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
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
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
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
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:Fragmentation and deforestation are one of the greatest threats to forests,and these processes are of even more concern in the tropics,where the seasonal dry forest is possibly one of the most threatened ec...Background:Fragmentation and deforestation are one of the greatest threats to forests,and these processes are of even more concern in the tropics,where the seasonal dry forest is possibly one of the most threatened ecosystems with the least remaining surface area.Methods:The deforestation and fragmentation patterns that had occurred in Ecuadorian seasonal dry forests between 1990 and 2018 were verified,while geographic information systems and land cover shapes provided by the Ecuadorian Ministry of the Environment were employed to classify and evaluate three types of seasonal dry forests:deciduous,semi-deciduous,and transition.The study area was tessellated into 10 km2 hexagons,in which six fragmentation parameters were measured:number of patches,mean patch size,median patch size,total edge,edge density and reticular fragmentation index(RFI).The RFI was also measured both outside and inside protected natural areas(unprotected,national protected areas and protected forest).Moreover,the areas with the best and worst conservation status,connectivity and risk of disappearance values were identified by means of a Getis-Ord Gi*statistical analysis.Results:The deforestation of seasonal dry forests affected 27.04%of the original surface area still remaining in 1990,with an annual deforestation rate of−1.12%between 1990 and 2018.The RFI has increased by 11.61%as a result of the fact that small fragments of forest have tended to disappear,while the large fragments have been fragmented into smaller ones.The semi-deciduous forest had the highest levels of fragmentation in 2018.The three categories of protection had significantly different levels of fragmentation,with lower RFI values in national protected areas and greater values in protected forests.Conclusions:The seasonal dry forest is fragmenting,deforesting and disappearing in some areas.An increased protection and conservation of the Ecuadorian seasonal dry forest is,therefore,necessary owing to the fact that not all protection measures have been effective.展开更多
Various methods have been used to estimate the amount of above ground forest biomass across landscapes and to create biomass maps for specific stands or pixels across ownership or project areas. Without an accurate es...Various methods have been used to estimate the amount of above ground forest biomass across landscapes and to create biomass maps for specific stands or pixels across ownership or project areas. Without an accurate estimation method, land managers might end up with incorrect biomass estimate maps, which could lead them to make poorer decisions in their future management plans. The goal of this study was to compare various imputation methods to predict forest biomass and basal area, at a project planning scale (a combination of ground inventory plots, light detection and ranging (LiDAR) data, satellite imagery, and climate data was analyzed, and their root mean square error (RMSE) and bias were calculated. Results indicate that for biomass prediction, the k-nn (k = 5) had the lowest RMSE and least amount of bias. The second most accurate method consisted of the k-nn (k = 3), followed by the GWR model, and the random forest imputation. For basal area prediction, the GWR model had the lowest RMSE and least amount of bias. The second most accurate method was k-nn (k = 5), followed by k-nn (k = 3), and the random forest method. For both metrics, the GNN method was the least accurate based on the ranking of RMSE and bias.展开更多
Currently there is an urgent and special attention in actions to restore tropical forests.In this study,we evaluated the effect of different restoration methods on aboveground biomass(AGB)stock,tree community diversit...Currently there is an urgent and special attention in actions to restore tropical forests.In this study,we evaluated the effect of different restoration methods on aboveground biomass(AGB)stock,tree community diversity and structure,in areas affected by the Fundão tailings dam collapse in Mariana,Minas Gerais state,Brazil.We measured and compiled data of the AGB,community diversity and structure attributes in 36 plots distributed in six restoration treatments and six replicas:planting of native tree seedlings with fertilization and pH correction(PSf)and without fertilization and pH correction(PS);seeding of native trees with fertilization and pH correction(SDf)and without fertilization and pH correction(SD);natural regeneration with fertilization and pH correction(NRf)and without fertilization and pH correction(NR).No significant differences in substrate properties and AGB between treatments.Although biomass storage between treatments was not statistically different,there is a clear pattern showing higher values active restoration method.The Pielou index ranged from 0.520(SDf)to 0.943(NR),except for SDf all the others treatments had values higher than 0.76.This result suggests floristic heterogeneity,without ecological dominance in the plant community.Overall,active restoration had important implications for the forest restoration where natural regeneration is limited.展开更多
