Logging Operations Research Articles

Prediction of Well Logs Data and Estimation of Petrophysical Parameters of Mishrif Formation, Nasiriya Field, South of Iraq Using Artificial Neural Network (ANN)

Petrophysical properties including volume of shale, porosity and water saturation are significance parameters for petroleum companies in evaluating the reservoirs and determining the hydrocarbon zones. These can be achieved through conventional petrophysical calculations from the well logs data such as gamma ray, sonic, neutron, density and deep resistivity. The well logging operations of the targeted limestone Mishrif reservoirs in Ns-X Well, Nasiriya Oilfield, south of Iraq could not be done due to some problems related to the well condition. The gamma ray log was the only recorded log through the cased borehole. Therefore, evaluating the reservoirs and estimating the perforation zones has not performed and the drilled well was abandoned. This paper presents a solution to estimate the missing open-hole logs of Mishrif Formation including sonic, neutron, density and deep resistivity using supervised Artificial Neural Network (ANN) in Petrel software (2016.2). Furthermore, the original gamma-ray log along with the predicted logs data from ANN models were processed, and the petrophysical properties including volume of shale, effective porosity and water saturation were calculated to determine the hydrocarbon zones. The ANN Mishrif Formation models recorded coefficient of determination (R2) of 0.65, 0.77, 0.82, and 0.04 between the predicted and the tested logs data with total correlations of 0.67, 0.91, 0.84 and 0.57 for sonic, neutron, density, and resistivity logs respectively. The best possible hydrocarbon-bearing zone ranges from the depth of about 1980-2030 m in the mB1unit. The ANN provides a good accuracy and data matching in clean and non-heterogeneous formations compared to those with higher heterogeneity that contain more than one type of lithology. The Ns-X Well can, therefore, be linked to the development plans of the Nasiriya Field instead of neglect it.

DONUTS: An efficient method for checkpointing in non‐volatile memories

SummaryNon‐volatile memory (NVM) is an emerging technology being explored as an alternative to DRAM main memory in computing systems because of its persistence, higher storage density, lower energy consumption, and access latency close to DRAM. However, persistent memory systems must ensure data consistency on system failures, a property known as crash consistency. One of the main challenges in these systems is creating efficient checkpointing mechanisms in terms of performance and usability. Thus, it is necessary to remove persistence from the critical execution path and reduce the excessive number of writes to NVM caused by logging operations, resulting in increased memory bandwidth usage. Another limitation is that most proposed mechanisms restrict application source code to programming interfaces based on transactional models, typed as software‐based approaches. These factors make it challenging to adopt NVM systems. This article presents a software‐transparent mechanism based on dynamic epochs with logging operations via processing‐in‐memory and checkpoints integrated into the cache replacement policy. Compared to the previous best‐performing system, our strategy reduces 50.6% of writes to NVM. Furthermore, it does not increase the average memory bandwidth usage, providing crash consistency with less than 2% runtime overhead.

ДВУХОСНЫЕ СОЧЛЕНЕННЫЕ ЛЕСОТРАНСПОРТНЫЕ МАШИНЫ В УСЛОВИЯХ ЛЕСОСЕКИ: ОЦЕНКА ПРИМЕНИМОСТИ

The study can provide decision-making support to loggers and participants in forest relations who are obliged to carry out reforestation activities to assess the factors that change the effectiveness of forestry and logging operations. The balance of production and environmental effects from the use of forest transport machines in the development of forestry is an important step in effective quality management of forest landscape restoration. The degree of compaction of the forest soil from the impact of propellers directly affects both the fuel consumption of the power plant of the forest transport machine and the ability of forest seeds of the main breed to germinate. The primary transportation of trees and their parts (whips, balances, assortments, waste residues and other waste of logging production) occupies an increasing volume in the energy balance of the timber transport machine. It is necessary to solve complex problems of choosing energy-efficient and maneuverable biaxial articulated timber transport vehicles in comparison with machines with a continuous frame for performing transport work in the conditions of a cutting area. In order to maximize the requirements for the efficient operation of machines in difficult cutting conditions, it is necessary to ensure, along with high operational properties (traction, cross-country ability, maneuverability, smooth running), a high level of technical and economic indicators. The assessment of the applicability of existing structures of forest transport vehicles was carried out by statistical methods of Ward and intergroup relations according to the criteria of soil compaction, patency, maneuvering, power circulation, traction losses, balance of weight distribution and purpose. When planning future research, it is necessary to answer a number of questions: which criterion should be used as a universal one for unambiguous selection of the type of forest transport vehicle? Is it possible to estimate the geomorphology of the future cutting area in advance with the use of unmanned aircraft systems and predict the effective trajectories of movement of articulated timber vehicles?

