Plenter forests,also known as uneven-aged or continuous cover forests enhance forest resilience and resistance against disturbances compared to even-aged forests.They are considered as an adaptation option to mitigate...Plenter forests,also known as uneven-aged or continuous cover forests enhance forest resilience and resistance against disturbances compared to even-aged forests.They are considered as an adaptation option to mitigate climate change effects.In this study,we present a conceptual approach to determine the potentially suitable area for plenter forest management within central European mixed species forests and apply our approach to the case study area in Styria,the south-eastern Province of Austria.The concept is based on ecological and technicaleconomic constraints and considers expected future climate conditions and its impact on plenter forest management.For each 1 ha forest pixel,we assess the ecological conditions for plenter forest management according to the autecological growth conditions of silver fir,and at least one additional shade tolerant tree species.The technical-economic constraints are defined by slope(≤30%)and distance to the next forest road(≤100 m)to ensure cost-efficient harvesting.The results show that under current climate conditions 28.1%or 305,349 ha of the forests in Styria are potentially suitable for plenter forest management.For the years 2071–2100 and under the climate change scenario RCP 4.5,the potential area decreases to 286,098 ha(26.3%of the total forest area)and for the scenario RCP 8.5 to 208,421 ha(19.1%of the total forest area).The main reason for these changes is the unfavourable growing conditions for silver fir in the lowlands,while in the higher elevations silver fir is likely to expand.Our results may serve forest managers to identify areas suitable for plenter forests and assist in the transformation of even-aged pure forests to uneven-aged forests to increase resistance,resilience,and biodiversity under climate change.展开更多
In this study,we used an extensive sampling network established in central Romania to develop tree height and crown length models.Our analysis included more than 18,000 tree measurements from five different species.In...In this study,we used an extensive sampling network established in central Romania to develop tree height and crown length models.Our analysis included more than 18,000 tree measurements from five different species.Instead of building univariate models for each response variable,we employed a multivariate approach using seemingly unrelated mixed-effects models.These models incorporated variables related to species mixture,tree and stand size,competition,and stand structure.With the inclusion of additional variables in the multivariate seemingly unrelated mixed-effects models,the accuracy of the height prediction models improved by over 10% for all species,whereas the improvement in the crown length models was considerably smaller.Our findings indicate that trees in mixed stands tend to have shorter heights but longer crowns than those in pure stands.We also observed that trees in homogeneous stand structures have shorter crown lengths than those in heterogeneous stands.By employing a multivariate mixed-effects modelling framework,we were able to perform cross-model random-effect predictions,leading to a significant increase in accuracy when both responses were used to calibrate the model.In contrast,the improvement in accuracy was marginal when only height was used for calibration.We demonstrate how multivariate mixed-effects models can be effectively used to develop multi-response allometric models that can be easily calibrated with a limited number of observations while simultaneously achieving better-aligned projections.展开更多
Nothofagus alessandrii forests in the Mediterranean region of Chile face significant threats from deforestation,fragmentation,wildfires,and climate change.This study investigated the temporal and spatial dynamics of N...Nothofagus alessandrii forests in the Mediterranean region of Chile face significant threats from deforestation,fragmentation,wildfires,and climate change.This study investigated the temporal and spatial dynamics of N.alessandrii populations and their implications for habitat fragmentation and connectivity.Using remote sensing data and geographic information system analysis,we assessed deforestation patterns,fragmentation metrics,and connectivity indices for different scenarios between 2009 and 2022.A reduction in the N.alessandrii forest area,extensive fragmentation,and decreased connectivity were observed over time,with wildfires exacerbating these trends.Reforestation simulations showed the potential of targeted restoration efforts to improve connectivity,especially when focusing on proximate patches.However,careful consideration of seed dispersal distances and wildfire risk is essential for effective reforestation planning.Overall,our findings underscore the urgent need for conservation interventions to preserve N.alessandrii forests and their biodiversity in Chile's coastal mountain ecosystems.A proactive and collaborative approach is essential to ensure the survival of these forests for future generations.展开更多
As the impact of climate change and anthropogenic disturbance continues to intensify around the world,the ecological integrity(EI)of forest ecosystems is compromised in various ways.This study aims to quantify ecologi...As the impact of climate change and anthropogenic disturbance continues to intensify around the world,the ecological integrity(EI)of forest ecosystems is compromised in various ways.This study aims to quantify ecological integrity,explore its latitudinal patterns,and identify the potential determinants behind it.We selected 15 indicators of forest composition,structure,and function and used two approaches to quantify ecological integrity.The results show a significant negative correlation between forest ecological integrity and increasing latitude.Climate emerged as the main driver of the latitudinal pattern compared to anthropogenic and other influencing factors.Our study offers a new approach to quantifying ecological integrity based on a set of indicators that may help assess the contribution of forest ecosystems in conservation,restoration,and ecosystem services.展开更多
Extreme disturbance activity is a signature of anthropogenic environmental change. Empirical information describing the historical normative limits of disturbance regimes provides baseline data that facilitates the de...Extreme disturbance activity is a signature of anthropogenic environmental change. Empirical information describing the historical normative limits of disturbance regimes provides baseline data that facilitates the detection of contemporary trends in both disturbances and community-level responses. Quantifying the attributes of historical disturbances is challenging due to their transient episodic nature, with decades-to centurieslong intervals between recurrences. Unmanaged primary forests that support centuries-old trees therefore serve as unique reference systems for quantifying past disturbance regimes. We surveyed relict stands of primary beech-dominated forests over wide environmental gradients in the Carpathian Mountains of Europe. We collected core samples from 3,026 trees in 208 field survey plots distributed across 13 forest stands in two countries. We used dendrochronological methods to analyze time-series of annually-resolved ring-width variation and to identify anomalous growth patterns diagnostic of past forest canopy removal. A 180-year record(1810–1990) of spatially and temporally explicit disturbance events(n =333) was compiled and used to derive s tatistical attributes of the disturbance regime. We quantified disturbance severity(canopy area lost), patch size, and return intervals. Our analyses describe a complex regime where a background of relatively frequent, smallscale, low-to intermediate-severity disturbance was punctuated by episodic large-scale high-severity events. Even the most severe events were non-catastrophic at a stand level, leaving significant residual tree cover that supported a continuity of ecological function. We did not detect evidence for an expected climate-induced intensification of disturbance with time, but methodological limitations precluded an assessment of disturbance activity in the decades since 1990.展开更多
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
