Forest Roads Research Articles

Examining Open-Top Culverts Impact on Forest Road Surface Deteriorations via UAVs

The life and robustness of forest roads depend on their protection from the harmful effects of water coming into the road surface. In particular, the deterioration of the road surface affects the safe navigation of vehicles and traffic safety. This situation requires that the surface be stable on forest roads. The aim of the study is to examine whether surface deterioration (erosion and accumulation) on forest roads due to the drainage problem of water falling on the road surface can be minimized by open-top culverts and to determine their effectiveness. These are used in three separate trial blocks every 25 m (A parcels; total of 3 parcels), every 50 m (B parcels; total of 3 parcels) and control block (C). Volumetric erosion and accumulation in these blocks was compared by UAV for about 3 years and the effectiveness of the open-top culverts was examined by this method. A 500 m section of the forest road coded 001 of the Kardüz Forest Operations Directorate (Düzce/Türkiye) was examined in the study. As a result, erosion and accumulation in all blocks have been found to have a dynamic course. It was determined that this mobility was greater in the control block than in the blocks with open-top culverts installed at intervals of 25 m and 50 m. The mean Z values for the blocks showed that the deterioration in the control block (C) was higher than in the blocks with 25 m and 50 m open culverts. The volumetric deterioration rate was 5 times higher in the control block than in the block installed at 25 m interval (A plots) and 2 times higher than in the block installed at 50 m interval (B plots). Similarly, the areal deterioration rate was 3.3 times higher in the control block than in the block installed at 25 m interval (A plots) and 1.4 times higher than in the block installed at 50 m interval (B plots). These results showed the effectiveness of open-top culverts and it was also determined that the open-top culverts installed at 25 m intervals were more effective than the open-top culverts established at 50 m intervals. In addition, according to the statistical analysis, a statistically significant difference was found between the erosion volume in the blocks. Open-top culverts should be used against forest road surface deterioration and UAV technology should be used for deterioration detection.

A study on measuring an objective aspect score for analysis in forestry

In forestry, measurements are made to understand the state of natural ecosystems and their changes. The studies have reported that geographical features such as elevation, slope and aspect affect the ecosystem dramatically and that it is crucial to measure them accurately. Also, in forestry analysis and risk assessments, these features are required to be scored objectively and accurately. Elevation and slope can be easily measured and scored using GISbased systems. Although the aspect can be measured simply, the studies suggested diverse approaches on scoring it. The reason for this diversity is essentially that the studies determine the aspect visually and that the circular structure of the aspect makes the scoring difficult. Also, the score of the aspect value differs according to the study hemisphere and concept. Therefore, the requirement of an objective and easily applicable GIS-based measurement and scoring method of the aspect is genuine. In the study, Maçka Forestry Enterprise, which is located in the Trabzon province of Türkiye, was chosen and the aspect map of the region was obtained. Then, 30 forest roads and 30 landslide areas were selected from the region. The forest roads and landslide areas were evaluated according to their aspect, visually. These visual assessments were scored according to the studies in the literature. After all, the aspect scores of the forest roads and landslide areas were also determined according to the proposed method. This method suggests scoring the aspect in a pixel-wise manner and circular averaging. The results were compared and have shown that the aspect scoring studies in the literature are subjective and contradict each other in many ways. The results also showed that the proposed method is accurate, objective, and effective in measuring and scoring the aspect. Also, the proposed method provides a virtual approach rather than a visual one. Finally, the proposed method is shared as an open-source ArcMap Toolbox to be delivered to the end-user.

