共查询到20条相似文献，搜索用时 31 毫秒
1.
Hans R. Heinimann 《Journal of Forest Research》1998,3(1):1-9
Road spacing on slpes depends on the underlying off-road transportation technology. One major decision in road network planning
is to determine under what terrain conditions ground- or cable based extraction systems should be applied. The present investigation
aims to develop a road spacing model for steep slope conditions and to implement a total cost model for skidder and cableyarder
based road network concepts. The study analyzes transportation and road geometry to specify the relationship between road
density, slope gradient, and road spacing. Production functions for skidder and yarder-systems make it possible to derive
transportation cost as a function of road density and slope gradient. A total cost function integrates road building cost,
harvesting strategy, and production economics to derive optimal road density for the two network concepts. The difference
between the cost levels at optimum road density is an indicator for differentiating cable and skidder-based extraction systems.
The model was implemented as a Visual Basic add-in for Microsoft Excel spreadsheet software. This flexible approach makes
future adaptations and changes very easy due to the modular concept. The validity of the model is limited to the production
functions of the underlying off-road transportation technologies. Future work needs to develop production functions for the
state-of-the-art technologies and to improve the road building cost model. 相似文献
2.
Adrian Enache Martin Kühmaier Rien Visser Karl Stampfer 《Scandinavian Journal of Forest Research》2016,31(4):412-427
Timber production is an important ecosystem service of European mountain forests. This paper aimed to assess the current practices in logging operations and to identify the efficiency gaps in timber production. The study was located in 7 case study areas from representative European mountain ranges, where 632 logging operations were analysed. The focus was on road infrastructure, transport systems, harvesting methods and extraction technologies. Often inappropriate technology was used in steep terrain; there was no correlation between the average slope and the selection of harvesting systems (HS). Skidding was the most common extraction method (75%), while cable yarding and forwarding had shares of 15% and 8%. The mean road density was 18.5?m?ha?1. The mean extraction distance was 501?m. The mean harvesting and extraction productivity were 9.0 and 10.2?m³?h?1; the mean costs were 11.1 and 11.7?€?m?³, respectively. Non-mechanized and obsolete HS reported the lowest efficiency and the highest environmental footprint, while fully mechanized systems reported the highest efficiency, the lowest number of accidents and the lowest stand damage. Cable yarders are the appropriate extraction technology in steep terrain, but they require a well-developed road network. Higher mechanization degree, improved quality of the road networks, knowledge transfer to practice and training of forest workers are some of the necessary measures to overcome the efficiency gaps in timber production in European mountain forests. 相似文献
3.
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 firesensitivity 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. 相似文献
4.
Hikaru Kitahara Yoichi Okura Toshiaki Sammori Akiko Kawanami 《Journal of Forest Research》2000,5(4):231-236
Universal Soil Loss Equation (USLE), originally developed by the USDA for agricultural lands and then used throughout the
world, was applied in mountainous forest terrain in Japan. The slope length and steepness factors were extended for long slope
lengths and steep slopes by recalculating the data from available literature in Japan and by using data from supplementary
erosion experiments. As such, we conclude that the USLE can be used successfully to estimate surface erosion on long, steep
mountainous forest slopes. The cover and management factors of many kinds of natural and artificial forest stands, cutting
types, and disturbance regimes were calculated from the literature. The support practice factors of many types of soil and
water conservation practices were also calculated from published information. Based on these results, we showed that the USLE
can be applied to estimations of soil erosion from wide areas including many kinds of agricultural and forest lands.
This study was funded by the Agricultural, Forestry, and Fishery Technology Council Office for comprehensive studies on agriculture,
forestry, and fisheries and the agricultural, forestry, and fishery trading, resources, and environments. 相似文献
5.
6.
Fraefel Marielle Bont Leo G. Fischer Christoph 《European Journal of Forest Research》2021,140(5):1195-1209
Efficient forest management, and wood production in particular, requires a forest road network of appropriate density and bearing capacity. The road network affects the choice of a suitable extraction method and the length of the transport route from the forest, while the road standard defines the truck type that can be used.
