In this study, magnetic Fe3O4 adsorbent was synthesized and functionalized with mesoporous silica-chitosan to create a multifunctional Fe3O4@mSiO2@Chitosan for the removal of heavy metal ions from aqueous solution through adsorption. Box-Behnken Design, an RSM tool, was used to create an experimental design for adsorption trials with 3 independent variables: pH of the solution, contact time, and concentration of metal ions. The mesoporous SiO2 shell, with a negative zeta potential of -42.2 mV, prevents aggregation and maintains a high surface area. Chitosan functionalization adds -NH2 and -OH groups to the adsorbent surface, providing strong chelation sites for Pb2+ and Cd2+. The positive zeta potential (+28.1 mV) of the chitosan coating enhances electrostatic attraction to partially hydrolyzed metal species. The optimized adsorption design for Fe3O4@mSiO2@Chitosan achieved 96% removal efficiency for Cd(II) and 95% removal efficiency for Pb(II). An isotherm study confirmed that the adsorption data were best described by the Langmuir isotherm model with R2 values ranging from 0.95 to 0.98. A shift from monolayer to multilayer adsorption was observed after functionalization of Fe3O4 with @mSiO2@Chitosan. An inert layer on silica-stabilized nanoparticles prevents their leaching and aggregation. The Fe3O4@mSiO2@chitosan adsorbent showed a 30% increase in adsorption capacity compared to pristine Fe3O4.

Pyrene accumulates in soil from a variety of sources, infiltrating the food chain and causing mutagenic and carcinogenic disorders in humans. Pyrene has since been effectively removed from soil using a variety of chemical and physical remediation techniques, but these approaches have a number of disadvantages, including being costly, time-consuming, labor-intensive, and producing secondary environmental pollutants. Therefore, this work employed an environmentally friendly and sustainable biological approach that utilized enzyme immobilization on biochar. Wheat straw biochar prepared by pyrolysis, followed by acid activation, and then laccase was immobilized on biochar using the cross-linked adsorption technique. Results showed that immobilized enzyme retained over 50% of enzyme activity at pH 3-7, 20-60 °C, and maintained over 50% relative activity after five cycles and 50 days of storage. Pyrene remediation reached 80.33% after 50 days of incubation while quadratic model indicated the remediation efficiency will increase over time, reaching 53.56%. Soil phenol oxidase, peroxidase, and dehydrogenase activities increased by 105.2-107.1%, 155.1-167.2%, and 104.8-157% respectively compared to control. Firmicutes, Actinobacteria, and Proteobacteria were the dominant phyla, while Bacillus, Lysinibacillus, Sedimentibacter, Brevundimonas, Christensenellaceae_R-7_group, Sphingobium, and Stenotrophomonas were the most abundant genera in immobilized enzyme treatments. These microbes involved in the degradation of pyrene and various organic contaminants in the soil. Thus, it may be concluded that laccase immobilization on wheat straw biochar is a green and sustainable method for pyrene remediation in soil, as well as suitable for agricultural and industrial applications.

Introduction Denitrification is an elusive process that remains notoriously difficult to measure under field conditions, yet it plays a crucial role as the only natural terrestrial sink for reactive nitrogen, especially in agricultural systems where large amounts of fertilizer are applied. Direct measurements of N2 fluxes over extended periods remain rare in the literature due to technical challenges.Methods In this study, we quantified and characterized denitrification emissions under two contrasting land-use practices-conventional and regenerative (unfertilized) agriculture-using a recently developed custom method combining a 15N isotopic tracer with an artificial atmosphere (improved 15N Gas Flux method). We conducted nine field campaigns over one year to (i) assess method applicability, (ii) derive a first annual estimate of denitrification, (iii) understand controls on denitrification dynamics, and (iv) trace denitrification-driven losses of applied synthetic nitrogen fertilizer in conventional agriculture.Results Our method successfully detected denitrified N2 fluxes in 90% of measurements and yielded annual budgets of 22.12 and 2.41 kg N ha-1 yr-1 in the conventional and regenerative fields, respectively. Soil moisture and nitrate availability (particularly under fertilized conditions) were the main controls on the denitrification product ratio (N2O/(N2O + N2)). We estimated that 11% of applied fertilizer nitrogen was lost via denitrification in the conventional field, with 7.3% of this loss emitted as N2O rather than N2.Discussion These results underscore the role of fertilization management in shaping denitrification dynamics and its potential to act as a sink for reactive nitrogen, while modulating N2O emissions.