Kaynasli District in the western Black Sea region of Turkey has long been vulnerable to frequent flood damage due to the establishment of settlements within and around stream channels without regard to fluctuating pea...Kaynasli District in the western Black Sea region of Turkey has long been vulnerable to frequent flood damage due to the establishment of settlements within and around stream channels without regard to fluctuating peakstreamflow frequencies. The aim of this research was to determine the measures needed to protect the towns and villages from this type of damage. Daily total precipitation data for 1975–2010 were analysed, and rainfall-runoff models developed to estimate the potential yearly maximum discharge from each stream of sub-watersheds dominated by forests and/or agriculture. This was then calculated for different frequencies of the yearly maximum discharge. Flood analysis and mapping was modified via the one-dimensional Hydrologic Engineering CentersRiver Analysis System software to produce potential maximum discharge and geometric data for Kaynasli Creek. As the main creek of the sub-watershed, its crosssection was shown to be insufficient and incapable of containing the maximum discharge at the 100-year frequency presumed for the watershed, and subsequently was seen as having a high level of casualty risk. It was concluded that the one dimensional model could be useful, but 2D models were more suitable for these types of watersheds.展开更多
Disturbances such as forest fires,intense winds,and insect damage exert strong impacts on forest ecosystems by shaping their structure and growth dynamics,with contributions from climate change.Consequently,there is a...Disturbances such as forest fires,intense winds,and insect damage exert strong impacts on forest ecosystems by shaping their structure and growth dynamics,with contributions from climate change.Consequently,there is a need for reliable and operational methods to monitor and map these disturbances for the development of suitable management strategies.While susceptibility assessment using machine learning methods has increased,most studies have focused on a single disturbance.Moreover,there has been limited exploration of the use of“Automated Machine Learning(AutoML)”in the literature.In this study,susceptibility assessment for multiple forest disturbances(fires,insect damage,and wind damage)was conducted using the PyCaret AutoML framework in the Izmir Regional Forest Directorate(RFD)in Turkey.The AutoML framework compared 14 machine learning algorithms and ranked the best models based on AUC(area under the curve)values.The extra tree classifier(ET)algorithm was selected for modeling the susceptibility of each disturbance due to its good performance(AUC values>0.98).The study evaluated susceptibilities for both individual and multiple disturbances,creating a total of four susceptibility maps using fifteen driving factors in the assessment.According to the results,82.5%of forested areas in the Izmir RFD are susceptible to multiple disturbances at high and very high levels.Additionally,a potential forest disturbances map was created,revealing that 15.6%of forested areas in the Izmir RFD may experience no damage from the disturbances considered,while 54.2%could face damage from all three disturbances.The SHAP(Shapley Additive exPlanations)methodology was applied to evaluate the importance of features on prediction and the nonlinear relationship between explanatory features and susceptibility to disturbance.展开更多
Integration system is used to denote practices that combine systematic use of the land and technologies,in which forest species are used in conjunction with herbaceous plants and/or animals respecting a spatial or tem...Integration system is used to denote practices that combine systematic use of the land and technologies,in which forest species are used in conjunction with herbaceous plants and/or animals respecting a spatial or temporal arrangement.Knowing that this type of production seeks to balance ecological and economic factors,it is important to understand the financial benefits and risks involved in this production.Financial analysis,therefore,acts as an important analysis tool to foster this type of activity.The paper aimed to conduct analysis of investment risk of a crop-livestock-forestry system deployed in Brazil,comparing two different production scenarios,scenario I with 17 ha and scenario II with 25 ha.The risk analysis was performed using the Monte Carlo method and sensitivity analysis(by varying the factors:the discount rate,productivity and price).A cash flow was elaborated based on annual cost and revenues data of the agricultural crops(corn and soybeans),livestock and eucalyptus,using an interest rate of 6%per year.The results indicated that the optimal age for cutting the eucalyptus was at seven years on both scenarios;scenario I had better return on investment using deterministic and probabilistic methods;scenario I presents higher investments risks;there is a negative relation between discount rate and annualized net present value(ANPV);increased productivity of crops provides greater profitability to the system;there has been an increase in the economic viability of the system,as value has been added to the products.Monte Carlo method and the sensitivity analysis showed to be an appropriate tool to analyze the risk of crop-livestock-forestry systems,making it possible to foresee how the project will respond to possible scenarios.展开更多
