The anthropogenic managements of forest have created a network of roads resulting in the loss and alternation of habitat. To better understand road′s impact on animal habitats, we assessed the habitat pattern of sabl...The anthropogenic managements of forest have created a network of roads resulting in the loss and alternation of habitat. To better understand road′s impact on animal habitats, we assessed the habitat pattern of sables(Martes zibellina), one of rodents within national first-class protected species, when roads are considered in Huzhong area in Da Hinggan Mountains, northeastern China. Employing published literatures about behavior ecology, aerial photographs and forest stand maps, we classified the study area into three habitat types including best-suitable, suitable and unsuitable habitats based on sable habitat requirements at the landscape scale including four variables derived from forest source map with attribute database. Results indicated the loss and significant fragmentation of best-suitable habitat and home range habitat when roads, especially 150 m avoidance distance of roads, were considered. The roads reduced and fragmented highly suitable habitats more significantly during earlier development period than the later development period. Additionally, the suitable area percentage increased with increasing distance to roads. This study helped to identify the suitable area for sables and location of sable population. Also, this study suggested the passage construction and road management involving road closure and removal will reduce the fragmentation functionally and benefit the sable population.展开更多
We developed a three-step classification approach for forest road extraction utilizing LiDAR data. The first step employed the IDW method to interpolate LiDAR point data （first and last pulses） to achieve DSM, DTM a...We developed a three-step classification approach for forest road extraction utilizing LiDAR data. The first step employed the IDW method to interpolate LiDAR point data （first and last pulses） to achieve DSM, DTM and DNTM layers （at 1 m resolution）. For this interpolation RMSE was 0.19 m. In the second step, the Support Vector Machine （SVM） was employed to classify the LiDAR data into two classes, road and non-road. For this classification, SVM indicated the merged distance layer with intensity data and yielded better identification of the road position. Assessments of the obtained results showed 63% correctness, 75% completeness and 52% quality of classification. In the next step, road edges were defined in the LiDAR-extracted layers, enabling accu- rate digitizing of the centerline location. More than 95% of the Li- DAR-derived road was digitized within 1.3 m to the field surveyed nor- rnal. The proposed approach can provide thorough and accurate road inventory data to support forest management.展开更多
A study was conducted to determine the influence of forest road on breeding of tits in artificial nest boxes in deciduous, coniferous and mixed forests in the Gwanak Arboretum （37° 25′ 05＂ N, 126° 56′ 85...A study was conducted to determine the influence of forest road on breeding of tits in artificial nest boxes in deciduous, coniferous and mixed forests in the Gwanak Arboretum （37° 25′ 05＂ N, 126° 56′ 85＂ E） of Seoul National University, Anyang, Korea from November 2002 to June 2003. Three tits species, varied tit （Parus varius）, marsh tit （P. palustris） and great tit （P. major）, breeding in artificial t nest boxes were investigated on number of breeding pairs, cultch size, and egg measurement. Resuls showed that the breeding pairs of varied tit was more in 75-150 m area than in 0-75m area from forest road for all the three study sites, and the clutch size and egg measurements （weight, Major axis and Minor axis） of varied tit was also higher in the area of 75-150 m than in the area of 0-75 m, while no differences in number of breeding pairs and clutch size were found for marsh tit and great tit between the two areas. Egg measurement of great tit was also higher in forest interior area than in forest edge area. It is concluded that varied tit were most significantly influenced by forest road, followed by great tit, whereas marsh tit were not influenced by forest road. Artificial nest box is roved to be good for cavity nester in disturbed areas by human activities. Supply of artificial nest can help population protection and management of bird species.展开更多
