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structura...Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structural components drive arthropod abundance and biomass remains poorly understood in temperate forests.This study examined how local and landscape-scale forest characteristics influence arthropod communities across vertical strata(forest floor(FF),herb layer(HL),and shrub layer(SL))in 19 temperate deciduous forests in Belgium,dominated by pedunculate oak,European beech,or Canadian poplar.At the local scale,we assessed dominant tree species identity,overall forest structural complexity,and its components(vertical and horizontal structure,woody layer,herbal layer,and deadwood).At the landscape scale,we evaluated forest area,edge length,forest cover,and vegetation greenness(normalized difference vegetation index(NDVI)).Contrary to expectation,arthropod biomass and abundance did not consistently increase with higher structural complexity.Instead,woody layer complexity,dominant tree species,and NDVI emerged as key drivers,with effects varying by context and stratum.Arthropod abundance and biomass were the highest in oak-and poplar-dominated forests and the lowest in beech forests,likely due to differences in litter quality,microhabitat availability,and understory development.Woody layer complexity positively influenced forest floor arthropods in poplar forests but had a negative effect in oak forests.At the landscape scale,NDVI unexpectedly showed negative relationships with arthropod abundance across strata and with arthropod biomass in the herb layer,likely reflecting dense canopy suppression of understory productivity.Arthropod biomass on the forest floor increased with forest cover,while abundance in the shrub layer decreased with forest cover but increased with forest area.These findings highlight the complex interplay between forest structural attributes,dominant tree species,and landscape factors in shaping arthropod communities.By identifying the key drivers of arthropod abundance and biomass,this study contributes to a better understanding of biodiversity patterns in temperate forests and their ecological dynamics.展开更多
Middle-sized chambers (40cmx40cmx20 cm) and an infrared gas analyzer (IRGA) were used for the measurement of net photosynthesis of the grass layer and soil CO2 evolution, in Quercus liaotungensis Koidz. forest, which ...Middle-sized chambers (40cmx40cmx20 cm) and an infrared gas analyzer (IRGA) were used for the measurement of net photosynthesis of the grass layer and soil CO2 evolution, in Quercus liaotungensis Koidz. forest, which is a typical temperate forest ecosystem in the mountainous areas of Beijing. Changes of CO2 concentrations in both the atmosphere (2m above canopy) and the forest canopy (2m below the top of the canopy) together with those of net photosynthesis and soil CO2 evolution were also examined, in order to find the characteristics of CO2 exchange between the different components of the temperate forest ecosystem and the atmosphere. Atmospheric CO2 averaged (323+10) and (330+1) mol mol-1 respectively in summer and autumn. During the 24-hour measurements, large differences as much as -46 and -61 mol mol-1 respectively in the atmosphere and forest were found. Net photosynthesis of the grass layer in summer was (2. 59 9+ 1.05) mol CO2 m-2 S-1, two times of that in autumn, (1.31+0.39) mol CO2 s-1 In summer, there was much more CO2 evolved from soil than in autumn, averaging (5.18+0.75) mol CO2 m-2 s-1 and (1.96 + 0.57) (mol CO2 m-2 s-1, respectively. A significant correlation was found between soil CO2 evolution and ground temperature, with F =-0.864 2+0.310 1X,r=0.7164, P<0.001 (n=117). Both the minimal atmospheric CO2 level and the maximum net photosynthesis occurred around 14:00; and an increase in atmospheric CO2 and of soil CO2 evolution during night times were also found to be remarkable.展开更多
Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The ...Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The wetland zone covered with Picea glehnii pure stand. The riparian zone was deciduous broad-leaved stand dominated by Alnus hirsuta and Salix spp., while the mixture of deciduous broadleaf and evergreen conifer dominated by Betula platyphylla, Quercus crispula and Abies sachalinensis distributed on the upland zone. Annual litterfall averaged 1444, 5122, and 4123 kg.hm^-2·a^-1 in the wetland, riparian and upland zones, respectively. Litterfall production peaked in September-October, and foliage litter contributed the greatest amount （73.4%-87.6 %） of the annual total litterfall. Concentrations of nutrients analyzed in foliage litter of the dominant species showed a similar seasonal variation over the year except for N in P glehnii and A. hirsuta. The nutrient fluxes for all elements analyzed were greatest on riparian zone and lowest in wetland zone. Nutrient fluxes via litterfall followed the decreasing sequence： N （11-129 kg.hm-2.aq） 〉 Ca （9-69） 〉 K （5-20） 〉 Mg （3-15） 〉 P （0.4-4.7） for all stands. Significant differences were found in litterfall production and nutrient fluxes among the different landscape components. There existed significant differences in soil chemistry between the different landscape zones. The consistently low soil C：N ratios at the riparian zone might be due to the higher-quality litter inputs （largely N-fixing alder）.展开更多
Background: Global change is causing an increase in the incidence of natural and anthropogenic disturbances on forests, which frequently interact synergistically and promote changes in forest structure, composition an...Background: Global change is causing an increase in the incidence of natural and anthropogenic disturbances on forests, which frequently interact synergistically and promote changes in forest structure, composition and functioning. In this study we evaluate the regeneration of Pinaceae and Fagaceae species in pure and mixed stands in Mexico to determine if current regeneration patterns are indicative of changes in the relative dominance of these two tree families, as observed in other temperate regions. We also identify the environmental factors that determine the regeneration patterns of Pinaceae and Fagaceae species in these forests.Results: We use data from two consecutive surveys of the National Inventory of Forests and Soils of Mexico(INFyS),obtained in 2004–2009 and 2009–2014. Our results show that the spatial patterns of regeneration are affected by forest structure, by climate, by the type and intensity of disturbances and by land tenure. Importantly, the presence and abundance of Fagaceae regeneration is generally higher than that of Pinaceae, and tends to be favoured(relative to Pinaceae) under warmer climates and by the presence of wildfires.Conclusions: The higher regeneration of Fagaceae relative to Pinaceae under warmer and fire-prone conditions could have important impacts on the composition and functioning of Mexican temperate forests under ongoing climate change, as well as affect their resilience to future disturbances.展开更多
基金supported by the National Key R&D Program of China(No.2023YFF1304001-01)the Science and Technology Project of the Department of Transportation of Heilongjiang Province(No.HJK2023B024-3)the Program of National Natural Science Foundation of China(No.32371870).
文摘The net primary productivity(NPP)of forest ecosystems plays a crucial role in regulating the terrestrial carbon cycle under global climate change.While the temporal effect driven by ecosystem processes on NPP variations is well-documented,spatial variations(from local to regional scales)remain inadequately understood.To evaluate the scale-dependent effects of productivity,predictions from the Biome-BGC model were compared with moderate-resolution imaging spectroradiometer(MODIS)and biometric NPP data in a large temperate forest region at both local and regional levels.Linear mixed-effect models and variance partitioning analysis were used to quantify the effects of environmental heterogeneity and trait variation on simulated NPP at varying spatial scales.Results show that NPP had considerable predictability at the local scale,with a coefficient of determination(R^(2))of 0.37,but this predictability declined significantly to 0.02 at the regional scale.Environmental heterogeneity and photosynthetic traits collectively explained 94.8%of the local variation in NPP,which decreased to 86.7%regionally due to the reduced common effects among these variables.Locally,the leaf area index(LAI)predominated(34.6%),while at regional scales,the stomatal conductance and maximum carboxylation rate were more influential(41.1%).Our study suggests that environmental heterogeneity drives the photosynthetic processes that mediate NPP variations across spatial scales.Incorporating heterogeneous local conditions and trait variations into analyses could enhance future research on the relationship between climate and carbon cycles at larger scales.
基金supported by the National Natural Science Foundation of China(Nos.42107476 and 42177421)the China Postdoctoral International Exchange Fellowship Program(No.PC2021099)+1 种基金the Science and Technology Innovation Program of Hunan Province(No.2020RC2058)the China Scholarship Council(CSC,No.202206600004,to D.Yuan).