Autonomous Intelligent Logging Platform Enables Cost and Time Savings

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31149, “Sensor Ball: Autonomous, Intelligent Logging Platform,” by Erjola Buzi, Huseyin R. Seren, SPE, and Max Deffenbaugh, SPE, ASC, et al. The paper has not been peer reviewed. Copyright 2021 Offshore Technology Conference. Reproduced by permission. _ The complete paper describes a method of retrieving downhole data that is a practical and inexpensive alternative to wireline or slickline logging and permanently installed sensors. The autonomous logging platform, called the Sensor Ball, is a handheld, untethered logging tool that one person can deploy and recover from a pressurized well with no special equipment or crew. The Autonomous Logging Platform The tool is a battery-powered, self-deployed logging platform. A small dissolvable metal weight is attached to the housing magnetically and helps the free-fall of the tool in the well. Once a desired and programmed depth is reached, the tool releases the weight, and thus changes buoyancy and floats back to surface. Deployment and retrieval of the tool is safe and simple and requires only a wrench to open the cap of the wellhead but does not require cranes, logging trucks, lubricators, or blowout preventers. By sequentially opening and closing the cap, swab, and master valves, in just a few minutes, the untethered logging platform passes the wellhead section and begins traveling downhole. Retrieval is performed by reversing this process. As it travels down and up, the tool records temperature, pressure, and magnetic field data continuously in its internal memory. The recorded data are wirelessly retrieved once the tool is back at the surface. A lightweight atmospheric housing provides buoyancy and insulates the electronics from the well fluids. While optimally exposing temperature and pressure sensors, the small body mass of the housing minimizes the temperature distortion in the downhole environment. The tool is deployed and retrieved several times in the field. Downhole temperature, pressure, and magnetic field data are recorded for several hours. Without the need for field crew or personnel to stand by during the logging operation, rig-up and deployment times decrease from several hours to a few minutes.

Evaluation of Different Modes for Yarding Windthrown Timber with a Double-Hitch Carriage

Yarding whole trees is the most efficient way of extracting timber in steep terrain and allows reaping the combined benefits of mechanization and biomass recovery. In downhill yarding, however, whole-tree extraction is associated with a greater risk of loosening rocks or debris by the incoming loads as they bounce around along the extraction corridor. That may also cause damage to the cables and anchors by corresponding shock loads, ultimately endangering the yarder and its crew. To avoid these risks, »double-hitch carriages« can be employed. They combine a conventional motorized dropline carriage with a secondary carriage (»trailer«), equipped with a further, independent dropline winch. Thus, loads can be attached at two points and transported fully suspended above the ground in a horizontal position.Operation of these carriages may not be limited to the »horizontal« mode: the main carriage could also be operated without trailer (»single« mode), or separate loads may be attached to the two droplines (»double« mode), but their impact on the efficiency and economy of yarding operations is yet unknown. Therefore, the present study investigated how these modes affect the productivity and cost of downhill whole tree yarding. To this end, a classic time and motion study was conducted during a salvage logging operation in Northern Italy under a strictly controlled experimental design.Average productivity (18.2±7.2 to 24.5±15.4 m³ PSH0-1 merchantable volume per productive system hour excluding delays) and extraction cost (18 to 20 Euro m-³) did not differ significantly between treatments, while load composition and time consumption by task did. More (2.2±0.5) pieces per load were yarded under the »double«, than under the »single« (1.4±0.5) and »horizontal« (1.1±0.3) treatments. Inhaul speed (3.1±0.6 m s-1) was significantly higher under the »horizontal« treatment, which compensated for increased loading time derived from attaching the load at least at one point outside the corridor. Unloading took significantly longer under the »double« treatment, as loads had to be dropped successively due to the confined conditions on the landing. Though slowest (2.5±0.9 m s-1) during inhaul, the »single« treatment exhibited none of the other treatments disadvantages and larger loads could be accumulated due to partial suspension. From an economic viewpoint, the »horizontal« mode may only be warranted over yarding distances substantially beyond average. On shorter ones, it must be justified by other reasons, such as minimizing product contamination, soil disturbance or excessive strain to the skyline when the terrain profile impedes sufficient ground clearance.