Geometric design of forest roads and design of their landscapes can reduce noise pollution and its harmful effects on human health. We investigated the effects of technical and biological parameters such as geometric ...Geometric design of forest roads and design of their landscapes can reduce noise pollution and its harmful effects on human health. We investigated the effects of technical and biological parameters such as geometric road design and various roadside tree stands on reducing noise pollution according to the tree density and distance from roadway in Darabkola Forests, Sari, Iran. We recorded the noise generated by a car （Land Rover） relative to changes in longitudinal slope, horizontal curve radius and type of road pavement. We also measured noise levels according to roadside tree density and stand type （coniferous and hardwood） in 40 rectangular plots of three widths （25, 100 and 300 m） and 50 m length that were randomly demar- cated along forest roads. The changes in noise level were recorded using a decibel meter with an accuracy of q-1.5 dB and resolution of 0.1 dB. Noise levels were higher alongside unpaved roads than alongside paved roads. There was an inverse relationship between the measured noise level and horizontal curve radius. The rate of noise level on horizontal curve with a radius less than 30, 30-45 m and more than 45 m were 64.8, 70.8 and 75.9 dB, respectively. The noise level increased with the increasing longitudinal slope of the road. There was a significant difference between the noise level on slopes less than 3 % （67 dB） and 3-8 % （71.2 dB） in comparison with slopes greater than 8 % （77.8 dB）, （p 〈 0.05）. Pinus brutia L. reduced the noise level more （about 6 dB） in stands of 1/3 density of mixed hardwoods within 25 m from middle of the road. Careful design of geometric properties of forest roads as well as planting coniferous trees with hardwoods is a suitable solution for reducing noise pollution.展开更多
We investigated forest road networks and forestry operations before and after mechanization on aggregated forestry operation sites. We developed equations to estimate densities of road networks with average slope angl...We investigated forest road networks and forestry operations before and after mechanization on aggregated forestry operation sites. We developed equations to estimate densities of road networks with average slope angles, operational efficiency of bunching operations with road network density, and average forwarding distances with operation site areas. Subsequently, we analyzed the effects of aggregating forests, establishing forest road networks, and mechanization on operational efficiency and costs. Six ha proved to be an appropriate operation site area with minimum operation expenses. The operation site areas of the forest owners＇ cooperative in this region aggregated approximately 6 ha and the cooperative conducted forestry operations on aggregated sites. Therefore, 6 ha would be an appropriate operation site area in this region. Regarding road network density, higher-density road networks increased operational expenses due to the higher direct operational expenses of strip road establishment. Therefore, road network density should be reduced to approximately 200 m.展开更多
The paper provides an overview of geometric solutions of marking all types of serpentine by the method of internal circular curve in designing forest roads directly in the field. The main objective of presenting this ...The paper provides an overview of geometric solutions of marking all types of serpentine by the method of internal circular curve in designing forest roads directly in the field. The main objective of presenting this original method for marking all serpentine types in one place is to show similarities and differences in marking different types of serpentine, and identify opportunities for further research of this type. The method is based on the establishment of the minimum number of elements necessary to mark the serpentine on the forest roads and other budget elements and their design in the field. By using this method, construction errors or the number of attempts of serpentine marking are reduced, which increases the effects of design compared to the ones reached by the previous method of marking the serpentine on forest roads.展开更多
Road prisms, such as cutslopes, fillslopes and road surfaces, can be important contributors of sediment to streams in forested watersheds. In this study rainfall simulations were carried out on cutslopes, fillslopes, ...Road prisms, such as cutslopes, fillslopes and road surfaces, can be important contributors of sediment to streams in forested watersheds. In this study rainfall simulations were carried out on cutslopes, fillslopes, road surfaces and forest grounds in hardwood forests of Lolet and Lat Talar, Iran. Water at intensity of 32.4 mm·h-1 was sprayed from a nozzle onto a square area of 0.48 m2. Runoff was collected by water gauge every 4 min and then runoff and sediment parameters were measured in each plot. Results indicated that on road surfaces, the runoff coefficient was 63.28%. On the cutslopes and fillslopes, the runoff coefficients were 35.14% and 10.23%, respectively. On the forest ground as a control, the runoff coefficient was 5.90%. Runoff volume was 2.73 mL·s^-1 on the road surfaces and 1.52 mL·s^-1 on cutslopes. On fillslopes the runoff volume was 0.44 mL·s^-1 and on the forest ground 0.25 mL·s^-1 The greatest rate of soil loss was found on the cutslope （280.79 g·m-2·h-1）. The total soil loss from the cutslopes was two times higher than that from the road surfaces and six times higher than that from the fillslopes. We conclude that cutslopes can be considered the main source of sediments in our study sites, but the function of road surface as a source of runoff generation is more important.展开更多