Warm-wet climatic conditions are widely regarded as conducive to remarkable tree growth,alleviating climatic pressures.However,the notable decline in tree growth observed in the southern edge of boreal forests has hei...Warm-wet climatic conditions are widely regarded as conducive to remarkable tree growth,alleviating climatic pressures.However,the notable decline in tree growth observed in the southern edge of boreal forests has heightened concerns over the spatial-temporal dynamics of forest decline.Currently,attaining a comprehensive grasp of the underlying patterns and their propelling factors remains a formidable challenge.We collected tree ring samples from a network of 50 sites across the Greater Xing'an Mountains.These samples were subsequently grouped into two distinct clusters,designated as Groups A and B.The percentage change of growth(GC,%)and the proportion of declining sites were utilized to assess forest decline.The decline in tree growth within Larix gmelinii forests exhibits significant regional variation,accompanied by temporal fluctuations even within a given region.Group A exhibited a pronounced increase in frequency(59.26%)of occurrences and encountered more severe declines(21.65%)in tree growth subsequent to the 1990s,contrasting sharply with Group B,which observed lower frequencies(20.00%)and relatively less severe declines(21.02%)prior to the 1980s.The primary impetus underlying the opposite radial growth increments observed in Larix gmelinii trees from the interplay between their differential response to temperatures and wetter climatic conditions,which is significantly influenced by varying stand densities.In cold-dry conditions,low-density forests may experience soil water freezing,exacerbating drought conditions and thereby inhibiting tree growth,in Group B.Trees growth in high-density stands is restrained by warm-wet conditions,in Group A.These results provide new insights into the variability at the southern edge of the boreal forest biome with different responses to density and climate.展开更多
Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety o...Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m,especially in Atlantic and sub-Mediterranean climates,and it is sensitive to low winter temperatures,early and late frosts,as well as high summer temperatures.Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech,European hornbeam,small-leaved lime and Acer spp.These form the understorey of sessile oak stands,promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches.Sessile oak is a long-lived,light-demanding and wind-firm species,owing to its taproot and heart-shaped root system.Its timber,one of the most valuable in Europe,is important for fur-niture-making(both solid wood and veneer),construction,barrels,railway sleepers,and is also used as fuelwood.It is one of the few major tree species in Europe that is regener-ated by seed(naturally or artificially)and by stump shoots in high forest,coppice-with-standards and coppice forests.Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood,group shelterwood,irregular shelterwood,irregular high forest,coppice-with-standards and simple coppice.Young naturally regenerated stands are managed by weeding,release cutting and cleaning-respacing,keeping the stands quite dense for good natural pruning.Plantations are based on(1)2-4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources,seed stands and seed orchards.The density of sessile oak plantations(mostly in rows,but also in clusters)is usually between 4000 and 6000 ind.ha^(−1).Sessile oak silviculture of mature stands includes crown thinning,focus-ing on final crop trees(usually a maximum of 100 ind.ha^(−1))and targeting the production of large-diameter and high quality trees at long rotation ages(mostly over 120 years,sometimes 250-300 years).In different parts of Europe,conversion of simple coppices and coppice-with-standards to high forests is continuing.Even though manage-ment of sessile oak forests is very intensive and expensive,requiring active human intervention,the importance of this species in future European forests will increase in the con-text of climate change due to its high resistance to distur-bance,superior drought tolerance and heat stress resistance.展开更多
Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for ...Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for this most important forest region in China. Accordingly, the objective of this study is to develop a first comprehensive system for estimating the wood production for the five dominant forest types.Methods: Based on a network of 384 field plots and using the state-space approach, we develop a system of dynamic stand models, for each of the five main forest types. Four models were developed and evaluated, including a base model and three extended models which include the effects of dominant height and climate variables. The four models were fitted, and their predictive strengths were tested, using the "seemingly unrelated regression"(SUR) technique.Results: All three of the extended models increased the accuracy of the predictions at varying degrees for the five major natural forest types of northeastern China. The inclusion of dominant height and two climate factors(precipitation and temperature) in the base model resulted in the best performance for all the forest types. On average, the root mean square values were reduced by 13.0% when compared with the base model.Conclusion: Both dominant height and climate factors were important variables in estimating forest production. This study not only presents a new method for estimating forest production for a large region, but also explains regional differences in the effect of site productivity and climate.展开更多
Forest ecosystems play a crucial role in mitigating global climate change by forming massive carbon sinks. Their carbon stocks and stock changes need to be quantified for carbon budget balancing and international repo...Forest ecosystems play a crucial role in mitigating global climate change by forming massive carbon sinks. Their carbon stocks and stock changes need to be quantified for carbon budget balancing and international reporting schemes. However, direct sampling and biomass weighing may not always be possible for quantification studies conducted in large forests. In these cases, indirect methods that use forest inventory information combined with remote sensing data can be beneficial. Synthetic aperture radar (SAR) images offer numerous opportunities to researchers as freely distributed remote sensing data. This study aims to estimate the amount of total carbon stock (TCS) in forested lands of the Kizildag Forest Enterprise. To this end, the actual storage capacities of five carbon pools, i.e. above- and below-ground, deadwood, litter, and soil, were calculated using the indirect method based on ground measurements of 264 forest inventory plots. They were then associated with the backscattered values from Sentinel-1 and ALOS-2 PALSAR-2 data in a Geographical Information System (GIS). Finally, TCS was separately modelled and mapped. The best regression model was developed using the HH polarization of ALOS-2 PALSAR-2 with an adjusted R^(2) of 0.78 (p < 0.05). According to the model, the estimated TCS was about 2 Mt for the entire forest, with an average carbon storage of 133 t ha^(−1). The map showed that the distribution of TCS was heterogenic across the study area. Carbon hotspots were mostly composed of pure stands of Anatolian black pine and mixed, over-mature stands of Lebanese cedar and Taurus fir. It was concluded that the total carbon stocks of forest ecosystems could be estimated using appropriate SAR images at acceptable accuracy levels for forestry purposes. The use of additional ancillary data may provide more delicate and reliable estimations in the future. Given the implications of this study, the spatiotemporal dynamics of carbon can be effectively controlled by forest management when coupled with easily accessible space-borne radar data.展开更多
Wild forest fires are one of the greatest environmental disasters affecting forest resources. Along the coastal zone of the Mediterranean region in Turkey, forested areas are classified as first-degree, fire-sensitive...Wild forest fires are one of the greatest environmental disasters affecting forest resources. Along the coastal zone of the Mediterranean region in Turkey, forested areas are classified as first-degree, fire-sensitive areas. Every year, thousands of hectares of forests have been destroyed in Turkey. In this study, fire-access zones were determined in the Mediterranean forests of Turkey, by utilizing geographic information systems （GIS） technology. The effective reach distance of fire hoses from both sides of roads was considered in order to delineate fireaccess zones. The effective reach distance can vary based on the technical capabilities and hydraulic capacity of fire trucks （minimum and maximum pressures on water pump）; terrain structures （uphill, downhill and flat）; and ground slope. These factors and their influences were studied in fire sensitive forest areas located in the eastern Mediterranean city of Kahramanmaras in Turkey. First, terrain structures on both sides of the road network and groundslope classes were determined based on GIS data layers. Then, fire access zones were delineated according to water pressure data, terrain structures, and ground-slope classes. The results indicated that 69.30 % of the forested areas were within the fire-access zones, while the rest of the forest was out of reach the fire hoses. The accessible areas were also calculated for forested areas with different fire- sensitivity degrees. The accessible areas were 69.59, 69.96, and 67.16 % for the forested areas that are sensitive to fires at the first, second, and third degrees, respectively. This finding has implications for the monitoring and management of fire threats in areas outside of the reach distance. The outside areas should receive extra attention and monitoring during the fire season so that fires are detected ahead of time and management has sufficient time to react. Besides, new roads should be considered for these areas in order to access more lands in a shorter amount of time.展开更多
