ABSTRACT:We summarized the results of the Road Network Analysis (RNA), when the shortest path to reduce travel time in the Gorgan city public road network, in Iran, was evaluated. The main objective was to determine whether by using a GIS-based new route approach it is possible to determine the shortest path from logging site to destination (mills). The results showed that by using the concept of travel time as a measure of the importance of nodes, the shortest path from origin to destination was found. A path with minimum links and lengths as well as maximum vehicle speed is the best. This dramatically reduced the search complexity in terms of routing.

The aim of this study is fire hazard zoning the Chehel-Chay watershed and analysis of road network in order to fire-fighting management. Using effective factors on fire occurrence, the fire hazard map of the study area produced by support vector machine algorithm and then was divided into four hazard classes. The road length and type were investigated in the each fire hazard classes. The results showed that most of occurred fires are located in the close distances of roads and forest areas. The results showed that road types and land cover are important in fire occurrences and suppression. In high dangerous zone, the roads pass through forestlands, but in low dangerous zone, the roads are passing from farmlands. The roads do not cover the half of area and do not pass at two third of high hazard class zones. Therefore, appreciate road network planning is necessary according to fire-fighting management.

Parsakhoo A., Mostafa M., Shataee S., Lotfalian M. (2017): Decision support system to find a skid trail network for extracting marked trees. J. For. Sci., 63: 62-69.Careful planning of skid trails as wood extraction routes in forests is an ongoing task and necessary for minimizing the environmental damage. The main objective of this study is to find skid trails to extract marked trees from stand sites to landing sites using a GIS-based decision support system (DSS) and network analysis techniques, where environmental information is incorporated into the objective. The techniques were applied in a stand where single trees are felled in near-to-nature conditions. This system is called a single tree selection cutting method. Parameters considered for mapping the terrain stability include slope, soil and stream network. The analytical hierarchy process was used to estimate the weights of these parameters. Routing between marked trees and log landing was done using a GPS-tracking survey and then the analysis was done using new route and service area tools in GIS. The service area tool shows accessibility of marked trees by skid trails. Results showed that on average the length of the route decreased by 6.65 and 19.22% with the use of a new route tool in compartments 29 and 4, respectively. In conclusion, DSS techniques increased accessibility of marked trees and decreased the length of the route.

The aim of this study was to determine the suitable conservation treatments to control water erosion from skid trails in ShastKalate forests. Two longitudinal slopes of 20-40% and > 40% were considered as critical slopes for skid trails. Treatments of water diversion ruts, water diversion ruts filled with slash and stones were implemented on each slope. A rubber bar was installed at the end of the slope to convert runoff into collectors. Sampling was done during rainfall events in autumn and winter seasons. Findings indicated that the treatment of water diversion ruts filled with slash was better than the other treatments in the control of sediment and soil loss, especially in the slope class of 20–40%. In the slope class of > 40%, there was not any significant difference between treatments in sediment and soil loss control, but generally water diversion ruts filled with slash and stones were better in soil erosion control than water diversion ruts. In both slope classes, the rainfall intensity of 0.11 mm·h^–1 (2.64 mm in 24 h) was the threshold of soil erosion on skid trails. The control of water erosion of soil on skid trails by the operation of water diversions is a suitable treatment for conserving skid trails.

Designing and constructing a road network is one of the most critical steps of the development process in managing natural resources. The current research is going to investigate the application of network connectivity indices to the analysis of road networks in the forested watershed. First, the road network suitability map (RNSM) was created to emphasize the technical and physiographic criteria and integrated management scenarios using a weighted linear combination (WLC) and analytic network process (ANP). Subsequently, three road network alternatives (RNA) were assigned based on the priorities in the RNSM. In order to try to determine the appropriate alternative, the network connectivity of the designed alternatives looked into the forest and non-forest land uses, as well as the whole study area, using the values of alpha (α), beta (β), gamma (γ), eta (η), network density (ND) and detour indices (DI) in the context of the graph theory. Results show that the road density of the RNA2 variant (11.56 m•ha -1 ) is shorter than the other alternatives and the existing road network (ERN). In addition, dealing with the whole study area, we realized that the index values which are related to the number two reflect a better status than the other alternatives of alpha, beta, gamma, eta and detour index, in which they were identified to be 0.44, 1.34, 1.16, 0.45 and 0.83, respectively. RNA2 is chosen as the appropriate road network according to the network connectivity, technical and physiographical criteria, along with integrated management scenarios. Further control measures and field surveys are recommended to achieve more relevant results.