We evaluate the forest road network’s economic suitability for harvesting operations in the entire Swiss forest, an area of about 13,000 km2 covering a range of topographies, based on the Swiss National Forest Inventory’s (NFI) forest road dataset. This dataset is based on information from an interview survey with the local forest services and includes all forest roads in Switzerland capable of carrying trucks. Extraction options and hauling routes are analysed together; thus, the entire logging process is examined.
Model results include maps of the most suitable extraction method; extraction costs; hauling costs; and a suitability map based on a combination of the results. While the larger part of the Swiss forest is classified as “suitable” for economic harvesting operations, significant portions also fall into the “limited suitability” and “not suitable” categories. Our analysis provides an objective, country-wide, spatially explicit assessment of timber accessibility. The resulting suitability map helps identify areas where timber harvesting is economic using the current forest road network, and where it is not. The model results can be used in road network planning and management, for example, by comparing road-network re-design scenarios, and compared to the spatial distribution of available wood volume.
相似文献7.
基于DEM的2种提取地形特征线算法对比研究 总被引：2，自引：0，他引：2
以云南省昭通市昭阳区1∶5万的DEM规则数据作为数据源,分别利用平面曲率与坡形组合提取法(基于平面曲率、坡向变率)、地形地表几何形态分析和流水物理模拟结合分析法提取其地形特征线(山脊线、山谷线),并根据提取效果选取研究区的西北区作为效果比对样区.对3个提取效果进行对比后发现:①分级阈值的合理判定是正确提取地形特征线的关键;②基于地形地表几何形态分析和流水物理模拟结合分析法提取的地形特征线效果最佳,而基于平面曲率、坡向变率提取的地形特征线效果各有优缺. 相似文献
8.
Timber harvesting on steep terrain is always a challenge in terms of safety, operating costs, and environmental impact. The motor-manual, cut-to-length method is the most common in harvesting operations in the mountainous areas of Thailand. The motor-manual operations are characterized by various negative features such as high fatality rates, expensive operating costs, and low productivity. The aims of this study were to evaluate the prevailing harvesting operations, to propose new working methods and systems, and to suggest work safety improvement measures. The results indicated an extremely high fatality rate in Thailand compared to the average in other countries. Possible reasons for this may include ineffective safety regulations, inadequate worker training programs, seasonal forestry workers, and a lack of personal protective equipment. Consequently, alternative working methods have been suggested as a system. The proposed working method was intended to improve work safety, enhance productivity and reduce operating costs using by simulation to find best solution. Shifting from a cut-to-length to tree-length processing and moving forward to mechanization was introduced as alternative harvesting systems. The results showed that partly-mechanized systems would significantly improve the productivity. Potential work safety improvement measures may consist of adequate training, personal protective equipment, and technological improvement. Obstacle for implementation is the high investment for forest machines and silvicultural practices. 相似文献
9.
以福建省永安市为案例,应用参与式农村快速评估技术对2001年以来闽山区竹山道路开设过程投入机制、开设模式和效应等进行调查。结果表明,通过政府部门的宣传引导和激励扶植,逐渐形成了以经营者主动投入为主的多元投入机制,并形成以村集体为主体或有一定经济实力和经营兴趣的农户及有关农户根据竹山便道受益面积形成合伙人组合形成经济实体,按竹山便道开设后有关农户的受益面积分摊筹集竹山便道开设经费等五种模式。竹山便道的开通,可有效节约劳动力,竹材生产成本可降低1.2~2.0元.株-1,并带动了经营观念的转变,对促进闽山区竹山道路开设的快速发展起到了积极的推动作用。 相似文献
10.
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 av... 相似文献
11.
We investigated the distribution and frequency of damage to tree stands adjacent to low-volume roads according to the type of hillside materials involved(soil or rock) and hillside gradient in mountainous forests of northern Iran. A total of 80 plots were systematically and randomly sampled to record damaged trees(bending,crushing and wounding) by class of hillside gradient and materials at the edge of road. Tree wounding and crushing at rock slopes was significantly greater than at hillsides with a mix of clay soil(p \ 0.05). Damage on hillsides with slope gradients[45% were 2, 8.5 and 2.3 times more frequent than on hillsides with slope gradient\15% for bending, crushing and wounding, respectively. The damage distribution varied according by type and the most frequent damage was tree wounding(p \ 0.05). The damage distribution was measured at distances of 4, 5 and 8 m from the road fillslope for tree bending, crushing and wounding, respectively. Using hydraulic excavators and physical barriers(wooden obstruction and synthetic holder) during earthworks for road construction could reduce these damage. 相似文献
12.