Although the scientific knowledge about some associations between physical parameters of the soil is consolidated,studies focused on investigating the dynamics of forest restoration processes and the structure of soil...Although the scientific knowledge about some associations between physical parameters of the soil is consolidated,studies focused on investigating the dynamics of forest restoration processes and the structure of soils remain incipient.The study area is located in Cerrado and is called as Private Natural Heritage Reserve(RPPN)Águas Perenes Forest(perennial water forest)and was selected as a“High Conservation Value Forest”,provides scope to investigate the soil physical properties recovery on passive restoration sites,with different ages but with the same land use history.So,the aim was to investigate the soil density,moisture,penetration resistance and infiltration rate with long-term from old(FA,46 year-old),medium(FB,11 year-old)and young(FC,8 year-old)passive restoration sites.It was observed differences in soil density,as well as in soil moisture,resistance to penetration and infiltration rate.Mean densities recorded for FA,FB and FC were 1.38,1.48 and 1.53 g cm^(-3),respectively.FA recorded higher mean soil moisture(14.9%)than FB(11.5%)and FC(10.0%),whereas mean soil resistance to penetration was increased from FA(0.87 MPa)to FB(0.91 MPa)and FC(1.10 MPa).The average infiltration rate was almost similar in FA and FB(FA=76.43 mm h^(-1);FB=77.48 mm h^(-1))and approximately 39%higher than FC(55.79 mm h^(-1)).Thus,although soil density and moisture were different in each passive restoration site,11 year-old passive restoration site showed similar resistance to penetration and infiltration rate to the old(46 years)passive restoration site.These features allowed seeing improvements in hydrological maintenance in the soil and revealed that passive restoration in Cerrado is able to improve the physical features on a soil presenting similar texture,climate and management history.展开更多
Background: The demographic trade-offs(i.e. growth and survival) play important roles in forest dynamics and they are driven by multiple factors, including species’ inherent life-history strategies(such as shade-tole...Background: The demographic trade-offs(i.e. growth and survival) play important roles in forest dynamics and they are driven by multiple factors, including species’ inherent life-history strategies(such as shade-tolerance and mycorrhizal type), neighborhood interactions(such as conspecific negative density dependence, CNDD), and abiotic environment pressures. Although studies found that CNDD occurred in tropical and temperate forest,attempts to identify how the variations in CNDD control their impacts on growth and survival remain debate. In the present study, we conducted an extensive field survey, and analyzed demographic rates from 24 co-occurring temperate tree species, in order to test the importance of CNDD in shaping the growth-survival trade-offs.Results: Our study found that density dependence and environmental filtering were strong predictors for individual growth-survival trade-offs, while they showed variations across shade-intolerant and ectomycorrhizal species, as well as saplings and juveniles with more negative CNDD. Species growth showed positive relationship with mortality. And our results also support the fact that CNDD drives species growth-survival trade-offs at the community level with environmental stress.Conclusions: Our study indicates that biotic interactions such as density dependence and environment filtering played an important role in growth-survival trade-offs, and confirmed that the Janzen-Connell hypothesis in temperate forest was associated with species life-history strategies. In addition, shade-tolerance, mycorrhizal type and life-stage of forest species responded differently to CNDD, thus providing insights regarding different community assembly mechanisms and their interactions. Therefore, it is important to take species survival with growth and species life-history strategies into account when focusing on forest dynamics.展开更多
Wildfires in recent years have resulted in degradation and damage to the Hyrcanian forest ecosystems in Northern Iran.This study was carried out to investigate fire damage to trees and changes in regeneration in early...Wildfires in recent years have resulted in degradation and damage to the Hyrcanian forest ecosystems in Northern Iran.This study was carried out to investigate fire damage to trees and changes in regeneration in early-season growth after wildfires in the Golestan Province.For this purpose,a random sampling plan was used,with 60 circular plots（each plot is 1000 m2） for each stand and 240 circular（25 m2） plots for regeneration within the burned and unburned areas,respectively.In each plot,habitat factors were recorded,including crown canopy percentage,forest stratum,herb-layer cover percentage,species,diameter at breast height,tree and regeneration quality,and quantity of seedlings and saplings.Our results showed that bark is an important factor for fire resistance in Hyrcanian forests.The Persian ironwood and European yew has the highest and lowest fire resistance;as broad leave species are more resistant than needle leaf species.Density of regeneration in unburned area was higher than burned area,and statistical analysis showed significant differences for all species between two areas.Fire effects on sapling were different among species which indicates sapling has different resistance to fire.Forest floor fuel,season,stand composition and microclimate have more effects on fire severity while environmental factors,regeneration and management practices shaping future composition stands.展开更多
Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest...Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes(plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests(SGF)after the deposition of mining tailings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and species composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemical properties between the two forest patches(SGF tailing and SGF non-tailing)evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and technosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that technosol fertility is positively affected by stand age,plant community composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.展开更多
Wildfires have environmental,economic,and social impacts,and can shape the landscape and benefit ecosystems such as the Cerrado.This study evaluated the diversity,similarity,and floristic and structural differences of...Wildfires have environmental,economic,and social impacts,and can shape the landscape and benefit ecosystems such as the Cerrado.This study evaluated the diversity,similarity,and floristic and structural differences of woody savanna and forest formations of the Cerrado,when affected and not affected by fire.Twenty-eight 25-400m2 plots were randomly allocated and divided into Burnt Cerrado and Unburnt Cerrado,Burnt Forest,and Unburnt Forest,and divided into three levels of inclusion according to diameter class(smaller than 2 cm,2-5 cm and larger than5 cm).Species were identified,DBH and height measured,and phyto sociological parameters such as volume,diversity,and floristic similarity evaluated.Burnt Cerrado had lower diversity,density,and dominance at all inclusion levels compared to the Unburnt Cerrado,and showed similarities between treatments at the inclusion levels.Burnt Forest had smaller differences in diversity,density,and dominance than Unburnt Forest.Forest formation was similar at level 1 of inclusion and in the total area.However,it was dissimilar at lower levels.The lower density and diversity of species at the lowest levels of inclusion was associated with mortality from fire.展开更多