文摘Tree growth synchrony serves as a valuable ecological indicator of forest resilience to climate stress and disturbances.However,our understanding of how increasing temperature affects tree growth synchrony during rapidly and slowly warming periods in ecosystems with varying climatic conditions remains limited.By using tree-ring data from temperate broadleaf(Fraxinus mandshurica,Phellodendron amurense,Quercus mongolica,and Juglans mandshurica)and Korean pine(Pinus koraiensis)mixed forests in northeast China,we investigated the effects of climate change,particularly warming,on the growth synchrony of five dominant temperate tree species across contrasting warm-dry and cool-wet climate conditions.Results show that temperature over water availability was the primary factor driving the growth and growth synchrony of the five species.Growth synchrony was significantly higher in warm-dry than in cool-wet areas,primarily due to more uniform climate conditions and higher climate sensitivity in the former.Rapid warming from the 1960s to the 1990s significantly enhanced tree growth synchrony in both areas,followed by a marked reversal as temperatures exceeded a certain threshold or warming slowed down,particularly in the warm-dry area.The growth synchrony variation patterns of the five species were highly consistent over time,although broadleaves exhibited higher synchrony than conifers,suggesting potential risks to forest resilience and stability under future climate change scenarios.Growing season temperatures and non-growing season temperatures and precipitation had a stronger positive effect on tree growth in the cool-wet area compared to the warm-dry area.High relative humidity hindered growth in the cool-wet area but enhanced it in the warm-dry area.Overall,our study highlights that the diversity and sensitivity of climate-growth relationships directly determine spatiotemporal growth synchrony.Temperature,along with water availability,shape long-term forest dynamics by affecting tree growth and synchrony.These results provide crucial insights for forest management practice to enhance structural diversity and resilience capacity against climate changeinduced synchrony shifts.
基金financially supported by the National Natural Science Foundation(No.32471868,No.32001324)Youth Lift Project of China Association for Science and Technology(No.YESS20210370)+1 种基金Fundamental Research Funds for the Central Universities(2572023CT01)We thank the Grassland Bureau and the National Innovation Alliance of Wildland Fire Prevention and Control Technology of China for supporting this research.
文摘Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest ecosystems,the effects of prescribed burnings on soil microbial community structure are less studied.It is also unclear that how post-fire soil physiochemical properties changes affected soil microbial communities.Here,we studied the impacts of prescribed burning on soil microbiome in three typical temperate forests of northern China by collecting soil physicochemical and high-throughput sequencing for 16S rRNA and 18S rRNA was applied to analyze the diversity and community composition of soil microbes(bacteria and fungi).Compared with pre-fire condition,prescribed burning significantly decreased Chaol index and altered soil bacterial communities(P<0.05),whereas it had no significant effect on fungal diversity and community structure of the(P>0.05).Planctomycetes and Actinobacteria made the greatest contributions to the bacterial community dissimilarity between the pre-fire and post-fire conditions.The main variables influencing the post-fire soil microbial community structure are soil pH,available phosphorus,total nitrogen,and the ratio of soil total carbon to soil total nitrogen,which could account for 73.5% of the variation in the microbial community structure in these stands.Our findings demonstrated a great discrepancy in the responses of bacteria and fungi to prescribed burning.Prescribed burning altered the soil microbial structure by modifying the physicochemical properties.Our results pointed that it is essential to evaluate the impact of prescribed burnings on forest ecosystem functions.These findings provide an important baseline for assessing post-fire microbial recovery in the region and offer critical guidance for restoration efforts.
基金sponsored by the National Natural Science Foundation of China(41877538,41671511)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB40000000,XDA23070201)the Funding of Special Support Plan of Young Talents Project of China and National Forestry and Grassland Administration in China(20201326015)。
文摘Litter and root activities may alter the temperature sensitivity(Q_(10))of soil respiration.However,existing studies have not provided a comprehensive understanding of the effects of litter and root carbon inputs on the Q_(10)of soil respiration in different seasons.In this study,we used the trench method under in situ conditions to measure the total soil respiration(R_(total)),litter-removed soil respiration(R_(no-litter)),root-removed soil respiration(R_(no-root)),and the decomposition of soil organic matter(i.e.,both litter and root removal;R_(SOM))in different seasons of pioneer(Populus davidiana Dode)and climax(Quercus liaotungensis Mary)forests on the Loess Plateau,China.Soil temperature,soil moisture,litter biomass,fine root biomass,litter carbon,and root carbon were analyzed to obtain the drive mechanism of the Q_(10)of soil respiration in the two forests.The results showed that the Q_(10)of soil respiration exhibited seasonality,and the Q_(10)of soil respiration was higher in summer.The litter enhanced the Q_(10)of soil respiration considerably more than the root did.Soil temperature,soil moisture,fine root biomass,and litter carbon were the main factors used to predict the Q_(10)of different soil respiration components.These findings indicated that factors affecting the Q_(10)of soil respiration highly depended on soil temperature and soil moisture as well as related litter and root traits in the two forests,which can improve our understanding of soil carbon–climate feedback in global warming.The results of this study can provide reference for exploring soil respiration under temperate forest restoration.