One of the principal difficulties related to road safety management in Brazil is the lack of data on road projects, especially those on rural roads, which makes it difficult to use road safety studies and models from ...One of the principal difficulties related to road safety management in Brazil is the lack of data on road projects, especially those on rural roads, which makes it difficult to use road safety studies and models from other countries as a reference. Updating road networks through the use of hyperspectral remote sensing images can be a good alternative. However, accurately recognizing and extracting hyperspectral images from roads has been recognized as a challenging task in the processing of hyperspectral data. In order to solve the aforementioned challenges, Hyperion hyperspectral images were combined with the Optimum Forest Path (OPF) algorithm for supervised classification of rural roads and the effectiveness of the OPF and SVM classifiers when applied to these areas was compared. Both classifiers produced reasonable results, however, the OPF algorithm outperformed SVM. The higher classification accuracy obtained by the OPF was mainly attributed to the ability to better distinguish between regions of exposed soil and unpaved roads.展开更多
The construction of expressway and high-speed rail is at the sacrifice of the soil ecological environment. It brings about much damaged land and bare slope. It is necessary to restore vegetation and rebuild landscape....The construction of expressway and high-speed rail is at the sacrifice of the soil ecological environment. It brings about much damaged land and bare slope. It is necessary to restore vegetation and rebuild landscape. In the design of target plant community and configuration plants,it is required to select as far as possible plants that can blossom and bear fruit or pods. Then seeds of these plants can be harvested,processed and sold,and applied for other projects,so as to develop into a complete forest and grass seed industry chain. This not only reasonably utilizes land resources,but also provides a new approach to the problem of insufficient fine forest seed sources in China. This paper discussed the use of land resources in road side slope and forest and grass seed selection and breeding technology,and elaborated the industrialized development paths for forest and grass seed industries in road side slope. Finally,it arrived at following recommendations.( i) The construction of forest and grass industry economic belt using land resources in road side slope can realize maximum land value. Building a road can help people there get rich,and the type of land and water cultivates its type of forest and grass.( ii) It can make up for the losses incurred from construction of expressway and high-speed rail or destroying forest land,and it can increase farmers' income.( iii) It can increase the supply of domestic seeds,reduce seed import,save foreign exchange,and partly solve the problem of insufficient supply of forest and grass seeds.( iv) It is able to form a complete forest and grass seed industry economic cycle chain,increase employment,and provide new approaches for enriching and benefiting farmers.展开更多
Natural regeneration is the basis of a dynamic and demographic balance of plant populations. The objective of this study was to assess the natural regeneration potential of woody species along secondary roads post-log...Natural regeneration is the basis of a dynamic and demographic balance of plant populations. The objective of this study was to assess the natural regeneration potential of woody species along secondary roads post-logging abandoned since 2008 and 2018. In the two Annual Allowable Cuts (AAC 2008 and AAC 2018), 24 regenerating sub-plots (i.e. 12 sub-plots for AAC 2008 and 12 sub-plots for AAC 2018) with a unit area of 5 m × 5 m were delimited with a total area of 0.06 ha (i.e. 0.03 ha for each AAC). The abundance and diversity of woody species were respectively inventoried and estimated. Two estimators of the specific richness were used to estimate the floristic diversity of each Annual Allowable Cuts (AAC). The results reveal globally 88 woody species in the AAC 2008 and 241 woody species in the AAC 2018, with respective average densities of 2933 stem/ha and 8033 stem/ha. There was a very highly significant difference between the mean densities of the two AAC (Kruskal-Wallis test;H = 2.36, p-value < 0.000). The results also highlight a great diversity and a relatively high abundance of woody species in the 2018 AAC compared to the 2008 AAC. Also, the spatial structuring of the sub-plots on the basis of Principal Component Analysis (PCA) demonstrates that the floristic composition of the two AAC is globally different. The study suggests silvicultural interventions and the long-term assessment of regenerating woody species along abandoned secondary roads in order to guarantee the sustainable management of their population.展开更多
