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Forecasting the effects of global change drivers on ecosystems is one of the most pressing challenges for scientists worldwide. Particularly, climate change and exotic pathogens might have a large impact on plant community dynamics and ecosystem functioning through changes in carbon uptake and sinks. Nevertheless, we still have a poor understanding of the combined effects of these two drivers on plant communities. Here, we explored the impact of rainfall reduction and exotic pathogens on the carbon balance of Mediterranean tree species. For this, we performed a 3‐year field experiment taking advantage of rainfall exclusion infrastructures (30% exclusion) installed in the southernmost European oak forests invaded by the aggressive exotic pathogen Phytophthora cinnamomi. We measured a set of 10 variables representative of tree carbon sources (photosynthetic rates) and sinks (primary production, reproduction, defence, and reserves) in adult trees of three species in two forest types: closed forests of Quercus suber and Q. canariensis, and open woodlands of Q. suber and Olea europaea. We found a large variability in the sensitivity of the different carbon sources and sinks to the effects of drought and pathogens, from variables highly sensitive to both factors (carbon fixation and reproduction, root chemistry) to variables only responsive to drought (litter production) or totally unresponsive (tree trunk, leaf chemistry). Although negative effects predominated, positive effects of rainfall exclusion were also detected in wet years, likely due to a reduction of pathogen abundance in drier soil. Trade‐offs between carbon sinks appeared in all tree species, but rainfall exclusion only modified trade‐offs in Q. suber, the species most susceptible to P. cinnamomi. Synthesis. We provide evidence on the complexity of the combined effects of abiotic (drought) and biotic (pathogens) global change drivers on carbon source and sinks of adult trees, including both negative direct effects and positive indirect effects. Our results showed that these effects varied among co‐existing species, particularly for carbon sinks directly related to tree demography (reproduction). Therefore, long‐term changes in the structure of Mediterranean mixed forests might be expected towards the dominance of species highly resistant to both drought and pathogens. [ABSTRACT FROM AUTHOR]

This study aimed to estimate the amount and quality of litter produced by pine and elm trees in the green space of the historic city of Yazd. Litterbags were used to collect the leaves for a year while the amount of nitrogen, phosphorus, calcium, sulfur, carbon, magnesium, and potassium levels was measured monthly for both species. The annual mean weight of all components of litter was found to be 4056.56 g for pine and 4106.67 g for elm trees. The results showed that the greatest fall of pine needles was recorded in September, while the highest fall of elm leaves was measured in November. The specific leaf area of elm and pine was calculated to be 169.38 and 29.96 cm2/g, respectively. The leaf area index for pine and elm was 0.91 and 7.99, respectively. There was no statistically significant difference between pine and elm trees in the leaf amount and total litter. However, the crown area of pine and elm trees had a direct effect on the amount of total litter produced (R2 = 0.72 and 0.60 respectively). There was a significant difference between the two species in organic matter percentage, while there was no significant difference in the carbon, calcium, and magnesium content. The specific leaf area of elm was higher than pine, making it better in this index. According to the amount of annual litter production of two species calculated in this research, it can be said that in the city of Yazd, pine and elm trees produce at least 158.9 and 804.5 tons of litter per year respectively. Since the minimum cost of litter collection per hectare of tree plantations in the city is $150, collecting pine and elm litter will cost the municipality $14,700 and $73,500, respectively. Our study showed that contrary to popular belief, pine needles play an important role in total leaf litter produced in arid regions like Yazd. Also, the process of collecting dead leaves continues throughout the year, especially in summer in arid areas.Highlights: The mean annual weight of all components of the lea litter in the historic city of Yazd was 4056.56 g for Eldar pine and 4106.67 g for umbreculifera elm trees. The greatest fall of pine needles was recorded in September. For umbreculifera elm trees the maximum rate was observed in November. This should be taken into account in terms of management. The specific leaf area of umbreculifera elm and Eldar pine was calculated to be 169.38 and 29.96 cm2/g, respectively. The leaf area index for pine and elm species was 0.91 and 7.99, respectively. Although pines are evergreens, they produce a lot of litter during the year which can be compared with broadleaved trees like umbreculifera elm. The municipality of the historic city of Yazd is facing 158.9 tons of Eldar pine leaf litter every year. Clearing these litters costs about 14700 $ across the city. [ABSTRACT FROM AUTHOR]

The concentrations and fluxes of arsenic (As) and cadmium (Cd) were examined in the hydrological cycle, litterfall and soils in a maquis broadleaved evergreen forest stand in western Greece. The concentrations of the metals in the hydrological cycle ranged from 0.076 to 0.306 μg L−1 and 0.040–0.050 μg L−1 for As and Cd, respectively. It was found that the enrichment of As in the atmosphere was both due to suspended geogenic material and long range transfer, whereas for Cd the long range transfer was the predominant way for deposition. Two models were assessed to find the volumes of percolation water to compare the fluxes with the estimated ones derived from soil solution measurements. The daily deterministic forest-hydrological model (WBS3) was found to perform better than the physically based 1D semi-distributed soil-plant-atmosphere model (BROOK90). When calculating the total amounts of the heavy metals in soils, the statistical uncertainty derived from every soil layer has to be taken into account. The residence time of Cd in the forest floor (L + FH) of the soils was found 6.4 years, whereas that of As 36.3 years. This difference shows the mobility of Cd in comparison to As in the soils of the area. [ABSTRACT FROM AUTHOR]