We synthesized SrO2(aq) and SrO2(et) nanoparticles (NPs) by treating strontium nitrate with aqueous and ethanolic extracts of Moringa oleifera leaves, respectively. This reaction was also performed in the presence of graphene oxide (GO) to produce SrCO3@GO(aq) and SrCO3@GO(et) nanocomposites (NCs), respectively. The nanomaterials (NMs) were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). FTIR spectroscopy confirmed the characteristic Sr-O vibrations, along with additional absorption bands arising from GO and phytochemical-derived organic moieties capping the nanoparticle surfaces. The synthesized NMs exhibited crystallite sizes ranging from 2 to 45 nm, particle sizes from 34 to 271 nm, and band gaps between 4.48 and 5.63 eV. EDX analysis verified the presence of Sr, O, and C, confirming their spatial distribution. TGA-DSC analysis confirmed distinct thermal stability profiles for all materials, with SrCO3@GO(et) exhibiting the highest mass loss and enthalpy. The synthesized nanoproducts were evaluated for electrochemical performance using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD), confirming their suitability as supercapacitor electrodes. The outstanding electrochemical performance of SrCO3@GO(et) (specific capacitance, 292.59 F g-1 at 1 mA) arises from the synergistic effects of M. oleifera ethanolic extract-derived phytochemicals, effective GO decoration, reduced crystallite and particle sizes, and the development of a porous, flower-like nanostructure. Collectively, these features position SrCO3@GO(et) as a highly promising electrode material for next-generation high-performance energy storage devices.

Phosphorus (P) can restrict the capacity of forests to store additional carbon (C) with increasing carbon dioxide (CO2) concentration. Although P limitation is widespread, P addition experiments in mature forests are rare, leaving large uncertainties about whether alleviating P limitation under elevated CO2 (eCO2) will enhance C storage or instead shift limitation toward nitrogen (N). Here, we used a parallel P-fertilization x eCO2 manipulation in a mature forest to investigate the acute nutrient cycling response to P fertilization under eCO2 with a particular focus on N cycling. In April 2023, a mature P-limited Eucalyptus Forest at the Euc-Free Air CO2 Enrichment (Euc-FACE) experiment in Australia, was fertilized with 1.5 g P m-2 following 10 years of CO2 enrichment. We measured soil gross N mineralization and compound-specific depolymerization rates – offering novel insights into microbial metabolic pathways – alongside extracellular enzymatic activities, and nutrient pools in the top 10 cm of soil before P addition, 10 days and two months afterwards. We found that P addition decreased extracellular soil enzymatic activities associated with C-N-P-mining (─ 50%), increased microbial NH4+ retention (immobilization: mineralization ratio; + 23%) and microbial C use efficiency (CUE; + 12%), causing a reduction in plant-available N (─ 30%) independently from eCO2. Under eCO2, P addition stimulated protein depolymerization and C-P enzyme activities. Compound specific analyses revealed increased microbial biosynthesis with P addition via the assimilation of key amino acids such as alanine, glycine and glutamate. These findings indicate that P limitation constrains microbial C-N cycling under eCO2 by diverting microbial C investment toward P acquisition rather than growth. While alleviating P limitation can rapidly stimulate microbial cycling and promotes microbial C retention under eCO2, this response may only be transient, as enhanced microbial growth drives the system towards N limitation.

A green route was established for the synthesis of cobalt oxide, i.e., Co3O4(aq) and Co3O4(et) nanoparticles (NPs) by treating cobalt(II) nitrate hexahydrate with aqueous and ethanolic extracts, respectively, of Bauhinia variegate leaves. The synthesized NPs were sonicated with carbon nanotubes (CNTs) in different (97:3, 94:6, and 91:9) ratios to produce Co3O4(aq)@CNT1, Co3O4(aq)@CNT2, Co3O4(aq)@CNT3, Co3O4(et)@CNT1, Co3O4(et)@CNT2, and Co3O4(et)@CNT3 nanocomposites (NCs). The structural, morphological, and thermal studies of the nanomaterials (NMs) were performed by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), UV-Visible, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and DSC analyses. The average crystalline sizes of Co3O4(aq) (22.54 nm) and Co3O4(et) (20.48 nm) were decreased to 13.73-16.82 nm and 16.08-19.47 nm, respectively, in their respective CNT decorated NC counterparts. The NMs derived from aqueous and ethanolic extracts of B. variegate leaves have shown band gaps in the ranges of 4.74-5.15 and 5.1-5.36 eV, respectively. SEM analysis revealed irregular, spherical, and porous morphologies, except for Co3O4(et), which was highly agglomerated. CNTs were well-dispersed within the Co3O4 matrix, forming smooth surfaces and enhancing electrical conductivity. The average particle sizes ranged from 22.81 to 54.65 nm. The electrochemical potential of the synthesized NMs was tested by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). All the NMs have shown oxidation and reduction peaks, elaborating their reversible charging and discharging behavior and their possible applications for battery. Co3O4et)@CNT3 exhibited the highest specific capacitance value of 989.25 F g-1, showcasing its exceptional potential as a supercapacitor (SC) material. All the synthesized NMs except Co3O4(aq) have shown significant antibacterial potential (ZOI = 9-13mm) as compared to tetracycline (ZOI = 21mm) against Bacillus subtilis (Gram-positive) by disc diffusion method.

