Search Results (57)

This study examined changes in runoff responses in a 17.8 ha catchment, with a focus on quick and delayed runoff components associated with logging and replantation. In total, 176 precipitation events were observed from 2011 to 2019, including in the pre-cutting, operation, and post-cutting periods. Approximately 70% of the catchment, which was originally dominated by Pitch pine (Pinus rigida), was clearcut between November 2013 and November 2014 and subsequently replanted with Japanese cypress (Chamaecyparis obtusa). Event-based results revealed that both quick and delayed runoff increased significantly under high-magnitude precipitation events (P_t > 60 mm), indicating that rainfall intensity primarily controlled the generation of event runoff. During the operation period, increases in quick runoff contributed to a larger quick-runoff fraction, whereas in the post-cutting period, replantation promoted hydrological recovery by increasing delayed runoff and extending the flow duration. These changes reflect shifts in internal hydrological pathways associated with forest removal and regrowth. Overall, the results highlight that the runoff responses to clearcutting and replantation are strongly mediated by event-scale runoff components and rainfall intensity. Full article

This paper explores the use of machine learning (ML) to analyze borehole data aiming to enhance geotechnical insights, using the Gaza Strip as a case study. The data set consists of 632 boreholes, with features including spatial coordinates, ground level, and soil type per depth. A random forest (RF) classification model was applied to predict soil types, achieving an accuracy of approximately 75%. Notably, the model retained this accuracy even when the data set size was reduced to 30%, suggesting predictable subsurface conditions over large areas. A comparative analysis of common misclassifications revealed that errors mostly occurred between similar soil types, indicating the model’s ability to capture meaningful geological patterns. Unsupervised learning using k-means clustering revealed no clear-cut boundaries between clusters, indicating localized geological anomalies despite large-scale predictability. These findings align with the demonstrated stability of the Gaza Tunnel Network (GTN), a vast network of tunnels which was constructed without comprehensive site investigations. This study demonstrates the potential of ML to improve geotechnical assessments and suggests that fewer boreholes may be needed for large-scale projects, offering cost-saving opportunities. For future research, it is recommended to integrate advanced ML tools, including large language models (LLMs) for analyzing qualitative data from borehole logs, and interpretability methods to enhance model explainability, thus enhancing geological understanding and increasing predictive power. Full article

Wildfires and logging play an important role in regulating soil carbon fluxes in forest ecosystems. In Siberia, large areas are disturbed by fires and logging annually. Climate change and increasing anthropogenic pressure have resulted in the expansion of disturbed areas in recent decades. However, few studies have focused on the effects of these disturbances on soil CO₂ efflux in the vast Siberian areas. The objective of our research was to evaluate differences in CO₂ efflux from soils to the atmosphere between undisturbed sites and sites affected by wildfire and logging in Scots pine forests of southern Siberia. We examined 35 plots (undisturbed forest, burned forest, logged plots, and logged and burned plots) on six study sites in the Angara region and four sites in the Zabaikal region. Soil CO₂ efflux was measured using an LI-800 infrared gas analyzer. We found that both fire and logging significantly reduced soil efflux in the first years after a disturbance due to a reduction in vegetation biomass and consumption of the forest floor. We found a substantially lower CO₂ efflux in forests burned by high-severity fires (74% less compared to undisturbed forests) than in forests burned by moderate-severity (60% less) and low-severity (37% less) fires. Clearcut logging resulted in 6–60% lower soil CO₂ efflux at most study sites, while multiple disturbances (logging and fire) had 48–94% lower efflux. The soil efflux rate increased exponentially with increasing soil temperature in undisturbed Scots pine forests (p < 0.001) and on logged plots (p < 0.03), while an inverse relationship to soil temperature was observed in burned forests (p < 0.03). We also found a positive relationship (R = 0.60–0.83, p < 0.001) between ground cover depth and soil CO₂ efflux across all the plots studied. Our results demonstrate the importance of disturbance factors in the assessment of regional and global carbon fluxes. The drastic changes in CO₂ flux rates following fire and logging should be incorporated into carbon balance models to improve their reliability in a changing environment. Full article