The shrub-tree floristic composition of the natural regeneration stratum of a bauxite mine in the process of restoration and in a reference ecosystem(remnant of a preserved secondary Seasonal Semi-Deciduous Forest)wer...The shrub-tree floristic composition of the natural regeneration stratum of a bauxite mine in the process of restoration and in a reference ecosystem(remnant of a preserved secondary Seasonal Semi-Deciduous Forest)were analysed to evaluate forest restoration conditions after five years of planting.The influence of canopy openness,accumulated leaf litter and soil attributes in the regeneration stratum were also investigated in both the forests.The floristic composition of the regeneration stratum in the forest under restoration(16 species and 5,083 individuals ha-1)and in the reference ecosystem(58 species and 26,250 individuals ha-1)are distinct due to the difference in the environmental variables.Results showed that the reference ecosystem favours the presence of species that tolerate environments with greater shading and higher aluminium and organic matter content in the soil like Psychotria carthagenensis Jacq.,while the forest under restoration favours the presence of species adapted to fertile soils and those that tolerate greater luminosity like Vernonanthura phosphorica(Vell.)H.Rob.展开更多
Ecological restoration in forest ecosystem is a priority in Mariana,Brazil.Thus,we evaluated the effects of passive and active restoration methods through different site preparation techniques by manipulating physical...Ecological restoration in forest ecosystem is a priority in Mariana,Brazil.Thus,we evaluated the effects of passive and active restoration methods through different site preparation techniques by manipulating physical-chemical properties of substrates on tree community coverage in Mariana,Brazil.A total of 48 plots(12×12 m each)were established in two areas along the flood plains with accumulation of tailings.The following treatments were established:(1)planting of native tree seedlings with fertilization(PSf)and(2)without fertilization(PS);(3)direct seeding of native trees with fertilization(SDf)and(4)without fertilization(SD);(5)natural regeneration with fertilization(NRf)and(6)without fertilization(NR).Differences in substrate properties and tree community coverage were evaluated between treatments,the substrate properties and tree community coverage relationship,and main effects of substrate fertility and texture on tree community coverage.There were marked differences in substrate and plant coverage between treatments.On average,the highest plant coverage was found in treatment with fertilization,such as NRf(59,5%)and SDf(48%).However,the treatment with seedling planting(PSf and PS)and NR did not show differences(~37%),while the lowest values were observed in SD(23%).There is a strong relationship between substrate fertility and plant community coverage,with significant positive effects.We observed that the passive and active restoration methods can be complementary in the soil and plant community coverage recovery.展开更多
The objective of this study was to compare the soil seed bank in an area under natural regeneration(F1)and another reforested through seedling planting(F2),seven years after bauxite mining,in Southeast,Brazil.In each ...The objective of this study was to compare the soil seed bank in an area under natural regeneration(F1)and another reforested through seedling planting(F2),seven years after bauxite mining,in Southeast,Brazil.In each area,10 sampling points were randomly distributed,using three samples of topsoil to represent each point.The samples were transported to a shade house and evaluated for six months,where emerging individuals were identified every two weeks.Floristic similarity was evaluated with cluster analysis based on the Jaccard index(SJ).Species richness and abundance of individuals were compared using Student's t test.In F1,2,114.94 propagules m-2 were registered,belonging to 51 species and 24 botanical families,Shannon-Wiener diversity index H’=2.770 and Pielou evenness index J’=0.705.In F2,1,168.62 propagules m-2 were registered,belonging to 42 species and 22 families,H’=2.618 and J’=0.700.The(SJ)between F1 and F2 was 0.61,indicating a high similarity.The results showed high density of propagules,good diversity and absence of ecological dominance.The high number of individuals and diversity of tree species with zoochoric dispersion found in the areas indicates that both natural regeneration and reforestation were efficient in the ecological restoration of bauxite mined areas.展开更多
