Search Results (282)

Integrated crop–livestock systems (ICLS) that couple crop production, cover crops, and grazing present a promising strategy for soil organic carbon (SOC) sequestration. Long-term assessments of SOC change under ICLS management are limited. This study quantified SOC stocks from management systems typical of the warm, humid southern Midwest, USA, including conventional continuous cereal crop production, permanent pasture, hardwood forest, and decadal-scale ICLS management. The ICLS consisted of no-till production of corn silage with a winter ryegrass cover crop grazed by cattle. We hypothesized greater SOC stocks in the ICLS relative to conventional management, with the greatest increase in surface horizons. Soil cores were collected to a depth of 120 cm, subset into 0–30 cm, 30–60 cm, and 60–120 cm sections, and analyzed for SOC, particulate, and mineral-associated organic matter. Results demonstrated that after 15 years, ICLS SOC stocks were significantly greater than conventionally managed fields and comparable to those of permanent pasture and hardwood forest. The SOC differences were predominantly in the upper 30 cm. Using a space-for-time approach, we calculated an average annual SOC accrual rate of 1.3 Mg C ha⁻¹ yr⁻¹, similar to estimated sequestration rates from biogeochemical model simulations. The majority of additional SOC was allocated to particulate organic matter. Significantly greater mineral-associated organic carbon was also observed. Stable carbon isotope data indicated the ryegrass cover crop was likely the primary source of additional SOC in the ICLS. These findings demonstrate the potential of ICLS to increase SOC and enhance soil health over decadal timescales. Full article

The concepts of anthromes and human appropriation of net primary production (HANPP) are both valuable in understanding our human-dominated planet, yet they have never been integrated theoretically or empirically. Here we utilize an extensive county-level dataset on HANPP and its product-level components to derive, through cluster analysis, ten contemporary US anthromes. From highest to lowest density of harvested HANPP, the anthromes are: rainfed corn–soy, dairy fodder, spring wheat–small grain, dryland winter wheat, subtropical soy–cotton, commercial timber, mixed hardwood and pasture, recovered eastern forest, prairie–sagebrush rangeland, and arid and alpine sparse grazing. Expanding to thirteen anthromes maintains these, while bifurcating the commercial timber (softwood, hardwood), rainfed corn–soy (core, fringe) and mixed hardwood and pasture anthromes. Trend analysis shows the expansion of the high-HANPP rainfed corn–soy and the low-HANPP recovered eastern forest anthromes between 2002 and 2017, while some other anthromes with moderate HANNP_harvest are contracting. The methods described here can be applied to any country where data on HANPP can be obtained. Full article

As the global climate change mitigation efforts urge the transition towards a green economy, comprehending the carbon footprint of forest industry supply chain is crucial to ensure sustainable management and utilization of renewable resources. This research quantified the carbon footprint of four different forest product industries: chip mill, hardwood sawmill, softwood sawmill, and in-woods chipping in the Northeastern U.S. Additionally, the impact of transportation (road and rail) on carbon footprint was analyzed. Life cycle assessment (LCA) was performed using SimaPro 9.3.0.3 software and allied databases (USLCI and US-EI). The functional unit was 1 tonne for chip mill (wood chips) and 1 m³ for sawmill (planks). The highest-contributing inputs for the chip mill and softwood sawmill were transportation. However, in-woods chipping and the hardwood sawmill had raw materials, residual wood, and round wood as the highest-contributing input. The study also enumerated the substances that contributed most to environmental impacts. The carbon footprint of chip mill, in-woods chipping, hardwood, and softwood sawmill were 49.5, 21.7, 72.9, and 73.7 kg CO₂ eq per respective functional units, respectively. The results could assist the forest industry in promoting wood feedstock with a minimal carbon footprint and have educated engagement in an ever-evolving carbon market. Full article