The present study on the sediment production in natural forests was carried out on an 13,284 ha area,ocated in Guilan Province, in the north of Iran. This area is under intensive management. We first analyzed the phys...The present study on the sediment production in natural forests was carried out on an 13,284 ha area,ocated in Guilan Province, in the north of Iran. This area is under intensive management. We first analyzed the physi- sal factors of the area. Then, the amount of road construction, afforestation and harvested wood volume, as well as the harvesting method in the region were determined for the years between 1993 and 2010. The results show that the aver- age annual amount of sediment production in the entire region, over this 18-year period, has increased annually at a rate of 3.54 t.km-2 （R2 = 0.56） at a confidence level of 95%. Operations management and management methods used in ：his forest area has affected the amount of sediment production. Clear cutting and extensive harvesting methods in the region caused an increase in the amount of sediment production, as indicated by a coefficient of determination of 0.71, mplying that forest management may be considered effective and in harmony with the environment.展开更多
This article addresses where ruts are likely to occur during in-field forest operations. This was done by inspecting high-resolution surface images across New Brunswick (NB) and elsewhere to mark where ruts have (1) a...This article addresses where ruts are likely to occur during in-field forest operations. This was done by inspecting high-resolution surface images across New Brunswick (NB) and elsewhere to mark where ruts have (1) and have not (0) occurred in harvested cutblocks. This marking revealed 1) where off-road operations were likely done on moist to wet and unfrozen soils;and 2) whether the ruts so incurred were water-logged at the time of imaging. Through geospatial processing of the NB-wide digital elevation model (DEM, available at 1 m resolution), the following attributes were added to each of the marked rut and no-rut locations: 1) the cartographic depth-to-water (DTW) as referenced to the nearest flow channels with >1 and >4 ha upslope flow accumulation areas (FA);2) the topographic position index (TPI) in reference to the mean annulus elevation 50 m away from each DEM cell;3) mean slope and curvatures within each cell-surrounding 10-m circle;4) the terrain wetness index (TWI);5) soil association type according to the NB forest soil map, adjusted for NB’s most recent hydrographic network delineations for waterbodies and wetlands. Subjecting these data to logistic regression analysis revealed that image-located off-road rutting occurred at about 90% probability in water-accumulating zones where TPI is <0 m and DTW is <1 m. Using slope, curvature, TWI, and soil type as additional rut occurrence predictors did not affect this zonation significantly.展开更多
为探究山区双车道公路行驶车辆的超车行为特性,基于无人机高空拍摄的超车行为视频数据,提出一种基于随机生存森林的超车持续时间预测模型.首先,利用Tracker软件提取超车行为相关车辆的行驶轨迹,并对超车行为特征进行分析;其次,采用非参...为探究山区双车道公路行驶车辆的超车行为特性,基于无人机高空拍摄的超车行为视频数据,提出一种基于随机生存森林的超车持续时间预测模型.首先,利用Tracker软件提取超车行为相关车辆的行驶轨迹,并对超车行为特征进行分析;其次,采用非参数Kaplan-Meier模型和全参数加速失效时间(Accelerated Failure Time, AFT)模型确定影响超车持续时间的关键协变量;最后,构建随机生存森林模型预测山区双车道公路的超车持续时间.结果表明:山区双车道公路平均超车持续时间为12.3 s,考虑超车类型的超车持续时间在无对向来车时表现出显著差异;相较于固定效应AFT模型,全参数AFT模型具有更好的拟合优度,超车距离、超车车辆最终速度、被超车辆类型是影响超车持续时间的关键变量;对比随机森林模型、生存支持向量模型、XG-Boost模型,随机生存森林模型在一致性指数和整合布里尔分数等方面均优于前三者,且考虑超车类型对山区双车道公路超车持续时间的预测效果影响较小;根据变量重要性排名,超车距离和两车的初始速度差对超车持续时间的影响较大.研究结果可为提高山区公路行车安全提供参考.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41271201,31070422,41201185)
文摘The anthropogenic managements of forest have created a network of roads resulting in the loss and alternation of habitat. To better understand road′s impact on animal habitats, we assessed the habitat pattern of sables(Martes zibellina), one of rodents within national first-class protected species, when roads are considered in Huzhong area in Da Hinggan Mountains, northeastern China. Employing published literatures about behavior ecology, aerial photographs and forest stand maps, we classified the study area into three habitat types including best-suitable, suitable and unsuitable habitats based on sable habitat requirements at the landscape scale including four variables derived from forest source map with attribute database. Results indicated the loss and significant fragmentation of best-suitable habitat and home range habitat when roads, especially 150 m avoidance distance of roads, were considered. The roads reduced and fragmented highly suitable habitats more significantly during earlier development period than the later development period. Additionally, the suitable area percentage increased with increasing distance to roads. This study helped to identify the suitable area for sables and location of sable population. Also, this study suggested the passage construction and road management involving road closure and removal will reduce the fragmentation functionally and benefit the sable population.