Recently, the use of powerful and heavy vehicles for timber harvesting on flat or slightly sloping terrains has been widely expanded to provide safe working conditions and high productivity. However, soil disturbances during ground-based mechanized operations in South Korea are not fully investigated and difficult to avoid. Therefore, we compared the soil displacement and compaction (bulk density and hydraulic conductivity) between two different operations: cut-to-length (CTL) logging with a harvester and forwarder, and whole-tree (WTH) logging with a harvester and skidder. After clear-cutting, severe visual disturbances and rut depths were more prevalent in the forwarding trails than in the skidding trails. The CTL harvesting method created larger amounts of slash (6.9 kg/m²) along the trails than the WTH harvesting did (1.8 kg/m²). We found a significant difference in the compaction between the reference and the track and a negative correlation between the slash quantity values and the percentage increase in compaction. Our results showed that using skidding extraction can cause more severe impacts than forwarding extraction. Thus, these results may be helpful in understanding the influence of ground-based CTL and WTH harvesting operations and achieving best practices to minimize the environmental impacts on soil. Full article

The Canadian boreal forest biome has been subjected to a long history of management for wood production. Here, we examined the cumulative impacts of logging on older forests in terms of area, distribution and patch configuration in the managed forest zones of the Eastern Canadian provinces of Ontario and Quebec. We also examined the consequences of these cumulative impacts on a once widely distributed and now threatened species, the woodland caribou (Rangifer tarandus caribou). The cumulative area of recently logged forest (since ~1976) was 14,024,619 ha, with 8,210,617 ha in Quebec and 5,814,002 ha in Ontario. The total area of older forests was 21,249,341 ha, with 11,840,474 ha in Quebec and 9,408,867 ha in Ontario. Patch statistics revealed that there were 1,085,822 older forests with core patches < 0.25 ha and an additional 603,052 < 1.0 ha. There were 52 > 10,00–50,000 ha and 8 < 50,000 ha. Older forest patches (critical caribou habitat) in the 21 local population ranges totalled 6,103,534 ha, distributed among ~387,102 patches with 362,933 < 10 ha and 14 > 50,000 ha. The median percentage of local population ranges that was disturbed was 53.5%, with Charlevoix having the maximum (90.3%) and Basse Côte-Nord the least (34.9%). Woodland caribou local population ranges with disturbed suitable habitats >35% are considered unable to support self-sustaining populations. We found that for the 21 caribou local population ranges examined, 3 were at very high risk (>75% area disturbed), 16 at high risk (>45 ≤ 75% area disturbed), and 2 at low risk (≤35% area disturbed). Major changes are needed in boreal forest management in Ontario and Quebec for it to be ecologically sustainable, including a greater emphasis on protection and restoration for older forests, and to lower the risks for caribou populations. Full article

The article aims to describe the patterns of changes in the number of vascular plant species in communities at different stages of forest regeneration after clearcutting using the space-for-time substitution method. Large-scale logging in boreal forests leads to a simplification of the territory’s forest cover (the formation of even-aged stands), which in turn leads to a decrease in the diversity of forest communities and species diversity. These tendencies have been confirmed for many groups of organisms, especially those associated with old trees and dead wood; however, this is not so clear for vascular plants. We investigated plant communities at different stages of regeneration. We used the so-called space-for-time substitution (chronosequence) method of building dynamic series for four forest ecotopes, where industrial clearcuts are most actively carried out. We showed that the fertility of forest ecotopes determines the species pool—the richer the conditions, the more species that can potentially inhabit the community. At the same time, the structure of the tree stand significantly affects the composition and number of species in the community. The lowest species richness was in old-growth forests characterized by the dominance of one species in the tree stand and one or two vascular plant species in the ground cover. With insignificant fluctuations in the average number of species between stages of forest regeneration after logging, some communities at clearcuts in bilberry (Vaccinium myrtillus L.) pine (Pinus sylvestris L.) and spruce (Picea abies (L.) H.Karst.) forests have high species diversity due to the occupation of the site by species of open habitats. These clearcuts are located not far from settlements and close to roads. Full article