Timber sale prices are influenced by multiple tract, product, and transaction characteristics. This study evaluates the effects of species composition, product class, sale method, harvest type, timber quality, and average tree diameter on timber stumpage prices using timber sale records from Alabama between 1 January 2010 and 31 December 2019. Prices were modeled on a per weight unit basis using a generalized linear model with a Gamma distribution and logarithmic link. Results indicate that larger average diameters were consistently associated with higher prices across most product classes. Harvest type also influenced prices, with salvage operations yielding prices approximately 8.3% lower than thinning operations. Timber quality had a moderate effect: good-to-excellent quality timber sold for about 4.8% higher prices than poor-to-fair quality timber. Sale method was an important determinant of price outcomes. Negotiated sales generated significantly lower prices than sealed-bid sales, averaging approximately 17% lower overall. However, interaction analysis revealed that negotiated sales produced higher prices for mixed hardwood sawtimber, likely reflecting the diverse end uses of these products. Regional effects were also evident, with higher prices observed in the southwestern portion of the state, likely due to proximity to the Port of Mobile and associated export markets. These findings highlight the importance of both tract and transaction characteristics in determining timber prices and provide guidance for landowners and forest managers when selecting sale strategies and management practices. Full article

Patterns of resource selection are driven by the decision-making processes of animals occurring at multiple scales from where to establish a home range (i.e., second order selection) to which resource patches to use within the home range (i.e., third order selection). Elk (Cervus canadensis) were reintroduced to southwestern Virginia, USA, from 2012 to 2014 following successful translocations onto reclaimed surface coal mines in the region. We sought to understand how elk have acclimated following their translocation using location data from GPS-collared adult female elk (n = 33) collected from 2019 to 2022 along with remotely sensed terrain and land cover data. We utilized continuous-time movement models paired with generalized linear mixed-effects modeling to describe seasonal resource selection at second and third orders. At both scales of selection and throughout the year, female elk selected reclaimed surface mines, conifer forests, ridgetops, and areas with lower terrain roughness, while avoiding mixed hardwood and oak (Quercus spp.) forests. Unmined open land was only selected at the third order during periods of forage scarcity (i.e., winter) and increased metabolic requirements (i.e., late gestation). Although surface coal mining leaves legacy environmental impacts on the landscape, management of these sites provides benefits to elk and maintains open habitat that is otherwise limited. Full article

Sustainable forest management requires current, territory-wide data, which is difficult to obtain in vast regions like Quebec, Canada. To complement ground inventories and photo-interpretation, the province developed an airborne laser scanning (ALS)-based model that performs well in coniferous stands, but its accuracy in hardwood stands remains untested. This study aims to evaluate the accuracy of the ALS-based prediction of stand basal area and then test new approaches to increase its performance. Airborne LiDAR data from 2011 to 2020 and 12,506 validation plots from sample plots were used. The ALS model accuracy was initially compared across the stand types, revealing lower accuracy in shade-tolerant deciduous stands. Three inputs were found to increase prediction accuracy: proportion of each species basal area in the stand, geographical coordinates, and meteorological data associated with location. Parametric and auto machine learning (AutoML) methods were employed using those inputs to improve accuracy, with AutoML achieving the highest improvement with initial R² of 0.27, 0.47 and 0.54 and after correction R² of 0.31, 0.56 and 0.67, respectively, for shade-tolerant deciduous, shade-intolerant deciduous, and coniferous stand. Even with the advancements made, further improvements will be necessary to consider using an ALS-based model for shade-tolerant deciduous species. Full article