Modelling tree height-diameter relationships in complex tropical rain forest ecosystems remains a challenge because of characteristics of multi-species, multi-layers, and indeterminate age composition. Effective model...Modelling tree height-diameter relationships in complex tropical rain forest ecosystems remains a challenge because of characteristics of multi-species, multi-layers, and indeterminate age composition. Effective modelling of such complex systems required innovative techniques to improve prediction of tree heights for use for aboveground biomass estimations. Therefore, in this study, deep learning algorithm (DLA) models based on artificial intelligence were trained for predicting tree heights in a tropical rain forest of Nigeria. The data consisted of 1736 individual trees representing 116 species, and measured from 52 0.25 ha sample plots. A K-means clustering was used to classify the species into three groups based on height-diameter ratios. The DLA models were trained for each species-group in which diameter at beast height, quadratic mean diameter and number of trees per ha were used as input variables. Predictions by the DLA models were compared with those developed by nonlinear least squares (NLS) and nonlinear mixed-effects (NLME) using different evaluation statistics and equivalence test. In addition, the predicted heights by the models were used to estimate aboveground biomass. The results showed that the DLA models with 100 neurons in 6 hidden layers, 100 neurons in 9 hidden layers and 100 neurons in 7 hidden layers for groups 1, 2, and 3, respectively, outperformed the NLS and NLME models. The root mean square error for the DLA models ranged from 1.939 to 3.887 m. The results also showed that using height predicted by the DLA models for aboveground biomass estimation brought about more than 30% reduction in error relative to NLS and NLME. Consequently, minimal errors were created in aboveground biomass estimation compared to those of the classical methods.展开更多
Elucidating woody community diversity and structure change along environmental gradients is still a central issue of tropical forest ecology. We have evaluated changes in alpha and beta diversity, community compositio...Elucidating woody community diversity and structure change along environmental gradients is still a central issue of tropical forest ecology. We have evaluated changes in alpha and beta diversity, community composition and structure of woody communities along an elevational gradient in Dwarf Cloud Forests, Southeast Brazil. We selected five areas along an elevational gradient(1,300-1,600 m asl), and randomly allocated 10 plots(10 m × 20 m) in each area in the Ibitipoca State Park(ISP), Serra da Mantiqueira, southeastern Brazil. All woody species(diameter at breast height ≥ 5.0 cm) were collected for taxonomic identification. Thus, we analysed the woody communities based on a phytosociological approach. Overall, 147 species and 37 families were recorded, distributed in 2,303 individuals. No differences in the species richness pattern were observed between areas using the rarefaction and extrapolation curves. Significant differences in species composition and structure between areas were observed. The high beta diversity observed, corroborated by the Jaccard coefficient, increases with decreasing altitude. Our results showed that woody communities in the studied Dwarf Cloud Forests have a higher diversity and structural variability along elevational gradient.展开更多
A conceptual hydrological model that links the Xin＇anjiang hydrological model and a physically based snow energy and mass balance model, described as the XINSNOBAL model, was developed in this study for simulating ra...A conceptual hydrological model that links the Xin＇anjiang hydrological model and a physically based snow energy and mass balance model, described as the XINSNOBAL model, was developed in this study for simulating rain-on-snow events that commonly occur in the Pacific Northwest of the United States. The resultant model was applied to the Lookout Creek Watershed in the H. J. Andrews Experimental Forest in the western Cascade Mountains of Oregon, and its ability to simulate streamflow was evaluated. The simulation was conducted at 24-hour and one-hour time scales for the period of 1996 to 2005. The results indicated that runoffand peak discharge could be underestimated if snowpack accumulation and snowmelt under rain-on-snow conditions were not taken into account. The average deterministic coefficient of the hourly model in streamflow simulation in the calibration stage was 0.837, which was significantly improved over the value of 0.762 when the Xin＇anjiang model was used alone. Good simulation performance of the XINSNOBAL model in the WS 10 catchment, using the calibrated parameter of the Lookout Creek Watershed for proxy-basin testing, demonstrates that transplanting model parameters between similar watersheds can orovide a useful tool for discharge forecastin~, in un^au^ed basins.展开更多
Background:The importance of biodiversity in maintaining multiple ecosystem functions has been widely accepted.However,the specific mechanisms affecting biodiversity and ecosystem multifunctionality(BEMF)relationships...Background:The importance of biodiversity in maintaining multiple ecosystem functions has been widely accepted.However,the specific mechanisms affecting biodiversity and ecosystem multifunctionality(BEMF)relationships in forests are largely unknown.This is particularly evident for the macroscale of a large forested landscape.Methods:Based on 412 one-tenth hectare field plots distributed over forested areas across northeastern China,we evaluated three alternative hypotheses explaining the relationships between BEMF,namely:niche complementarity,mass ratio,and vegetation quantity effect.We used Rao's quadratic entropy and community weighted mean trait values to quantify forest“biodiversity”.These two variables represent two complementary aspects of functional properties,which are in line with niche complementary and mass ratio effects,respectively.Results:Ecosystem multifunctionality was negatively associated with the community weighted mean values of acquisitive traits(a proxy of mass ratio effect).Rao's quadratic entropy(a proxy of niche complementarity)had no relationship with ecosystem multifunctionality.Higher stand biomass greatly increased ecosystem multifunctionality,which is in line with the vegetation quantity effect.Our results confirm that in the temperate forests of northeastern China,the relationship of BEMF was primarily affected by vegetation quantity,followed by mass ratio effects.Conclusions:The results of this study contribute to a better understanding of the main drivers of ecosystem multifunctionality in forest ecosystems.The results of this study provide additional evidence to support the vegetation quantity and mass ratio hypotheses in forest ecosystems.展开更多
基金part of the project“Areas of Forest Innovation Climate Smart Forestry”(project nr.101726),WP Modelling Plenter Forest vs.Even-aged Forest,funded by the Austrian Ministry of Agriculture,Forestry,Regions and Water Managementfunded by the province of Styria(Austria),the Austrian Federal Ministry of Agriculture,Forestry,Regions and Water Management and the European Union via the projects“Waldtypisierung Steiermark-FORSITE”(LE14-20)and“FORSITEⅡ-Investigation of the ecological base line information for a dynamic forest site classification in Upper Austria,Lower Austria and Burgenland”(101746)financial support came from BOKU University。
文摘Plenter forests,also known as uneven-aged or continuous cover forests enhance forest resilience and resistance against disturbances compared to even-aged forests.They are considered as an adaptation option to mitigate climate change effects.In this study,we present a conceptual approach to determine the potentially suitable area for plenter forest management within central European mixed species forests and apply our approach to the case study area in Styria,the south-eastern Province of Austria.The concept is based on ecological and technicaleconomic constraints and considers expected future climate conditions and its impact on plenter forest management.For each 1 ha forest pixel,we assess the ecological conditions for plenter forest management according to the autecological growth conditions of silver fir,and at least one additional shade tolerant tree species.The technical-economic constraints are defined by slope(≤30%)and distance to the next forest road(≤100 m)to ensure cost-efficient harvesting.The results show that under current climate conditions 28.1%or 305,349 ha of the forests in Styria are potentially suitable for plenter forest management.For the years 2071–2100 and under the climate change scenario RCP 4.5,the potential area decreases to 286,098 ha(26.3%of the total forest area)and for the scenario RCP 8.5 to 208,421 ha(19.1%of the total forest area).The main reason for these changes is the unfavourable growing conditions for silver fir in the lowlands,while in the higher elevations silver fir is likely to expand.Our results may serve forest managers to identify areas suitable for plenter forests and assist in the transformation of even-aged pure forests to uneven-aged forests to increase resistance,resilience,and biodiversity under climate change.