Application of Phytoremediation to Hydraulic Binders Alkaline Inclusion in Forest Roads Pavement Construction

The use of hydraulic binder materials for the improvement of pavement subgrade has many implications for the surrounding ecosystem due to the possible leakage of alkaline compounds. The objective of this study is to evaluate the capacity of plants to remedy the subgrade affected by alkaline inclusion. To reduce the impact and return the subgrade to its original state, a phytoremediation process is studied. The impact of two materials commonly used for the subgrade improvement is analysed – fluid ash (slag) and lime+cement mixture. Three different mixes of plants – Mix A, Mix B and the native natural vegetation Mix N – are proposed. Totally 99 samples were collected and 990 specimens were chemically and geotechnically analysed and statistically evaluated. The success of phytoremediation process for both Mix A and Mix B can be observed. It is considerably higher for the undersurface alkaline inclusion than for the surface one. Mix B appears to be the best for fluid ash binder and Mix A for lime+cement mixture binder. It is worth noting that the native natural vegetation in Mix N also contributes to the phytoremediation process and that the appropriate plant selection – e.g. Mix A and Mix B – can accelerate this process.

Bayesian inference of forest road failure frequency depending on rainfall intensity for every prefecture in Japan

ABSTRACT To make a quantitative prediction on forest road failures in the future under the influence of climate change, forest road failure frequency depending on rainfall intensity needs to be clarified. The forest road failure frequency at a certain rainfall intensity should vary regionally because of the variability in susceptibility. In the current situation of a lack of nationwide detailed forest road failure inventory data and GIS-based forest road data, this study analyzed the relationship between rainfall intensity and forest road failure frequency based on Bayesian inference using data available for all the 47 prefectures in Japan; the annual number of forest road failures, forest road length, analyzed precipitation data and polygon data of forest areas. The predicted forest road failure frequency varied broadly by prefecture; 10−4–10−2 km−1 at a rainfall event of 100 mm/24 h, while 10−2–100 km−1 at that of 400 mm/24 h. The frequency at the same rainfall intensity tended to be lower in conventionally rainy prefectures. The results imply that the number of forest road failures in currently less rainy regions may show a larger increase in the future as intense rainfall events are predicted all over Japan due to climate change.

National-Scale Detection of New Forest Roads in Sentinel-2 Time Series

The Norwegian Environment Agency is responsible for updating a map of undisturbed nature, which is performed every five years based on aerial photos. Some of the aerial photos are already up to five years old when a new version of the map of undisturbed nature is published. Thus, several new nature interventions may have been missed. To address this issue, the timeliness and mapping accuracy were improved by integrating Sentinel-2 satellite imagery for the detection of new roads across Norway. The focus on new roads was due to the fact that most new nature interventions include the construction of new roads. The proposed methodology is based on applying U-Net on all the available summer images with less than 10% cloud cover over a five-year period, with an aggregation step to summarize the predictions. The observed detection rate was 98%. Post-processing steps reduced the false positive rate to 46%. However, as the false positive rate was still substantial, the manual verification of the predicted new roads was needed. The false negative rate was low, except in areas without vegetation.

Comprehensive Review of Fly Ash: Environmental Impact and Applications

ABSTRACTFly ash (FyA), a byproduct from coal combustion in power plants, has become increasingly valuable due to its pozzolanic properties. Primarily, FyA finds applications in the construction industry, including road and brick construction, forest road building, and the cement industry. When added to concrete, it enhances splitting tensile strength, compressive strength, and workability, while also reducing the environmental impact of cement production. Beyond construction, FyA is utilized for air pollutant removal and serves as an adsorbent for various contaminants. It also plays a role in creating geopolymers and nanocomposites, promoting the development of eco‐friendly construction materials. This review article presents current data on thermal power plants (ThPPs) in India, the challenges in FyA management, and its environmental impact. It also discusses relevant Indian policies and highlights ongoing research aimed at improving the efficiency and expanding the applications of FyA in various industrial sectors, such as battery manufacturing, zeolite synthesis, and cenosphere extraction. These efforts underscore FyA's potential in supporting sustainable practices. The findings of this review address critical issues related to FyA. By reducing the environmental footprint of cement manufacturing, removing air pollutants, and acting as an adsorbent for various contaminants, FyA demonstrates significant potential in pollution mitigation. It also contributes to the development of eco‐friendly construction materials and promotes sustainability in the construction sector. Effective management practices are essential to minimize FyA's negative impact on human health and the environment. The article emphasizes the need for greater awareness and implementation of policies to address these issues comprehensively. By providing a detailed understanding of the benefits and challenges associated with FyA, it aims to pave the way for more effective and sustainable utilization of this industrial byproduct.

