Temperate Zone Research Articles

Carbon carrying capacity in primary forests shows potential for mitigation achieving the European Green Deal 2030 target

Carbon accounting in the land sector requires a reference level from which to calculate past losses of carbon and potential for gains using a stock-based target. Carbon carrying capacity represented by the carbon stock in primary forests is an ecologically-based reference level that allows estimation of the mitigation potential derived from protecting and restoring forests to increase their carbon stocks. Here we measured and collated tree inventory data at primary forest sites including from research studies, literature and forest inventories (7982 sites, 288,262 trees, 27 countries) across boreal, temperate, and subtropical Global Ecological Zones within Europe. We calculated total biomass carbon stock per hectare (above- and below-ground, dead biomass) and found it was 1.6 times larger on average than modelled global maps for primary forests and 2.3 times for all forests. Large trees (diameter greater than 60 cm) accounted for 50% of biomass and are important carbon reservoirs. Carbon stock foregone by harvesting of 12–52% demonstrated the mitigation potential. Estimated carbon gain by protecting, restoring and ongoing growth of existing forests equated to 309 megatons carbon dioxide equivalents per year, additional to, and higher than, the current forest sink, and comparable to the Green Deal 2030 target for carbon dioxide removals.

Decoupling the multi-drivers of urban extreme heat environment in urban agglomerations using ensemble learning

Urban extreme heat (UEH) has been imparting a formidable menace to various facets of sustainable urban and regional development. While increasing studies have examined the urban thermal environment, a gap exists in decoupling the nonlinear multi-drivers of UEH environment in intra-urban regions, especially across the urban agglomerations. In this study, we estimated UEH through the land surface temperature (LST) in the extended summer season exceeding a specific threshold computed through cross-regional statistics. Furthermore, an additive interpretable ensemble learning model enhanced via the Bayesian Optimization algorithm (BO) and Monte Carlo Simulation framework (MCS) was employed to dissect the intricate nonlinear interplay between UEH and intra-urban morphology, green-blue composition, and atmospheric determinants. Our results highlight the indispensably suppressive effect of green and blue factors on UEH, whereas urban morphological variables generally exhibit an opposite trend. Interestingly, we reveal heterogeneity responses of building heights, elevated urban structures mitigate UEH in temperate monsoon and subtropical monsoon zones and exhibit diminished marginal utility in temperate continental zones. Furthermore, the arid climatic characteristics are expected to exert an unexpectedly enhancing effect on water bodies' cooling capacity. These findings provide heterogeneous local guidance for landscape and urban planning towards the severe challenges of climate change.

Does the Amount of Pre-Sowing Nitrogen Fertilization Affect Sugar Beet Root Yield and Quality of Different Genotypes?

There has always been a specific focus on nitrogen fertilization in sugar beet production due to its important effect on sugar beet root yield and quality. For stable sugar beet growth and satisfactory root yield and quality, balanced N fertilization is crucial. Thus, this study aimed to investigate spring N fertilization in two seasons as the following treatments: N0—control, N1—only pre-sowing fertilization, and N2—pre-sowing with topdressing. Four different genotypes were included in the study (Serenada, Colonia, Fred, and Danton). The experiment was set up in a plain area, belonging to the temperate climate zone in Eastern Croatia (Županja and Vrbanja), with the long-term mean (LTM) (March–October) air temperature around 16 °C and the total precipitation of 515 mm. Pre-sowing N fertilization had a smaller impact on root yield in the year with higher precipitation (31% higher than LTM). Therefore, the average yields with pre-sowing fertilization (N1) and pre-sowing fertilization with top dressing (N2) were very similar and were only 7% higher than those of the control. In a season with less rainfall (29% less than LTM), pre-sowing fertilization with top dressing (N2) had a more pronounced effect on the increase in sugar beet root yield, which was 17% higher compared to that of the control treatment. The sugar beet sucrose content and quality parameters (brei impurities, loss of sugar in molasses, extractable sugar) differed when N fertilization was applied among locations in both seasons. The white sugar yield was the highest at N2 treatment with pre-sowing and topdressing N fertilization. In general, according to the average of all locations and years of research, the Serenada hybrid achieved the highest average root yield (81.1 t ha−1), while Colonia exhibited the highest root sugar content (14.5%) and white sugar yield (9.7 t ha−1).