基金financially supported by the Fundamental Research Funds for the Central Universities(Grant No.YX2014-10)the Normal Sustainability Fund for the Taiyueshan Long-Term Forest Ecology Research Station(2017-LYPT-DW-148)
文摘Background: The large potential of the soil organic carbon(SOC) pool to sequester CO2from the atmosphere could greatly ameliorate the effect of future climate change. However, the quantity of carbon stored in terrestrial soils largely depends upon the magnitude of SOC mineralization. SOC mineralization constitutes an important part of the carbon cycle, and is driven by many biophysical variables, such as temperature and moisture.Methods: Soil samples of a pine forest, an oak forest, and a pine and oak mixed forest were incubated for 387 days under conditions with six temperature settings(5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C) and three levels of soil moisture content(SMC, 30%, 60%, 90%). The instantaneous rate of mineralized SOC was periodically and automatically measured using a Li-Cor CO2analyzer. Based on the measured amount of mineralized SOC,carbon fractions were estimated separately via first-order kinetic one-and two-compartment models.Results: During the 387 day incubation experiment, accumulative mineralized carbon ranged from 22.89 mg carbon(C) ·g-1SOC at 30 °C and 30% SMC for the mixed forest to 109.20 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest. Mineralized recalcitrant carbon varied from 18.48 mg C·g-1SOC at 30 °C and 30% SMC for the mixed forest to 104.98 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest, and contributed at least 80% to total mineralized carbon.Conclusions: Based on the results of this experiment, the soil organic matter of the pure broadleaved forest is more vulnerable to soil microbial degradation in northern China; most of the amount of the mineralized SOC derived from the recalcitrant carbon pool. Labile carbon fraction constitutes on average 0.4% of SOC across the three forest types and was rapidly digested by soil microbes in the early incubation stage. SOC mineralization markedly increased with soil moisture content, and correlated parabolically to temperature with the highest value at 15 °C. No significant interaction was detected among these variables in the present study.
基金conducted as a part of the project on the endemic birds in the Western Ghats funded by the Ministry of Environment and Forest, Government of India (23-1/2001-RE)
文摘Plants diversity and phenological pattern of the trees were monitored in a montane wet temperate forest （shola） in the Kukkal Forest, Palni hills of the southern Western Ghats, India. Twelve random plots were selected for sampling the vegetation. For phenological studies, twenty-three fleshy fruit trees were identified in the study area and 10 individuals of each species were selected to record the phenological events fortnightly between April 2002 and April 2004. The phenological events were divided into vegetative and reproductive phases. A total of 2279 individuals were inventoried which belong to 83 species, 68 genera and 40 families. About 30% of the species were endemic to the Western Ghats. The most dominant species （〉 1 cm dbh） was Psychotria nilgiriensis var. astephana （Rubiaceae）, which accounted for 12% of the total sampled individuals. Lauraceae was the dominant family accounting for 20% of the individuals. Fruiting peak occurred in July 2003 and least in June 2002. During the peak period, fruits of 85 individuals of six species were observed. Syzygium tamilnadensis, Ilex wightiana and Beilschmiedia wightii fruited only once during the two years of study. The number of fruiting species showed no correlation with rainfall （r = 0.26, p = 0.2）, while a correlation was found with fruit abundance （r = 0.40, p 〈 0.05）. The results indicate that the montane wet temperate forest is unique in their diversity and a conspicuous display in phenology.
基金financed by the Cooperation Research Program of KUPRIthe MEXT Grant-in-Aid for JSPS Fellows, the 21st Century COE ProgramGlobal COE Program "Formation of a Strategic Base for Biodiversity and Evolutionary Research: from Genome to Ecosystem"
文摘Fruiting phenology, assessed by seed fall, in five warm- and cool-temperate forests on Yakushima Island, southern Japan, was studied for two years in one 50 m × 50 m plot and for four years in four 100 m ×50 m plots. The elevation of the plots ranged between 170 and 1200 m a.s.l. Seed fall phenology showed annual periodicity in all five plots. This was clear when assessed by the number of species but became less clear when assessed by the biomass of seed litter. Community-level annual periodicity was based on the prevalence of population-level annual periodicity and interspecific synchronization of the fruiting peak from autumn to winter. Fleshy fruits had peaks of seed fall in a wider range of months than non-fleshy fruits, since it is sometimes beneficial to bear fruit outside the community-level fruiting peaks in order to avoid interspecific competition for animal seed dispersers. No consistent effect of climatic factors on seed fall phenology was detected.
