• Journal of the Korean Association of Geographic Information Studies
• /
• v.5 no.3
• /
• pp.99-106
• /
• 2002

The application method of GIS for planning of forest road network can be save the efforts and cost by frequently change of forest road and evaluation the forest road route before construction. The purpose of this study is to suggest the proper method for planning an optimal forest road network in mountains forest using geographic information system(GIS) in the national forest of Mt. Kumsan at Namhae-gun, Gyungsangnam-do. In the forest road network planning by the minimum longitudinal gradient, The total length was 20.41km, and road density was 6.92m/ha. In the forest road network planning by mixed with the minimum longitudinal gradient and the maximization of investment effect, The total length was 21.15km, and road density was higher than that of the minimum longitudinal gradient as 7.17m/ha. The road length overlapped by cost path was more short than 3.52m/ha of the minimum longitudinal gradient as 1.73km. So, it appeared that forest road has an high effectiveness in yarding function. Therefore, it considered that the geographic information system could provide an effective and resonable solutions for planning of optimal forest road network.

• Journal of Korean Society of Forest Science
• /
• v.85 no.3
• /
• pp.513-523
• /
• 1996

This study was a med at predicting running speed related to alignment factors of forest road, and recommending the improvement method of forest road construction using the running speed of vehicles. For these purposes, this study proceeds to select forest roads after reviewing the planning papers and maps, to measure the road alignment factors such as longitudinal gradient, width of roadway, radius of curve, length of curve, superelevation, and conditions of road surface on the subject forest road. It was found that the running speed of vehicle on forest road is mainly influenced by the conditions of road surface, radios of curve, compound gradient, length of curve, longitudinal gradient and so on. The average running speed of cargo truck showed lower value than that of the expected speed of 'Forest Road Construction Regulations and Rules', and the average running speed of loaded truck showed 70-85% of the speed of empty truck. According to the road conditions, the changes of running speed can be expressed mathematically in terms of the increment of radius of curve and longitudinal gradient. The results of the study on the running speed of vehicle subject to the alignment of forest roads make it possible for one to judge the quality of the existing and to be constructed forest roads, to select the structure of forest road to improve the running speed of vehicle on forest road.

• Journal of Forest and Environmental Science
• /
• v.20 no.1
• /
• pp.93-109
• /
• 2004

To provide the basic informations related to forest road construction of mountainous terrain, we analyzed changes of the road structure factors such as banking and cutting slope gradients, slope length, road width by the environmental factors such as locations, slope gradients, soil types, road position on physically stabilized forest roads constructed in Gangwon-do. All factors related to the road structures by locations were significant except for banking slope length. Road width, longitudinal gradients, banking and cutting slope length by slope gradients were not significantly different and banking slope gradients in the range less than $30^{\circ}$, from $30^{\circ}$ to $35^{\circ}$ and more than $40^{\circ}$ and cutting slope gradients were significantly different for all areas. Road width, longitudinal gradients, banking slope length by soil types were not significantly different and others were significantly different. All factors related to the road structures by road position were significant except for cutting slope gradients.

• Journal of Korean Society for Geospatial Information Science
• /
• v.11 no.1 s.24
• /
• pp.21-28
• /
• 2003

This study was aimed at suggest a proper planning method to select a optimal forest road network in mountains forest using GIS(Geographic Information System). To examine the field applicability, the method was applied to the National Forest at Mt. Kumsan in Namhae-gun, Gyungsangnam-do. The main results from altogether six alternative road route plans were derived from these criteria obtained the alternative route plan No.2 has two layout criteria, longitudinal gradient and earth work volume, and it showed similar pattern of existing forest road network which was designed mainly ground slope and longitudinal gradient. The alternative route plan No.6 has four criteria, longitudinal gradient, earth work volume, investment effect and landscape impact. It was different for the lowest forest road density among the alternatives and the pattern of the forest road layout was radial form, which was also quite different to other alternatives. For optimal forest road network planning, GIS provide the efficient and resonable solutions for decision making to provide the support for evaluation about various alternative road networks. If detailed inventory and relevant data are provided and also clear and objective indicators for evaluations are set up, it could be applied to preliminary analysis and detail planning stage to prevent undesirable effect such the land slide and soil erosion due to inadequate planning for forest road network.