基金supported by the European Union and the Romanian Government through the Competitiveness Operational Programme 2014–2020, under the project“Increasing the economic competitiveness of the forestry sector and the quality of life through knowledge transfer,technology and CDI skills”(CRESFORLIFE),ID P 40 380/105506, subsidiary contract no. 17/2020partially by the FORCLIMSOC Nucleu Programme (Contract 12N/2023)+2 种基金project PN 23090101CresPerfInst project (Contract 34PFE/December 30, 2021)“Increasing the institutional capacity and performance of INCDS ‘Marin Drǎcea’in RDI activities-CresPer”LM was financially supported by the Research Council of Finland's flagship ecosystem for Forest-Human-Machine Interplay–Building Resilience, Redefining Value Networks and Enabling Meaningful Experiences (UNITE)(decision number 357909)
文摘In this study,we used an extensive sampling network established in central Romania to develop tree height and crown length models.Our analysis included more than 18,000 tree measurements from five different species.Instead of building univariate models for each response variable,we employed a multivariate approach using seemingly unrelated mixed-effects models.These models incorporated variables related to species mixture,tree and stand size,competition,and stand structure.With the inclusion of additional variables in the multivariate seemingly unrelated mixed-effects models,the accuracy of the height prediction models improved by over 10% for all species,whereas the improvement in the crown length models was considerably smaller.Our findings indicate that trees in mixed stands tend to have shorter heights but longer crowns than those in pure stands.We also observed that trees in homogeneous stand structures have shorter crown lengths than those in heterogeneous stands.By employing a multivariate mixed-effects modelling framework,we were able to perform cross-model random-effect predictions,leading to a significant increase in accuracy when both responses were used to calibrate the model.In contrast,the improvement in accuracy was marginal when only height was used for calibration.We demonstrate how multivariate mixed-effects models can be effectively used to develop multi-response allometric models that can be easily calibrated with a limited number of observations while simultaneously achieving better-aligned projections.
基金funded by Universidad Cato lica del MauleProyectos de Investigacio n con Financiamiento Interno 2022 línea Fortalecimiento Fondecyt Regular。
文摘Nothofagus alessandrii forests in the Mediterranean region of Chile face significant threats from deforestation,fragmentation,wildfires,and climate change.This study investigated the temporal and spatial dynamics of N.alessandrii populations and their implications for habitat fragmentation and connectivity.Using remote sensing data and geographic information system analysis,we assessed deforestation patterns,fragmentation metrics,and connectivity indices for different scenarios between 2009 and 2022.A reduction in the N.alessandrii forest area,extensive fragmentation,and decreased connectivity were observed over time,with wildfires exacerbating these trends.Reforestation simulations showed the potential of targeted restoration efforts to improve connectivity,especially when focusing on proximate patches.However,careful consideration of seed dispersal distances and wildfire risk is essential for effective reforestation planning.Overall,our findings underscore the urgent need for conservation interventions to preserve N.alessandrii forests and their biodiversity in Chile's coastal mountain ecosystems.A proactive and collaborative approach is essential to ensure the survival of these forests for future generations.
基金funded by the National Key R&D Program of China(No.2023YFF1304001-01)the Program of National Natural Science Foundation of China(No.32371870)。
文摘As the impact of climate change and anthropogenic disturbance continues to intensify around the world,the ecological integrity(EI)of forest ecosystems is compromised in various ways.This study aims to quantify ecological integrity,explore its latitudinal patterns,and identify the potential determinants behind it.We selected 15 indicators of forest composition,structure,and function and used two approaches to quantify ecological integrity.The results show a significant negative correlation between forest ecological integrity and increasing latitude.Climate emerged as the main driver of the latitudinal pattern compared to anthropogenic and other influencing factors.Our study offers a new approach to quantifying ecological integrity based on a set of indicators that may help assess the contribution of forest ecosystems in conservation,restoration,and ecosystem services.
基金supported by the Czech Science Foundation project GACR21-27454STechnology Agency of the Czech Republic(project Center for Landscape and Biodiversity,SS02030018).
文摘Extreme disturbance activity is a signature of anthropogenic environmental change. Empirical information describing the historical normative limits of disturbance regimes provides baseline data that facilitates the detection of contemporary trends in both disturbances and community-level responses. Quantifying the attributes of historical disturbances is challenging due to their transient episodic nature, with decades-to centurieslong intervals between recurrences. Unmanaged primary forests that support centuries-old trees therefore serve as unique reference systems for quantifying past disturbance regimes. We surveyed relict stands of primary beech-dominated forests over wide environmental gradients in the Carpathian Mountains of Europe. We collected core samples from 3,026 trees in 208 field survey plots distributed across 13 forest stands in two countries. We used dendrochronological methods to analyze time-series of annually-resolved ring-width variation and to identify anomalous growth patterns diagnostic of past forest canopy removal. A 180-year record(1810–1990) of spatially and temporally explicit disturbance events(n =333) was compiled and used to derive s tatistical attributes of the disturbance regime. We quantified disturbance severity(canopy area lost), patch size, and return intervals. Our analyses describe a complex regime where a background of relatively frequent, smallscale, low-to intermediate-severity disturbance was punctuated by episodic large-scale high-severity events. Even the most severe events were non-catastrophic at a stand level, leaving significant residual tree cover that supported a continuity of ecological function. We did not detect evidence for an expected climate-induced intensification of disturbance with time, but methodological limitations precluded an assessment of disturbance activity in the decades since 1990.
