Forest Road Construction Research Articles

Modeling erosion and sediment delivery from unpaved roads in the north mountainous forest of Iran

Forest road networks are usually a main source of sediment in forested watersheds. An understanding of sediment delivery from roads to streams is important to aid in mitigating the adverse impacts to the environment. In this study an empirical model based on the Washington road surface erosion model was employed to estimate the effects of unpaved roads on erosion rates in the north mountainous (Caspian) forest of Iran. The main expected advantages of the chosen model were the ability to deal with different environmental settings, and simulate the effects of road-related best management practices (BMPs). Data required for modeling were obtained either by using of a GIS-automated technique or through field-based measurement. The outputs of the model show estimated annual sediment yields from unpaved roads, and predict the impacts of road management on sediment yields. The results suggest that (1) nearly 298 t/year of sediment is produced from road erosion in the study forest; (2) \(\sim \)6 % of the sediment is delivered to the streams; (3) BMPs need to be employed in the Caspian forest for reducing sediment delivery to the streams. These results can be used as basic data to develop prudent long-term management plans for forest road construction.

THE MAINTENANCE OF FOREST TRUCK ROADS IN FOREST MANAGEMENT REGIONS OF SARAJEVO CANTON

UDK: 630*38:625.711.84(497.6 Sarajevo)
 The time period of forests opening and construction of forest truck roads in the analyzed area is longer than half of century. In such long time interval different types of vehicles for transport of timber assortments have been applied. Due to this fact technical elements of constructed roads are different. The vehicles currently used for the transport of timber assortments cause an accelerated destruction of forest truck roads due to inappropriate carriage way quality. Besides traffic load the forest truck roads are exposed to permanent atmospheric influences. The above specified and other reasons condition obligatory and regular maintenance and reconstruction of forest truck roads depends on the current condition of forest truck roads as well as on the plans for further use.
 In this article the condition of forest truck roads in the Forest management regions of Sarajevo Canton has been determined. The most frequent types of damages and causes of their occurrence have been registered. The methods for maintenance and rehabilitation-reconstruction of forest truck roads have been selected and their costs have been calculated. In the time when construction of new kilometers of forest truck roads is more and more rare, timely, adequate and financially justified maintenance of the existing network of forest truck roads is one of the key question for their undisturbed use. On the basis of results obtained in this research the guidelines for the time period and the ways of maintenance of forest truck roads have been given. The application of these guidelines should help in achieving of the best and most economical total results through the long-term use of forest truck roads.

Исследование влияния циклов «Замораживание – оттаивание» на характеристики лесных почво-грунтов, используемых при строительстве лесных дорог

Исследование влияния циклов «Замораживание – оттаивание» на характеристики лесных почво-грунтов, используемых при строительстве лесных дорог

Estimating sediment reduction cost for low-volume forest roads using a lidar-derived high-resolution dem

Traditional methods of designing forest roads using topographic maps and aerial photos are not always capable of leading to an optimal road alignment solution that minimizes the environmental effects of road construction. Forest road construction activities have the potential to cause more environmental impacts, especially excessive amount of sediment production, than perhaps any other forest management activity. In order to select an optimum road alignment that considers environmental constraints, mathematical optimization techniques are applied to a digital landscape in order to identify and evaluate a potentially large number of alignment solutions. A 3D forest road alignment optimization model TRACER was developed to assist road managers in designing a preliminary forest road alignment while minimizing total road cost and considering design specifications, environmental requirements, and driver safety. A 3D forest road alignment optimization model TRACER relies on a high resolution Digital Elevation Model for accurate representation of the terrain, while sediment production estimates are derived from a GIS-based SEDiment MODeL (SEDMODL). In this study, the 3D forest road alignment optimization model was used to generate two road alignments: 1) an optimum alignment with minimum total cost and, 2) a road alignment with minimum sediment delivery to streams. Both road alignment options were then analysed to better investigate the cost of sediment reduction associated with forest road construction.