基金financed by the Cooperation Research Program of KUPRI,the MEXT Grant-in-Aid for JSPS Fellows,the 21st Century COE Program,the Global COE Program "Formation of a Strategic Base for Biodiversity and Evolutionary Research:from Genome to Ecosystem"
文摘Quantification of fruit fall is the only way to compare fruit food availability among different studies. This study aims to reveal the general characteristics of fruit fall in temperate forests, which should offer indispensable information for using fruit fall data as food availability for frugivores. Fruit fall in three warm-temperate and two cool-temperate forests on Yakushima, an island in southwestern Japan, were studied for two years in one cool-temperate plot of 50 m × 50 m in size and for four years in other plots of 100 m × 50 m in size. The elevations of the plots ranged 170-1200 m a.s.1. Fruit fall was highest in the lowland forests （599 and 564 DW kg·ha^-1·year^-1 and lowest in the mid-elevation forest （198 DW kg·ha^-1·year^-1）. Fleshy fruits and food-fruits for Japanese macaques constituted 3-37% and 4-87% of the total fruit fall, respectively. When only fleshy-fruit fall was compared, it was higher in the western lowland forest （222 DW kg.ha^-1.year^-1） than in any other forests （9-66 DW kg-ha^-1.year^-1）. The pulp of fleshy fruits, presumably the edible parts for frugivores, was only 1.1-12.7% of the total fi ait fall. The edible parts for Japanese macaques constituted 3-54% of the fruit fall, showing a high value where acorns are abundant. Half of the fruit-fall biomass consisted of only one or two non- fleshy-fruited species, which are usually dominant in many other temperate forests, such as Quercus and conifers. These variations agreed with the variations in occurrence of frugivorous （such as Japanese macaques）.
基金supported by National Key R&D Program of China(Grant No.2024YFD1501600)the National Natural Science Foundation of China(Grants No.42071025,42371075)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2023240).
文摘Temperate forests exert significant biogeophysical influences on local and regional climates through modulating the energy and moisture exchanges between the land surface and the atmosphere,thereby serving as crucial barriers with significant buffering impacts on the productivity of adjacent agricultural ecosystems.However,the extent and underlying mechanisms of these biogeophysical and buffering effects of temperate forest barriers remains insufficiently understood.In this study,we integrated the dynamic crop model Noah-MP-Crop with the Weather Research and Forecasting(WRF)model to investigate the biogeophysical climate regulation of temperate forests and its buffering effects on crop yields in adjacent agricultural lands across Northeast China.Our findings revealed that temperate forest barriers induced significant local climate effects by cooling air and surface temperatures and reducing wind speeds within forested areas during the growing season,while also regulating non-local climate,particularly by altering regional precipitation patterns,2 m water vapor mixing ratio(Q2),and soil moisture,predominantly in adjacent cropland areas.Furthermore,these forest barriers were found to modulate climate extremes,through affecting maximum temperature and wind speed on a local scale,as well as both maximum and minimum Q2 in non-local croplands.Our study also observed that temperate forest barriers,through biogeophysical climate regulation,enhanced GPP,NPP,and grain yields across most cropland areas.This productivity boost was especially pronounced,with yield increases up to 20%in certain regions during the extreme drought conditions of 2017,underscoring the critical role of temperate forest barriers in sustaining and enhancing crop yields under severe climatic stress.Our findings underscore the significant buffering effects of temperate forest barriers on regional agricultural production,having important implications for climate adaptation strategies aimed at bolstering agricultural resilience in the face of increasing climate variability and extremes.
基金supported by National Natural Science Foundation of China(31321061,31330012)National Basic Research Program of China on Global Change(2014CB954001)
文摘Numerous efforts have been made to characterize forest carbon （C） cycles and stocks in various ecosystems. However, long-term observation on each component of the forest C cycle is still lacking. We measured C stocks and fluxes in three per- manent temperate forest plots （birch, oak and pine forest） during 2011-2014, and calculated the changes of the components of the C cycle related to the measurements during 1992-1994 at Mr. Dongling, Beijing, China. Forest net primary production in birch, oak, and pine plots was 5.32, 4.53, and 6.73 Mg C ha-1 a-1, respectively. Corresponding net ecosystem production was 0.12, 0.43, and 3.53 Mg C ha-1 a-1. The C stocks and fluxes in 2011-2014 were significantly larger than those in 1992-1994 in which the biomass C densities in birch, oak, and pine plots increased from 50.0, 37.7, and 54.0 Mg C ha-1 in 1994 to 101.5, 77.3, and 110.9 Mg C ha a in 2014; soil organic C densities increased from 207.0, 239.1, and 231.7 Mg C ha-1 to 214.8, 241.7, and 238.4 Mg C ha-l; and soil heterotrophic respiration increased from 2.78, 3.49, and 1.81 Mg C ha-1 a-1 to 5.20, 4.10, and 3.20 Mg C ha-1 a-l. These results suggest that the mountainous temperate forest ecosystems in Beijing have served as a carbon sink in the last two decades. These observations of C stocks and fluxes provided field-based data for a long-term study of C cycling in temperate forest ecosystems.