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National Nature Science Foundation of China(No.32371871)。
文摘Warm-wet climatic conditions are widely regarded as conducive to remarkable tree growth,alleviating climatic pressures.However,the notable decline in tree growth observed in the southern edge of boreal forests has heightened concerns over the spatial-temporal dynamics of forest decline.Currently,attaining a comprehensive grasp of the underlying patterns and their propelling factors remains a formidable challenge.We collected tree ring samples from a network of 50 sites across the Greater Xing'an Mountains.These samples were subsequently grouped into two distinct clusters,designated as Groups A and B.The percentage change of growth(GC,%)and the proportion of declining sites were utilized to assess forest decline.The decline in tree growth within Larix gmelinii forests exhibits significant regional variation,accompanied by temporal fluctuations even within a given region.Group A exhibited a pronounced increase in frequency(59.26%)of occurrences and encountered more severe declines(21.65%)in tree growth subsequent to the 1990s,contrasting sharply with Group B,which observed lower frequencies(20.00%)and relatively less severe declines(21.02%)prior to the 1980s.The primary impetus underlying the opposite radial growth increments observed in Larix gmelinii trees from the interplay between their differential response to temperatures and wetter climatic conditions,which is significantly influenced by varying stand densities.In cold-dry conditions,low-density forests may experience soil water freezing,exacerbating drought conditions and thereby inhibiting tree growth,in Group B.Trees growth in high-density stands is restrained by warm-wet conditions,in Group A.These results provide new insights into the variability at the southern edge of the boreal forest biome with different responses to density and climate.
文摘Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m,especially in Atlantic and sub-Mediterranean climates,and it is sensitive to low winter temperatures,early and late frosts,as well as high summer temperatures.Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech,European hornbeam,small-leaved lime and Acer spp.These form the understorey of sessile oak stands,promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches.Sessile oak is a long-lived,light-demanding and wind-firm species,owing to its taproot and heart-shaped root system.Its timber,one of the most valuable in Europe,is important for fur-niture-making(both solid wood and veneer),construction,barrels,railway sleepers,and is also used as fuelwood.It is one of the few major tree species in Europe that is regener-ated by seed(naturally or artificially)and by stump shoots in high forest,coppice-with-standards and coppice forests.Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood,group shelterwood,irregular shelterwood,irregular high forest,coppice-with-standards and simple coppice.Young naturally regenerated stands are managed by weeding,release cutting and cleaning-respacing,keeping the stands quite dense for good natural pruning.Plantations are based on(1)2-4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources,seed stands and seed orchards.The density of sessile oak plantations(mostly in rows,but also in clusters)is usually between 4000 and 6000 ind.ha^(−1).Sessile oak silviculture of mature stands includes crown thinning,focus-ing on final crop trees(usually a maximum of 100 ind.ha^(−1))and targeting the production of large-diameter and high quality trees at long rotation ages(mostly over 120 years,sometimes 250-300 years).In different parts of Europe,conversion of simple coppices and coppice-with-standards to high forests is continuing.Even though manage-ment of sessile oak forests is very intensive and expensive,requiring active human intervention,the importance of this species in future European forests will increase in the con-text of climate change due to its high resistance to distur-bance,superior drought tolerance and heat stress resistance.
基金supported by the Key Project of National Key Research and Development Plan(No.2017YFC0504104)the Program of National Natural Science Foundation of China(No.31670643)
文摘Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for this most important forest region in China. Accordingly, the objective of this study is to develop a first comprehensive system for estimating the wood production for the five dominant forest types.Methods: Based on a network of 384 field plots and using the state-space approach, we develop a system of dynamic stand models, for each of the five main forest types. Four models were developed and evaluated, including a base model and three extended models which include the effects of dominant height and climate variables. The four models were fitted, and their predictive strengths were tested, using the "seemingly unrelated regression"(SUR) technique.Results: All three of the extended models increased the accuracy of the predictions at varying degrees for the five major natural forest types of northeastern China. The inclusion of dominant height and two climate factors(precipitation and temperature) in the base model resulted in the best performance for all the forest types. On average, the root mean square values were reduced by 13.0% when compared with the base model.Conclusion: Both dominant height and climate factors were important variables in estimating forest production. This study not only presents a new method for estimating forest production for a large region, but also explains regional differences in the effect of site productivity and climate.
文摘Forest ecosystems play a crucial role in mitigating global climate change by forming massive carbon sinks. Their carbon stocks and stock changes need to be quantified for carbon budget balancing and international reporting schemes. However, direct sampling and biomass weighing may not always be possible for quantification studies conducted in large forests. In these cases, indirect methods that use forest inventory information combined with remote sensing data can be beneficial. Synthetic aperture radar (SAR) images offer numerous opportunities to researchers as freely distributed remote sensing data. This study aims to estimate the amount of total carbon stock (TCS) in forested lands of the Kizildag Forest Enterprise. To this end, the actual storage capacities of five carbon pools, i.e. above- and below-ground, deadwood, litter, and soil, were calculated using the indirect method based on ground measurements of 264 forest inventory plots. They were then associated with the backscattered values from Sentinel-1 and ALOS-2 PALSAR-2 data in a Geographical Information System (GIS). Finally, TCS was separately modelled and mapped. The best regression model was developed using the HH polarization of ALOS-2 PALSAR-2 with an adjusted R^(2) of 0.78 (p < 0.05). According to the model, the estimated TCS was about 2 Mt for the entire forest, with an average carbon storage of 133 t ha^(−1). The map showed that the distribution of TCS was heterogenic across the study area. Carbon hotspots were mostly composed of pure stands of Anatolian black pine and mixed, over-mature stands of Lebanese cedar and Taurus fir. It was concluded that the total carbon stocks of forest ecosystems could be estimated using appropriate SAR images at acceptable accuracy levels for forestry purposes. The use of additional ancillary data may provide more delicate and reliable estimations in the future. Given the implications of this study, the spatiotemporal dynamics of carbon can be effectively controlled by forest management when coupled with easily accessible space-borne radar data.