In the original publication [...].

Predicting soil carbon sequestration after reforesting former farmland requires understanding how tree types and seasons influence fast- and slow-cycling carbon in the rhizosphere. This study investigated the impact of species and seasonal shifts on the distribution and mineralization of labile and stable carbon pools of young forests. We compared a young ( 5-year) N₂-fixing alder (Alnus glutinosa) with a non-N₂-fixing oak (Quercus robur) across the growing season, expecting mineral-associated organic carbon (MAOC) to dominate total soil organic carbon (SOC), and C mineralization potential to peak in spring. We fractionated rhizosphere soils into particulate organic carbon (POC; >53 μm) and MAOC (< 53 μm) and measured CO₂ efflux from each fraction to predict C mineralization potential using a Gompertz model. In this young reforested system, MAOC dominated soil carbon pools (> 70

Soil fungal communities play central roles in decomposition. Rising atmospheric CO2 levels may impact these communities as additional carbon becomes available for allocation to soil fungi, with potential repercussions for soil carbon and nutrient cycling via decomposition.To explore this, soil fungal communities were analysed from a long-term litter decomposition experiment at the Birmingham Institute of Forest Research Free Air Carbon dioxide Enrichment Facility (BIFoR FACE), a unique experiment in England in which patches of mature oak-dominated woodland have been exposed to elevated [CO2] (+150 μmol/mol) throughout each growing season since 2017. Litterbags of three different mesh sizes (1 μm, 41 μm, 2 mm) and two litter types (oak roots, leaves) were buried under elevated and ambient [CO2] at BIFoR FACE in November 2020. Each consisted of an inner mesh bag containing the litter within an outer mesh bag containing soil. Soil from within the litterbags collected at three timepoints (March 2021, February 2022, May 2024) was used for ITS metabarcoding and the resulting data were analysed in conjunction with soil chemistry data from the experiment.Timepoint was found to be the dominant factor structuring fungal communities. Across all mesh sizes, soil from May 2024 showed significantly higher relative abundances of ectomycorrhizal fungi and lower relative abundances of saprotrophs relative to the earlier timepoints, and a concurrent increase in Basidiomycota at the expense of Ascomycota. In parallel with these fungal community shifts, soil C:N returned in May 2024 to levels similar to those of March 2021 (mean 12.9 ± 0.1 SE at both timepoints), having fallen to a minimum in February 2022 (mean 10.8 ± 0.1 SE). The later increase in soil C:N was driven primarily by reduced total soil nitrogen; this may reflect a decline in available N contributing to increased ectomycorrhizal abundance, which in turn led to further N losses through ectomycorrhizal N mining . Having accounted for the effect of timepoint, however, neither saprotrophic nor ectomycorrhizal relative abundances were related to litter mass loss. CO2 enrichment had little impact on soil fungal OTU richness or guild relative abundances and no taxa were differentially abundant between ambient and elevated [CO2]. However, CO2 enrichment was found to be significantly associated with fungal beta diversity (alongside timepoint, mesh size, litter type, dissolved organic carbon, pH, and soil moisture).These results demonstrate clear patterns of fungal community change as decomposition progresses. These patterns were largely unaffected by CO2 enrichment, despite the fact that decomposition rates have been found to differ between ambient and elevated CO2 in the same experiment. The most notable change was an increased relative abundance of ectomycorrhizal taxa by the final timepoint, likely related to declining N levels.