Моделирование теплового режима дорожной одежды и земляного полотна лесовозных дорог

Soil freezing is observed throughout almost the entire forested area of the Russian Federarion in winter. The effect of negative temperatures on dusty-clay soils causes a number of adverse processes that change the properties of the soils themselves. One of the most unfavorable of these processes is the accumulation of moisture in soils under the influence of the movement of the freezing front. When freezing, water-saturated clay soils increase dramatically in volume. This leads to the appearance of frost heaving in the active zone of the forest roadbed, which has an extremely adverse effect on the structure of the entire pavement and can lead to damage to the pavement with a sharp deterioration in the transport and operational qualities of forest roads. To combat frost heaving, it is necessary to study the patterns of changes in the water-thermal regime of road structures. The depth of freezing of the pavement and the roadbed is of the greatest importance for predicting frost heaving and developing measures to combat this phenomenon. The article describes the developed system for monitoring the temperature of the road structure to a depth of 3 m and the measurement results which allow us to evaluate the temperature change at different depths from the road surface and determine the freezing depth. A total of 32 sensors have been installed with a step of 10 cm. A numerical simulation of the freezing process of the pavement and the upper part of the roadbed of a forest road has been performed, with the results compared with the indicators of field observations. Good data convergence has been revealed. According to the results of experimental studies, the freezing value has been 173 cm, and according to the results of numerical simulation – 190 cm. The average error in the results of numerical simulation of the freezing process of the pavement and the upper zone of the forest roadbed has been 8–10 % compared to the experimental data.

Effect of Trail Condition, Slope, and Direction of Extraction on Forwarding Performance: Insights from a Controlled Comparative Study

The performance of timber harvesting equipment is important for local operational planning and for making decisions on the way in which the forests should be opened up. However, there are many options used to extract timber, and there is a high variability in their performance. Forwarding is commonly used and became an attractive option for low-access forests. A controlled experiment was set up in this study to see how the configuration of the trails, characterized in terms of slope and surface condition, and the extraction direction (uphill or downhill) may affect the performance of forwarding operations. GNSS (Global Navigation Satellite System) data were collected at a rate of 5 s for five replications of moving empty downhill and uphill, respectively, on a dirt trail, measuring 250 m in length and having a slope of about 11%. The same experiment was run with the machine loaded at full capacity, then four replications with the machine loaded and unloaded moving downhill and uphill, respectively, were performed on a forest road resembling a rocky trail, which measured 390 in length and had a slope of about 4%. GNSS data were used to extract the moving speed for all the tested conditions with the aim to compute the cycle time, and the payload volume estimate was used to estimate efficiency, and productivity, depending on extraction distance in a range of 50 to 1000 m. For the first trail, statistical comparison tests indicated significant differences in the speed of uphill and downhill movement, for both empty and loaded conditions, whereas for the second trail, there were no significant differences in speed. In addition, on the second trail, the sustained speed was almost double. These were reflected sharply in the cycle time, efficiency, and productivity, depending on extraction distance and trail condition. These findings are important for decision making on local operational planning and forest opening up.