基金This research was supported by the National Natural Science Foundation of China(No.41630750 and No.41271059)the National Key Basic Research Special Foundation of China(No.2011FY110300).
文摘Aims Species assembly is shaped by the interactions among ecological and evolutionary processes.By integrating the niche conservatism and evolutionary history,the tropical niche conservatism hypoth-esis(TCH)has clarified species latitudinal diversity gradient at large scales.One of the TCH’s central predictions,though lack-ing empirical evidence,implies that positive relationship between clade age and temperature along the altitudinal gradient should also be observed.Thus,we aim to test this prediction using a data set derived from forest communities of Mt.Taibai,central China.Methods We systematically established 49 plots(20 m×30 m)along the north slope on Mt.Taibai,China.We calculated the mean family age(MFA)and its corresponding standardized values through rarefi-cation and standardization,for woody and herbaceous angiosperm assemblages in each community respectively.Generalized linear models with Akaike weight and correlation analysis was used to evaluate the relationships between MFA with seven environmental predictors.Important Findings For both woody and herbaceous assemblages,the standardized MFA showed significant decreasing tendencies along the eleva-tional gradient and positive associations with minimum temperature(measured as mean temperature of the coldest month).Additionally,minimum temperature is the dominant predictor compared with the others in the regression models.These findings are generally con-sistent with the age-related predictions of the TCH,but are contrary to the results of related studies conducted in tropical regions.
基金We express our sincere thanks to Dr.Ernest Bernard(University of Tennessee,Knoxville,USA)for his kind help.At the same time,we would like to thank Dr.Xiaoqiang Li,Dr.Zhenghai Wang,Huiying Han,Hongyue Li,Wenli Xue,Yumei Guo,and Xinchang Kou for their help with field work and laboratory analyses。
文摘A total of 900 soil samples were collected from five habitats,including primary coniferous broad-leaved mixed forests,secondary coniferous broad-leaved mixed forests,secondary broad-leaved forests,secondary shrub forests,and cutover lands in spring,summer,and autumn to quantify responses of soil Collembolans(springtails)to the restoration of vegetation of temperate coniferous and broad-leaved mixed forests.The results reveal that the taxonomic composition of Collembolans varied in the different stages of vegetation restoration.Seasonal variations were in regard to their abundance and richness.High similarities existed in Collembola communities at different stages of vegetation restoration,and distribution patterns of Collembola taxa displayed an evenness throughout all habitats.Soil Collembolans tended to gather on litter layers and soil surface;the highest abundance was found in the upper 5 cm soil layer during the initial stages of vegetation recovery.Tomocerus,Proisotoma,and Folsomia genera responded positively to the restoration of vegetation.However,responses of Ceratophysella and Parisotoma genera were negative.In addition,the Onychiuridae family did not respond to the vegetation restoration process.It was concluded that restoration of vegetative cover can increase the abundance of soil Collembolans,but different genera respond differently.
基金The National Forestry Commission of Mexico and The Mexican National Council for Science and Technology(CONAFOR-CONACYT-115900)。
文摘Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management and research.Our study aims to develop basal area growth models for tree species cohorts.The analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,Mexico.First,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster analyses.Then,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site quality.The principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the community.The generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak cohort.The developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.