数字地形模型(DTM)是资源信息系统中的重要组成部分。以格网方式建立的地形模型具有定位及定量化的优点,用途很广。本文详细介绍了DTM中数据采集、坡度和坡向数据的计算、格网的加密、地形模型的建立和三维立体绘图的原理和方法。并对在微机环境下建立的DTM的功能做了系统介绍。由本系统建立的数字地形模型可广泛用于遥感图像处理、植被分类、立地条件划分、坡度和坡向图制作,也可用于林区道路选线、土石方计算、水库选址和坝高与库容计算及洪水危害估计等方面。 相似文献
13.
Kotaro Zushi 《Journal of Forest Research》2006,11(5):351-358
Digital terrain modeling was used to evaluate landscape-level spatial variation of soil C and N storage and site productivity
in Japanese cedar (Cryptomeria japonica D. Don) stands. Soil C and N storage were measured in samples from surface soils (0–25 cm depth) of 29 Japanese cedar stands
in the 205-ha Myougodani watershed, Toyama Prefecture. The site index (C. japonica tree height at age 40 years) was used as a measure of forest productivity. Seven terrain attributes (elevation, slope gradient,
aspect, profile curvature, plan curvature, openness, and wetness index) were calculated from a digital elevation model. Soil
C and N storage were negatively correlated with slope gradient and positively correlated with openness. Variation in the site
index was closely related to the wetness index. The prediction models using terrain attributes as explanatory variables explained
50% of the variability in soil C storage, 53% of the variability in soil N storage, and 75% of the variability in site index.
This result demonstrated that this technique is useful for estimating the spatial distribution of soil properties and productivity
in forest landscapes. On the other hand, there was no correlation between site index and soil C and N storage. Use of the
prediction models in a geographic information system revealed that the spatial distribution of forest productivity differed
considerably from those of soil C and N storage. 相似文献
14.
Over the past two decades, sets of timber harvesting guidelines designed to mitigate the deleterious environmental impacts of tree felling, yarding, and hauling have become known as “reduced-impact logging” (RIL) techniques. Although none of the components of RIL are new, concerns about destructive logging practices and worker safety in the tropics stimulated this recent proliferation of semi-coordinated research and training activities related to timber harvesting. Studies in Southeast Asia, Africa, and South and Central America have clearly documented that the undesired impacts of selective logging on residual stands and soils can be substantially reduced through implementation of a series of recommended logging practices by crews that are appropriately trained, supervised, and compensated. Whether reducing the deleterious impacts of logging also reduces profits seems to depend on site conditions (e.g., terrain, soil trafficability, and riparian areas), whether the profits from illegal activities are included in the baseline, and the perspective from which the economic calculations are made. A standardized approach for calculating logging costs using RILSIM software is advocated to facilitate comparisons and to allow uncoupling RIL practices to evaluate their individual financial costs and benefits. Further complicating the matter is that while there are elements common to all RIL guidelines (e.g., directional felling), other components vary (e.g., slope limits of 17–40° with ground-based yarding). While use of RIL techniques may be considered as a prerequisite for sustaining timber yields (STY), in particular, and sustainable forest management (SFM), in general, RIL should not be confounded with STY and SFM. This confusion is particularly problematic in forests managed for light-demanding species that benefit from both canopy opening and mineral soil exposure as well as where harvesting intensities are high and controlled primarily by minimum diameter cutting limits. These qualifications notwithstanding, since logging is the most intensive of silvicultural treatments in most tropical forests managed for timber, some aspects of RIL are critical (e.g., protection of water courses) whether forests are managed for STY, SFM, or even replacement by agricultural crops. 相似文献
15.
16.
In this study, we combined a program to optimize forest road alignments with a method for prediction of surface erosion and
related sediment delivered to streams. Combining the forest road design program with the high-resolution digital elevation
model made it possible to estimate soil sediment based on a standard methodology, because a relatively accurate road prism
could be generated. The combined program properly places and spaces drainage structures based on the Washington State Forest practice board manual. We applied the program to a part of Capitol State Forest in Washington State and optimized horizontal and vertical alignments
while estimating movement of soil sediment from roads to streams. We discussed the effects of road surface materials, near-stream
culvert distance to stream, and out-sloped forest road template on total road costs and soil sediment delivered to streams.