Volume and biomass equations are essential tools to determine forest productivity and enable forest managers to make informed decisions. However, volume and biomass estimation equations are scarce for Afromontane fore...Volume and biomass equations are essential tools to determine forest productivity and enable forest managers to make informed decisions. However, volume and biomass estimation equations are scarce for Afromontane forests in Africa in general and Ethiopia in particular. This limits our knowledge of the standing volume of wood, biomass, and carbon stock of the forests therein. In this study, we developed a new mixed-species volume and biomass equations for Afromontane forests and compared them with generic pantropical and local models. A total of 193 sampled trees from seven dominant tree species were used to develop the equations. Various volume and biomass equations were fitted using robust linear and nonlinear regression. Model comparison indicated that the best model to estimate stem volume was ln(v)=-9.909+ 0.954*ln(d<sup>2</sup>h), whereas the best model to estimate biomass was ln(b)=-2.983+ 0.949*ln(ρd<sup>2</sup>h) . These equations explained over 85% of the variations in the stem volume and biomass measurements. The mean density and basal area of trees in the forest with d ≥ 2 cm was 631.5 stems·ha<sup>-1</sup> and 24.4 m<sup>2</sup>·ha<sup>-1</sup>. Based on the newly developed equations, the forest has on average 303.0 m<sup>3</sup>·ha<sup>-1</sup> standing volume of wood and 283.8 Mg·ha<sup>-1</sup> biomass stock. The newly developed allometric equations derived from this study can be used to accurately determine the stem volume, biomass, and carbon storage in the Afromontane forests in Ethiopia and elsewhere with similar stand characteristics and ecological conditions. By contrast, the generic pan-tropical and other local models appear to provide biased estimates and are not suitable for dry Afromontane forests in Ethiopia. The estimated stem biomass and carbon stock in the Chilimo forest are comparable with the estimates from various tropical forests and woodlands elsewhere in Africa, indicating the importance of dry Afromontane forest for climate change mitigation.展开更多
Unoccupied aircraft systems (UAS) are increasingly used to create spatial databases for use in natural resource research and in other disciplines. We describe our experience with the recovery of an UAS platform that b...Unoccupied aircraft systems (UAS) are increasingly used to create spatial databases for use in natural resource research and in other disciplines. We describe our experience with the recovery of an UAS platform that became lodged in a tree located next to a small river island after experiencing communication loss. The UAS platform was a DJI M200 series aircraft that we had used for remote sensing applications over several years without issue. During remote sensing of a riparian restoration project, the M200 descended vertically downward after communication loss, became lodged in a tree crown, and was suspended above the river. A tree climber was temporarily able to grasp the platform but a landing support released and the platform fell into the river. Although being submerged for less than 30 seconds, inspection of the internal chassis later revealed at least some moisture had infiltrated into the chassis likely impacting electrical components. The sensor escaped without noticeable damage and operated without apparent impact after being subjected to prolonged drying. We were unable to determine the specific reason for communication loss after examining digital flight logs but investigated other similar reported loss occurrences to better understand what may have transpired. We provide some recommendations for minimizing loss based on our analysis of reported incidents with similar UAS platforms and from our experiences in using UAS for remote sensing in forested environments.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
In this study,2~5 （five factors at two-level factorial design） design of experiment was applied to investigate a set of optimal machining parameters to achieve a minimum surface roughness value for Abies nordmannian...In this study,2~5 （five factors at two-level factorial design） design of experiment was applied to investigate a set of optimal machining parameters to achieve a minimum surface roughness value for Abies nordmanniana.Wood specimens were prepared using different values of spindle speed,feed rate,depth of cut,tool radius,and cutting directions.Average surface roughness （R_z） values were applied using a stylus.The objectives were to：（1）obtain the effective variables of wood surface roughness;（2） analyze which of these factors had an impact on variability in the CNC machining process;（3） evaluate the optimal cutting values within the range of different cutting levels of machining parameters.The results indicate that the design of experiment（DOE） based on the desirability function approach determined the optimal machining parameters successfully,leading to minimum R_a compared to the observed value.Minimum surface roughness values of tangential and radial cutting directions were 3.58 and 3.21 μm,respectively.展开更多
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.