How Artificial Salt Marsh Vegetation Reduces The Threshold For Sediment Resuspension In Wave-Current Flows

Suspended sediment transport and retention within salt marshes is a key factor in their resilience against erosion associated with threats such as sea level rise and coastal squeeze. Salt marshes are vegetated intertidal wetlands found in temperate climate zones. Their presence contributes to flood protection, coastal flora and fauna, and carbon sequestration (Temmerman et al., 2013). Vegetation-induced resuspension of fine sediment helps to transport fine particles deeper into salt marshes. The interaction between waves, currents, and vegetation may resuspend sediment sooner than it would without vegetation. It has been shown in conditions with only currents (Liu et al., 2021; Tinoco & Coco, 2014) or only waves (Tinoco & Coco, 2018) that the threshold for resuspension is lower within vegetated meadows than without vegetation. However, the threshold has not yet been studied for combined wave-current conditions, which often exist in the marsh environment. Identifying this threshold will enable us to predict when in a tidal cycle sediment resuspension occurs and can be used to improve sediment transport model. We use flume experiments to methodically identify the threshold of sediment resuspension in artificial salt marsh meadows of three different area densities under combined wave-current flows.

The correlation between autumnal landscape colors and environmental factors and the analysis of ecological service functions in subtropical urban scenic forests

Background and objectivesUrban scenic forests are a main component of forest parks, and a quantitative study of the landscape color of urban scenic forests can provide a scientific reference for the planning of forest parks and the design of scenic forest management measures. The purpose of the study is to find the quantitative correlation between autumn landscape color and ecological service functions and to obtain the important influencing factors.Materials and methodsThis study focuses on Purple Mountain National Forest Park in Nanjing as a case study area and uses forest resource survey data from Purple Mountain National Forest Park in 2020, autumn landscape color photograph data from Purple Mountain National Forest Park in 2020, and digital elevation model data as the main information sources. The correlation between two ecological functions of above-ground biomass (AGB), tree species diversity (TSD), and influencing factors (including color factors, stand factors, and terrain factors) were both analyzed by Pearson correlation analysis. Then, multiple linear regression (MLR) and random forest (RF) methods were used to perform the quantitative relationship between the functions.ResultsThe results show that, in the established quantitative models of AGB, with TSD as the dependent variable, the correlation coefficients of the MLR model are both above 0.784, while the correlation coefficients of the RF model are all above 0.872. Moreover, the brightness value of the main color (BRI), the number of yellow-green blocks (NYG), and the number of yellow blocks (NY) have important effects on the two ecological service functions.ConclusionIn conclusion, there are complex non-linear relationships between the ecological service functions of AGB, TSD, and influencing factors, and the landscape color can reflect the ecological function of the scenic forest to some extent. In addition, stand factors and color factors have important effects on the ecological function of AGB. Color factors and terrain factors have important effects on the ecological function of TSD. BRI, NYG, and NY have important effects on the two ecological functions. Finally, this quantitative method has universal applicability in the temperate zone, warm temperate zone, and subtropical zone of China.

Spatial-temporal variation of water vapor scale height and its impact factors in different climate zones of China

Water vapor scale height reflects the vertical distribution of water vapor in the atmosphere, which is a vital parameter in tropospheric zenith wet delay (ZWD) modeling and GNSS meteorology. This study accurately calculated the long-term water vapor scale height using 89 radiosonde stations in China, analyzed the characteristics in temporal ad spatial variations and explored the impacts factors of the water vapor scale height from the perspective of the climate zones. The numerical results indicate that the water vapor scale height in China exhibits annual and semiannual variations with a rising-then-decreasing trend across the four seasons. A relatively larger value for the water vapor scale height were observed in the subtropical monsoon climate and the temperate continental climate zone, in which the values are greater than 2.35 km, while the values in temperate monsoon climate and the alpine plateau climate zone are relatively small. In addition, the water vapor scale height in different climate zones shows different trends, with a downward trend appeared in the subtropical monsoon climate and the alpine plateau climate zone, while an upward trend was observed in the temperate monsoon climate and the temperate continental climate zone. Furthermore, a positive correlation between water vapor scale height and temperature, pressure, and atmospheric precipitable water was found in China, with a varied degree of correlation in different climate zones.