The logging of mature tree stands, where part of the forest is clear-cut, results in the formation of an ecotone complex (EC) consisting of the forest (F), a transition from forest to a clear-cut site under canopy cover (forest edge—FE), a transition from forest to a clear-cut site outside of canopy cover (clear-cutting edge—CE), and the clear-cut site per se (C). Ground vegetation descriptions (percentage cover of dominants and height of subshrubs) were carried out on the sampling subplots along the transects running from spruce forest into the clear-cut site. We studied the effects of the time since logging and some microhabitat factors (aspect, coniferous and deciduous regeneration, downed deadwood, microrelief, and the abundance of subshrubs, grasses, and forbs) on the abundance of the main ground vegetation dominants of the bilberry-type spruce stands and the clear-cut sites: Vaccinium myrtillus, V. vitis-idaea, Deschampsia flexuosa, and Epilobium angustifolium, in different EC zones. The factor found to have the greatest modifying effect on the abundance of all the species in the CE and C zones was the time since clear-cutting. The clear-cutting pioneer species Deschampsia flexuosa and Epilobium angustifolium preferred open areas in the clear-cut site, whereas the abundance of V. myrtillus and V. vitis-idaea positively correlated with the amount of coniferous and deciduous regeneration. Some factors (downed deadwood, microrelief, coniferous regeneration) were found to act similarly on subshrubs both under the tree canopy (F and FE) and in clear-cut microhabitats (CE and C). The shoot height of subshrubs as well as its percentage cover varied depending on the time since clear-cutting and the microhabitat conditions. Full article

In Brazil, logging in the Seasonally Dry Tropical Forest (SDTF) under management plans that include clear-cutting has increased in recent decades, and the structure, composition, diversity and functioning of the forest likely must have been affected. The aim of this study was to understand the growth dynamics of shrub–tree biomass (STB), species richness and vegetation structure as a function of regeneration time after clear-cutting (treatments), taking the Legal Reserve (40 years of regeneration) as reference. The study was carried out in 2018 at the Ramalhete Settlement, General Sampaio, in the state of Ceará. All plants with a circumference at breast height (CBH) ≥ 6 cm were identified and the CBH was measured across 42 sample plots (20.0 m × 20.0 m), using seven plots per treatment (3, 5, 8, 11 and 15 years after clear-cutting, and the Legal Reserve, 40 years of regeneration). The following were determined: STB (total and by species), density and basal area (by ecological group and diameter class), basal area (species of higher added value), diversity (Hill numbers), and the importance value index (IVI). It was found that during the early years (up to at least 11 years), many important forest characteristics related to the composition of the ecological groups and vegetation structure were strongly affected, and major impacts can be seen, the effects of which, however, decreased over time of regeneration, having almost no effect after 15 years. After 15 years following clear-cutting, the SDTF presented accumulated STB, species richness and structure similar to the area undergoing regeneration for 40 years. However, the small number of indicator species of more-preserved areas (even at T15 and T40) points out that management needs to be improved. However, promoting species of greater added value and determining whether the forest recovers its structure and diversity after successive cutting cycles also still need to be addressed. Full article

The future development of forest industries in Russia, besides the country’s geopolitical issues, could be seriously undermined by the depletion of forest resources available under the current model of forest management that mainly relies on clearcutting mature coniferous forests and leaving these areas for natural regeneration. The introduction of a new model that prioritizes efficient forest regeneration faces many problems on the ground. The efficiency of the use of funds allocated by both governmental and private logging companies for forest regeneration and subsequent tending of young stands should urgently be significantly increased. The government should also develop pragmatic economic incentives to encourage logging concession holders to switch to the new model and to address the problem of the spatial shift (demarginalization) of the country’s forest complex from northern and eastern “green fields” to secondary mixed and southern taiga forests. Instead of harvesting low-productivity northern taiga forests of European Russia and remote areas of Central and Eastern Siberia, wood sourcing should be mainly concentrated in the immediate vicinity of existing mills. Moreover, the development of “greenfield” projects in wilderness forest areas that currently lack any kind of infrastructure should not be encouraged. The focus on the regions with productive southern taiga, mixed and broadleaf forests, developed wood-processing infrastructure, and high forest roads density could ensure the economically beneficial transition towards resilient forestry. Full article