基金supported by Tarbiat Modares University(TMU)of Iran
文摘We developed a three-step classification approach for forest road extraction utilizing LiDAR data. The first step employed the IDW method to interpolate LiDAR point data （first and last pulses） to achieve DSM, DTM and DNTM layers （at 1 m resolution）. For this interpolation RMSE was 0.19 m. In the second step, the Support Vector Machine （SVM） was employed to classify the LiDAR data into two classes, road and non-road. For this classification, SVM indicated the merged distance layer with intensity data and yielded better identification of the road position. Assessments of the obtained results showed 63% correctness, 75% completeness and 52% quality of classification. In the next step, road edges were defined in the LiDAR-extracted layers, enabling accu- rate digitizing of the centerline location. More than 95% of the Li- DAR-derived road was digitized within 1.3 m to the field surveyed nor- rnal. The proposed approach can provide thorough and accurate road inventory data to support forest management.
文摘A study was conducted to determine the influence of forest road on breeding of tits in artificial nest boxes in deciduous, coniferous and mixed forests in the Gwanak Arboretum （37° 25′ 05＂ N, 126° 56′ 85＂ E） of Seoul National University, Anyang, Korea from November 2002 to June 2003. Three tits species, varied tit （Parus varius）, marsh tit （P. palustris） and great tit （P. major）, breeding in artificial t nest boxes were investigated on number of breeding pairs, cultch size, and egg measurement. Resuls showed that the breeding pairs of varied tit was more in 75-150 m area than in 0-75m area from forest road for all the three study sites, and the clutch size and egg measurements （weight, Major axis and Minor axis） of varied tit was also higher in the area of 75-150 m than in the area of 0-75 m, while no differences in number of breeding pairs and clutch size were found for marsh tit and great tit between the two areas. Egg measurement of great tit was also higher in forest interior area than in forest edge area. It is concluded that varied tit were most significantly influenced by forest road, followed by great tit, whereas marsh tit were not influenced by forest road. Artificial nest box is roved to be good for cavity nester in disturbed areas by human activities. Supply of artificial nest can help population protection and management of bird species.
文摘Geometric design of forest roads and design of their landscapes can reduce noise pollution and its harmful effects on human health. We investigated the effects of technical and biological parameters such as geometric road design and various roadside tree stands on reducing noise pollution according to the tree density and distance from roadway in Darabkola Forests, Sari, Iran. We recorded the noise generated by a car （Land Rover） relative to changes in longitudinal slope, horizontal curve radius and type of road pavement. We also measured noise levels according to roadside tree density and stand type （coniferous and hardwood） in 40 rectangular plots of three widths （25, 100 and 300 m） and 50 m length that were randomly demar- cated along forest roads. The changes in noise level were recorded using a decibel meter with an accuracy of q-1.5 dB and resolution of 0.1 dB. Noise levels were higher alongside unpaved roads than alongside paved roads. There was an inverse relationship between the measured noise level and horizontal curve radius. The rate of noise level on horizontal curve with a radius less than 30, 30-45 m and more than 45 m were 64.8, 70.8 and 75.9 dB, respectively. The noise level increased with the increasing longitudinal slope of the road. There was a significant difference between the noise level on slopes less than 3 % （67 dB） and 3-8 % （71.2 dB） in comparison with slopes greater than 8 % （77.8 dB）, （p 〈 0.05）. Pinus brutia L. reduced the noise level more （about 6 dB） in stands of 1/3 density of mixed hardwoods within 25 m from middle of the road. Careful design of geometric properties of forest roads as well as planting coniferous trees with hardwoods is a suitable solution for reducing noise pollution.
文摘We investigated forest road networks and forestry operations before and after mechanization on aggregated forestry operation sites. We developed equations to estimate densities of road networks with average slope angles, operational efficiency of bunching operations with road network density, and average forwarding distances with operation site areas. Subsequently, we analyzed the effects of aggregating forests, establishing forest road networks, and mechanization on operational efficiency and costs. Six ha proved to be an appropriate operation site area with minimum operation expenses. The operation site areas of the forest owners＇ cooperative in this region aggregated approximately 6 ha and the cooperative conducted forestry operations on aggregated sites. Therefore, 6 ha would be an appropriate operation site area in this region. Regarding road network density, higher-density road networks increased operational expenses due to the higher direct operational expenses of strip road establishment. Therefore, road network density should be reduced to approximately 200 m.