Phytochemicals from Bark Extracts and Their Applicability in the Synthesis of Thermosetting Polymers: An Overview.

This review focuses on recent research on the phytochemicals found in bark from different trees and their potential to be used as substrates for the synthesis of thermosetting resins. Recent studies about the influence of each bark harvesting step on the extracted phytochemicals, from debarking to extraction, are investigated. A comparison of bark extracts in terms of the correlation between extraction conditions and efficiency (based on the total phenolic content (TPC) and extraction yield) is presented for six groups of trees (Norway spruce, pine species, other conifers, oak species, other deciduous trees of the north temperate zone, tropical and subtropical trees) and evaluated. The evaluation revealed that there is an interesting relationship between the extraction time and the type of solvent for some types of tree bark. It was found that a relatively short extraction time and a solvent temperature close to the boiling point are favourable. The latest research on the application of bark extracts in different types of thermosetting resins is described. This review discusses the attractiveness of bark extracts in terms of functional groups and the possibilities arising from extractable phytochemicals. In addition, different approaches (selective versus holistic) and methods of application are presented and compared.

The genus Oxytropis DC: application, phytochemistry, pharmacology, and toxicity.

Oxytropis DC is a perennial plant of Fabaceae family, which is widely distributed in the northern temperate zone. It is known as "locoweed" because of its toxic component swainsonine. However, it is widely used in Tibetan medicine and Mongolian medicine, mainly for the treatment of heat-clearing and detoxifying, pain-relieving, anti-inflammatory, hemostasis, and other diseases. To provide a basis for the further development and utilization of Oxytropis DC, the pieces of literature about the application, phytochemistry, pharmacological action, and toxicity of Oxytropis DC were reviewed and analyzed. A total of 373 chemical constituents were found from Oxytropis DC, including flavonoids, alkaloids, steroids, terpenoids, and others. Pharmacological actions mainly include antitumor, antioxidation, anti-inflammatory, analgesic, antibacterial, antifibrosis, and other pharmacological actions, among them, the antitumor effect is particularly prominent. At present, studies on its pharmacological effects are mainly concentrated on the extracts, some flavonoids, and alkaloids. In the follow-up studies, research on the pharmacological activities of the other chemical constituents in Oxytropis should be strengthened. It has the potential to pave the way for research and development of novel Oxytropis medicines.

Traces of Local Adaptive Acclimatization Response in the Tracheid Anatomical Traits between Dry and Wet Mesic Norway Spruce (Picea abies) Forests in Moravia, Czech Republic?

Norway spruce (Picea abies) forests in temperate zones are already reacting to short-term extreme summer heatwaves, threatening the vitality of trees and forest productivity, and can even lead to local and regional dieback events. Examining quantitative wood anatomy can provide helpful information in terms of understanding the physiology mechanisms and related responses of conifer trees to local environmental interactions in relation to tracheid adaptive capacity. This study analysed the tracheid functional anatomical traits (FATs) plasticity of six young Norway spruce trees growing in two mesic research plots with high annual precipitation (~43%) and air temperature differences during 2010–2017. The research plots are located in the sub-mountainous (Rájec Němčice) and mountainous (Bílý Kříž) belts of the Moravia region, Czech Republic. Vapour pressure deficit and cell wall reinforcement index (CWRI) were shown to be the most representative environmental parameters as proxies of dry conditions. Tracheid FATs indicated latewood phenological plasticity sensitivity, with more pronounced variability in the warmer and drier plots. Latewood tracheids of Norway spruce trees grown in the RAJ formed significantly thicker cell walls than BK during the studied period. The observed differences between the two research plots indicate additional support for tracheid cells’ hydraulic safety against cavitation and potential traces of adaptive acclimatization response.