The use of soilless media is critical for producing high-quality horticultural seedlings. This study was conducted to identify the optimal soilless media formulation for mango nursery production, evaluating combinations of sugarcane bagasse, coconut fiber, peat moss, and organic compost. A total of six media treatments were arranged in a Randomized Complete Block Design (RCBD) with three replications. Key vegetative, physiological, and grafting parameters were assessed. The media combination T2 (65% bagasse, 5% coconut fiber, and 30% peat moss) consistently yielded superior results. Plants in T2 exhibited the highest values for plant height (52.6 cm), stem girth (9.4 mm), and leaf number (17.3), along with the most rapid flush and scion emergence. Furthermore, the physical and chemical properties of T2, including its pH (7.0), water-holding capacity (44%), and air-filled porosity (12.5%), were within the ideal range for plant growth, despite a higher electrical conductivity (922.5 µS/cm). It is concluded that the T2 formulation is the most effective soilless medium for enhancing mango seedling vigor and is highly recommended for commercial nursery production.

Cadmium (Cd) contamination of agricultural soils presents a severe threat to global food security by impairing crop productivity and introducing toxins into the food chain. Seeking an effective and sustainable remediation strategy, this study investigated the synergistic potential of zinc ferrite nanoparticles (ZnFe₂O₄NPs) and plant growth-promoting rhizobacteria (PGPR; Citrobacter sp. NCCP-668) in enhancing cadmium stress tolerance and the productivity of okra (Abelmoschus esculentus). A pot experiment was designed employing two levels of Cd stress (30 µM and 60 µM), simulating conditions from moderately to highly contaminated soils. Ten distinct treatment groups were established, including controls, individual applications of ZnFe₂O₄ NPs (100 mg/L) and PGPR, and their combined application. The results unequivocally demonstrated that exposure to Cd stress alone significantly inhibited key germination metrics, vegetative traits, and anatomical features by 16

Drought stress severely threatens global crop productivity. This study investigated the synergistic potential of zinc ferrite nanoparticles (ZnFe₂O₄ NPs) and plant growth promoting rhizobacteria (PGPR) to ameliorate drought-induced damage in common bean (Phaseolus vulgaris L.). Under greenhouse conditions, plants were subjected to two drought durations (10 and 20 days) and treated with ZnFe₂O₄ NPs (100 mg L⁻¹) and PGPR. The combined application (ZnFe₂O₄ NPs + PGPR) exhibited pronounced synergistic effects, enhancing germination rate index by 39.7

Reactive nitrogen losses from agriculture contribute substantially to greenhouse gas emissions, water pollution and ecosystem degradation. Controlled-release fertiliser technologies offer potential solutions, yet few comprehensively evaluate performance across multiple nitrogen loss pathways and soil types. This study evaluated the environmental performance and agronomic efficacy of urea-doped amorphous calcium phosphate (U-ACP) nanoparticles compared to conventional urea across three contrasting soil types (sandy, sandy loam, clay loam) using lettuce (Lactuca sativa) as a model crop. U-ACP nanoparticles (20-100 nm) were synthesised and characterised for dissolution kinetics in simulated soil environments. Controlled glasshouse experiments (8 weeks, 100 kg N ha (-) (1) application rate) quantified gaseous emissions (ammonia, nitrous oxide, nitric oxide), aqueous leaching losses, soil biochemical properties, plant nitrogen uptake and functional gene abundances for nitrogen cycling processes. U-ACP demonstrated significantly reduced reactive nitrogen losses across all pathways and soil types. Cumulative ammonia volatilisation decreased by 53%-57% in sandy and sandy loam soils compared to conventional urea (p < 0.001), whilst nitrous oxide emissions declined by 19%-27% across all soil types (p < 0.001). Total nitrogen leaching concentrations were 44% lower in sandy soils where losses are typically highest (p < 0.001), with ammonium leaching reduced by 71%-85% across soil types. Cumulative gaseous nitrogen losses decreased by 20%-48% depending on soil type. Despite these substantial reductions in nitrogen losses, U-ACP maintained comparable plant biomass whilst achieving 52%-89% higher nitrogen uptake index across soil types (p < 0.001). U-ACP also supported enhanced soil microbial functionality, with significantly elevated complete ammonia oxidiser (comammox) and alkaline phosphatase (phoD) gene abundances (p < 0.05). Calcium phosphate-based nanocomposite fertilisers offer a viable pathway towards sustainable intensification of agriculture by simultaneously reducing environmental nitrogen pollution whilst maintaining or improving crop productivity across diverse soil conditions.

