浅谈公路改造升级中旧路路基帮宽的处理措施

关于在旧路帮宽改造工程施工中，防止在帮宽处产生纵向裂缝，造成缩短道路使用寿命，影响行车安全，应采取的几种措施。     

论林区公路路面结构

本文论述了多层结构路面的面层、基层、垫层、磨耗层和保护层的材料、用量、结构和强度等问题。提出了按“薄面、强基和稳土基”及按应力分布和各层的刚度相适应的原则设计林区公路路面结构。     

谈林区公路中涵洞位置的设计

本对林区公路涵洞位置提出了几种设计方法。即（１）逢沟设涵;（２）改移河槽;（３）截弯曲直;（４）特殊情况下的涵洞设计。     

林区公路的路基养护和维修及病害治理

本文论述了路肩的养护及维修,边坡的养护及维修,路基翻浆的治理及其维修,同时又介绍了治理翻浆的几种办法。     

林业公路沿溪线水毁的治理

通过对东茶线水毁的成功治理，提出了治理林业公路沿溪水毁多发段所采取的措施和方法。     

林区公路干砌涵石盖板的实践

东方红平沙公路，通过跨径为0.8m、1．0m、1.2m共32座涵洞的工程实践证明，干砌涵结构在林区公路中具有造价低、工期短、施工简便、宜在盛产石材地区推广应用。     

我国林区道路运输规划建设的可持续发展分析

提出了林区道路运输规划可持续发展原则，并从路网密度、并从路网密度、林道功用、林道路网结构、线路建设时序、建设标准、线路走向方面分析了我国以入林区道路运输规划存在的问题，同时针对这些问题和规划原则提出了解决对策。     

Modeling spatial variability in the life-cycle costs of low-volume forest roads

Cost estimation is probably the most decisive factor in the process of computer-aided, preliminary planning for low-volume road networks. However, the cost of construction is normally assumed to be route-independent for a specific project area, resulting in sub-optimal layouts. This is especially true for mountainous terrain and in areas with unstable subsoil. Here, we present a model for more accurately estimating spatial variability in road life-cycle costs, based on terrain surface properties as well as geological properties of the subsoil. This parametric model incorporates four structural components: embankment, retaining structures, pavement, and drainage and stream-crossing structures. It is linked to a geo-database that allows users to derive location-specific parameter values as input. In applying this model, we have demonstrated that variability in costs ranges widely for mountainous areas, with the most expensive construction being approximately five times greater there than on more favorable sites. This variability strongly affects the optimal layout of a road network. First, when location-specific slope gradients are considered, costs are reduced by about 17% from those calculated via currently available engineering practices; when both slope gradient and geotechnical formations are included, those costs are decreased by about 20%. Second, the length of the road network is increased by about 4% and 10% respectively, compared with current practices.     

Tabu search optimization of horizontal and vertical alignments of forest roads

This article describes a program for optimizing horizontal and vertical alignments of forest roads using Tabu search, a modern heuristic technique. Once a series of intersection points (IPs) is selected manually, the program generates alternative horizontal and vertical alignments. The program precisely generates ground profile and cross sections using a high-resolution digital elevation model (DEM) derived from light detection and ranging (LiDAR) data. It accurately calculates earthwork volumes for curved roadways using the Pappus-based method. The program also estimates construction and maintenance costs. Tabu search optimizes forest road alignments based on the total costs. The application of the program to part of Capitol State Forest in Washington State, USA, indicated that the program successfully found better alignments than manually selected initial alignments. The effect of initial solutions and the number of iterations on the Tabu search process was examined. The result showed that the solutions were improved using the best solutions with the smaller number of grade change points as the initial solutions. It also showed that a small number of iterations could be used to reduce computation time due to the fact that Tabu search is based on a gradient search technique. Finally, the Dijkstra method was examined to find initial solutions without manually initialized solutions. The program, when combined with the Dijkstra method, could find similar-quality solutions from manually initialized solutions. The program will become useful with further tests and verifications.     

在韩国片断化林区内道路对小型啮齿类种群的影响

The road effect on small rodent population is investigated at 8 fragmented forest areas in the Baekdudaegan moun-tain range, South Korea in September 2001, We especially focused on the distribution and body condition of small rodents near the roads, Korean field mouse (Apodemus peninsulae) seems to be more sensitive to the existence of a road than striped field mouse (Apodemus agradus), Korean field mouse prefers interior forest area to around road. Striped field mouse is a habitat generalist and has wide distributional range around road, but Korean field mouse is forest-inhabiting species and their distribu-tion is limited in forest area. These results suggest the effect of road is different on each small rodent species and their habitat preferences.     

Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north-eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some species, e.g. Hura crepitans L., displayed patchy regeneration coinciding with the presence of adult trees. Our results suggest that current management practices could be improved by intensifying logging in some areas to improve regeneration of light demanding species. Sufficient seed input in logged areas should be ensured by interspersing large patches of unlogged forest with logged areas. This may also assist regeneration of species that perform poorly in disturbed areas.     