Assessing the invasive potential of parthenogenetic marbled crayfish Procambarus virginalis Lyko, 2017 (Decapoda, Astacidea) in the water bolies of the temperate zone of Europe

The experiment examined the effect of temperature on the parameters of reproduction and growth in female marbled crayfish. At temperatures close to 20 °C, females began to reproduce at 10–11 months with a body weight of 0.84–1.20 g, but up to 80 % of their egg clutches were nonviable. The duration of egg embryogenesis with an increase in temperature from 16–17 to 26–27 °C decreased from 66–69 days to 21–24 days with a lower temperature development threshold equal to 13.1 °C. A similar molting value that determined the growth rate of individuals in juveniles weighing up to 0.34 g was 13–14 °C, but in sexually mature females it decreased to 5 °C. In water bodies of the temperate zone with a short growing season, females were able to reach sexual maturity only in the third summer of life and produced no more than two clutches of eggs during their life cycle. Hence, the invasive potential of marbled crayfish in the temperate zone of Europe is very limited.

Colonisation patterns and reef growth of the invasive serpulid Ficopomatus enigmaticus in a Greek coastal lagoon

The reef-building serpulid polychaete Ficopomatus enigmaticus is an invasive species in brackish waters in tropical and temperate zones worldwide and often has massive impacts on ecosystems and anthropogenic activities. In Prokopos Lagoon in Greece, the species has constructed large reefs over the past few decades which occupy a large area of the lagoon. In this study, we used high-resolution aerial photography to map the distribution of these reefs, and conducted a one-year field survey to investigate settlement and growth parameters, including abundance, biomass and body length, using artificial settlement panels. We correlated our findings with physicochemical measurements, specifically focusing on temperature, salinity and dissolved oxygen. Salinity exhibited marked and rapid fluctuations, ranging from less than 2 to over 42 Practical Salinity Units (PSU). These variations did not affect the adult population, but settlement only occurred at salinities above approximately 10 PSU and only when water temperatures surpassed 18–20 °C. Settlement was reduced when temperatures were high (> 28 °C) but was not affected by high salinity. The maximum abundance measured was 880 000 individuals m−2, and reefs attained a weight of 18 kg m−2 in 11 months. This study contributes further to understanding the species’ environmental tolerances and life cycle, which in turn may help to design future management measures.

Mitigating urban heat and air pollution considering green and transportation infrastructure

Global urbanization is causing an increase in population and transportation along with a reduction of green spaces. This phenomenon is leading to the development of Urban Heat Island (UHI) and Urban Pollution Island (UPI) effects, negatively impacting the urban environment. Numerous mitigation strategies have been proposed to reduce heat and air pollution. However, the combined impact of green and transportation infrastructure and their potential to mitigate heat and air pollution remains partially understood. This review aims to contribute by systematically investigating studies on mitigation strategies for urban green and transportation infrastructure from 2003 to 2023. These strategies are classified into two types: green infrastructure-related (greenery, green roofs, and green walls) and transportation-related (transportation fuel, transportation networks, and transportation organization systems). The findings are presented under five aspects: (1) Most research on transportation infrastructure adopts qualitative research methods, whereas research on green infrastructure tends to adopt quantitative methods; (2) Developed countries prioritize upgrading their transportation fuel, while developing countries remain inclined towards developing urban green spaces; (3) In subtropical and temperate zones, green roofs and green walls may cool the local ambient (within 1 m above the surface) by up to 10℃, whereas the cooling effect in other climate zones is within 5℃; (4) More focus was put on reducing the surface temperature rather than the air temperature. Green roofs and green walls are found to cool the former 2–3 times more than the latter; (5) Green infrastructure in the subtropical zone is 1.2 to 2 times more effective at adsorbing gaseous pollutants than in the temperate zone. This review can assist policymakers, urban planners and researchers in effectively mitigating urban heat and air pollution, and guide future research endeavors.