Integrated Approach Determines Formation-Water Salinity

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22548, “Integrated Approach for Formation-Water-Salinity Determination,” by Tariq Alshaikhmubarak, SPE, and Laila Mira, SPE, Saudi Aramco, and Sherif Ghadiry, Schlumberger, et al. The paper has not been peer reviewed. Copyright 2022 International Petroleum Technology Conference. Reproduced by permission. _ In the complete paper, two methodologies are tested to achieve measurement of formation-water salinity. First, a novel dry-weight chlorine (DWCL) measurement from an advanced spectroscopy tool is used to estimate the formation salinity at the depth of investigation of the device. The second methodology uses a new downhole induction resistivity cell in the formation-tester tool. The chlorine measurement, along with the flowline-induction-resistivity measurement, helps enhance the quality of saturation evaluation for quick decision making during logging operations and acceleration of evaluation studies instead of waiting on laboratory results. Chlorine Work Flow The ability to quantify chlorine concentration can help derive formation salinity as a continuous curve. Because chlorine has a large capture cross section, it is possible to extract it from capture gamma ray spectra with acceptable uncertainty, but the real challenge is to split the total chlorine signal seen by the tool into formation chlorine signal and borehole contribution. The chlorine signal split is a fundamental step in this work flow, outlined in Fig. 1. Once the chlorine concentration in the formation is obtained—expressed as DWCL—several petrophysical applications are enabled. The first is computation of water volume assuming a known formation-water salinity. The second is computation of the sodium chloride (NaCl) equivalent salinity from an independent volume of water and DWCL. Finally, one can solve for the NaCl equivalent water salinity. Equations to achieve these steps are provided in the complete paper. Interpretation Considerations Capture spectroscopy measurements have a shallow depth of investigation (DOI) in the range of 8–10 in., which means sensitivity to mud-filtrate invasion in the volume of rock probed by the tool. The mud-filtrate invasion is controlled by several factors, including mud overbalance, formation exposure time to mud, formation porosity and permeability, and mudcake-formation process and efficiency. These factors must be considered when using the chlorine work flow to assess the effect of the invading water-based-mud (WBM) filtrate, which normally has a different salinity than the formation water. The main effect of oil-based-mud (OBM) filtrate invasion, assuming that only the oil phase is invading the formation, is a reduction of water volume at the measurement DOI, degrading the statistical precision of the DWCL and increasing the uncertainty in the computed salinity.

Petrographic and Kinematic Analysis of the Itombwe Synclinorium Formations Exposed at Tshondo and Bugoy (South-Kivu region, Democratic Republic of the Congo)

The purpose of this study is to investigate the Itombwe synclinorium formations that were affected by the late Pan-African orogenesis in the nordeastern Congo. A variety of controversies surround Tshondo and Bugoy's tectonic evolution and associated metasedimentary formations. A field-based approach combined with paleostress inversion techniques and petrographic analyses were conducted on 190 structural measurements and 6 rock samples used in this study. The results reveal the presence of four major petrographic facies: conglomeratic facies (conglomerate and diamictite), carbonate facies (travertine), greenschist facies (graphitic black shale and pelite), as well as quatzitic facies (quartzite and sandstone). The mineral assemblages consisting of high contents (>70%) of muscovite/sericite and biotite albite, plagioclase, quartz, and some opaque minerals. With the assistance of Win-Tensor software, the kinematic analysis reveals two major deformation phases, (1) a ductile deformation phase (D1-2), which is associated with isoclinal folds and strike-slip faults, and (2) a submeridian brittle deformation phase (D2), which generated extensive faults trending NNW-SSE to NE-SW directions, while reactivating bedding surfaces (NE-SW) in a series of secondary faults. The findings of this research may assist geologists in conducting core logging operations and provide a baseline for understanding the relationship between rock, minerlization, and tectonics in mineral-rich areas.