The analysis of the operating conditions of a heavy-duty engine of a vehicle designated for timber transport in terms of compliance with the RDE procedures

According to the data provided by Polish Central Statistical Office, the years 2000–2020 have seen a general increase in the amount of extracted timber reaching 43%. The process of obtainment and transport of timber has many stages involving multiple vehicles and machines. The prevailing type of machinery are HDVs (heavy-duty vehicles). Their application is dictated by the fact that high tonnage-rated vehicles are characterized by the greatest efficiency. The vehicles from this group are homologated under laboratory and actual traffic conditions. It is noteworthy that the transport process of timber takes place under extremely varied conditions – paved urban and rural roads a well as unpaved forest tracks. This renders the mode of operation non-compliant with the conditions set forth in the UE 582/2011 standard. Therefore, the authors decided to carry out an analysis of the operating conditions of a vehicle fitted with an HD engine used in the process of timber transport in terms of its compliance with the RDE (Real Driving Emissions) procedures. The analysis was performed based on investigations carried out under actual traffic conditions with the use of the PEMS equipment. The research object was a tractor-trailer fitted with removable stanchions and a crane used for timber handling. The paper presents, inter alia, the engine operating time share characteristics as a function of engine load and speed. The authors also compared the real-world engine operating conditions with the assumptions of the RDE procedures.

Method of designing forest road construction scenario with GIS-based calibration using sustainable forestry model

In Japan, where planted forest resources have matured, the growing demand for harvesting work has necessitated road network expansion. To address this challenge, a model grounded in graph theory was developed to design a road network aligned with Japan's environmental and social conditions. This model integrates the road network with a forest management plan to ensure that timber collection aligns with each year's business scenarios. The slope parameters in the model were fine-tuned using road network data from sustainable forestry locations and simulations were conducted in forests near Tokyo. The designed working road boasts an average slope of 13–14 %, and the final road network density, including primary roads, surpassed the city's development target of 85.08 m ha−1. An evaluation using the Hausdorff distance indicated that the road network layout was generally appropriate for actual data. These findings are expected to contribute significantly to the effective forest resource utilization.

Distribution pattern and assembly mechanism of microbial community to cause biological aging of asphalt materials in forest road domain

The biological aging of asphalt due to microorganism decomposition causes such distresses as loosening and spalling on asphalt pavement in forest region, which deteriorates the durability of asphalt pavement. To study the distribution regularities of microbial communities in forest road domain and reveal the assembly mechanisms of microbial communities, 16S rRNA full-length sequencing was utilized to analyze the collected samples from three forest areas. Results show that when compared with those in roadside slope, the evenness and diversity of microbial community in asphalt pavement are decreased, but the richness of microbial community is significantly increased. Mycolicibacterium is screened for a biomarker in asphalt pavement. Additionally, the increase in the relative abundances of Bacteroidetes and Proteobacteria, which are the dominant bacteria in asphalt pavement, reshapes the co-occurrence network relationship among the microorganisms. The total carbon (TC) plays an important role in regulating the composition of microbial community. The microbial community in roadside slope is dominated by stochastic processes, while the strong interspecies interactions and selection effect of asphalt on microbial community strengthen the role of deterministic processes in remodeling the microbial community structure in asphalt pavement. This study is of great significance for understanding the biological aging mechanism of asphalt pavement.

Identifying suitable areas for plenter forest management

Plenter forests, also known as uneven-aged or continuous cover forests enhance forest resilience and resistance against disturbances compared to even-aged forests. They are considered as an adaptation option to mitigate climate change effects. In this study, we present a conceptual approach to determine the potentially suitable area for plenter forest management within central European mixed species forests and apply our approach to the case study area in Styria, the south-eastern Province of Austria. The concept is based on ecological and technical-economic constraints and considers expected future climate conditions and its impact on plenter forest management. For each 1 ha forest pixel, we assess the ecological conditions for plenter forest management according to the autecological growth conditions of silver fir, and at least one additional shade tolerant tree species. The technical-economic constraints are defined by slope (≤ 30%) and distance to the next forest road (≤ 100 m) to ensure cost-efficient harvesting. The results show that under current climate conditions 28.4% or 308,349 ha of the forests in Styria are potentially suitable for plenter forest management. For the years 2071 to 2100 and under the climate change scenario RCP 4.5, the potential area decreases to 286,098 ha (26.3% of the total forest area) and for the scenario RCP 8.5 to 208,421 ha (19.1% of the total forest area). The main reason for these changes is the unfavourable growing conditions for silver fir in the lowlands, while in the higher elevations silver fir is likely to expand. Our results may serve forest managers to identify areas suitable for plenter forests and assist in the transformation of even-aged pure forests to uneven-aged forests to increase resistance, resilience, and biodiversity under climate change.