• Journal of Korean Society of Forest Science
• /
• v.89 no.3
• /
• pp.397-404
• /
• 2000

This study was carried out to investigate the influence of the road structure and site conditions on side-ditch stability of forest road. For experimental purposes, the forest road in the Kwangrung Experimental Forest, Korea Forestry Research Institute, was chosen as a study site. A total of 556 plots wes set up as every longitudinal gradient changing points by belt-transect method. Data of 10 road structural characteristics and side-ditch stability were collected from each plot and analysed by Quantification II. The main factors in order of partial correlation coefficient were longitudinal gradient, road position, inclination of cut-slope, constituent material of cut-slopes, distance of surface flow, cross-sectional shape of road, pavement material, vegetation of cut-slopes and length of cut-slope. The erosion of side-ditch of forest road occurred in the following cases; more than 8% of the longitudinal gradient, road position of hill under side and foot hill, more than $50^{\circ}$ of inclination of cut-slope, constituent material of cut-slopes of hard soil and gravel soil, more than 80m of distance of surface flow, pavement material with earth or gravel, more than medium covered of vegetation of cut-slopes, and the straight and convex form of road-bed.

• Journal of Korean Society of Forest Science
• /
• v.89 no.1
• /
• pp.33-40
• /
• 2000

This study was carried out to evaluate the fill slope failure possibility of forest road in Metamorphic rock area using fuzzy theory which is non-linear model. The results were summarized as follows. The potential slope failure by nine factors was mainly occurred under the such conditions as the total road width ranging from 4m to 5m, longitudinal gradients below $2^{\circ}$, fill slope length greater than 8m, fill slope gradients steeper than $40^{\circ}$, road on ridge position, soil types with weathered rock, slope gradients steeper than $40^{\circ}$, aspect of NW, and longitudinal slope form in convexity. The weight of importance by factors on fill slope failure was ranked in the order of fill slope length, fill slope gradient, road position, soil type, aspect and longitudinal slope form. The analysis showed that the fill slope failure possibility was low with less than 0.485 of the fuzzy integral value and high with more than 0.620 of the value. And the discriminant accuracy was 74.6%. The analysis with six out of nine factors indicated that the possibility was low with less than 0.441 of the fuzzy integral value and high with more than 0.583 of the value. In this case, the discriminant accuracy was slightly increased to 78.0%.

• Korean Journal of Agricultural Science
• /
• v.23 no.1
• /
• pp.138-149
• /
• 1996

This study was aimed at predicting to running speed related to alignment factors of forest road, and recommending the improvement method of forest road construction using the running speed of vehicles. For these purposes, this study proceeds to select forest roads after reviewing the planning papers and maps, to measure the road alignment factors such as longitudinal gradient, width of roadway, radius of curve, length of curve, superelevation, and conditions of road surface on the subject forest road. It was found that the average running speed of logging truck showed lower value than that of the expected speed of 'Forest Road Construction Regulations and Rules', and the average running speed of loaded truck showed 70-85% of the speed of empty truck. According to the road conditions, speed index (reductive ratio of running speed) was also calculated with respect to radius of curve, longitudinal dradient. The results of the study on the running speed of vehicle subject to the alignment of forest roads make it possible for one to judge the quality of the existed and to be constructed forest roads, to select the structure of forest road to improve the running speed of vehicle on forest road.

