古满公路前段涵洞破坏原因的分析

针对古满公路前段涵洞破坏严重这一事实，分析了造成这一现象的几方面原因，同时指出冻害是造成这一现象的主要原因，供多年冻土地区的公路涵洞的设计、施工和使用管理单位参考。     

林区公路线形设计浅谈

本文作者结合自己多年的工程实践,对林区公路线形设计进行了论述,并提出了一些理论与实践相结合的方法。     

林区公路线形设计美学探讨

本以美学的角度出发，对林区公路线形设计进行了初步的探讨，分析了林区公路设计时在平面、纵断面三方面应注意的基础原则。     

高寒林区公路设计应注意的几个问题

高寒地区的冬季长且气温低、气温最低可达-50℃度以下,地表水都会结冰,在水量丰富的地段容易形成冰湖,给车辆通行带来困难,严重时阻断交通。当春季来临时,冰湖熔化、给道路造成水害,增加车辆通行和道路养护费用。笔者认为这些问题在公路设计时要引起特别的注意,以保证高寒地区车辆行驶的安全,降低公路使用维护费用。     

袖珍计算器在林区公路设计上的运用

袖珍计算器在林区公路设计上的运用齐志（白石山林业局综合设计队）从事林区公路设计的人都知道，在以往的导线测量时，总要带上一本厚厚的《公路曲线测设用表》。测设平曲线时要反复翻查和计算，完成一个平曲线的计算至少需要十分钟。不仅查表麻烦、计算繁琐、费时费力，...     

基于GIS的林区公路路线设计

在林区公路建设中，传统的路线勘察方法成本高，耗时长。通过分析最佳路线的基本原理，阐述了应用ArcGIS的空间分析模块进行最佳路线选择的方法和步骤，并以某林场林区公路路线设计为例说明基于GIS的最佳路线分析的具体应用。基于GIS林区公路路线设计新方法的可行性，在很大程度上缩短了勘查中的工作量。     

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。     

林区公路及森林防火道勘测设计的探讨

林区公路及森林防火道勘测设计的探讨吕健南（句容市林场，２１２４２４）句容市林场在５０年代交通十分闭塞，整个山区只有羊肠小道，直到１９６３年才修建一条从石山头到桥头的林区公路；但随着林业生产的发展，特别是杉木林，已从１９８１年开始进入主伐、低改阶段，林...     

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。     

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。     

论林区公路路基排水问题

本文论述了林区公路路基排水情况;路基排水的几种方法及林区筑路的排水问题.     

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。     

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.     

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.     

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.     

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.     

东北林区道路发展方向的系统工程分析法

诠释了东北林区道路规划布局的新理念。即采用系统工程的理论,东北林区规划看作一个系统,东北林区道路规划以若干个子系统之一的形式出现,研究探讨东北林区道路规划子系统与其它子系统的相关关系,以及由此影响系统目标优化的种种制约因素。