Mercury contamination severely threatens maize growth and development, creating gap for effective mitigation practices. The experiment assesses the ameliorative effect of Glutamate-stabilized Zerovalent Iron Nanoparticles (Glu-ZVFeNPs) and Benzyl Amino Purine (BAP), applied individually and in combination, on physiological and biochemical responses of maize exposed to 20 and 40 ppm mercuric chloride (HgCl2) stress. Results showed that HgCl2 significantly reduce growth, biomass accumulation photosynthetic pigment and biochemical traits, particularly under 40 ppm HgCl2, though stress indicators increased. Covertly, BAP and Glu-ZVFeNPs application improved plant performance under stress levels. Their combine application at 20 ppm (T4) resulted maximum shoot fresh weight (5.48 g) shoot dry weight (0.6 g), root fresh weight (1.05 g), root moisture (80.6%), leaf fresh and dry weight (1.74 and 0.23 g), leaf area (76.21 cm2) and SVI (2338). Similar treatments also increased total chlorophyll (0.051 mg/g), carotenoids (5.57 mg/g), sugar (6.55 mg/g) and protein (190.7 mg/g), while reduce proline accumulation compared with stressed plants. Combine application more improved root length, shoot length, germination, leaf dry biomass and moisture content across stress levels. These results concludes that combined BAP and Glu-ZVFeNPs synergistically mitigate HgCl2 toxicity and enhanced maize tolerance through different physiological and biochemical protection mechanisms.

SrO 2 and SrCO 3 @GO nanomaterials were synthesized using aqueous/ethanolic extracts of Moringa oleifera leaves. SrCO 3 @GO (et) exhibited superior electrochemical performance (292.59 F g −1 ), highlighting its potential for advanced energy storage systems.

Nature-based solutions to climate change must incorporate mitigation strategies that sustain and enhance forest carbon sequestration, requiring comprehensive accounting of forest carbon budgets, including carbon stored in roots and soils. Forests' capacity to remain as carbon sinks under elevated CO2 (eCO(2)) may depend on tree root systems adjusting to overcome nutrient and water limitation. It remains uncertain whether and how root systems can change across depth under eCO(2) in mature forests. We assessed fine root biomass, morphology, depth distribution and C:N ratio, using 1-m-deep soil cores from Years 5 and 7 of the Birmingham Institute of Forest Research Free-Air CO2 Enrichment experiment (BIFoR FACE), a mature, deciduous forest subject to eCO(2) (+150 mu l/L, i.e., mid-21st century projected atmospheric CO2 concentration). Fine root biomass was similar to 40% greater under eCO(2), concentrated in the top 50 cm and equivalent to similar to 36% more root carbon standing stock. Contrary to previous results, the distribution of fine root biomass did not shift to greater depths. Changes in morphology were variable, but, on average, there was greater fine root length under eCO(2) and, with depth, higher specific root length. Under eCO(2), greater fine root biomass and changes in morphology result in higher fine root surface area and thereby a greater potential for resource acquisition across the soil profile. Better characterisation of fine roots under eCO(2) can benefit belowground carbon modelling, improving predictions of forest carbon sinks and refining estimates of forests as natural climate solutions for climate policy.

The rapid expansion of agricultural and industrial activities has intensified the accumulation of organic pollutants in soils, posing a significant threat to soil ecosystem integrity and its functions. These pollutants disrupt microbial community composition, reduce diversity, suppress enzymatic activity, and impair the metabolic and genetic functions critical for nutrient cycling. Biochar, a carbon-rich amendment derived from biomass pyrolysis, has great potential to mitigate these adverse effects. Its high surface area, porosity, and reactive surface groups enable strong contaminant adsorption, reduced bioavailability, and improved soil structure and aeration. Biochar promotes microbial recovery by enhancing diversity, restoring enzyme activity, and stimulating beneficial microbial functions associated with carbon and nitrogen cycling. Furthermore, biochar facilitates the biodegradation of organic contaminants, lowers pollutant uptake by plants, and supports overall soil fertility and crop productivity. This review highlights the mechanistic understanding of biochar-microbe-contaminant interactions, emphasizing adsorption, electrostatic attraction, hydrogen bonding, and pore-filling processes in biochar-amended microbial systems. This study also explored the ecological significance of biochar application in restoring microbial health and improving soil ecosystem stability. This review aims to provide an integrated perspective on how biochar mediates microbial responses to organic contaminants and to identify future directions for sustainable soil remediation practices.