Biodegradation mechanism of asphalt by microbial consortia in asphalt pavement of forest area road

To study the degradation behaviors of asphalt by microorganisms and reveal biodegradation mechanism of asphalt, 16S rRNA full-length sequencing was utilized to analyze the collected samples from three forest areas. Five strains, namely Sphingomonas polyaromaticivorans, Pseudomonas putida, Pseudomonas fluorescens, Bacillus cereus, and Bacillus subtilis, were selected for compounding microbial consortium to study its degradation effects on asphalt. The micromorphology, elemental chemical states, micromechanical properties, molecular weight distribution, and functional groups of degraded asphalt were studied using environmental scanning electron microscopy, X-ray photoelectron spectroscopy, atomic force microscopy, gel permeation chromatography, and Fourier transform infrared spectroscopy. The results show that the biodegradation of asphalt by microbial consortium increases the surface roughness of asphalt and reduces surface adhesion. Asphalt is used as the sole carbon source by microbial consortium, resulting in a continuous decrease in the contents of C and N elements, while the content of O element is continuously increased. Simultaneously, under the action of microbial enzymes, C-C/C-H bonds which are combined with molecular oxygen in asphalt are continuously broken and converted to C-O-C/C-O-H bonds. The continuous reductions in methylene index and butadiene index of asphalt, as well as the production of carbonyl functional groups confirm the oxidative degradation of asphalt by microbial consortium. Additionally, with the extension of degradation time, the large molecular substances in asphalt are gradually degraded by microbial consortium, leading to a more concentrated molecular weight distribution. This study is of great importance to understand biodegradation mechanism of asphalt.

Expanding the Accessible Forest Areas by Improving Forest Road Standards and Utilizing Mobile Fire-fighting Teams

In Turkey, most of the roads (66%) in forests consist of Type-B secondary forest roads with limited technical standards. The lack of technical standards used on these roads and the lack of road structures and surface material limit the fire truck’s speed and increase the travel time of the firefighting team. Improving forest road standards will contribute to driving safety and increasing the design speed, thereby expanding the forest areas that can be reached within the critical response period, reducing possible wood raw material losses. There is no study in the national and international literature investigating the contribution of forest road standards improvement to firefighting activities and the effects on possible wood raw material losses due to forest fires. In this study, it was aimed to investigate the effects of improving forest road standards on expanding accessible forest areas within the critical response time, especially in forests with high fire risk, and thus reducing potential wood raw material losses. Antalya Forestry Regional Directorate, where forest fires are seen most frequently and the amount of burned area is the highest in Turkey, was selected as the study area as one of the forest regional directorates where forest fires are seen most frequently and the amount of burned area is the highest in Turkey. In the solution process, primarily the forest areas that can be reached by the firefighting team (including mobile teams used in emergencies) within the critical response time were determined by considering the existing road network in the study area. Then, the possible increase in the accessible forest areas was investigated when the road standards are improved. Within the scope of the study, the impact of mobile teams used in emergency situations on forest areas reached during the critical response period was also evaluated. According to the results, in the scenario where current road standards and stationary teams were evaluated, it was determined that only 59.54% of the forest areas could be reached by initial response teams during the critical response time, and if road standards were improved, this rate increased to 71.69%. On the other hand, in the scenario where current road standards and stationary and mobile teams were evaluated together, it was determined that 70.40% of the forest areas could be reached by initial response teams during the critical response time, and if road standards were improved, this rate increased to 78.17%. The results obtained have shown that improvements in road standards and the presence of mobile teams have a very effective role in combating forest fires.