Spatial interpolation methods of determination of digital elevation models for forestry planning

Topographic data acquisition methods are generally subject to measurement errors and subsequent digital terrain models (DTM) interpolation models can propagate these errors. For the forestry sector, the use of the DTM facilitates the planning stage in the road construction and mechanization phase in mountainous areas, especially in subsoiling, pesticide application and logging operations. To evaluate the results of interpolation methods, it is very common to use indicators such as the multiple determination coefficient and the residual error. This study aimed to compare and choose the best interpolation method in an elevation dataset to construct a DTM by applying the Taylor diagram to graphically analyze the results. Seventeen different methods of spatial interpolation were tested. The Spline method was selected as the best model tested over geostatistical models, most commonly adopted in spatial variability assays. The statistics of all methods were very similar, with slight variations, with the square mean square root error and the Spline method correlation being closer to the observed data, as easily shown by the Taylor diagram.

Assessment of slope stability on logged forest‐hill slopes using ground‐penetrating radar and electrical resistivity tomography

The use of ground‐penetrating radar (GPR) and electrical resistivity tomography (ERT) geophysical methods are considered a useful tool for assessing forest soil slope instabilities. These techniques provide a detailed survey regarding changes because of logging operations in an area, where the combination of soil, water, and rock conditions predisposes to the development of slope instabilities. In the current study, such geophysical survey techniques were applied at two localities, Bukovinka and Zemanův žleb near Křtiny (Southern Moravia, Czech Republic), during three sessions over 1 year. The selected survey sites were on different terrains but the same subsurface (sediments of Lower Marine Carboniferous). The condition for their selection was the absence of other major external influences apart from wood harvesting. The GPR and ERT measurements were carried out along the same lines, and changes in the geophysical profiles over time were observed. The results demonstrate the processes that lead to visible changes on both localities in the results of measurements. Both methods showed shifts in some soil properties configuration, separating partial rock masses or even incipient soil/rock movement. The ERT also detected a significant expansion of wet areas inside both studied rock masses, which may be because of the development of new channels for infiltration of rainwater. Considering that the only major external factor that could change the slopes drainage properties was the wood harvesting, it is reasonable to conclude that the observed changes are associated with the logging operations.

Full-scale experiments to examine the role of deadwood in rockfall dynamics in forests

Abstract. Forests are rockfall-protective ecological infrastructures as a significant amount of kinetic energy is absorbed during consecutive rock–tree impacts. Although many recent works have considered rock impacts with standing trees, the effect of lying deadwood in forests has not yet been considered thoroughly, either experimentally or numerically. Here, we present a complete examination of induced rockfall experiments with sensor-equipped, 45 kg, artificial rocks on a forested area in three different management stages. The trilogy is conducted in a spruce forest stand (i) in its original state of forest; (ii) after a logging operation with fresh, lying deadwood; and (iii) after the removal of the deadwood. The tests allow us to directly quantify the effect of fresh deadwood on overall rockfall risk for the same forest (slope, species) under three different conditions. The study yields quantitative results on the barrier efficiency of the deadwood logs as only 3.6 % of the rocks surpass the deadwood section. The mean run-out distance is reduced by 42 %. Conversely, the run-out distance increases by 17 % when the cleared stand is compared to the original forest. These results quantitatively confirm the benefits of nature-based mitigation measures integrated into forestry practice, whose detailed effect has to be scrutinized for higher rockfall energies. Based on the experimental results, we extended a modern rockfall code by three-dimensional deadwood logs to incorporate such complex but realistic forest boundary conditions.