The contribution of the forest sector to climate change mitigation needs to rely on optimal strategies that include forest management, wood supply, wood product disposal, and replacement of GHG-intensive materials and energy sources. Our study aimed to assess the impact of alternative forest management practices applied at the stand scale on the capacity of the forest sector to reduce its radiative forcing, using the boreal forests of eastern Canada as a case study. We simulated management of a balsam fir–white birch stand over a sixty-year period and determined the sectorial carbon and radiative forcing budget for a reference scenario (no harvest) and for nineteen clearcut and partial cut alternatives. The results suggest that logging may not significantly reduce carbon emissions compared to a preservation practice and does not yield any climate benefits in terms of radiative forcing. In a context for which the substitution effect of wood products on markets is expected to be limited, the mitigation potential of a scenario is mostly driven by the capacity of the forest ecosystem carbon sink to compensate for the substantial CO${}_2$ and CH${}_4$ emissions from wood product decay in landfills. The improved assessment of carbon emission temporality, incorporation of ecosystem carbon dynamics, and improved consideration of substitution and the decay of wood products are essential in the development of any forest management strategy. Neglecting these elements can lead to misconceptions and prevent informed mitigation decisions. Full article

Leaf traits reflect the ecological strategy in heterogeneous contexts and are widely used to explore the adaption of plant species to environmental change. However, the knowledge of short-term effect of canopy management on understorey plant leaf traits is still limited. Here, we studied the short-term effect of crown–thinning on the leaf morphological traits of bamboo (Chimonobambusa opienensis), an important understorey plant and staple food for the giant panda (Ailuropoda melanoleuca) of Niba Mountain. Our treatments were two crown–thinnings (spruce plantation, CS, and deciduous broad-leaved forest, CB) and two controls (broad-leaved forest canopy, FC, and the bamboo grove of clearcutting, BC). The results showed that: the CS enhanced the annual leaf length, width, area, and thickness, CB decreased almost all annual leaf traits, and perennial leaf traits in CS and CB were the opposite. The log-transformed allometric relationships of length vs. width, biomass vs. area were significantly positive while those of specific leaf area vs. thickness were significantly negative, which varied largely in treatments and age. The leaf traits and allometric relationships suggested that the CS created a more suitable habitat for bamboo growth. This study highlighted that the understorey bamboo leaf traits could adapt the improved light environment induced by crown–thinning rapidly. Full article

Reforestation with native and non-native tree species is one of the most effective strategies to cope with climate change, and is also the most effective management method for solving soil erosion problems in degraded forests around the world. The current research investigates three skid trails, which were planted with three species in the clearcutting areas, in comparison with a natural forest of hornbeam (CB; Carpinus betulus L.) and velvet maple (AV; Acer velutinum Boiss.) and degraded land without trees (DL), as well as evaluates the recovery of soil characteristics in the skid trails in response to the planting of native species, including black alder (Alnus glutinosa (L.) Gaertn.), and non-native species, including eastern cottonwood (Populus deltoides L.) and Italian cypress (Cupressus sempervirens L. var. horizontalis (Mill.) Gord.) in a mid-term period of 25 years, in the Hyrcanian forests in northern Iran. Significantly higher litter nitrogen (N), phosphorus (P), and potassium (K) were detected in the plantation of black alder (AG), whereas the lowest values were measured under the DL treatment. Soil physio-chemical properties significantly differed among treatments, except silt content. Among the soil chemical properties, N storage and available nutrients of P and K under the black alder plantation were fully restored as compared to the value observed at the hornbeam and velvet maple (CB-AV) stand over a 25-year period after soil disturbance and planting. Over a 25-year period after logging operations, soil biological and microbial properties of carbon and nitrogen, and enzyme activity in the black alder plantation were partially recovered, but these values have not returned to pre-harvest level at the CB-AV treatment as control. Overall, these results suggested that black alder had greater positive effects on the recovery of soil properties than other trees due to the faster litter decomposition as a N-fixing species, and its labile substrate with low organic C and high N concentration. Therefore, black alder reforestation should be increase in future ecosystem restoration in the area influenced by logging operations. Full article