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.
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 European Regional Development Fund(ERDF)and the Consejería de Transformación Económica,Industria,Conocimiento y Universidades(project reference:1264483-R)Rafael M Navarro Cerrillo is particularly grateful for the support of the ISOPINE(UCO-1265298)ESPECTRAMED(CGL2017–86161-R)projects.
文摘Background:Fragmentation and deforestation are one of the greatest threats to forests,and these processes are of even more concern in the tropics,where the seasonal dry forest is possibly one of the most threatened ecosystems with the least remaining surface area.Methods:The deforestation and fragmentation patterns that had occurred in Ecuadorian seasonal dry forests between 1990 and 2018 were verified,while geographic information systems and land cover shapes provided by the Ecuadorian Ministry of the Environment were employed to classify and evaluate three types of seasonal dry forests:deciduous,semi-deciduous,and transition.The study area was tessellated into 10 km2 hexagons,in which six fragmentation parameters were measured:number of patches,mean patch size,median patch size,total edge,edge density and reticular fragmentation index(RFI).The RFI was also measured both outside and inside protected natural areas(unprotected,national protected areas and protected forest).Moreover,the areas with the best and worst conservation status,connectivity and risk of disappearance values were identified by means of a Getis-Ord Gi*statistical analysis.Results:The deforestation of seasonal dry forests affected 27.04%of the original surface area still remaining in 1990,with an annual deforestation rate of−1.12%between 1990 and 2018.The RFI has increased by 11.61%as a result of the fact that small fragments of forest have tended to disappear,while the large fragments have been fragmented into smaller ones.The semi-deciduous forest had the highest levels of fragmentation in 2018.The three categories of protection had significantly different levels of fragmentation,with lower RFI values in national protected areas and greater values in protected forests.Conclusions:The seasonal dry forest is fragmenting,deforesting and disappearing in some areas.An increased protection and conservation of the Ecuadorian seasonal dry forest is,therefore,necessary owing to the fact that not all protection measures have been effective.
文摘Various methods have been used to estimate the amount of above ground forest biomass across landscapes and to create biomass maps for specific stands or pixels across ownership or project areas. Without an accurate estimation method, land managers might end up with incorrect biomass estimate maps, which could lead them to make poorer decisions in their future management plans. The goal of this study was to compare various imputation methods to predict forest biomass and basal area, at a project planning scale (a combination of ground inventory plots, light detection and ranging (LiDAR) data, satellite imagery, and climate data was analyzed, and their root mean square error (RMSE) and bias were calculated. Results indicate that for biomass prediction, the k-nn (k = 5) had the lowest RMSE and least amount of bias. The second most accurate method consisted of the k-nn (k = 3), followed by the GWR model, and the random forest imputation. For basal area prediction, the GWR model had the lowest RMSE and least amount of bias. The second most accurate method was k-nn (k = 5), followed by k-nn (k = 3), and the random forest method. For both metrics, the GNN method was the least accurate based on the ranking of RMSE and bias.
基金To the National Council of Scientific and Technological Development of Brazil(CNPq),provided for research fellowships for S.V.Martins and to the Fundação Renova for provided infrastructure and financial support for the project.