基金supported by the National Natural Science Foundation of China(32071749)。
文摘Root tips are the main components of absorptive fine roots,but their seasonal dynamics and relationship to environmental factors remain unclear due to the difficulties in methodology.In this study,we explored the temporal patterns of root-tip production and mortality in monoculture plantations of five temperate tree species at a common site in northeastern China,and identified the general environmental controls on such processes.We made monthly in-situ assessments of root tip length(RTL)production and mortality in two hardwood and three coniferous species with a minirhizotron(MR)method during the growing seasons of 2008 and 2009.Air temperature,rainfall,soil temperature and water content at 10 cm depth were determined concurrently.RTL production in all species exhibited consistent peaks in summer(June–August)in two growing seasons.RTL mortality showed substantial interannual and interspecific variability,with peaks in autumn and winter in 2008,but various patterns in 2009.RTL production positively correlated with monthly soil and air temperature across all species,and with monthly rainfall in three coniferous species.However,there was no significant correlation between RTL production and soil water content.By contrast,RTL mortality was weakly related to environmental factors,showing positive correlations with soil temperature in Korean spruce,and with rainfall in Korean pine and Korean spruce.Our findings suggest that the seasonal patterns of RTL production are convergent across the five temperate tree species due to the overlapped distribution of heat and rainfall,which can conduce roots to maximizing the acquisition of nutrient resources in the soil.
基金supported part ia l l y by LIFE4Oak Forests Project LIFE16NAT/IT/000245)the RRF 2.3.121202200008 projectthe MERLiN project funded under the European Commission H2020 Programme(101036337 MERLiN H2020 LC GD 2020)。
文摘Increasing human activity is altering the struc-ture of forests,which affects the composition of communi-ties,including birds.However,little is known about the key forest structure variables that determine the richness of bird communities in European temperate oak forests.We,there-fore,aimed to identify key variables in these habitats that could contribute to the design of management strategies for forest conservation by surveying 11 oak-dominated forest sites throughout the mid-mountain range of Hungary at 86 survey points to reveal the role of different compositional and structural variables for forest stands that influence the breeding bird assemblages in the forests at the functional group and individual species levels.Based on decision tree modelling,our results showed that the density of trees larger than 30 cm DBH was an overall important variable,indi-cating that large-diameter trees were essential to provide diverse bird communities.The total abundance of birds,the foliage-gleaners,primary and secondary cavity nest-ers,residents,and five specific bird species were related to the density of high trunk diameter trees.The abundance of shrub nesters was negatively influenced by a high density of trees over 10 cm DBH.The density of the shrub layer positively affected total bird abundance and the abundance of foliage gleaners,secondary cavity nesters and residents.Analysis of the co-dominant tree species showed that the presence of linden,beech,and hornbeam was important in influencing the abundance of various bird species,e.g.,Eur-asian Treecreeper(Certhia familiaris),Marsh Tit(Poecile palustris)and Wood Warbler(Phylloscopus sibilatrix).Our results indicated that large trees,high tree diversity,and dense shrub layer were essential for forest bird communities and are critical targets for protection to maintain diverse and abundant bird communities in oak-dominated forest habitats.
基金supported by the UGent GOA project“Forest biodiversity and multifunctionality drive chronic stress-mediated dynamics in pathogen reservoirs(FORESTER)”(No.BOF20/GOA/009).
文摘Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structural components drive arthropod abundance and biomass remains poorly understood in temperate forests.This study examined how local and landscape-scale forest characteristics influence arthropod communities across vertical strata(forest floor(FF),herb layer(HL),and shrub layer(SL))in 19 temperate deciduous forests in Belgium,dominated by pedunculate oak,European beech,or Canadian poplar.At the local scale,we assessed dominant tree species identity,overall forest structural complexity,and its components(vertical and horizontal structure,woody layer,herbal layer,and deadwood).At the landscape scale,we evaluated forest area,edge length,forest cover,and vegetation greenness(normalized difference vegetation index(NDVI)).Contrary to expectation,arthropod biomass and abundance did not consistently increase with higher structural complexity.Instead,woody layer complexity,dominant tree species,and NDVI emerged as key drivers,with effects varying by context and stratum.Arthropod abundance and biomass were the highest in oak-and poplar-dominated forests and the lowest in beech forests,likely due to differences in litter quality,microhabitat availability,and understory development.Woody layer complexity positively influenced forest floor arthropods in poplar forests but had a negative effect in oak forests.At the landscape scale,NDVI unexpectedly showed negative relationships with arthropod abundance across strata and with arthropod biomass in the herb layer,likely reflecting dense canopy suppression of understory productivity.Arthropod biomass on the forest floor increased with forest cover,while abundance in the shrub layer decreased with forest cover but increased with forest area.These findings highlight the complex interplay between forest structural attributes,dominant tree species,and landscape factors in shaping arthropod communities.By identifying the key drivers of arthropod abundance and biomass,this study contributes to a better understanding of biodiversity patterns in temperate forests and their ecological dynamics.