浅析困扰商品林发展的因素

通过对困扰商品林发展的林木采伐管理政策、林业生产责任制、采造挂勾制度等因素分析,提出了有利于商品林发展的建议,对促进商品林发展有一定的实用价值。     

林区公路小桥涵位置与型式的选择

本文主要介绍林区公路小桥涵位置确定的原则、步骤及位置的测量;小桥涵型式选择的决定因素。     

The method for designing the profile of forest roads supported by genetic algorithm

This study examines a method for designing an optimum profile of a forest road in a short matter of time. In this method, a genetic algorithm (GA) searches for points where the gradient changes and dynamic programing (DP) designs the longitudinal slope. This method can be applied to the ground heights of an actual forest road. The evaluation function of the DP assesses the total expenditure. The inverse of this function is the fitness function. Crossover and mutation are operators of an evolution simulation of a GA. They are each repeated 20 times and 420 profiles are designed and assessed, all within about 10 min. A comparison of the profile designed by the GA with that of an actual forest road shows only one section where the formation level differed substantially. Overall, both profiles seem to show a high degree of correspondence. From this result, we believe that the profile designed by the GA is best, or the one of the best. A conventional method takes about 65 h to calculate all changing points of gradients. However, by using the GA, the calculation time was reduced to about 1/389 that of the coventional method, showing that the method which uses the GA through the profile design is very useful.     

宝密桥林场森林资源动态与分析评价

通过对宝密桥林场1999年和2009年的二类调查资料进行对比分析,研究了该林场在这10年里的森林资源变化情况,评价其经营管护效果,并提出了经营利用意见。     

美国的森林动态评价模型及其对中国森林健康评价的启示

应用动态模型评价森林健康状况,预测树木或林分的生长与收获,以及在不同立地条件下采用某些特定的营林技术措施后林分的动态变化,一直是森林健康评价及管理的核心问题.当前在美国应用的两个森林动态评价及决策模型SIMPPLLE和MAGIS主要是用来评价当前林分状况、模拟林分发展以及预测不同经营管理方式下林分未来的动态变化状况,通过分析不同决策下森林植被的收获状况,选择最优化的管理措施以及实施措施的时间及地点制定最优化决策.针对现阶段中国森林健康评价中,以建立评价指标体系进行静态评价、缺乏空间信息数据和森林健康经营动态变化规律模型等问题,提出今后应针对中国实际情况开展切合实际的研究,开发出以促进森林健康经营为目的的动态预测模型和决策模型,提高森林健康的预测能力,完善森林健康经营综合评价技术体系.     

吉林省林区道路山洪灾害的防治措施

吉林省林区道路易发生山洪水灾的主要原因是特殊的地理位置及气候条件、设计等级低、施工水平差、日常保养不到位。防治的主要措施有对现有道路进行技术改造、提高养护水平、加强道路管理等。     

江苏省森林资源二类调查消长动态变化分析

江苏省最近的森林资源二类调查分别为1989年和2009年完成,两期调查都获取了详实的森林资源数据。通过全面对比调查结果,从林地面积、林种结构、林木蓄积、龄组结构、树种组成和森林资源质量等6个方面客观反映了全省森林资源动态变化现状,并深入分析了森林资源面积、蓄积和林种等主要因子的变化原因,总结了全省森林资源的变化特点：①...     

Effects of roads,topography, and land use on forest cover dynamics in the Brazilian Atlantic Forest

Roads and topography can determine patterns of land use and distribution of forest cover, particularly in tropical regions. We evaluated how road density, land use, and topography affected forest fragmentation, deforestation and forest regrowth in a Brazilian Atlantic Forest region near the city of São Paulo. We mapped roads and land use/land cover for three years (1962, 1981 and 2000) from historical aerial photographs, and summarized the distribution of roads, land use/land cover and topography within a grid of 94 non-overlapping 100 ha squares. We used generalized least squares regression models for data analysis. Our models showed that forest fragmentation and deforestation depended on topography, land use and road density, whereas forest regrowth depended primarily on land use. However, the relationships between these variables and forest dynamics changed in the two studied periods; land use and slope were the strongest predictors from 1962 to 1981, and past (1962) road density and land use were the strongest predictors for the following period (1981–2000). Roads had the strongest relationship with deforestation and forest fragmentation when the expansions of agriculture and buildings were limited to already deforested areas, and when there was a rapid expansion of development, under influence of São Paulo city. Furthermore, the past (1962) road network was more important than the recent road network (1981) when explaining forest dynamics between 1981 and 2000, suggesting a long-term effect of roads. Roads are permanent scars on the landscape and facilitate deforestation and forest fragmentation due to increased accessibility and land valorization, which control land-use and land-cover dynamics. Topography directly affected deforestation, agriculture and road expansion, mainly between 1962 and 1981. Forest are thus in peril where there are more roads, and long-term conservation strategies should consider ways to mitigate roads as permanent landscape features and drivers facilitators of deforestation and forest fragmentation.     

基于统计算法的森林资源变化检测的研究

以汪清林业局金沟岭林场为研究区域,按照两期影像归一化植被指数（NDVI）的差值服从正态分布的规律,应用概率论中3a原则检测森林资源变化状况。结果表明：利用两期影像NDVI差值进行检测,可检测出地类发生明显变化地段的资源变化状态,并可精确定位,而对于小强度择伐、透光伐等未发生明显地类变化的地段检测不够精确。