Sustainability Assessment of Certified Tropical Forestry using Emergy Analysis

Sustainable forestry production systems, such as certified forestry, re- duced impact logging or sustainable forest management, have become an important part of tropical countries’ strategy to oversee their forest re- sources. Particularly, certification of forest products has become a widely adopted practice as a response to a growing international concern over the ecological and economic sustainability of harvesting natural tropical forests because of the benefits on reducing excessive and unnecessary construction of forest roads, reducing excessive use of heavy machinery, diminishing excessive collateral damage, and improving the inefficient milling processes and wasting of residues. To accomplish the aim of this study, which is to compare conventional and certified forestry we used a systems analysis tool that could integrate various benefits of certified forestry including, stand age, wood harvest, soil losses and economic gain or loss. We found that the affected area under uncertified logging practices is twice the area of certified forestry because conventional prac- tices require more roads, more logging decks and more skid trails. Also, the rate of soil erosion between uncertified logging (154 Mg/ha/yr) and certified logging (66 Mg/ha/yr) is different. Based on these data, we es- timated that the total emergy removed from certified forests was 40% less than the forest under conventional forestry. The fact that certification does a better job of preserving forest while removing wood was also demonstrated through the Environmental Loading Ratio (ELR). We also found that certification leaves forests with a 30% better chance to recover after logging because less wood is removed. But forestry using certifica- tion showed a lower Emergy Yield Ratio (EYR) because the lower yield and the extra cost of certification. Certification is also favored for the higher price for certified wood in international markets. Then, when Bo- livia exports uncertified wood, it obtains a positive benefit, but lower than using uncertified wood domestically (EYR = 20.4). In other words the worst thing the country could do is certify wood for their domestic market and sell uncertified wood abroad.

Performance of Granitic, Shale, and Limestone Forest Road Aggregates Subjected to Repeated Loading

AbstractThis study compared the performance of three aggregate layers, commonly used in the construction of unbound forest roads in Ireland, when they were subjected to repeated loading in a new large-scale test rig. These layers comprised: (1) a layer of uncrushed, granitic, sandy gravel-a good quality road aggregate, (2) a layer of shale-a poor quality aggregate, and (3) a layer of crushed limestone–an excellent quality aggregate with a wet mix macadam (WMM) grading–on top of a poor quality shale subbase layer. The repeated load testing rig was designed and constructed to test different surface or completion layering thicknesses of the aggregates over a common formation or subgrade material of silty sandy soil. This testing was achieved by surface loading the aggregates through a 200-mm-diameter rubber pad-attached to a hydraulic actuator on the test rig-for up to 150,000 load applications. The subgrade pressures and surface deflections were measured at applied stresses of 500, 750, and 1,000 kPa. The g...

The Eastern Hoolock Gibbon (Hoolock leuconedys) in Eastern Arunachal Pradesh, India

Lowland tropical forest in the Lower Dibang Valley district in the state of Arunachal Pradesh is the prime habitat in India of the eastern hoolock gibbon (Hoolock leuconedys). The present study was conducted to assess the threats to the population of H. leuconedys in the unprotected forest fragments of the Lower Dibang Valley district, Arunachal Pradesh. Besides field observations, we employed a structured questionnaire survey method to interview villagers, including the Gaon Burha (village head) and local hunters. Based on our observations and the interviewees' responses, we recorded that gibbons were occasionally hunted for bushmeat, and that dogs, the Mountain Hawk Eagle (Nisaetus nipalensis), and monitor lizards (Varanus) were evidently predators of, particularly young, gibbons in the fragmented forest patches. Indirect threats included habitat destruction and fragmentation, deforestation, extraction of non-timber forest products, livestock grazing, road construction, selective (illegal) logging, shifting cultivation, commercial cash-crops, and permanent human settlement. A conservation action plan is urgently needed to protect and conserve the eastern hoolock gibbon from extinction in the region.

A program for cost estimation of forest road construction using engineer's method

Modeling the cost of road construction is a prerequisite for evaluation and planning of different alternatives for low-volume road networks included in a forest management plan. In this paper, a model for cost estimation of forest roads is presented, based on the standard engineering properties of cross sections and the location-specific parameters of terrain slope and vegetation information. The model assumes six main cost elements of clearing operations, embankment, pavement, grading, culverts and ditch for total construction cost calculation. To validate the performance, the outputs of the model were compared with the experts’ prediction for an existing forest road project in a mountain condition. The final result of the research showed that the model could estimate total cost of road construction in an accuracy range of ±6.5%. The results of the validation process showed a 66.51% underestimate for clearing operation, 3.56% underestimate for embankment, 3.85% underestimate for surfacing, 3.32% underestimate for culverts, 20.54% underestimate for ditch excavation, and 22.33% overestimate for grading of the cut slope and travel way. According to the reasonable estimation for total cost, the model could be applied as an evaluation function in finding the optimized layout of a forest road network.