Past restoration of hardwood forests prioritized planting of woody vegetation cover, particularly oaks (Quercus spp.). This restoration regime often did not consider other microhabitat components, which failed to restore habitat complexity. Giant cane (Arundinaria gigantea (Walter) Muhl.) was an important microhabitat feature for creating a dense understory structure within the hardwood forest landscape. Many bird species are associated with stands of giant cane (canebrakes) for food, cover, and nesting ground. The decline of canebrakes may reduce nesting and foraging habitat, negatively impacting bird communities. Here, we used a hierarchical multi-species occupancy model to assess how giant cane and its associated overstory forest structure influenced breeding bird occupancy in southern Illinois. Bird surveys were conducted from May to July 2022–2024 at 100 site-years using passive acoustic monitoring. Responses to the vegetation structure (tree density and size) and canebrakes varied among species and nesting guilds (overstory, understory, and ground). Occurrence probabilities of 54% of the bird species increased with the presence of canebrake. We did not find any significant relationships between bird occupancy and vegetation structure and canebrake characteristics. Overall, maintaining a hardwood forest stand with a heterogeneous canopy cover would create variations in light environments, allowing canebrakes to benefit bird species across nesting guilds. Full article

Persistent cloud cover and frequent rainfall in subtropical regions throughout the year significantly limit the applicability of optical remote sensing for tree species identification, thereby constraining dynamic forest monitoring and precise management of forest resources. To address this challenge, this study proposes a tree species identification method that integrates multi-source remote sensing temporal features. By combining multi-temporal optical imagery from Sentinel-2 and dual-polarisation Synthetic Aperture Radar (SAR) data from Sentinel-1, we constructed a comprehensive feature set that incorporates spectral, structural, and phenological attributes, including various vegetation indices, backscatter coefficients, and polarimetric decomposition parameters. Through correlation analysis and assessment of temporal feature variability, five distinct integration strategies (T1-T5) were developed to classify six typical subtropical tree species: Pinus massoniana, Pinus elliottii, Acacia, Eucalyptus grandis, Mangrove, and Other hardwoods, using a random forest classifier. The results indicate that the multi-source feature fusion approach significantly outperforms single-source models, with the T5 strategy achieving the highest overall accuracy (OA) of 95.33% and a Kappa coefficient of 0.94. The red-edge vegetation indices and SAR polarimetric features were identified as major contributors to improving the classification accuracy of hardwood species. This study demonstrates that multi-source remote sensing data fusion can effectively mitigate the spatiotemporal constraints of optical imagery, providing a viable solution and technical framework for high-accuracy remote sensing classification in complex subtropical forest environments. Full article

We conducted a long-term assessment of how natural free-water surface (FWS) wetlands respond to sustained loads of partially treated municipal effluent. We quantified the effects on vegetative cover, ammonium concentration, and fecal coliform bacteria densities and compared them to constructed wetlands with hydrologically defined flows. Variations in the area of open water and floating vegetation converted from emergent marsh, shrub or bottomland hardwood forest (0 to 124.6 ha) were directly proportional to the nitrogen loading at all eight sites (range 5.4 to 24.6 thousand Kg N yr⁻¹). Trees exposed to effluent at five locations sometimes died in the first year, or they took decades to die. At the one location with fecal coliform data, their densities were directly related to ammonium concentrations, which were within the concentration range of untreated municipal sewage water. Ammonium levels exceeded US EPA chronic toxicity standards at three locations and aquatic toxicity levels developed by independent scientists at all eight locations. The loss of organic peat and habitat has multiple consequential effects that may be quick to happen or subtle, and be slow to restore, if at all. Compared to constructed wetland treatment systems, FWS systems are more difficult to constrain, have much reduced predictabilities and bring unwelcome consequences. Full article

Many native mammal species rely on the habitat elements provided by old-growth forests in the eastern United States (U.S.). Today, old-growth forests persist as remnant stands in the landscape. Historically, they included a mosaic of eastern forest types including mixed mesophytic, oak–hickory, southeastern evergreen, and hemlock-white pine-northern hardwood forests. Due to the rapid (<250 years) and almost complete (99% loss) removal of old-growth forests from eastern U.S. landscapes, research regarding the current and historic relationship between native mammals and old-growth forests is lacking. Using comparisons with better-studied old-growth forests in the western U.S., historical accounts of mammal distribution, and the habitat elements of eastern old-growth forest types, we aim to describe the mammals currently and historically supported by these rare forests in this scoping review. Full article