Old-growth forests in the Dinaric Alps of Bosnia-Herzegovina and Montenegro: a continental hot-spot for research and biodiversity

IntroductionAccording to various censuses, Europe has less than 1.5 million ha of old-growth forests (OGF). Most of them are in the boreal zone, while their presence in the temperate zone is residual and fragmented.In the framework of the EU biodiversity strategy, it has been adopted a broad definition of OGF which includes late-seral forests and forests with some management legacies. However, research purposes need to identify strictly defined OGFs characterized by structure, disturbance history, and processes typical and exclusive of the last stage of the forest dynamic.MethodsThe present paper wants to contribute to this debate by presenting a research network of four mixed (Fagus-Abies-Picea) montane OGFs in the Dinaric Alps (Lom, BiH; Janj, BiH; Perućica, BiH; Biogradska Gora, MNE), summarizing 20 years of multidisciplinary research by focusing on the structural characteristics and the disturbance history of the whole network and their coherency with strict OGF indicators. These sites were selected in relatively structurally uniform study areas, where 142 permanent plots have been established since 2002.Results and discussionThe study sites have a high living (747–1,201 m3 ha−1) and coarse woody debris (CWD) biomass (304–410 m3 ha−1), resulting in the highest forest carbon sink at the continental level (398–484  Mg C ha−1). The presence of large and old trees is one of the critical characteristics of the old-growth stage: in Lom and Perućica, there are 19 trees and 14  ha−1 larger than 1 m at breast height, respectively, and 14 trees and 15 trees ha−1 older than 400  years. In the last three centuries, continuous small-scale disturbances have driven forest dynamics, developing stands characterized by gap-phase dynamics and quasi-equilibrium structure. The Dinaric OGF network presents robust indicators of old-growthness, similar structural characteristics, and dynamic processes across all four sites. Identifying this sub-set of OGF using strict criteria is critical for recognizing conservation priorities and for quantifying, along an old-growthness chronosequence, the current structural differences of managed or recently abandoned forests. Besides, only OGF selected with rigorous criteria can act as a reliable reference for ecological restoration and sustainable forest management as a benchmark for carbon sink and for quantifying the impact of climate change on forests.

Global review of quantitative studies of primary moult of birds using the Underhill-Zucchini moult model

Knowledge about the timing of moult and how it fits into the annual cycle, along with breeding and, in some cases migration, is an important component of understanding the life history of birds. In comparison with breeding and migration, there is a lack of knowledge about the moult of birds. Primary moult can be quantified using models such as the Underhill-Zucchini moult model. Studies that included estimates of primary moult parameters (duration, mean start date and standard deviation of mean start date) obtained using the Underhill-Zucchini moult model were compiled from the literature to generate a moult analysis database. These parameters provide information about the timing of moult, how it fits into the annual cycle and how synchronised moult is in the population. Relationships between the estimated moult parameters and a series of explanatory variables were explored. Critical gaps in our understanding of primary moult were revealed. The available data are taxonomically biased towards Charadriiformes and Passeriformes and there are substantial gaps in coverage across the phylogenetic tree. There are severe biases in the global distribution of moult studies across continents, with Africa having almost half of all applications of the moult model. Latitude emerged as an important explanatory variable but there are latitudinal gaps in the data, especially from the Tropic of Capricorn extending to 40°N and in the far northern and far southern hemispheres. Citizen scientists, both bird ringers and photographers, have a key role to play in helping to fill these data gaps. An emerging pattern in the available data is that the timing of primary moult is more synchronised in populations in far northern and far southern latitudes than in temperate or tropical zones, but more data in the far south is needed to confirm this. Timing of moult shows great variability in the tropics and sub-tropical regions of the southern hemisphere. In species that undertake an annual sequential moult, larger birds take longer to moult than smaller birds, but the allometric relationship is not tight. Migrants appear to be more synchronised in their moult than residents.

Evaluation of 22 CMIP6 model-derived global soil moisture products of different shared socioeconomic pathways