Rising atmospheric carbon dioxide (CO2) concentration could enhance forest carbon (C) uptake, but nitrogen (N) is thought to progressively constrain this effect. Yet, significant biomass gains were demonstrated in a mature oak forest after 6 years of Free Air CO2 Enrichment. This study investigates whether changes in soil N fluxes explain these gains. We show that enhanced N mineralization and ecosystem N conservation support increased productivity under elevated CO2 (eCO2). In situ net and gross N ammonification was enhanced by ∼30%, with a pronounced effect at oak budburst. Higher N ammonification rates were associated with increases in both fine root biomass and soil respiration. Gross nitrification was reduced, revealing a faster-yet-tighter cycle facilitated by plant-soil interactions. Hence, forest N cycling can adapt to support C uptake under eCO2, but in the longer term, this capacity may be constrained by soil-accessible organic N stocks and reductions in anthropogenic N deposition.

Enhanced ‘woody growth’ (dry matter increments, specifically), averaging 10%, has been sustained in patches of long-established (180+ years old) oak forest through 9 years of treatment with elevated CO2 (eCO2; 150 ppm above ambient). Root exudation of carbon (C) into the rhizosphere increased by 63%, which primed the microbes for nutrient acquisition to meet enhanced tree N demands. A ‘faster-tighter’ nitrogen cycle accelerates the return of nitrogen via ammonification to plant-available forms and suppresses processes such as nitrification. This ecosystem-scale N conservation strategy supports increased net productivity by maintaining the nutritional balance of the trees in the C-rich atmosphere. The faster-tighter N-cycle makes an additional 25 kg N ha-1 yr-1 available to the trees under eCO2. That is, the forest’s N-cycle adjusts to the increased C supply, but whether this capacity to adjust endures may be constrained by soil organic N stocks and anthropogenic N deposition. Further, when considering broader aspects of the forest under eCO2, we find nutritional deficiencies producing a cascade of nascent ecosystem fragility in pollen, seeds, seedlings, and food webs. The clear policy implications are: (i) that enhanced net primary productivity does not, in itself, guarantee forest resilience; (ii) that both C and N emission pathways must be accounted for when forecasting 21st-century C uptake into temperate forests; and (iii) that, when proposing forests as natural climate solutions, understanding C-nutrient interactions is of primary concern.

European forests play a central role for meeting the EU's climate targets, but the declining carbon sink has left them trailing behind climate goals. Reversing this trend requires a systematic understanding of forest responses to shifting global change drivers, explicitly integrating aboveground and belowground processes. Here, we provide our perspective on the effects of multiple global change drivers on ecosystem-scale carbon fluxes (including both carbon dioxide (CO2) and methane (CH4)) and the resilience of these fluxes, based on direct flux observations (e.g., from eddy covariance towers). First, we present changes in several key drivers (warming, drought, atmospheric CO2, nitrogen deposition, winter warming, excess precipitation, late frost), over recent decades, some of which (winter warming, windthrow, excess precipitation, late frost) have received limited attention in forest carbon assessments. Some of these-such as winter warming-are expected to become increasingly frequent in the future. We then explicitly summarize how the four (more-frequently studied) key drivers affect carbon fluxes (i.e., CO2 and CH4 fluxes). The response of the net CO2 sink (i.e., net ecosystem productivity) is presented through its two component processes: gross primary productivity (GPP) and ecosystem respiration (Reco). When considered individually, global change drivers often produce relatively predictable responses in forest carbon fluxes: warming tends to enhance both GPP and Reco, elevated atmospheric CO2 generally stimulates photosynthesis, and moderate nitrogen (N) inputs can enhance productivity in N-limited systems. However, when drivers interact, ecosystem responses frequently become non-linear, amplified, or even reversed relative to single-driver expectations. For example, warming alone may extend the growing season and increase GPP, but in combination with drought, elevated vapor pressure deficit suppresses stomatal conductance, reduces GPP, and can increase respiration losses during rewetting events. Similarly, the positive effect of rising CO2 on productivity may be constrained by nutrient limitation or drought stress, while historical N deposition can temporarily sustain CO2 fertilization effects but also increase vulnerability to climatic stressors. Under compound disturbances-such as drought followed by extreme precipitation or winter warming-ecosystem respiration pulses and structural damage can further reduce net ecosystem productivity (NEP). Collectively, these findings indicate that forest carbon dynamics cannot be reliably inferred from single-driver responses alone; instead, interacting drivers shape ecosystem resilience through feedbacks among physiological processes, soil biogeochemistry, and disturbance regimes, often leading to thresholds or tipping points in carbon sink strength.