Search

Changes in forest landscapes resulting from road construction have increased remarkably in the last few years. On the other hand, the sustainable management of forest resources can only be achieved through a well-organized road network. In order to minimize the environmental impacts of forest roads, forest road managers must design the road network efficiently and environmentally as well. Efficient planning methodologies can assist forest road managers in considering the technical, economic, and environmental factors that affect forest road planning. This paper describes a three-stage methodology using the Delphi method for selecting the important criteria, the Analytic Hierarchy Process for obtaining the relative importance of the criteria, and finally, a spatial multi-criteria evaluation in a geographic information system (GIS) environment for identifying the lowest-impact road network alternative. Results of the Delphi method revealed that ground slope, lithology, distance from stream network, distance from faults, landslide susceptibility, erosion susceptibility, geology, and soil texture are the most important criteria for forest road planning in the study area. The suitability map for road planning was then obtained by combining the fuzzy map layers of these criteria with respect to their weights. Nine road network alternatives were designed using PEGGER, an ArcView GIS extension, and finally, their values were extracted from the suitability map. Results showed that the methodology was useful for identifying road that met environmental and cost considerations. Based on this work, we suggest future work in forest road planning using multi-criteria evaluation and decision making be considered in other regions and that the road planning criteria identified in this study may be useful. [ABSTRACT FROM AUTHOR]

An efficient and low-cost transportation network is necessary for sustainable management. Roading and log skidding are the most expensive and destructive operations in forest environment, unless carefully planned and evaluated. A transportation network has to be assessed and optimized to minimize the total cost of road construction and its environmental impact. The aim of this study was determining the optimum forest road network density, and evaluating the quantity and quality of the existing forest road network. In order to determine the optimum forest road network density, skidding cost, road construction and maintenance costs, and harvesting volume in each compartment were considered. Then optimum skidding distance was calculated with regard to optimum road density and total correction factors. The relative openness and efficiency coefficient of the existing forest road network were determined for the calculated optimum skidding distance, using ArcGIS. The results showed that the optimum road density, relative openness and road network efficiency coefficient were 21.5 m ha-1, 90% and 32%, respectively. As a result, when the quality of a forest road network has to be evaluated, road network efficiency coefficient is more efficient than relative openness, that per se cannot be considered as an appropriate indicator. [ABSTRACT FROM AUTHOR]

It is very important for managers to plan a road network that meets all the requirements for tourism development and management. The aim of this study was to evaluate and modify an existing road network for tourism purposes in the Arasbaran protected area. First, the map layers of effective criteria were prepared in GIS and were standardized by a fuzzy logic approach and finally combined considering their relative importance weights obtained through pair-wise comparison technique. A suitability map was then acquired. After that, 14 different scenarios of road network were designed to access the recreational area using PEGGER extension in ArcView. Then, they were evaluated in terms of technical, environmental, and socio-economic criteria to achieve the optimal-designed road network. Moreover, the existing road network was modified according to the optimal-designed road scenario. Finally, a modified version of the existing road network was proposed for tourism development and management in the Arasbaran region. Regarding the results, the slope criterion with a value of 0.289 was identified as the most important factor in providing a suitability map for road planning. The seventh scenario, with a road density of 3.34 m ha−1 and accessibility (hard) of 64.68%, was chosen as the optimal option to modify the existing road network due to the best performances in terms of minimum costs and environmental impacts on the basis of the highest value per unit length (72.26). According to the assessments and chi-square test comparison, the optimal-designed road network and the proposed road network were identified as better alternatives compared to the existing road. Based on this work, it can be concluded that the combination of GIS-MCDM approaches can properly assist in tourism planning and management. [ABSTRACT FROM AUTHOR]

Although selection cutting has many advantages, its potential for damage to residual trees is a major challenge of forest management. The present study evaluated damage to residual trees during manual felling and cable-skidder logging operations in 18 instances of selection cutting in the Caspian forests of Iran. Data was collected from 100 m × 100 m systematic sample plots (0.1 ha) at each logging site. Harvest intensity ranged from 3.8 to 11 trees ha −1 and it averaged 7.3 trees ha −1 . Damage to residual trees was 10.5–23.6% with an average of 16.9%. There was a positive and significant correlation between amount of damage and harvest intensity ( R 2 = 0.65, P < 0.01). The multiple regression analyses also indicated that there were statistically significant relation ( R 2 = 0.77, P < 0.01) between amounts of trees damage and independent variables (harvest intensity, ground slope and stand density). Injury to the bottoms of tree boles 100–200 cm 2 in size was the most common types of damage. Damage was concentrated in small diameter trees (DBH < 40 cm). Most logging damage occurred during winching. Results suggest adherence to two silvicultural practices: (1) limit harvest intensity to 6 trees ha −1 , (2) limit selection cutting in slopes, less than 50%. Additional operational suggestions are implementation of felling direction and avoid log extraction through dense stands. [ABSTRACT FROM AUTHOR]