The Sixth Phase of the Coupled Model Intercomparison Project (CMIP6) provides ample soil moisture (SM) products during 2015–2100, which are widely used in investigating future hydrological pattern. However, there remains limited understanding regarding the accuracy of multi-model CMIP6 SM future simulations following different Shared Socioeconomic Pathways (SSP). This study assesses the spatial–temporal accuracy of 22 CMIP6 model-derived SM products using 670 ground observation stations globally during 2015–2023. Each CMIP6 model encompasses SM estimations from SSP1-2.6 (The sustainable pathway), SSP2-4.5 (The medium pathway), and SSP5-8.5 (Fossil-fueled development). The latest Soil Moisture Active Passive (SMAP) and European Centre for Medium-Range Weather Forecast Reanalysis v5-Land (ERA5-Land) SM products serve as reference benchmarks. The SM among three SSPs within the same model exhibits similar performance in in situ validation, the extended triple collocation assessment, and the classical seasonal decomposition trend analysis. This similarity may suggest a subtle variation in the influence of different SSPs on SM in the early stages of the future scenario. The majority of CMIP6 model-derived SM could reasonably capture the spatial distribution pattern and temporal evolution trend of the truth value. Meanwhile, noticeable discrepancies in accuracy, particularly regarding goodness-of-fit, are evident when compared to SMAP and ERA5-Land SM products. The CMIP6 models could provide better SM estimation in temperate and tropical zones than cold zones. In terms of differences between the land cover types, CMIP6 model-derived SM products perform well over various vegetated regions except for barren, where there are sequential overestimation and relatively low fitting degree. Extensive accuracy discrepancies exist among the 22 CMIP6 model-derived SM products due to variations in model parameterization methods and atmospheric variables.

Elucidate the complex drivers of significant greening on the Loess Plateau from 2000 to 2020

Greening and its drivers in the Loess Plateau of China have been extensively studied, but attributional explorations regarding vegetation restoration in different climatic zones remain unclear. This study quantitatively evaluated greening on the Loess Plateau based on Fraction Vegetation Cover (FVC) calculated by MOD13Q1 dataset, compared FVC in different climatic zones, and explored the relationship between greening and precipitation, evaporation, soil water content (SWC), surface water bodies, and human activities. The study found that FVC on the Loess Plateau increased significantly at a rate of 0.538% yr−1 from 2000 to 2020, resulting in 94% greening. The greening rate was higher in the middle temperate zones (0.557% yr−1) than in the southern temperate zones (0.532% yr−1), but its average FVC was lower. This suggests that the greening rate (0.551% yr−1) is higher within 5 km of water bodies. Cropland (15.26%), grassland (13.66%) and trees (12.57%) had higher FVC increment than other types, while the six-fold increase in urban area is a significant impediment to greening. Additionally, there is a significant positive correlation with FVC when the urban economy exceeds 100 billion. The interaction of natural factors and human activities made the greatest contribution to greening, as calculated by the GeoDetector. It is hypothesized that there is significant potential for greening in the middle temperate zones. However, large-scale tree planting may not have a catalytic effect and could even be counterproductive. To achieve sustainable greening of the Loess Plateau in the future, shrubs and artificial water storage facilities may be key.

Exploring Biochar with N-Fertilizer Effects on Soil CO2 Emissions and Physical-Chemical Properties as a Climate Change Mitigation Tool

Abstract The global agriculture industry is facing never before faced issues in the form of soil degradation, water scarcity, rising greenhouse gas emissions, and climate change. Among the possible remedies, applying biochar to the soil has drawn interest as a viable strategy. Although a great deal of literature has been written about the benefits and drawbacks of applying biochar initially, there is still a significant amount of research on the effects of using biochar repeatedly. This study seeks to address this gap by examining the varied effects of both the initial application (at rates of 0 t.ha−1, 10 t.ha−1, and 20 t.ha−1) and the reapplication of biochar (at rates of 0, 10, and 20 t.ha−1), especially when combined with different levels of nitrogen fertilizer (0, 108, and 162 kg.ha−1). The investigation focuses on soil properties and CO2 emissions from Haplic Luvisol in the temperate climate zone (Slovakia). The results showed that biochar generally improved soil properties, such as soil pH (KCl) (p <0.05), shifting it from acidic towards moderately acidic, and generally led to a decrease in ammonium (NH4 +) and nitrate (NO3 -) content. The second level of fertilization, combined with different biochar treatments, yielded the most efficient results in physical properties such as soil temperature, bulk density (BD), and soil water content (SWC) compared to control treatments without biochar. Biochar application contributed to the reduction of both average daily CO2 emissions and cumulative CO2 emissions during the study period (April – October) in 2022 compared to the control without biochar application.