Artificial hybrid pine (Pinus × rigitaeda) plantations, widely established in Northeast Asia for reforestation and timber production, have reached maturity, necessitating an evaluation of their ecological sustainability and successional dynamics. Although numerous studies have examined succession in pure Pinus rigida or Pinus densiflora stands, the long-term structural transition and regeneration potential of hybrid P. × rigitaeda plantations remain poorly understood. This study quantitatively assessed the successional stage and potential transition pathways of P. × rigitaeda stands using an integrated analytical framework combining vegetation classification (TWINSPAN), ordination (NMDS), successional index, survival analysis (Weibull model), and growth–environment modeling (GAM). Multi-layer vegetation data were analyzed to evaluate compositional changes, structural attributes, and nonlinear environmental responses. The results revealed that the dominance of P. × rigitaeda declined markedly while native deciduous species increased in lower strata. The Weibull survival model (k = 1.3) indicated accelerating mortality with stand aging, and the successional index showed the highest value (0.4) for Castanea crenata, followed by other Quercus species, confirming an ongoing shift toward hardwood dominance. GAM analysis confirmed that growth stability was influenced by stand age and precipitation. These findings demonstrate that P. × rigitaeda plantations are not merely artificial production forests but function as self-organizing systems facilitating natural forest recovery. In this respect, the hybrid pine plantation can be interpreted as a spontaneous ecological experiment, highlighting the restoration value of artificial hybrids as transitional stages bridging artificial afforestation and natural forest succession in temperate monsoon regions. Full article

Background/Objectives: Land management practices strongly influence soil biochemical processes, yet conventional soil measurements often overlook dynamic small-molecule variation underlying nutrient cycling and microbial activity. This study aimed to evaluate whether MS¹-based untargeted metabolomics can resolve meaningful biochemical differences among soil systems under distinct land management practices. Methods: Soils from six land-use types—conventional cultivation, organic cultivation, pasture, white pine, tulip poplar, and hardwood forest—were analyzed using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS). Multivariate analyses, including PLS-DA, were performed to evaluate metabolic variation across systems. Both identified metabolites and unknown spectral features (MSI Level 4) were assessed, and biosynthetic class assignment of unknown features was performed using NPClassifier. Results: Metabolic features revealed clear separation between land management systems, demonstrating distinct chemical fingerprints across ecosystems. While conventional elemental ratios (e.g., C/N) showed minimal differentiation, phosphorus-related stoichiometric ratios (C/P and N/P) displayed strong land-use-dependent differences. NPClassifier superclasses highlighted unique chemical patterns, with forest soils enriched in diverse secondary metabolites, cultivated soils characterized by simplified profiles, and pasture soils dominated by microbial membrane lipids and alkaloids. Conclusions: Untargeted MS¹-based metabolomics effectively distinguished soil systems under different land-use practices and revealed ecologically meaningful variation even without complete structural identification. This study demonstrates that an MS¹-only workflow leveraging unknown spectral features can robustly distinguish soil systems, underscoring their value in untargeted metabolomics analyses. Full article