• Journal of Korean Society of Forest Science
• /
• v.76 no.2
• /
• pp.161-168
• /
• 1987

Forest road (10 Km) constructed for the demonstrational purpose by Forest Work Training Center (F.T.C.) in 1984 was partly damaged through the roadside landside and ditch erosion by the typhoon in 1986. The causes were investigated to apply for protecting against the damage of mountain forest road. The damaging length caused by roadside landside is around 3% out of total length of 10 Km forest road, and mostly coming from the curve road filled up more than 10 m slope length on the concave mountain slope, partly from the foot of fillslope along the ever-following valley and from the both side of fillslope under the outlet of culvert with ever-flowing water. In case of ditch erosion, the big damage at V-type ditch is coming from the overflow of valley water flowing down along the inside slope. Other problem is also showing in the steepness of longitudial gradient, which is felt as a problem in road to be constructed under more than 10 persent of gradient. Other cause of ditch erosion is coming from the bury of sand basin (water collecting wall) by the debris in small diameter culvert zone, namely less than 400mm, in diameter and by the soil mass slumped down from steep wall slope. From above results the causes of F.T.C. model road damage is showing to come from no-following the general guide or little experience to protect against the forest road damage. When improved above mentioned mistakes, F.T.C. Method of mountain forest road type could be developed as a model of Mountain forest road.

• Journal of Korean Society of Forest Science
• /
• v.88 no.2
• /
• pp.240-248
• /
• 1999

On the basis of data obtained from five forest roads collapsed due to a heavy rainfall of 1995 in Chunchon, Kangwon-do, this study was carried out to evaluate and predict the fill slope failure of forest roads with four factors of forest road structure and those of location condition by using Quantification theory(II). The results were summarized as follows ; In the structure factors of forest road, the fill slope failure was mainly occurred in longitudinal gradients less than $2^{\circ}$ or more than $4^{\circ}$, distance of surface-flow longer than 80m, fill slope length greater than 6m, and fill slope gradients steeper than $35^{\circ}$. In the factors of location condition, the failure was mainly occurred in ridge portion of road position, weathered rock and soft rock of constituent material, slope gradients in the range from $35^{\circ}$ to $45^{\circ}$, and concave and convex of longitudinal slope forms. The priority order for factors influencing on fill slope failure was ranked by fill slope length, constituent material, road position, and so on. And the rate of correct discrimination by analysis of fill slope failure was estimated at the high prediction of 86.5%.

• Journal of Korean Society of Forest Science
• /
• v.86 no.1
• /
• pp.69-79
• /
• 1997

The purpose of this study is to acquire essential data to reduce the amount of woody debris resulted from the debris flow. This research examined topographic characteristics of the channelbed affecting generation, movement and storage of woody debris and woody characteristics related to number, sizes, shapes, decay, storage direction to mountainous stream. 1. The number of woody debris had a tendency to increase in proportion to stream width, but it was hardly affected by longitudinal gradient of stream. Especially, the greater amount of woody debris was stored at wide section of the stream with compound channel, and it was found in deposits of channelbed rather than in the present channel. 2. Total woody debris over 10cm in diameter and over 2m in length was 402 units and storage number was 35.3 units per 100m of stream. Average diameter of breast height and length were 14cm and 4m, respectively. The woody debris appeared shorter in length and greater in diameter at down-stream than up-stream. 3. Since woody debris met sediments and bed-materials of great roughness in moving, the greater amount of woody debris without root was found in up-stream and down-stream, but deformed woody debris was discovered in upper stream. Decay of woody debris was more severe in down-stream and woody debris on rotting process was found down-stream. 4. Storage direction of woody debris was mainly parallel to center line of stream, and rate of parallel and perpendicularity was 276 and 126 units, respectively. But, as woody debris storing to the perpendicular direction was unstable, the traveling debris could easily be stored. Therefore, some counterplan was required to prevent the traveling woody debris. 5. Tree species of woody debris was mainly larch, which occupied about two third of total woody debris(256 units). The woody debris of larch is easy to move due to hitting of channelbed materials or lower channelbed fluctuation because the lower part of larch is weaker than its upper part. Therefore, the section of the tree species planting in the riparian vegetation needs much more carefulness.