基金This is a key project of National Natural Science Foundation of China.
文摘Middle-sized chambers (40cmx40cmx20 cm) and an infrared gas analyzer (IRGA) were used for the measurement of net photosynthesis of the grass layer and soil CO2 evolution, in Quercus liaotungensis Koidz. forest, which is a typical temperate forest ecosystem in the mountainous areas of Beijing. Changes of CO2 concentrations in both the atmosphere (2m above canopy) and the forest canopy (2m below the top of the canopy) together with those of net photosynthesis and soil CO2 evolution were also examined, in order to find the characteristics of CO2 exchange between the different components of the temperate forest ecosystem and the atmosphere. Atmospheric CO2 averaged (323+10) and (330+1) mol mol-1 respectively in summer and autumn. During the 24-hour measurements, large differences as much as -46 and -61 mol mol-1 respectively in the atmosphere and forest were found. Net photosynthesis of the grass layer in summer was (2. 59 9+ 1.05) mol CO2 m-2 S-1, two times of that in autumn, (1.31+0.39) mol CO2 s-1 In summer, there was much more CO2 evolved from soil than in autumn, averaging (5.18+0.75) mol CO2 m-2 s-1 and (1.96 + 0.57) (mol CO2 m-2 s-1, respectively. A significant correlation was found between soil CO2 evolution and ground temperature, with F =-0.864 2+0.310 1X,r=0.7164, P<0.001 (n=117). Both the minimal atmospheric CO2 level and the maximum net photosynthesis occurred around 14:00; and an increase in atmospheric CO2 and of soil CO2 evolution during night times were also found to be remarkable.
基金The project was supported by Japanese Society for Promotion of Sciences (15P03118).
文摘Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The wetland zone covered with Picea glehnii pure stand. The riparian zone was deciduous broad-leaved stand dominated by Alnus hirsuta and Salix spp., while the mixture of deciduous broadleaf and evergreen conifer dominated by Betula platyphylla, Quercus crispula and Abies sachalinensis distributed on the upland zone. Annual litterfall averaged 1444, 5122, and 4123 kg.hm^-2·a^-1 in the wetland, riparian and upland zones, respectively. Litterfall production peaked in September-October, and foliage litter contributed the greatest amount （73.4%-87.6 %） of the annual total litterfall. Concentrations of nutrients analyzed in foliage litter of the dominant species showed a similar seasonal variation over the year except for N in P glehnii and A. hirsuta. The nutrient fluxes for all elements analyzed were greatest on riparian zone and lowest in wetland zone. Nutrient fluxes via litterfall followed the decreasing sequence： N （11-129 kg.hm-2.aq） 〉 Ca （9-69） 〉 K （5-20） 〉 Mg （3-15） 〉 P （0.4-4.7） for all stands. Significant differences were found in litterfall production and nutrient fluxes among the different landscape components. There existed significant differences in soil chemistry between the different landscape zones. The consistently low soil C：N ratios at the riparian zone might be due to the higher-quality litter inputs （largely N-fixing alder）.
基金supported by “‘Consejo Nacional de Ciencia y Tecnología-CONACYT’“by a national research grant/scholarship(CVU 225254)to TARby the Spanish government through grant CGL2013–46808-R.JMV benefits from an ICREA Academia award
文摘Background: Global change is causing an increase in the incidence of natural and anthropogenic disturbances on forests, which frequently interact synergistically and promote changes in forest structure, composition and functioning. In this study we evaluate the regeneration of Pinaceae and Fagaceae species in pure and mixed stands in Mexico to determine if current regeneration patterns are indicative of changes in the relative dominance of these two tree families, as observed in other temperate regions. We also identify the environmental factors that determine the regeneration patterns of Pinaceae and Fagaceae species in these forests.Results: We use data from two consecutive surveys of the National Inventory of Forests and Soils of Mexico(INFyS),obtained in 2004–2009 and 2009–2014. Our results show that the spatial patterns of regeneration are affected by forest structure, by climate, by the type and intensity of disturbances and by land tenure. Importantly, the presence and abundance of Fagaceae regeneration is generally higher than that of Pinaceae, and tends to be favoured(relative to Pinaceae) under warmer climates and by the presence of wildfires.Conclusions: The higher regeneration of Fagaceae relative to Pinaceae under warmer and fire-prone conditions could have important impacts on the composition and functioning of Mexican temperate forests under ongoing climate change, as well as affect their resilience to future disturbances.