文摘Currently there is an urgent and special attention in actions to restore tropical forests.In this study,we evaluated the effect of different restoration methods on aboveground biomass(AGB)stock,tree community diversity and structure,in areas affected by the Fundão tailings dam collapse in Mariana,Minas Gerais state,Brazil.We measured and compiled data of the AGB,community diversity and structure attributes in 36 plots distributed in six restoration treatments and six replicas:planting of native tree seedlings with fertilization and pH correction(PSf)and without fertilization and pH correction(PS);seeding of native trees with fertilization and pH correction(SDf)and without fertilization and pH correction(SD);natural regeneration with fertilization and pH correction(NRf)and without fertilization and pH correction(NR).No significant differences in substrate properties and AGB between treatments.Although biomass storage between treatments was not statistically different,there is a clear pattern showing higher values active restoration method.The Pielou index ranged from 0.520(SDf)to 0.943(NR),except for SDf all the others treatments had values higher than 0.76.This result suggests floristic heterogeneity,without ecological dominance in the plant community.Overall,active restoration had important implications for the forest restoration where natural regeneration is limited.
文摘Kaynasli District in the western Black Sea region of Turkey has long been vulnerable to frequent flood damage due to the establishment of settlements within and around stream channels without regard to fluctuating peakstreamflow frequencies. The aim of this research was to determine the measures needed to protect the towns and villages from this type of damage. Daily total precipitation data for 1975–2010 were analysed, and rainfall-runoff models developed to estimate the potential yearly maximum discharge from each stream of sub-watersheds dominated by forests and/or agriculture. This was then calculated for different frequencies of the yearly maximum discharge. Flood analysis and mapping was modified via the one-dimensional Hydrologic Engineering CentersRiver Analysis System software to produce potential maximum discharge and geometric data for Kaynasli Creek. As the main creek of the sub-watershed, its crosssection was shown to be insufficient and incapable of containing the maximum discharge at the 100-year frequency presumed for the watershed, and subsequently was seen as having a high level of casualty risk. It was concluded that the one dimensional model could be useful, but 2D models were more suitable for these types of watersheds.
文摘Disturbances such as forest fires,intense winds,and insect damage exert strong impacts on forest ecosystems by shaping their structure and growth dynamics,with contributions from climate change.Consequently,there is a need for reliable and operational methods to monitor and map these disturbances for the development of suitable management strategies.While susceptibility assessment using machine learning methods has increased,most studies have focused on a single disturbance.Moreover,there has been limited exploration of the use of“Automated Machine Learning(AutoML)”in the literature.In this study,susceptibility assessment for multiple forest disturbances(fires,insect damage,and wind damage)was conducted using the PyCaret AutoML framework in the Izmir Regional Forest Directorate(RFD)in Turkey.The AutoML framework compared 14 machine learning algorithms and ranked the best models based on AUC(area under the curve)values.The extra tree classifier(ET)algorithm was selected for modeling the susceptibility of each disturbance due to its good performance(AUC values>0.98).The study evaluated susceptibilities for both individual and multiple disturbances,creating a total of four susceptibility maps using fifteen driving factors in the assessment.According to the results,82.5%of forested areas in the Izmir RFD are susceptible to multiple disturbances at high and very high levels.Additionally,a potential forest disturbances map was created,revealing that 15.6%of forested areas in the Izmir RFD may experience no damage from the disturbances considered,while 54.2%could face damage from all three disturbances.The SHAP(Shapley Additive exPlanations)methodology was applied to evaluate the importance of features on prediction and the nonlinear relationship between explanatory features and susceptibility to disturbance.
文摘Integration system is used to denote practices that combine systematic use of the land and technologies,in which forest species are used in conjunction with herbaceous plants and/or animals respecting a spatial or temporal arrangement.Knowing that this type of production seeks to balance ecological and economic factors,it is important to understand the financial benefits and risks involved in this production.Financial analysis,therefore,acts as an important analysis tool to foster this type of activity.The paper aimed to conduct analysis of investment risk of a crop-livestock-forestry system deployed in Brazil,comparing two different production scenarios,scenario I with 17 ha and scenario II with 25 ha.The risk analysis was performed using the Monte Carlo method and sensitivity analysis(by varying the factors:the discount rate,productivity and price).A cash flow was elaborated based on annual cost and revenues data of the agricultural crops(corn and soybeans),livestock and eucalyptus,using an interest rate of 6%per year.The results indicated that the optimal age for cutting the eucalyptus was at seven years on both scenarios;scenario I had better return on investment using deterministic and probabilistic methods;scenario I presents higher investments risks;there is a negative relation between discount rate and annualized net present value(ANPV);increased productivity of crops provides greater profitability to the system;there has been an increase in the economic viability of the system,as value has been added to the products.Monte Carlo method and the sensitivity analysis showed to be an appropriate tool to analyze the risk of crop-livestock-forestry systems,making it possible to foresee how the project will respond to possible scenarios.