Spatial Evaluation and Modelling of Fire Stations Layout to Access Forest Fires by Roads (Case Study: Krasnoyarsk Region, Russia)

Regional forest fire protection services on the ground usually have a fire station infrastructure with firefighting vehicles capable of moving by public and forest roads. The location of fire stations is a subject of evaluation on the regional scale and a matter of constant research interest. Infrastructure and transport accessibility, as well as the spatial location of fire stations worldwide and in Russia, were discussed. Location-Allocation ArcGIS tool and the access routes database for Krasnoyarsk region (archived data of 2002-2022 forest fires detected by MODIS containing 60637 records) were the base of methodology to evaluate fire station layout. The settlement dataset from Open Street Map (OSM) was used to analyze new locations as candidates for a fire station. Standard Deviational Ellipse ArcGIS tool was applied to define an optimal area for the current fire station from which routes to the nearest fires are built. OSM settlements inside of 1-sd area of the ellipse were used to generate the candidate list of settlements to find new locations instead of the current fire station. Results have been evaluated for 3 groups of access routes: 3 hours and less, more than 3 hours, and access routes of any duration according to the Russian forestry rules. The proposed fire station layout has improved forest fire accessibility with OSM candidates for 39 stations; 20 of 59 remain spatially unchanged. Total regional forest fire accessibility changed from the current to the proposed layout in absolute values from 47331 to 48905 fires. Analysis of 39 relocated stations showed that the new fire station layout is more optimal than the current one because it provides access to an additional 20 % of forest fires with a decrease in average weighted time to reach them by 30 %. The described methodology could make an emergency response during a fire-hazardous period more effective.

Environmental Fragility in Commercial Forest Plantations Aiming at Sustainable Management

Objective: The objective of this study is to investigate the environmental fragility of two landscapes in which there is a predominance of commercial forest plantations, with the aim of analyzing this fragility through multicriterial evaluation, focusing on the planning of forest roads. Theoretical Framework: The theory of environmental fragility, multi-criteria evaluation methods, and principles of landscape management stand out, providing a solid basis for understanding the context of the investigation. These frameworks are crucial for analyzing the impact of forest roads on environmental variables such as water dynamics, sediment production, and soil erodibility. The integration of these theories allows for a comprehensive assessment of environmental fragility, essential for effective forest planning and road maintenance in forested areas Method: The methodology adopted involves a multi-criteria evaluation approach to assess environmental fragility in forest landscapes. Key criteria, including slope, distance from water bodies, soil erodibility, and topographic humidity, were integrated to create fragility maps. Data were collected through geographical and environmental analysis, processed with spatial analysis tools, and supplemented by principal component analysis to identify influential criteria. This approach enabled a detailed assessment of forest roads' environmental impact, supporting informed decisions in road planning and landscape management. Results and Discussion: The results revealed notable variations in environmental fragility. The analysis of forest roads highlighted their varying impact on environmental fragility. These results are framed within the context of environmental fragility and multi-criteria evaluation, emphasizing the role of criteria such as slope, proximity to water bodies, soil erodibility, and topographic humidity in assessing landscape degradation. The study underscores the need for careful forest road planning to mitigate environmental impacts and promotes the use of comprehensive evaluation methods in sustainable landscape management. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of forest management and environmental conservation. These implications could encompass forest road planning, sustainable landscape management, and the development of environmental policies aimed at mitigating the impact of infrastructure on natural ecosystems.The study's findings emphasize the need for incorporating multi-criteria evaluation methods into forest planning processes to identify and mitigate areas of high environmental fragility. This approach can guide decision-makers in prioritizing areas for road maintenance, rehabilitation, or even rerouting to minimize ecological damage. Furthermore, the research underscores the importance of integrating environmental fragility assessments into broader forest management strategies, enhancing the sustainability of commercial forestry operations while preserving essential ecosystem services. Originality/Value: This study contributes to the literature by introducing an innovative application of multi-criteria evaluation in assessing environmental fragility within forest landscapes, specifically in the context of forest road planning. The research combines various environmental criteria into a comprehensive fragility map, offering a nuanced understanding of landscape vulnerability that is less commonly addressed in existing studies. Notably, this methodology focused on forest roads has not been previously explored in the literature, highlighting the unique contribution of this research to the field.The relevance and value of this research are evidenced by its potential to influence forest management practices, particularly in the sustainable planning and maintenance of forest roads.