Detecting land cover disturbances in the Lappi reindeer herding district using multi-source remote sensing and GIS data

Land use intensification in northern regions has resulted in major land cover transformations that have generally negative impacts on traditional land use systems. We examined land cover disturbances in the Lappi reindeer herding district in North-Eastern Finland between 1965 and 2005 using multi-source remote sensing and GIS data. We utilised a series of Landsat MSS and TM data, KH-9 images, aerial photography and national GIS databases to detect land cover changes and accumulation of disturbances in a study area of 4504km2. The results showed that the cover of continuous (old) coniferous forests was notably reduced by the 1970s, and the undisturbed forest cover further declined from 87 to 77% during the study period. The length of the road network increased from 835km in 1972 to 1855km in 2010. We estimate that circa 27% of the total area in the reindeer herding district has experienced major disturbances since the late 1960s owing to modern forest management, road construction and hydroelectric reservoirs. These long-lasting or permanent land cover changes have had several negative effects on reindeer pastures and have increased vulnerability of the reindeer herding system.

Environmental impacts of forest road construction on mountainous terrain

Forest roads are the base infrastructure foundation of forestry operations. These roads entail a complex engineering effort because they can cause substantial environmental damage to forests and include a high-cost construction. This study was carried out in four sample sites of Giresun, Trabzon(2) and Artvin Forest Directorate, which is in the Black Sea region of Turkey. The areas have both steep terrain (30-50% gradient) and very steep terrain (51-80% gradient). Bulldozers and hydraulic excavators were determined to be the main machines for forest road construction, causing environmental damage and cross sections in mountainous areas.As a result of this study, the percent damage to forests was determined as follows: on steep terrain, 21% of trees were damaged by excavators and 33% of trees were damaged by bulldozers during forest road construction, and on very steep terrain, 27% of trees were damaged by excavators and 44% of trees were damaged by bulldozers during forest road construction. It was also determined that on steep terrain, when excavators were used, 12.23% less forest area was destroyed compared with when bulldozers were used and 16.13% less area was destroyed by excavators on very steep terrain. In order to reduce the environmental damage on the forest ecosystem, especially in steep terrains, hydraulic excavators should replace bulldozers in forest road construction activities.

Hazel grouse winter habitat selection and conservation in temperate forest

I investigated the small-scale winter habitat selection of hazel grouse Bonasa bonasia in temperate forest, South Korea. The birds showed a preference for natural deciduous forest, followed by mixed forest, coniferous plantations, and deciduous plantations. The top-ranked model for winter habitat selection by the hazel grouse (ω=0.72, r2=0.81) was 0.42 [understory cover]+0.33 [forest type]+0.24 [distance from the nearest forest road]+0.18 [number of birches]+0.12 [number of alders]. These results suggest that the conservation of natural deciduous forest, dense understory vegetation, and food trees (birches and alders), as well as a reduction in forest road construction, could enhance critical winter habitat for hazel grouse. A multi-scale approach is needed to understand the relative importance of small and large scale landscape factors that influence hazel grouse habitat selection. Future research on habitat selection by the hazel grouse should use a multi-scale approach and should assess the birds’ preferences throughout the year.

An environmental assessment of forest stands damages caused by excavators during road construction in Beech forests

Construction of forest roads can cause short-term and long-term negative effects on forest ecosystems in different ways if they are not well planned and appropriately maintained. In this research, environmental damages caused by an excavator during road construction were examined in steep terrain covered by beech (Fagus orientalis L.) stands. The study was conducted along a 1.5 km road in western Blacksea Region of Turkey. All of the road construction operations were monitored during a construction period, and measurements of cross sections sizes and stand damages were measured during and after the construction activities. The road construction was evaluated according to the appropriate method and standards. The average widths of roadway, fill slope and construction zone were 4.82, 6.91, and 16.61 m, respectively. Along the 1,500 m road, forested area impacted was 24,915 m2 while the number of trees cut was 1,495 and rate of the damaged trees below the fill slope was found to be 24.7 %. In the study, based on the appropriate method and standards, less forested area might have been impacted (23 %). As a result of regression analysis, it was found that the rate of damaged trees increased as the values of the proportion of rocks, the width of the road surface and the width of the cut-slope increased. To reduce the negative effects of forest road construction on the environment, new forest road construction by excavators should be performed using appropriate methods within mountainous terrains.