基金supported by The Scientific and Technological Research Council of Turkey(TUBITAK,Grant number:110O928)
文摘Wild forest fires are one of the greatest environmental disasters affecting forest resources. Along the coastal zone of the Mediterranean region in Turkey, forested areas are classified as first-degree, fire-sensitive areas. Every year, thousands of hectares of forests have been destroyed in Turkey. In this study, fire-access zones were determined in the Mediterranean forests of Turkey, by utilizing geographic information systems （GIS） technology. The effective reach distance of fire hoses from both sides of roads was considered in order to delineate fireaccess zones. The effective reach distance can vary based on the technical capabilities and hydraulic capacity of fire trucks （minimum and maximum pressures on water pump）; terrain structures （uphill, downhill and flat）; and ground slope. These factors and their influences were studied in fire sensitive forest areas located in the eastern Mediterranean city of Kahramanmaras in Turkey. First, terrain structures on both sides of the road network and groundslope classes were determined based on GIS data layers. Then, fire access zones were delineated according to water pressure data, terrain structures, and ground-slope classes. The results indicated that 69.30 % of the forested areas were within the fire-access zones, while the rest of the forest was out of reach the fire hoses. The accessible areas were also calculated for forested areas with different fire- sensitivity degrees. The accessible areas were 69.59, 69.96, and 67.16 % for the forested areas that are sensitive to fires at the first, second, and third degrees, respectively. This finding has implications for the monitoring and management of fire threats in areas outside of the reach distance. The outside areas should receive extra attention and monitoring during the fire season so that fires are detected ahead of time and management has sufficient time to react. Besides, new roads should be considered for these areas in order to access more lands in a shorter amount of time.
基金We appreciate the cooperation of the International Paper from Brazil LTDA(Process 23112.000670/2015-59)Federal University of Sao Carlos and the Brazilian National Council for Scientific and Technological Development(CNPq).
文摘Although the scientific knowledge about some associations between physical parameters of the soil is consolidated,studies focused on investigating the dynamics of forest restoration processes and the structure of soils remain incipient.The study area is located in Cerrado and is called as Private Natural Heritage Reserve(RPPN)Águas Perenes Forest(perennial water forest)and was selected as a“High Conservation Value Forest”,provides scope to investigate the soil physical properties recovery on passive restoration sites,with different ages but with the same land use history.So,the aim was to investigate the soil density,moisture,penetration resistance and infiltration rate with long-term from old(FA,46 year-old),medium(FB,11 year-old)and young(FC,8 year-old)passive restoration sites.It was observed differences in soil density,as well as in soil moisture,resistance to penetration and infiltration rate.Mean densities recorded for FA,FB and FC were 1.38,1.48 and 1.53 g cm^(-3),respectively.FA recorded higher mean soil moisture(14.9%)than FB(11.5%)and FC(10.0%),whereas mean soil resistance to penetration was increased from FA(0.87 MPa)to FB(0.91 MPa)and FC(1.10 MPa).The average infiltration rate was almost similar in FA and FB(FA=76.43 mm h^(-1);FB=77.48 mm h^(-1))and approximately 39%higher than FC(55.79 mm h^(-1)).Thus,although soil density and moisture were different in each passive restoration site,11 year-old passive restoration site showed similar resistance to penetration and infiltration rate to the old(46 years)passive restoration site.These features allowed seeing improvements in hydrological maintenance in the soil and revealed that passive restoration in Cerrado is able to improve the physical features on a soil presenting similar texture,climate and management history.
基金supported by the Program of National Natural Science Foundation of China(No.31971650)the Key Project of National Key Research and Development Plan(No.2017YFC0504104)Beijing Forestry University Outstanding Young Talent Cultivation Project(No.2019JQ03001).
文摘Background: The demographic trade-offs(i.e. growth and survival) play important roles in forest dynamics and they are driven by multiple factors, including species’ inherent life-history strategies(such as shade-tolerance and mycorrhizal type), neighborhood interactions(such as conspecific negative density dependence, CNDD), and abiotic environment pressures. Although studies found that CNDD occurred in tropical and temperate forest,attempts to identify how the variations in CNDD control their impacts on growth and survival remain debate. In the present study, we conducted an extensive field survey, and analyzed demographic rates from 24 co-occurring temperate tree species, in order to test the importance of CNDD in shaping the growth-survival trade-offs.Results: Our study found that density dependence and environmental filtering were strong predictors for individual growth-survival trade-offs, while they showed variations across shade-intolerant and ectomycorrhizal species, as well as saplings and juveniles with more negative CNDD. Species growth showed positive relationship with mortality. And our results also support the fact that CNDD drives species growth-survival trade-offs at the community level with environmental stress.Conclusions: Our study indicates that biotic interactions such as density dependence and environment filtering played an important role in growth-survival trade-offs, and confirmed that the Janzen-Connell hypothesis in temperate forest was associated with species life-history strategies. In addition, shade-tolerance, mycorrhizal type and life-stage of forest species responded differently to CNDD, thus providing insights regarding different community assembly mechanisms and their interactions. Therefore, it is important to take species survival with growth and species life-history strategies into account when focusing on forest dynamics.
文摘Wildfires in recent years have resulted in degradation and damage to the Hyrcanian forest ecosystems in Northern Iran.This study was carried out to investigate fire damage to trees and changes in regeneration in early-season growth after wildfires in the Golestan Province.For this purpose,a random sampling plan was used,with 60 circular plots（each plot is 1000 m2） for each stand and 240 circular（25 m2） plots for regeneration within the burned and unburned areas,respectively.In each plot,habitat factors were recorded,including crown canopy percentage,forest stratum,herb-layer cover percentage,species,diameter at breast height,tree and regeneration quality,and quantity of seedlings and saplings.Our results showed that bark is an important factor for fire resistance in Hyrcanian forests.The Persian ironwood and European yew has the highest and lowest fire resistance;as broad leave species are more resistant than needle leaf species.Density of regeneration in unburned area was higher than burned area,and statistical analysis showed significant differences for all species between two areas.Fire effects on sapling were different among species which indicates sapling has different resistance to fire.Forest floor fuel,season,stand composition and microclimate have more effects on fire severity while environmental factors,regeneration and management practices shaping future composition stands.
文摘Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes(plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests(SGF)after the deposition of mining tailings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and species composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemical properties between the two forest patches(SGF tailing and SGF non-tailing)evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and technosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that technosol fertility is positively affected by stand age,plant community composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.