There is a widespread belief that koala conservation measures should be focused on ending forestry operations in native forests and that plantations should be the alternative source for timber. While advocates for conservation continue to promote this strategic approach, they overlook the fact that hardwood plantations also provide important habitats. Ongoing operations in both natural and planted forests continue to threaten the viability of the koala species, and populations in one of the koala’s core habitats in northern New South Wales (NSW) continue to decline. To improve conservation outcomes for this species in the wild, the Great Koala National Park (GKNP) has been proposed. While the process of establishing this park continues, ongoing forestry operations exert continuous pressure on koalas and their habitat within the proposed area of the park. This paper investigates how community stakeholders are collaborating with scientists to identify areas of high koala habitat value within the hardwood eucalypt plantations inside the proposed GKNP that are currently excluded from conservation and will be subject to ongoing timber extraction. Investigations of Tuckers Nob State Forest, which is inside the proposal area, confirmed the presence of both koalas and original forest inside the plantations which were excluded from conservation by the state government. Original trees and remnants were identified using historical aerial photography, which were orthorectified and matched against current NSW government imagery (SIX Maps); composite mosaics of photographic sheets and closeups (Quantum GIS) were imported into Google Earth Pro. Koala drone surveys, habitat ground-truthing, and on-ground scat and koala surveys of 120 ha involving various community stakeholders were conducted in December 2024 and revealed 25 koalas records, necessitating the reclassification of this area from plantation to prime koala habitat. Here, as in many other plantations in NSW, the findings of this study indicate significant numbers of original trees that are part of highly diverse nutrient-rich sites attractive to koalas. This leads to the conclusion that the exclusion of specific areas of the proposed park from conservation to allow for ongoing logging is inconsistent with recognized koala protection strategies. Hence, koala protection strategies need to consider the integrity of the reserve system in its entirety, and the whole area of the GKNP should be accorded the requisite status of a World Heritage Site. Full article

Northern hardwood forests of the Lake Superior region face a series of novel disturbance pressures including canopy dieback. Previous studies have linked regional sugar-maple (Acer saccharum) canopy dieback to introduced earthworms, which may have coinciding impacts on the ground-layer plant community. Dieback–earthworm interactions may lead to important longer-term changes in forest structure and function, but these relationships but have not been characterized. We sampled ground-layer plant communities in five national forest units in Michigan, Wisconsin, and Minnesota in 2010, and again just over a decade later in 2021. Non-metric multidimensional scaling ordination and indicator species analysis were used to assess relationships among ground-layer community composition and structure, functional traits, and environmental gradients including forest-floor condition and A. saccharum canopy dieback. Increases in dieback and earthworm disturbance in the decade between inventories were accompanied by a marked divergence in observed ground-layer plant community structure between national forests. Ordinations of 2021 data indicated a strengthening relationship between forest-floor condition and earthworm abundance. Our results suggest that earthworm impacts and A. saccharum dieback are driving changes in the ground layer on broad geographic and temporal scales, with short- and long-term implications for plant-community structure and function, and higher trophic levels. Full article

Commercial forest plantations (CFPs) provide timber and ecosystem services, particularly carbon (C) sequestration, but the performance of native tropical hardwoods in pure versus mixed systems is still poorly understood. We evaluated growth, productivity, biomass, and C storage in 17-year-old plantations of Tabebuia rosea, T. donnell-smithii, and Swietenia humilis in western Mexico. Four plantation systems were assessed: pure T. rosea (PPT1), pure T. donnell-smithii (PPT2), mixed T. rosea + T. donnell-smithii (MPT1T2), and mixed T. donnell-smithii + S. humilis (MPT2S). Tree structure (DBH, height, basal area, volume), litter layer, and soils (0–15 cm) were measured. Thirty trees per species were destructively sampled to develop species-specific biometric models. Model performance was evaluated with adjusted R², RMSE, and residual analysis. PPT1 was the most productive system (39.8 m³ ha⁻¹; 55 Mg C ha⁻¹), while PPT2 had the lowest values (20.5 m³ ha⁻¹; 45.1 Mg C ha⁻¹). MPT1T2 increased basal area (+29.8% vs. PPT1) and litter layer C (3.3 Mg C ha⁻¹; +190% vs. PPT2) but did not surpass PPT1 in standing volume. Soil C was highest in PPT1 (36.5 Mg C ha⁻¹). Biometric models achieved high accuracy (R² = 0.91–0.99), confirming DBH as a reliable predictor of biomass and C. We conclude that pure T. rosea maximizes short-term productivity and soil C, whereas mixed systems diversify C allocation by enhancing litter layer pools. These findings highlight the complementary roles of pure and mixed CFPs and provide reliable models for C accounting in tropical hardwood plantations. Full article