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Qualitative evaluation and optimization of forest road network to minimize total costs and environmental impacts

Abstract: 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.

Distribution of Rare Plants- Ulsan, Busan, Yangsan

A total of 15 rare plant species, including CR species of Abelia spathulata Siebold & Zucc., Tricularia yakusimensis Masam., Wikstroemia ganpi (Siebold & Zucc.) Maxim., EN species of Jeffersonia dubia (Maxim.) Benth. & Hook.f., Hololeion maximowiczii Kitam., Deutzia paniculata Nakai, VU species of Drosera rotundifolia L., Pogonia japonica Rchb.f., Euphorbia fauriei H. Lev. & Vaniot, LC species of Iris ensata var. spontanea (Makino) Nakai, Lysimachia coreana Nakai, Iris ensata var. spontanea (Makino) Nakai, Utricularia racemosa Wall. and DD species of Veronica pusanensis Y. Lee and Glaux maritima var. obtusifolia Fernald, were observed during the study conducted on the distribution of rare plant species in the Ulsan·Busan·Yangsan region. Of the 15 taxa, 3 were trees and 12 were herbs. 6 taxa (Tricularia yakusimensis Masam., Hololeion maximowiczii Kitam., Drosera rotundifolia L., Pogonia japonica Rchb.f., Iris ensata var. spontanea (Makino) Nakai, Utricularia racemosa Wall.) were those found in wetlands, 4 taxa (Wikstroemia ganpi (Siebold & Zucc.) Maxim., Jeffersonia dubia (Maxim.) Benth. & Hook.f., Lysimachia coreana Nakai, Iris ensata var. spontanea (Makino) Nakai) on mountain slopes, 3 taxa (Euphorbia fauriei H. Lev. & Vaniot, Veronica pusanensis Y. Lee, Glaux maritima var. obtusifolia Fernald) in the coastal region, and 2 taxa (Abelia spathulata Siebold & Zucc., Deutzia paniculata Nakai) in the valley area. In the case of rare plant species found in wetlands, there has been damage caused by coast elevation, forest road construction and farming, and in the case of other rare plant species, there has been damage caused by developments and other detrimental factors. Wikstroemia ganpi (Siebold & Zucc.) Maxim. and Veronica pusanensis Y. Lee are especially in need of protective measures, since their habitat is decreasing and they are being damaged via picking.

Reducing erosion from forest roads and skid trails by management practices

A road network in forest lands provides easy access to forest resources for extraction, regeneration, protection and recreation activities. Erosion from forest roads and skid trails is a major concern in forest management due to the capability to cause adverse environmental effects. The objective of this paper is to introduce two methods for reducing erosion on forest roads and skid trails: water diversion and vegetation cover. Factors affecting erosion on forest roads and skid trails are climate, quality of forest road surfacing material, traffic, slope and vegetation cover. There are several management practices to mitigate the impact of logging and forest road and skid trail construction on stream water quality. Sediments delivered to streams from roads and skid trails lead to a number of dramatic effects on water quality and aquatic life. These management practices were found to be effective in controlling and reducing the runoff volume and soil erosion. Therefore, management and maintenance of forest roads and skid trails are essential elements to mitigate erosion.  

The investigation of approximate cost and progress payment for forest road building in Lakes Region of Turkey

Forest roads are high-cost basic facilities allowing economic, ecological and social functions of forests to be fulfilled. Because the most essential work item affecting road construction cost is excavation works, amount of excavation and land classifications have to be most appropriately determined within bidding process. In regard to application, the amount of work given in approximate cost sheet required for bidding for forest road construction is determined by means of observational methods and the bidding is conducted within the scope of Public Procurement Law No:4734 before the project is made. After the documents including approximate cost, bidding and payment for 43 forest roads built in The Lakes Region of Turkey (Isparta Regional Directorate of Forestry) during the period (2003-2008) were obtained, the project started. The amount and cost of work determined in the bidding process for the roads involved in the research have been compared with those determined in the progress payment process. Within these comparisons, a consideration has been carried out by using tables, graphics and statistical methods. After the bidding files in the scope of Public Procurement Law in force were inspected, faulting components of the current application have been determined and solutions are suggested. It has been detected that the cost and amount of excavation determined in the bidding process differ from those determined in the payment process. It has been found out that it is not sufficient to determine amount of work given in bidding sheets related to road construction only by means of observation-based field reconnaissance. Projects providing better results as a result of using modern methods which can specify structure of land depth while conducting a road construction shall be designed. For this reason, geophysical methods can be benefited from. In order to conduct effectively biddings for forest road construction, amount of excavation and its distribution to land classifications shall be most appropriately determined.