Use of Hydrological Models to Predict Risk for Rutting in Logging Operations

Using hydrological models with a high temporal resolution to predict risk for rutting may be a possible method to improve planning of forwarder trails or to schedule logging operations in sites with low bearing capacity to periods when soil moisture content is at a minimum. We have studied whether descriptions of rut variations, collected in 27 logging sites, can be improved by using hydrological data, modeled by Swedish HYdrological Prediction for Environment (S-HYPE). Other explanatory variables, such as field-surveyed data and spatial data, were also used to describe rut variations within and across logging sites. The results indicated that inclusion of S-HYPE data led to only marginal improvement in explaining the observed variations of the ruts in terms of both “rut depths” within the logging sites and “proportion of forwarder trails with ruts” across the logging sites. However, application of S-HYPE data for adapting depth-to-water (DTW) maps to temporal changes of soil moisture content may be a way to develop more dynamic soil moisture maps for forestry applications.

The Forestry Industry in Papua New Guinea: Issues of Development and Environmental Protection

Papua New Guinea’s rain forest is the third-largest in the world following, the Amazon in South America and those in the Republic of Congo. So as a consequence, it represents a great storehouse of sequestering greenhouse gases, which are pivotal in controlling a rise in global temperature. The activities of the forestry industry have received opposition from environmental groups and the World Bank, but this opposition has not been welcomed by the local communities desirous of the level of development that accompanies logging operations. Recently non-governmental organization publications and media outlets have alleged that Papua New Guinea’s loggers are rampantly, increasingly, and illegally destroying the indigenous forests, earning “hundreds of millions in revenue” while refusing to pay taxes. However, it is necessary to gain some perspective on the industry by focusing on the most recent developments regarding the allegations of excessive and increased logging, and the actual revenues paid to the government and other stakeholders. This article considers these issues and recent government policy, particularly underlining the progressive export tax increase from 33percent to 55percent of the free onboard value. This article evaluates the consequences of the Government’s policies and suggests alternative ways to achieve sustainable forms of logging, which may also better satisfy the demands for increased development from local communities.

Evaluating ground disturbance at elephant skid trails, logging roads and log landings under the Myanmar selection system

ABSTRACT There has been growing interest in the practice of reduced-impact logging (RIL) to enhance various ecological services of selectively logged tropical forests. It is thus important to evaluate the effectiveness of different logging operations between RIL and conventional logging (CON). The Myanmar Selection System (MSS) has a long history and is well known for its use of elephants for skidding, which is considered one form of RIL. However, the difference in the impacts of logging operations between the MSS using elephants for skidding and machine-only-based operations commonly adopted in other countries is unknown. The present study evaluated ground disturbance along elephant skid trails, along logging roads and at log landings in four compartments logged under the MSS, comparing with reported values for CON and RIL in the other countries. The ground disturbance in the MSS compartments was, respectively, 2.1% and 0.4% in average for logging roads and log landings; it is not significantly different from that for CON and RIL (p > 0.05). In contrast, the disturbed area along elephant skid trails (0.9%) is much lower than that for CON (5.2%) and RIL (4.7%) (p < 0.05). A large difference in the width of skid trails was found between elephant skidding (1.0 m) and machinery (CON: 5.5 m, RIL: 4.6 m) (p < 0.0001). We conclude that elephant skidding can largely reduce ground disturbance due to much narrower width of the skid trails as compared with machine skidding, while MSS does not differ from the other countries in ground disturbance at logging roads and log landings.

New wellbore temperature control design for preventing failure and poor performance of logging tools in high pressure – high temperature wells