基金To the National Council of Scientific and Technological Development of Brazil(CNPq),provided fellowships for K.A.Silva(CNPq 142415/2013-8)research fellowships for S.V.Martins.The Companhia Brasileira de Alumínio(CBA)for provided infrastructure and financial support for the project.
文摘The shrub-tree floristic composition of the natural regeneration stratum of a bauxite mine in the process of restoration and in a reference ecosystem(remnant of a preserved secondary Seasonal Semi-Deciduous Forest)were analysed to evaluate forest restoration conditions after five years of planting.The influence of canopy openness,accumulated leaf litter and soil attributes in the regeneration stratum were also investigated in both the forests.The floristic composition of the regeneration stratum in the forest under restoration(16 species and 5,083 individuals ha-1)and in the reference ecosystem(58 species and 26,250 individuals ha-1)are distinct due to the difference in the environmental variables.Results showed that the reference ecosystem favours the presence of species that tolerate environments with greater shading and higher aluminium and organic matter content in the soil like Psychotria carthagenensis Jacq.,while the forest under restoration favours the presence of species adapted to fertile soils and those that tolerate greater luminosity like Vernonanthura phosphorica(Vell.)H.Rob.
文摘Ecological restoration in forest ecosystem is a priority in Mariana,Brazil.Thus,we evaluated the effects of passive and active restoration methods through different site preparation techniques by manipulating physical-chemical properties of substrates on tree community coverage in Mariana,Brazil.A total of 48 plots(12×12 m each)were established in two areas along the flood plains with accumulation of tailings.The following treatments were established:(1)planting of native tree seedlings with fertilization(PSf)and(2)without fertilization(PS);(3)direct seeding of native trees with fertilization(SDf)and(4)without fertilization(SD);(5)natural regeneration with fertilization(NRf)and(6)without fertilization(NR).Differences in substrate properties and tree community coverage were evaluated between treatments,the substrate properties and tree community coverage relationship,and main effects of substrate fertility and texture on tree community coverage.There were marked differences in substrate and plant coverage between treatments.On average,the highest plant coverage was found in treatment with fertilization,such as NRf(59,5%)and SDf(48%).However,the treatment with seedling planting(PSf and PS)and NR did not show differences(~37%),while the lowest values were observed in SD(23%).There is a strong relationship between substrate fertility and plant community coverage,with significant positive effects.We observed that the passive and active restoration methods can be complementary in the soil and plant community coverage recovery.
基金To the CNPq,Fapemig and Capes by research fellowships for the authors and to the Companhia Brasileira de Alumínio for provided infrastructure and financial support for the project.
文摘The objective of this study was to compare the soil seed bank in an area under natural regeneration(F1)and another reforested through seedling planting(F2),seven years after bauxite mining,in Southeast,Brazil.In each area,10 sampling points were randomly distributed,using three samples of topsoil to represent each point.The samples were transported to a shade house and evaluated for six months,where emerging individuals were identified every two weeks.Floristic similarity was evaluated with cluster analysis based on the Jaccard index(SJ).Species richness and abundance of individuals were compared using Student's t test.In F1,2,114.94 propagules m-2 were registered,belonging to 51 species and 24 botanical families,Shannon-Wiener diversity index H’=2.770 and Pielou evenness index J’=0.705.In F2,1,168.62 propagules m-2 were registered,belonging to 42 species and 22 families,H’=2.618 and J’=0.700.The(SJ)between F1 and F2 was 0.61,indicating a high similarity.The results showed high density of propagules,good diversity and absence of ecological dominance.The high number of individuals and diversity of tree species with zoochoric dispersion found in the areas indicates that both natural regeneration and reforestation were efficient in the ecological restoration of bauxite mined areas.