Inappropriate forest management activities, above all clear-cutting, are recognized as the major threats to an iconic orchid species—the lady’s slipper orchid (Cypripedium calceolus), the flagship species of nature protection in Europe. Although clear-cutting in protected species’ localities is strongly regulated in many European countries, salvage logging is allowed in some circumstances (e.g., following windstorms, and insect outbreaks) and can threaten C. calceolus populations. In this paper, we review a database of recently registered populations of this species in the Czech Republic and study historical maps, to better understand the history of local habitat conditions and assess threats to C. calceolus populations by bark beetle outbreaks. We found that about one-third of the C. calceolus populations have suffered in coniferous or mixed tree plantations with a high proportion of spruce trees, which are forests with a high risk of bark beetle infestation. We review bark beetle management measures and distinguish management efforts in areas with known C. calceolus populations that result in no damage to the population and, at times, improve habitat conditions for the species. Thus, the bark beetle—usually understood as the enemy—can be transformed into a savior if smart management measures will replace the panic salvage logging. Full article

The vast Angara region, with an area of 13.8 million ha, is located in the southern taiga of central Siberia, Russia. This is one of the most disturbed regions by both fire and logging in northern Asia. We have developed surface and ground fuel-load maps by integrating satellite and ground-based data with respect to the forest-growing conditions and the disturbance of the territory by anthropogenic and natural factors (fires and logging). We found that from 2001 to 2020, fuel loads increased by 8% in the study region, mainly due to a large amount of down woody debris at clearcuts and burned sites. The expansion of the disturbed areas in the Angara region resulted in an increase in natural fire hazards in spring and summer. Annual carbon emissions from fires varied from 0.06 to 6.18 Mt, with summer emissions accounting for more than 95% in extreme fire years and 31–68% in the years of low fire activity. While the trend in the increase in annual carbon emissions from fires is not statistically significant due to its high interannual variability and a large disturbance of the study area, there are significantly increasing trends in mean carbon emissions from fires per unit area (p < 0.005) and decadal means (p < 0.1). In addition, we found significant trends in the increase in emissions released by severe fires (p < 0.005) and by fires in wetter, dark, coniferous (spruce, p < 0.005 and Siberian pine, p < 0.025) forests. This indicates deeper burning and loss of legacy carbon that impacts on the carbon cycle resulting in climate feedback. Full article

Monitoring changes in tree cover for assessment of deforestation is a premise for policies to reduce carbon emission in the tropics. Here, a U-net deep learning model was used to map monthly tropical tree cover in the Brazilian state of Mato Grosso between 2015 and 2021 using 5 m spatial resolution Planet NICFI satellite images. The accuracy of the tree cover model was extremely high, with an F1-score >0.98, further confirmed by an independent LiDAR validation showing that 95% of tree cover pixels had a height >5 m while 98% of non-tree cover pixels had a height <5 m. The biannual map of deforestation was then built from the monthly tree cover map. The deforestation map showed relatively consistent agreement with the official deforestation map from Brazil (67.2%) but deviated significantly from Global Forest Change (GFC)’s year of forest loss, showing that our product is closest to the product made by visual interpretation. Finally, we estimated that 14.8% of Mato Grosso’s total area had undergone clear-cut logging between 2015 and 2021, and that deforestation was increasing, with December 2021, the last date, being the highest. High-resolution imagery from Planet NICFI in conjunction with deep learning techniques can significantly improve the mapping of deforestation extent in tropical regions. Full article