Wild Boar Proves High Tolerance to Human-Caused Disruptions: Management Implications in African Swine Fever Outbreaks.

Currently, African swine fever (ASF), a highly fatal disease has become pervasive, with outbreaks recorded across European countries, leading to preventative measures to restrict wild boar (Sus scrofa L.) movement, and, therefore, keep ASF from spreading. This study aims to detail how specific human activities-defined as "car", "dog", "chainsaw", and "tourism"-affect wild boar behavior, considering the disturbance proximity, and evaluate possible implications for wild boar management in ASF-affected areas. Wild boar behavior was studied using advanced biologging technology. This study tracks and analyzes wild boar movements and behavioral responses to human disturbances. This study utilizes the dead reckoning method to precisely reconstruct the animal movements and evaluate behavioral changes based on proximity to disturbances. The sound of specific human activities was reproduced for telemetered animals from forest roads from different distances. Statistical analyses show that wild boars exhibit increased vigilance and altered movement patterns in response to closer human activity, but only in a small number of cases and with no significantly longer time scale. The relative representation of behaviors after disruption confirmed a high instance of resting behavior (83%). Running was the least observed reaction in only 0.9% of all cases. The remaining reactions were identified as foraging (5.1%), walking (5.0%), standing (2.2%), and other (3.8%). The findings suggest that while human presence and activities do influence wild boar behavior, adherence to movement restrictions and careful management of human activity in ASF-infected areas is not a necessary measure if human movement is limited to forest roads.

Application of IMU/GPS Integrated Navigation System Based on Adaptive Unscented Kalman Filter Algorithm in 3D Positioning of Forest Rescue Personnel.

Utilizing reliable and accurate positioning and navigation systems is crucial for saving the lives of rescue personnel and accelerating rescue operations. However, Global Navigation Satellite Systems (GNSSs), such as GPS, may not provide stable signals in dense forests. Therefore, integrating multiple sensors like GPS and Inertial Measurement Units (IMUs) becomes essential to enhance the availability and accuracy of positioning systems. To accurately estimate rescuers' positions, this paper employs the Adaptive Unscented Kalman Filter (AUKF) algorithm with measurement noise variance matrix adaptation, integrating IMU and GPS data alongside barometric altitude measurements for precise three-dimensional positioning in complex environments. The AUKF enhances estimation robustness through the adaptive adjustment of the measurement noise variance matrix, particularly excelling when GPS signals are interrupted. This study conducted tests on two-dimensional and three-dimensional road scenarios in forest environments, confirming that the AUKF-algorithm-based integrated navigation system outperforms the traditional Extended Kalman Filter (EKF), Unscented Kalman Filter (UKF), and Adaptive Extended Kalman Filter (AEKF) in emergency rescue applications. The tests further evaluated the system's navigation performance on rugged roads and during GPS signal interruptions. The results demonstrate that the system achieves higher positioning accuracy on rugged forest roads, notably reducing errors by 18.32% in the north direction, 8.51% in the up direction, and 3.85% in the east direction compared to the EKF. Furthermore, the system exhibits good adaptability during GPS signal interruptions, ensuring continuous and accurate personnel positioning during rescue operations.