文摘Volume and biomass equations are essential tools to determine forest productivity and enable forest managers to make informed decisions. However, volume and biomass estimation equations are scarce for Afromontane forests in Africa in general and Ethiopia in particular. This limits our knowledge of the standing volume of wood, biomass, and carbon stock of the forests therein. In this study, we developed a new mixed-species volume and biomass equations for Afromontane forests and compared them with generic pantropical and local models. A total of 193 sampled trees from seven dominant tree species were used to develop the equations. Various volume and biomass equations were fitted using robust linear and nonlinear regression. Model comparison indicated that the best model to estimate stem volume was ln(v)=-9.909+ 0.954*ln(d<sup>2</sup>h), whereas the best model to estimate biomass was ln(b)=-2.983+ 0.949*ln(ρd<sup>2</sup>h) . These equations explained over 85% of the variations in the stem volume and biomass measurements. The mean density and basal area of trees in the forest with d ≥ 2 cm was 631.5 stems·ha<sup>-1</sup> and 24.4 m<sup>2</sup>·ha<sup>-1</sup>. Based on the newly developed equations, the forest has on average 303.0 m<sup>3</sup>·ha<sup>-1</sup> standing volume of wood and 283.8 Mg·ha<sup>-1</sup> biomass stock. The newly developed allometric equations derived from this study can be used to accurately determine the stem volume, biomass, and carbon storage in the Afromontane forests in Ethiopia and elsewhere with similar stand characteristics and ecological conditions. By contrast, the generic pan-tropical and other local models appear to provide biased estimates and are not suitable for dry Afromontane forests in Ethiopia. The estimated stem biomass and carbon stock in the Chilimo forest are comparable with the estimates from various tropical forests and woodlands elsewhere in Africa, indicating the importance of dry Afromontane forest for climate change mitigation.
文摘Unoccupied aircraft systems (UAS) are increasingly used to create spatial databases for use in natural resource research and in other disciplines. We describe our experience with the recovery of an UAS platform that became lodged in a tree located next to a small river island after experiencing communication loss. The UAS platform was a DJI M200 series aircraft that we had used for remote sensing applications over several years without issue. During remote sensing of a riparian restoration project, the M200 descended vertically downward after communication loss, became lodged in a tree crown, and was suspended above the river. A tree climber was temporarily able to grasp the platform but a landing support released and the platform fell into the river. Although being submerged for less than 30 seconds, inspection of the internal chassis later revealed at least some moisture had infiltrated into the chassis likely impacting electrical components. The sensor escaped without noticeable damage and operated without apparent impact after being subjected to prolonged drying. We were unable to determine the specific reason for communication loss after examining digital flight logs but investigated other similar reported loss occurrences to better understand what may have transpired. We provide some recommendations for minimizing loss based on our analysis of reported incidents with similar UAS platforms and from our experiences in using UAS for remote sensing in forested environments.
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performed in the laboratuary of Istanbul University,Faculty of Forestry where the authors are employed at present
文摘In this study,2~5 （five factors at two-level factorial design） design of experiment was applied to investigate a set of optimal machining parameters to achieve a minimum surface roughness value for Abies nordmanniana.Wood specimens were prepared using different values of spindle speed,feed rate,depth of cut,tool radius,and cutting directions.Average surface roughness （R_z） values were applied using a stylus.The objectives were to：（1）obtain the effective variables of wood surface roughness;（2） analyze which of these factors had an impact on variability in the CNC machining process;（3） evaluate the optimal cutting values within the range of different cutting levels of machining parameters.The results indicate that the design of experiment（DOE） based on the desirability function approach determined the optimal machining parameters successfully,leading to minimum R_a compared to the observed value.Minimum surface roughness values of tangential and radial cutting directions were 3.58 and 3.21 μm,respectively.