文摘The paper provides an overview of geometric solutions of marking all types of serpentine by the method of internal circular curve in designing forest roads directly in the field. The main objective of presenting this original method for marking all serpentine types in one place is to show similarities and differences in marking different types of serpentine, and identify opportunities for further research of this type. The method is based on the establishment of the minimum number of elements necessary to mark the serpentine on the forest roads and other budget elements and their design in the field. By using this method, construction errors or the number of attempts of serpentine marking are reduced, which increases the effects of design compared to the ones reached by the previous method of marking the serpentine on forest roads.
基金supported by a grant from the Basij Organizationfor Research, Science and Technology in Mazan-daran Province, Iran
文摘Road prisms, such as cutslopes, fillslopes and road surfaces, can be important contributors of sediment to streams in forested watersheds. In this study rainfall simulations were carried out on cutslopes, fillslopes, road surfaces and forest grounds in hardwood forests of Lolet and Lat Talar, Iran. Water at intensity of 32.4 mm·h-1 was sprayed from a nozzle onto a square area of 0.48 m2. Runoff was collected by water gauge every 4 min and then runoff and sediment parameters were measured in each plot. Results indicated that on road surfaces, the runoff coefficient was 63.28%. On the cutslopes and fillslopes, the runoff coefficients were 35.14% and 10.23%, respectively. On the forest ground as a control, the runoff coefficient was 5.90%. Runoff volume was 2.73 mL·s^-1 on the road surfaces and 1.52 mL·s^-1 on cutslopes. On fillslopes the runoff volume was 0.44 mL·s^-1 and on the forest ground 0.25 mL·s^-1 The greatest rate of soil loss was found on the cutslope （280.79 g·m-2·h-1）. The total soil loss from the cutslopes was two times higher than that from the road surfaces and six times higher than that from the fillslopes. We conclude that cutslopes can be considered the main source of sediments in our study sites, but the function of road surface as a source of runoff generation is more important.
文摘One of the principal difficulties related to road safety management in Brazil is the lack of data on road projects, especially those on rural roads, which makes it difficult to use road safety studies and models from other countries as a reference. Updating road networks through the use of hyperspectral remote sensing images can be a good alternative. However, accurately recognizing and extracting hyperspectral images from roads has been recognized as a challenging task in the processing of hyperspectral data. In order to solve the aforementioned challenges, Hyperion hyperspectral images were combined with the Optimum Forest Path (OPF) algorithm for supervised classification of rural roads and the effectiveness of the OPF and SVM classifiers when applied to these areas was compared. Both classifiers produced reasonable results, however, the OPF algorithm outperformed SVM. The higher classification accuracy obtained by the OPF was mainly attributed to the ability to better distinguish between regions of exposed soil and unpaved roads.
基金Supported by National Spark Plan Project(2010GA781004)Science and Technology Planning Project of Shenzhen(GCZX2015051514435234,CXZZ20150527171538718,and CXZZ20140422142833835)
文摘The construction of expressway and high-speed rail is at the sacrifice of the soil ecological environment. It brings about much damaged land and bare slope. It is necessary to restore vegetation and rebuild landscape. In the design of target plant community and configuration plants,it is required to select as far as possible plants that can blossom and bear fruit or pods. Then seeds of these plants can be harvested,processed and sold,and applied for other projects,so as to develop into a complete forest and grass seed industry chain. This not only reasonably utilizes land resources,but also provides a new approach to the problem of insufficient fine forest seed sources in China. This paper discussed the use of land resources in road side slope and forest and grass seed selection and breeding technology,and elaborated the industrialized development paths for forest and grass seed industries in road side slope. Finally,it arrived at following recommendations.( i) The construction of forest and grass industry economic belt using land resources in road side slope can realize maximum land value. Building a road can help people there get rich,and the type of land and water cultivates its type of forest and grass.( ii) It can make up for the losses incurred from construction of expressway and high-speed rail or destroying forest land,and it can increase farmers' income.( iii) It can increase the supply of domestic seeds,reduce seed import,save foreign exchange,and partly solve the problem of insufficient supply of forest and grass seeds.( iv) It is able to form a complete forest and grass seed industry economic cycle chain,increase employment,and provide new approaches for enriching and benefiting farmers.