Economics of a hydraulic hammer for forest road construction in a mountainous area

 This research deals with productivity and cost of rock disintegration and side casting of materials with the use of a hydraulic hammer mounted on a PC 220 Komatsu crawler excavator, which is used on rocky slopes of Hyrcanian forests of Iran. A continuing time study was applied during the road construction. To estimate the volume of rock disintegration, the average end area equation was used. The increasing cut-slope height decreased productivity. The productivity of hydraulic hammer averaged at 5.5 m<sup>3</sup>·h<sup>–1</sup> for the mean work volume of 5.07 m<sup>3</sup>·m<sup>–1</sup>. The unit cost of the system was 7.7 €·m<sup>–3</sup>. From the economic point of view a new machine with multipurpose system could be recommended for forest road construction operations in rocky areas.  

Evaluation of drainage system of forest roads in Iran: Darabkola forest roads

It is necessary that forest roads be constructed according to standards considering the importance of forest roads in the forestry plans and sustainable management. The Standard Drainage system is one of the most important technical buildings in the forest road construction. Darabkola forests have been located in the central part of the northern margin of Alborz Mountains in watershed basin 74 which have been established in 1.5 km distance of sari. Darabkola forest’s area is 2612 ha. The effective factors on road drainage such as road width, cross and longitudinal slopes of road, slope of excavation and embankment ranges, longitudinal slope of ditch and basal area of ditch were measured in each 40 m of 1.5 km of forest road length. Then the sample point's locations were recoded using GPS (Global Position System) and the related map was prepared. The Culverts diameter and the Culverts distance of each other was measured in the current drainage system and the culverts location was also recorded using GPS. In addition, road route was tracked and recorded using GPS to obtain more accuracy. Finally, the drainage system of study forest road was compared with accepted standards. Results showed that there is significant difference between the current drainage system of Darabkola forest roads and accepted standards in some cases and the drainage system of these roads was evaluated in the medium situation. Key words: Culvert, drainage system, forest roads, global position system (GPS), Iran.

Spatial Relationships between Landslides and Topographical Factors at the Liukuei Experimental Forest, Southwestern Taiwan after Typhoon Morakot

Typhoon Morakot produced copious amounts of rainfall and triggered enormous landslides in southern Taiwan when it hit Taiwan on 8~9 August 2009. The Liukuei Experimental Forest (LEF) managed by the Taiwan Forestry Research Institute was located in the peak rainfall region and inescapably incurred severe landslides and road destruction. This paper presents a statistical approach to study spatial relationships between landslides and their geographic factors in the LEF after typhoon Morakot. The normalized difference vegetation index (NDVI) of satellite images SPOT2 and SPOT4 photographed before and after typhoon Morakot were compared to extract landslide patches. Those extracted patches, consisting of 10 x 10-m digital elevation model (DEM) data and the related coverage of vegetation of LEF, were examined using the WinGrid computer software for the topographic analysis. Results indicated that the extremely heavy rainfall was the main factor that triggered landslides during the typhoon. There were 204 locations which experienced identifiable landslides, and their total area was about 804.49 ha. The elevation and types of vegetation cover were not factors related to the failure of the slopes. Steepness, aspect, and distances to roads and streams were factors that contributed to instability of the slopes. About 70.2% of the total area of landslides occurred on slopes with steepness in the range of 60~80%, and this showed that steep slopes are prone to collapse. Landslides with distance of the lower edge to a stream of ＜ 10 m occurred in 49 locations, and their areas accounted for 33.6% of the total landslide areas. In addition, 34 landslides (24.7% of all landslides areas) occurred within 50 m of a forest road, and the average area of those landslides was 5.79 ha. The deeply concentrated surface flows resulting from the extreme rainfall in streams and on road surfaces striking against the foot of hillslopes that contained saturated soil water were the main factors causing slides of large area. This also indicated that landslides in the LEF were closely related to stream systems, and forest road construction. The aspect of slope was not the main factor related to landslides in most cases. However, slopes with southerly and southeasterly aspects directly faced the strong winds and heavy rainfall brought by typhoon Morakot, and more landslides occurred on those slopes than on slopes with other aspects.