基金Fundacao Grupo Boticário de ProtecaoàNatureza,CAPES,FAPEMIG and CNPQ。
文摘Wildfires have environmental,economic,and social impacts,and can shape the landscape and benefit ecosystems such as the Cerrado.This study evaluated the diversity,similarity,and floristic and structural differences of woody savanna and forest formations of the Cerrado,when affected and not affected by fire.Twenty-eight 25-400m2 plots were randomly allocated and divided into Burnt Cerrado and Unburnt Cerrado,Burnt Forest,and Unburnt Forest,and divided into three levels of inclusion according to diameter class(smaller than 2 cm,2-5 cm and larger than5 cm).Species were identified,DBH and height measured,and phyto sociological parameters such as volume,diversity,and floristic similarity evaluated.Burnt Cerrado had lower diversity,density,and dominance at all inclusion levels compared to the Unburnt Cerrado,and showed similarities between treatments at the inclusion levels.Burnt Forest had smaller differences in diversity,density,and dominance than Unburnt Forest.Forest formation was similar at level 1 of inclusion and in the total area.However,it was dissimilar at lower levels.The lower density and diversity of species at the lowest levels of inclusion was associated with mortality from fire.
文摘Modelling tree height-diameter relationships in complex tropical rain forest ecosystems remains a challenge because of characteristics of multi-species, multi-layers, and indeterminate age composition. Effective modelling of such complex systems required innovative techniques to improve prediction of tree heights for use for aboveground biomass estimations. Therefore, in this study, deep learning algorithm (DLA) models based on artificial intelligence were trained for predicting tree heights in a tropical rain forest of Nigeria. The data consisted of 1736 individual trees representing 116 species, and measured from 52 0.25 ha sample plots. A K-means clustering was used to classify the species into three groups based on height-diameter ratios. The DLA models were trained for each species-group in which diameter at beast height, quadratic mean diameter and number of trees per ha were used as input variables. Predictions by the DLA models were compared with those developed by nonlinear least squares (NLS) and nonlinear mixed-effects (NLME) using different evaluation statistics and equivalence test. In addition, the predicted heights by the models were used to estimate aboveground biomass. The results showed that the DLA models with 100 neurons in 6 hidden layers, 100 neurons in 9 hidden layers and 100 neurons in 7 hidden layers for groups 1, 2, and 3, respectively, outperformed the NLS and NLME models. The root mean square error for the DLA models ranged from 1.939 to 3.887 m. The results also showed that using height predicted by the DLA models for aboveground biomass estimation brought about more than 30% reduction in error relative to NLS and NLME. Consequently, minimal errors were created in aboveground biomass estimation compared to those of the classical methods.
基金This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico—CNPq(grants 454008/2014-7 and 435598/2018-0)Fundação de ApoioàPesquisa do Estado de Minas Gerais—FAPEMIG(grant APQ 2165/14)F.A.C.holds a CNPq productivity fellowship.
文摘Elucidating woody community diversity and structure change along environmental gradients is still a central issue of tropical forest ecology. We have evaluated changes in alpha and beta diversity, community composition and structure of woody communities along an elevational gradient in Dwarf Cloud Forests, Southeast Brazil. We selected five areas along an elevational gradient(1,300-1,600 m asl), and randomly allocated 10 plots(10 m × 20 m) in each area in the Ibitipoca State Park(ISP), Serra da Mantiqueira, southeastern Brazil. All woody species(diameter at breast height ≥ 5.0 cm) were collected for taxonomic identification. Thus, we analysed the woody communities based on a phytosociological approach. Overall, 147 species and 37 families were recorded, distributed in 2,303 individuals. No differences in the species richness pattern were observed between areas using the rarefaction and extrapolation curves. Significant differences in species composition and structure between areas were observed. The high beta diversity observed, corroborated by the Jaccard coefficient, increases with decreasing altitude. Our results showed that woody communities in the studied Dwarf Cloud Forests have a higher diversity and structural variability along elevational gradient.
基金supported by the National Natural Science Foundation of China (Grants No. 40901015 and41001011)the Major Program of the National Natural Science Foundation of China (Grants No. 51190090 and 51190091)+3 种基金the Fundamental Research Funds for the Central Universities (Grants No. B1020062 andB1020072)the Ph. D. Programs Foundation of the Ministry of Education of China (Grant No.20090094120008)the Special Fund of State Key Laboratories of China (Grants No. 2009586412 and 2009585412)the Programme of Introducing Talents of Disciplines to Universities of the Ministry of Education and State Administration of the Foreign Experts Affairs of China (the 111 Project, Grant No.B08048)
文摘A conceptual hydrological model that links the Xin＇anjiang hydrological model and a physically based snow energy and mass balance model, described as the XINSNOBAL model, was developed in this study for simulating rain-on-snow events that commonly occur in the Pacific Northwest of the United States. The resultant model was applied to the Lookout Creek Watershed in the H. J. Andrews Experimental Forest in the western Cascade Mountains of Oregon, and its ability to simulate streamflow was evaluated. The simulation was conducted at 24-hour and one-hour time scales for the period of 1996 to 2005. The results indicated that runoffand peak discharge could be underestimated if snowpack accumulation and snowmelt under rain-on-snow conditions were not taken into account. The average deterministic coefficient of the hourly model in streamflow simulation in the calibration stage was 0.837, which was significantly improved over the value of 0.762 when the Xin＇anjiang model was used alone. Good simulation performance of the XINSNOBAL model in the WS 10 catchment, using the calibrated parameter of the Lookout Creek Watershed for proxy-basin testing, demonstrates that transplanting model parameters between similar watersheds can orovide a useful tool for discharge forecastin~, in un^au^ed basins.
基金supported by the Program of National Natural Science Foundation of China(No.31971650)the Key Project of National Key Research and Development Plan(No.2017YFC0504005)the National Natural Science Foundation of China(No.31800362).
文摘Background:The importance of biodiversity in maintaining multiple ecosystem functions has been widely accepted.However,the specific mechanisms affecting biodiversity and ecosystem multifunctionality(BEMF)relationships in forests are largely unknown.This is particularly evident for the macroscale of a large forested landscape.Methods:Based on 412 one-tenth hectare field plots distributed over forested areas across northeastern China,we evaluated three alternative hypotheses explaining the relationships between BEMF,namely:niche complementarity,mass ratio,and vegetation quantity effect.We used Rao's quadratic entropy and community weighted mean trait values to quantify forest“biodiversity”.These two variables represent two complementary aspects of functional properties,which are in line with niche complementary and mass ratio effects,respectively.Results:Ecosystem multifunctionality was negatively associated with the community weighted mean values of acquisitive traits(a proxy of mass ratio effect).Rao's quadratic entropy(a proxy of niche complementarity)had no relationship with ecosystem multifunctionality.Higher stand biomass greatly increased ecosystem multifunctionality,which is in line with the vegetation quantity effect.Our results confirm that in the temperate forests of northeastern China,the relationship of BEMF was primarily affected by vegetation quantity,followed by mass ratio effects.Conclusions:The results of this study contribute to a better understanding of the main drivers of ecosystem multifunctionality in forest ecosystems.The results of this study provide additional evidence to support the vegetation quantity and mass ratio hypotheses in forest ecosystems.