文摘Natural regeneration is the basis of a dynamic and demographic balance of plant populations. The objective of this study was to assess the natural regeneration potential of woody species along secondary roads post-logging abandoned since 2008 and 2018. In the two Annual Allowable Cuts (AAC 2008 and AAC 2018), 24 regenerating sub-plots (i.e. 12 sub-plots for AAC 2008 and 12 sub-plots for AAC 2018) with a unit area of 5 m × 5 m were delimited with a total area of 0.06 ha (i.e. 0.03 ha for each AAC). The abundance and diversity of woody species were respectively inventoried and estimated. Two estimators of the specific richness were used to estimate the floristic diversity of each Annual Allowable Cuts (AAC). The results reveal globally 88 woody species in the AAC 2008 and 241 woody species in the AAC 2018, with respective average densities of 2933 stem/ha and 8033 stem/ha. There was a very highly significant difference between the mean densities of the two AAC (Kruskal-Wallis test;H = 2.36, p-value < 0.000). The results also highlight a great diversity and a relatively high abundance of woody species in the 2018 AAC compared to the 2008 AAC. Also, the spatial structuring of the sub-plots on the basis of Principal Component Analysis (PCA) demonstrates that the floristic composition of the two AAC is globally different. The study suggests silvicultural interventions and the long-term assessment of regenerating woody species along abandoned secondary roads in order to guarantee the sustainable management of their population.
文摘The present study on the sediment production in natural forests was carried out on an 13,284 ha area,ocated in Guilan Province, in the north of Iran. This area is under intensive management. We first analyzed the physi- sal factors of the area. Then, the amount of road construction, afforestation and harvested wood volume, as well as the harvesting method in the region were determined for the years between 1993 and 2010. The results show that the aver- age annual amount of sediment production in the entire region, over this 18-year period, has increased annually at a rate of 3.54 t.km-2 （R2 = 0.56） at a confidence level of 95%. Operations management and management methods used in ：his forest area has affected the amount of sediment production. Clear cutting and extensive harvesting methods in the region caused an increase in the amount of sediment production, as indicated by a coefficient of determination of 0.71, mplying that forest management may be considered effective and in harmony with the environment.
文摘This article addresses where ruts are likely to occur during in-field forest operations. This was done by inspecting high-resolution surface images across New Brunswick (NB) and elsewhere to mark where ruts have (1) and have not (0) occurred in harvested cutblocks. This marking revealed 1) where off-road operations were likely done on moist to wet and unfrozen soils;and 2) whether the ruts so incurred were water-logged at the time of imaging. Through geospatial processing of the NB-wide digital elevation model (DEM, available at 1 m resolution), the following attributes were added to each of the marked rut and no-rut locations: 1) the cartographic depth-to-water (DTW) as referenced to the nearest flow channels with >1 and >4 ha upslope flow accumulation areas (FA);2) the topographic position index (TPI) in reference to the mean annulus elevation 50 m away from each DEM cell;3) mean slope and curvatures within each cell-surrounding 10-m circle;4) the terrain wetness index (TWI);5) soil association type according to the NB forest soil map, adjusted for NB’s most recent hydrographic network delineations for waterbodies and wetlands. Subjecting these data to logistic regression analysis revealed that image-located off-road rutting occurred at about 90% probability in water-accumulating zones where TPI is <0 m and DTW is <1 m. Using slope, curvature, TWI, and soil type as additional rut occurrence predictors did not affect this zonation significantly.
文摘为探究山区双车道公路行驶车辆的超车行为特性,基于无人机高空拍摄的超车行为视频数据,提出一种基于随机生存森林的超车持续时间预测模型.首先,利用Tracker软件提取超车行为相关车辆的行驶轨迹,并对超车行为特征进行分析;其次,采用非参数Kaplan-Meier模型和全参数加速失效时间(Accelerated Failure Time, AFT)模型确定影响超车持续时间的关键协变量;最后,构建随机生存森林模型预测山区双车道公路的超车持续时间.结果表明:山区双车道公路平均超车持续时间为12.3 s,考虑超车类型的超车持续时间在无对向来车时表现出显著差异;相较于固定效应AFT模型,全参数AFT模型具有更好的拟合优度,超车距离、超车车辆最终速度、被超车辆类型是影响超车持续时间的关键变量;对比随机森林模型、生存支持向量模型、XG-Boost模型,随机生存森林模型在一致性指数和整合布里尔分数等方面均优于前三者,且考虑超车类型对山区双车道公路超车持续时间的预测效果影响较小;根据变量重要性排名,超车距离和两车的初始速度差对超车持续时间的影响较大.研究结果可为提高山区公路行车安全提供参考.