Comparative Analysis of Machine Learning-Based Predictive Models for Fine Dead Fuel Moisture of Subtropical Forest in China

The moisture content of fine dead surface fuel in forests is a crucial metric for assessing its combustibility and plays a pivotal role in the early warning, occurrence, and spread of forest fires. Accurate prediction of the moisture content of fine dead fuel on the forest surface is a critical challenge in forest fire management. Previous research on fine surface fuel moisture content has been mainly focused on coniferous forests in cold temperate zones, but there has been less attention given to understanding the fuel moisture dynamics in subtropical forests, which limits the development of regional forest fire warning models. Here, we consider the coupled influence of multiple meteorological, terrain, forest stand, and other characteristic factors on the fine dead fuel moisture content within the subtropical evergreen broadleaved forest region of southern China. The ability of five machine learning algorithms to predict the moisture content of fine dead fuel on the forest surface is assessed, and the key factors affecting the model accuracy are identified. Results show that when a single meteorological factor is used as a forecasting model, its forecasting accuracy is less than that of the combined model with multiple characteristic factors. However, the prediction accuracy of the model is improved after the addition of forest stand factors and terrain factors. The model prediction ability is the best for the combination of all feature factors including meteorology, forest stand, and terrain. The overall prediction accuracy of the model is ordered as follows: random forest > extreme gradient boosting > support vector machine > stepwise linear regression > k-nearest neighbor. Canopy density in forest stand factors, slope position and altitude in terrain factors, and average relative air humidity and light intensity in the previous 15 days are the key meteorological factors affecting the prediction accuracy of fuel moisture content. Our results provide scientific guidance and support for understanding the variability of forest surface fuel moisture content and improved regional forest fire warnings.

Ascochyta erotica sp. nov. Pathogenic on Convolvulus arvensis

Convolvulus arvensis is an herbaceous dicotyledonous plant in the Convolvulaceae family that is native to Europe and Asia. It is a perennial soboliferous plant and is one of the most harmful weeds. This weed is successful in many types of climates, including temperate, tropical, and Mediterranean climates, but it is most troublesome for agriculture throughout the temperate zone. In this study, several pathogenic isolates were collected from this host. The internal transcribed spacer (ITS) and large subunit (28S) or ribosomal DNA, partial DNA-directed RNA polymerase II subunit (rpb2), and β-tubulin (tub2) genes were amplified and sequenced for all the isolates studied. Further, both a multilocus phylogenetic analysis of DNA sequences and an analysis of morphological features were implemented. Based on the results obtained, all the studied isolates were found to be distinct from any described species in the genus Ascochyta and are, therefore, described here as a new species Ascochyta erotica sp. nov. The pathogenicity of A. erotica sp. nov. was also tested and confirmed on leaf segments of C. arvensis.

Differentiated influences of atmospheric dryness on urban plant cooling effect between temperate and tropical/subtropical zones

Atmospheric vapor pressure deficit (VPD) is a critical variable related to water flux that may either promote or limit plant evapotranspiration under different conditions, consequentially, influencing the effect of urban vegetation on mitigating urban heat island. However, how VPD influence the cooling effect of urban vegetation in different climate zones, have not been examined to date. Here, we combined field observations of 3634 samples from the global published literature and satellite data to investigate the spatial-temporal impacts of VPD on vegetation cooling and reveal the pathways of “atmospheric dryness-evapotranspiration-climate effect”. Our results showed that the cooling effect was generally remarkable in urban areas in the humid season of the tropical/subtropical zones and in the warm season of temperate zones. In the tropical/subtropical zones, the cooling effect was enhanced with increasing VPD across the range of low VPD, but was obviously constrained by high atmospheric dryness when VPD exceeded 9.43 hPa. In contrast, the cooling effects of urban vegetation were gradually strengthened as VPD increased in temperate zones. Notably, tropical and subtropical urban vegetation began to exert a great cooling effect when evapotranspiration per unit leaf area was >31.93 mm/month. Our findings suggest that stronger constraints of atmospheric dryness on cooling effect in the tropical/subtropical zones versus the temperate zone. These findings provide important insights for understanding the patterns of urban vegetation response to atmospheric dryness. They can also assist managers and decision-makers in optimizing the design of urban green space in different geographic locations.