Failure and poor performance of logging tools in high pressure-high temperature wells; the associated technical consequences and the resultant high cost of logging operations are recurrent problems in the oil & gas industry worldwide. The aforesaid prompted this work to invent the “New Wellbore Temperature Control Design” for protection of logging tools against high bottom-hole temperatures. It hinges on the novel concept of thermal drainage radius and the temperature-drop effect of chilled oil-based mud to reduce bottom-hole temperature prior to logging. The methods applied include laboratory testing, mathematical modeling and design. The novel concept of “thermal drainage radius” quantified the radial extent of temperature-drop effect in the formation, away from the wellbore. Novel mathematical models were also invented. Laboratory results showed that the formation temperature-drop from bottom-hole temperature to thermal equilibrium temperature increased with bottom-hole temperature per chilled oil-based mud. The temperature-drop duration and temperature-rise duration increased with bottom-hole temperature per chilled oil-based mud. The temperature-rise duration increased with decrease in the temperature of the chilled oil-based mud per bottom-hole temperature. Job design results showed that when placed in the zone of interest in the wellbore the heat energy absorbed increased with quantity of the chilled oil based mud but the temperature rise duration decreased with increasing heat transfer rate from the formation and vice versa. Furthermore, results revealed that the higher the thermal conductivity of the formation, the longer the thermal drainage radius and vice versa. The logging operation should commence after placement of the chilled oil-based mud in the zone of interest (no circulation of the chilled oil-based mud) and be completed before the end of the temperature-rise duration. Oil-based mud is cheap and available in every country unlike the expensive vacuum flasks and thermal insulating jackets currently used for protecting logging tools against high temperature. The new wellbore temperature control design has global applicability.

A Study of Failure Recovery and Logging of High-Performance Parallel File Systems

Large-scale parallel file systems (PFSs) play an essential role in high-performance computing (HPC). However, despite their importance, their reliability is much less studied or understood compared with that of local storage systems or cloud storage systems. Recent failure incidents at real HPC centers have exposed the latent defects in PFS clusters as well as the urgent need for a systematic analysis. To address the challenge, we perform a study of the failure recovery and logging mechanisms of PFSs in this article. First, to trigger the failure recovery and logging operations of the target PFS, we introduce a black-box fault injection tool called PFault , which is transparent to PFSs and easy to deploy in practice. PFault emulates the failure state of individual storage nodes in the PFS based on a set of pre-defined fault models and enables examining the PFS behavior under fault systematically. Next, we apply PFault to study two widely used PFSs: Lustre and BeeGFS. Our analysis reveals the unique failure recovery and logging patterns of the target PFSs and identifies multiple cases where the PFSs are imperfect in terms of failure handling. For example, Lustre includes a recovery component called LFSCK to detect and fix PFS-level inconsistencies, but we find that LFSCK itself may hang or trigger kernel panics when scanning a corrupted Lustre. Even after the recovery attempt of LFSCK, the subsequent workloads applied to Lustre may still behave abnormally (e.g., hang or report I/O errors). Similar issues have also been observed in BeeGFS and its recovery component BeeGFS-FSCK. We analyze the root causes of the abnormal symptoms observed in depth, which has led to a new patch set to be merged into the coming Lustre release. In addition, we characterize the extensive logs generated in the experiments in detail and identify the unique patterns and limitations of PFSs in terms of failure logging. We hope this study and the resulting tool and dataset can facilitate follow-up research in the communities and help improve PFSs for reliable high-performance computing.

Physiological workload of workers employed during motor-manual timber harvesting in young alder stands in different seasons.

This study examined the physiological strain experienced by workers employed in motor-manual timber harvesting performed in winter and summer, and the applicability of heart rate indices for estimating energy expenditure. The heart rates (HR) of 2 teams consisting of 2 persons working simultaneously during felling and forwarding, in both winter and summer, were measured. Heart rate at work (HRwork), resting heart rate (HRrest), relative heart rate (%HRR), ratio of working heart rate to resting heart rate, and 50% level were used to estimate the physiological workload in particular jobs. The HRindex (HRwork/HRrest) equation was used to estimate the energy expenditure (EE). For all jobs, significantly higher physiological workload and energy expenditure were recorded during winter. The season significantly affects the physiological workload during logging operations. If there is no possibility of harvesting wood in summer, in order to limit the workload of workers during winter activity, attention should be paid to the proper organization of work and selection of workers. Int J Occup Med Environ Health. 2022;35(4):437-47.