Using lower quality rock surfacing reduced total costs, but the amount of soil sediment from lower quality rock surfacing
was 1.5 times more than that on a higher quality rock traction surface. Therefore, lower quality rock surfacing should not
be used near the stream. The placement of near-stream culverts 15 m upstream and out-sloped road template were examined using
a traction surface on 15-m sections upstream and lower quality rock surfacing on other sections in order to reduce soil sediments
to the stream and total costs. As a result, placing near-stream culverts 15 m upstream and using an out-sloped road template
significantly reduced total road cost and soil sediment. Finally, we optimized horizontal and vertical alignments while limiting
soil sediment to a specified maximum level. The model successfully optimized forest road alignments, which reduced total road
cost as well as soil sediment. 相似文献
17.
在水利、道路及城市建设过程中,因人工开挖往往形成人工高陡岩质边坡,如不加以支护加固处理,在降雨及其他因素作用或影响下易形成崩塌或滑坡灾害,造成人员或财产损失。以巫师附小治理工程为例,对高陡的边坡采取加固处理,加固措施采用1000 kN级预应力锚索,共42束,进尺1010 m,施工后对边坡进行了变形监测,监测数据表明:加固后的边坡满足设计要求。 相似文献
18.
Surface area processing in GIS for different mountain regions 总被引：1，自引：0，他引：1
Surface area is a fundamental parameter derived from terrain analysis in geographical information systems (GIS) for modeling the real world. Therefore, an evaluation of the techniques implemented by GIS models is important in order to obtain reliable area measurements. The study compares two raster-based methods with a TIN-based (triangulated irregular network) method for surface area approximation using a digital elevation model (DEM) with 25 m × 25 m resolution in six mountain regions of Shandong Province, China. Raster-based method Ⅰ calculates surface-area grids from DEMs directly. Eight 3-dimensional triangles connecting the center point of each cell with the center points of the eight surrounding cells are generated and then the areas of the portions of each triangle that lay within the cell boundary are calculated and summed. Raster-based method Ⅱ produces the surface area of each cell directly from the pixel size and the slope value for the pixel. The results demonstrate that the surface areas calculated by raster-based method Ⅰ are equal to those of the TIN-based method. The results of raster-based method Ⅱ are the lowest but the difference in areas between the two raster-based methods decreases with the decrease in terrain complexity. Compared to the method with TINs, raster-based method Ⅱ can do better because it has some advantages, such as neighborhood analysis, more consistent output and faster processing speed. The results also demonstrate that the difference between surface and horizontal areas should be considered if more than 30% of the area of a region has slopes steeper than 18.2 degrees. 相似文献
19.
本文主要介绍了填石路堤施工的材料、机械要求和有关的技术要求。通过在厚大公路上的应用 ,证明填石路堤在山区公路中是一种经济合理的形式 相似文献
20.
建立在GIS技术之上的多准则决策（MCDA）情境规划方案,能够提供一个新类型的问题识别和决策支持方法,从而解决高速公路规划这个复杂的多重因素控制下的不确定性问题.论文以南京东郊为案例研究地区,以2011年的南京ALOS遥感影像和2000年由国防部国家测绘局（NIMA）和美国太空总署（NASA）联合测量的SRTM高程数据为信息源,分别采用逻辑与（AND）、逻辑或（OR）、有序加权平均（OWA）3种方法进行高速公路建设用地适宜度分析.在此基础上,以宁镇、宁杭和沪宁3条高速公路的建设用地选址为例,从建造成本和地形条件两个方面构建5个指标对三种情景构建方案进行评价.结果表明：OWA方案高速公路总长度为43.452 km,平均坡度为2.467°.OR方案总长度为43.506 km,平均坡度为2.122°,AND方案总长度为42.362 km,平均坡度为2.383°; AND方案与OR方案和OWA方案相比建造成本较低,地形条件较优,从而为高速公路多情景规划方案的选择提供科学依据. 相似文献