Mobile laser scanning as reference for estimation of stem attributes from airborne laser scanning

The acquisition of high-quality reference data is essential for effectively modelling forest attributes. Incorporating close-range Light Detection and Ranging (LiDAR) systems into the reference data collection stage of remote sensing-based forest inventories can not only increase data collection efficiency but also increase the number of attributes measured with high quality. Therefore, we propose a model-based forest inventory method that uses reference data collected by a car-mounted mobile laser scanning (MLS) system along boreal forest roads. This approach is used for the estimation of diameter at breast height (DBH) and stem volume at the individual tree-level from airborne laser scanning (ALS) data. In addition, we compare the estimates obtained using the proposed method with the ones derived from reference data collected by traditional field inventory of 265 field plots systematically distributed over the study area. The accuracy of the estimates remained comparable regardless of the reference dataset used for estimation of DBH and stem volume. When using the field inventory dataset for model training, the root mean square error (RMSE) of DBH estimates were 4.06 cm (18.8 %) for Norway spruce trees, 6.3 cm (29.6 %) for Scots pine and 8.61 cm (55.9 %) for deciduous trees. Similarly, when evaluating predictions based on the MLS dataset as reference, RMSEs were equal to 3.97 cm (18.4 %) for Norway spruce, 6.12 cm (28.8 %) for Scots pine, and 8.98 cm (58.3 %) for deciduous trees. In general, biases were below 1 cm for most species classes, with the exception of deciduous trees. The accuracy of stem volume also had RMSEs varying across different tree species. For the estimates based on traditional field inventory, the RMSEs were 0.176 m3 (38.8 %) for Norway spruce, 0.228 m3 (52.4 %) for Scots pine and 0.246 m3 (158 %) for deciduous trees. When using the MLS dataset as a reference, the RMSEs were equal to 0.176 m3 (38.8 %), 0.228 m3 (52.4 %), and 0.246 m3 (158 %) for Norway spruce, Scots pine, and deciduous trees, respectively. Car-mounted MLS demonstrated its potential as an efficient alternative for collecting reference data in remote sensing-based forest inventories, which could complement traditional methods.

The effect of mosses on the relocation of SOC and total N due to soil erosion and percolation in a disturbed temperate forest

Forests cover one-third of the global land and are important components of carbon and nitrogen cycling. Anthropogenic disturbances, such as forest road systems or skid trails for timber harvesting, can dramatically change the nutrient cycling in these ecosystems. Skid trails increase soil erosion and thus the displacement of soil organic carbon (SOC) and total nitrogen (Nt). Additionally, runoff transports high amounts of dissolved organic carbon (DOC), which can have a negative impact on aquatic ecosystems. One of the most important countermeasures against soil erosion is the quick recolonization of vegetation. To date, the extent to which natural vegetation succession influences the relocation of SOC and Nt, and in particular the role of mosses in this context, has not been well investigated. This study investigates the influence of natural vegetation succession and in particular of mosses on the displacement process of SOC and Nt as well as DOC caused by soil erosion. To this end, we combine the results of a field study using in-situ rainfall simulations with small-scale runoff plots in skid trails of the Schönbuch Nature Park in southwestern Germany with the results of ex-situ rainfall simulation experiments with infiltration boxes containing the substrate from the respective skid trails. The eroded sediments of skid trails were on average enriched in SOC by 16% and in Nt by 35% compared to the original soil, which lead to a decrease of the C/N ratio in sediments. As vegetation succession progressed, the displacement of SOC and Nt was reduced, confirmed by a negative correlation between the enrichment ratios of SOC (ERSOC), Nt and total vegetation cover. However, mosses tended to reduce ERSOC more than vascular plants. Additionally, mosses significantly decreased DOC concentration in surface runoff compared to bare soils, while no difference in DOC concentration in percolated water could be observed. Future research should explore the role of mosses in the storage of SOC and Nt in the soil and their impact on soil stability. Thus, utilizing mosses could potentially minimize environmental impacts from soil disturbances in forests.