Effects of Pre-Bunching Trees With a Tethered Feller-Buncher on Cable Logging Productivity and Costs: A Case Study in Southern Oregon

AbstractWinch-assist or tethered logging technology is rapidly being adopted by the forest industry across the western United States to replace conventional and dangerous manual tree falling in cable logging areas. Although the safety benefits of the technology are widely acknowledged, the effects of tethered mechanized timber falling and pre-bunching on the subsequent cable yarding operations have not been thoroughly investigated. We conducted a field study in southern Oregon to compare manual versus mechanized timber falling side-by-side for their impacts on the productivity and costs of cable logging operations. Our study shows that the costs of mechanized timber falling were higher than manual falling owing to high costs of tether equipment, but the ability of the felling machine to pre-bunch trees into piles along designated skyline corridors made subsequent cable yarding operations significantly more efficient. The efficiency gained during yarding was sufficient not only to offset cost increase in felling but also to reduce the total production costs of felling and yarding operations by 32% compared with cable yarding after manual timber falling.

Dynamics of a Forest Submitted to Logging in the Eastern Amazon, Brazil

ABSTRACT Logging is an economically important activity in the Amazon; however, there are doubts regarding its sustainability, even under planned systems. This study sought to evaluate the dynamics of the structure and composition of a forest undergoing logging operations in a Sustainable Management Unit (SMU) located in the Mamuru–Arapiuns lots of the cities of Juruti and Santarém, in the state of Pará, Brazil. The studied areas are under public concession and are closely monitored by Brazilian environmental agencies. Data were collected from permanent plots before and after logging (years 2012 to 2015). Our findings raise concerns regarding the prospects of sustainable logging because mortality rates exceeded recruitment rates, causing significant decreases in tree density per hectare and basal forest area. The diameter increment rate in the forest community was 0.82 cm year−1; crown shape and lighting significantly influenced tree diameter growth. There was initially a decrease in tree diversity followed by an increase, resulting in higher diversity levels than those observed prior to logging. There were minor changes in the composition of the forest community, with a particular shift toward pioneer species. We concluded that logging affected forest dynamics at a level that calls its prospects for sustainability into question.

Evaluating the effect of DEM resolution on performance of cartographic depth-to-water maps, for planning logging operations

Reliable and accurate soil moisture maps are needed to minimise the risk of soil disturbance during logging operations. Depth-to-water (DTW) maps extracted from digital elevation models have shown potential for identifying water flow paths and associated wet and moist areas, based on surface topography. We have examined whether DEMs from airborne LiDAR data with varying point density can improve performance of DTW maps in planning logging operations. Soil moisture content was estimated on eight sites after logging operations and compared to DTW maps created from DEMs with resolutions of 2 m, 1 m, and 0.5 m. Different threshold values for wet soil (1 m and 1.5 m depth to water) were also tested. The map performances, measured by accuracy (ACC) and Matthews Correlation Coefficient (MCC), changed slightly (79%, 81% and 82% and 0.33, 0.26 and 0.30 respectively) when DEM resolutions varied from 2 m to 1 m, and 0.5 m. The corresponding values when the DTW threshold value for wet/dry soil changed from 1 m to 1.5 m were 70%, 72%, 71% and 0.38, 0.41 and 0.39. LiDAR-based DEM resolutions of 1–2 m were found to be sufficient for extraction of DTW maps during planning of logging operations, when knowledge about soil hydrological features, associated wet and moist areas, and their connectivity is beneficial.

Digital Mapping of East Fennoscandian Vegetation Based on Remote Sensing Data

Digital mapping of boreal zone vegetation based on remote sensing data is of the utmost significance for monitoring the natural and anthropogenic dynamics of North Russian forest ecosystems. Revealing the actual state and qualitative changes of the forest cover at the regional and local levels can help achieve a wide range of sustainable development targets. Interpretation of alternative Landsat multispectral images has enabled spatial models to be developed for a number of East Fennoscandian regions. Over the last 30 years, four zones with active logging operations and substantial reduction in mature conifer forest areas have been revealed along with a substantial increase in clear cutting and the area occupied by deciduous stands. During this period, the natural landscapes of the Onezhskoe Pomorye National Park and Kostomukshsky Strict Nature Reserve managed to avoid large scale catastrophic events. So, most appear stable at the moment.&#x0D; Keywords: multispectral space images, supervised classification, Landsat program, vegetation spatial dynamics, forests, remote sensing data, interpretation