Quercus suber woodlands are widely distributed around the Western Mediterranean basin. Although assumed well-adapted to recurrent seasonal droughts, water availability during critical phases can limit Q. suber crown development and, consequently, photoassimilate production and growth. This work aims to assess the relationships between climate conditions and seasonal and interannual variation of multiple vegetative and reproductive growth traits in Q. suber and identify possible mechanisms governing within-tree competition for resources and trade-offs between vegetative and reproductive growth. Data collection occurred between 2010 and 2019 and involved the monthly monitoring of reproductive and vegetative phenology, stem radial growth, and litterfall collection in a Q. suber woodland in central Portugal. Winter and autumn precipitation reductions (20 and 30%, respectively) during 2015–2019 resulted in a 23% decrease in leaf biomass production (compared to 2010–2014). Results show that mean March temperatures have a pivotal role in balancing vegetative/reproductive biomass investment, being positively correlated with the growth of vegetative structures (r = 0.81) and negatively correlated with acorn production (r=-0.83). PCA results also confirm the existence of competitive interaction between reproductive and vegetative growth in Q. suber trees, with mast cropping years resulting in reductions in annual leaf biomass production (26%). Dry years affected annual stem radial growth negatively (ca. 48%), reducing the period of phellogen activity and anticipating annual radial growth peaks by two months, consequently shortening the window for a safe cork extraction. Our results provide valuable information to adapt the management of Q. suber woodlands to ongoing environmental changes and contribute to ecosystem sustainability. [ABSTRACT FROM AUTHOR]

In cocoa agroforestry systems, cycling of leaves, pods, and branches are key for organic matter sustenance. We investigated annual total litterfall, annual nutrient stocks in total litterfall, cocoa pods and beans, as well as cocoa leaf decomposition rates in cocoa agroforestry systems under conventional and organic management in Suhum Municipality, Eastern Region of Ghana. The study was conducted using six cocoa agroforests for each management selected from a total of four villages. Litterfall was collected monthly using litterboxes and a litterbag technique was employed to study the rates of leaf decomposition and nutrient release for 12 months. In June and July, total litterfall in organic farms were 94% and 65%, respectively, higher than in conventional farms, but management had no effect on average annual total litterfall of 8.8 t ha−1 yr−1 litterfall. Due to the trees' reduced transpiration, 61% of the annual total litterfall occurred during the dry season. Whereas average leaf litter nitrogen (N) concentration was 17% higher in the rainy season than dry season, potassium (K) concentration was 38% higher during the dry season than rainy season. This likely reflected the contribution of N rich green leaves to litterfall in the rainy season and plant coping strategy to drought leading to K accumulation. Cocoa leaf decomposition was not affected by management. Annual potassium (K) and calcium (Ca) stocks in cocoa pod husk were four and nine-fold, respectively, higher than in cocoa beans. We conclude that organic versus conventional management had no effect on litterfall and cocoa leaf decomposition rather season influenced litterfall quantity and chemistry. Irrespective of management the spreading of cocoa pod husk after harvest will improve internal nutrient cycling in cocoa agroforestry systems. [ABSTRACT FROM AUTHOR]

Understanding the process of litterfall production is crucial for sustainable development of plantations. However, the underlying dynamics of litterfall and its nutrient return in plantation agroforestry systems remain unclear. In this study, we investigated litterfall, including leaves, branches, flowers, and fruits, in three patterns: Hevea monoculture system (RM), Hevea-Michelia intercropping system (RAS1), and Hevea-Mytilaria intercropping system (RAS2) in Hainan Island, China. Our findings indicate that total litterfall was significantly higher in RAS1 (27,309 kg ha-1) and RAS2 (34,477 kg ha-1) than in RM (22,364 kg ha-1) and was predominantly composed of leaf litterfall in all three patterns, followed by branches, flowers, and fruits. The seasonal dynamics litterfall production of RM, RAS1, and RAS2 showed characteristic patterns. Litterfall nutrients exhibited peak and sub-peak monthly dynamics, peaking from February to March, during the dry season. Total nitrogen (TN), total phosphorus (TP), and total potassium (TK) content of annual litterfall in RAS1 significantly increased by 120 kg ha-1, 30kgha-1, and 139 kg ha-1, respectively, compared to those in RM, with percentage increases of 67.88%, 122.79% and 96.27%, respectively. Similarly, TN, TP, and TK content of annual litterfall in RAS2 significantly increased by 185 kg ha-1, 35 kg ha-1, and 170 kg ha-1, respectively, with percentage increases of 103.70%, 159.15% and 139.46%, respectively, for the abovementioned in RM. Litterfall showed a strong correlation with monthly average temperature, monthly minimum temperature, and monthly average wind speed, contributing 80.5%, 75.5%, 69.8%, and 69.6% to the total litterfall and its components, respectively. Further analysis indicated that monthly average temperature, monthly minimum temperature, and monthly average wind speed contributed 73.9%, 43.0%, and 66.6%, respectively, to TN, TP, and TK content of the annual litterfall, highlighting the significant influence of temperature and wind speed. These findings enhance our understanding of carbon and nutrient cycling and contribute to the sustainable management of tropical plantation ecosystems. [ABSTRACT FROM AUTHOR]

As a component of the biogeochemical cycle, litterfall contributes carbon and nutrients to forest ecosystems by transferring organic material to mineral soil. Litterfall therefore serves as an important indicator for soil fertility and ecosystem health. This study aimed to determine the impact of different levels of thinning (light, moderate, and heavy) on litterfall quantity (needles, branches, bark, cones, and miscellaneous parts) and on the amount of carbon and nutrients entering the ecosystem in black pine afforestation areas. Three levels of low thinning, namely light, moderate, and heavy thinning (15%, 25%, and 35% of breast height area, respectively), were applied as treatments. Additionally, a control plot was included in the experiment. Litterfall samples were collected four times per year (once per season) from 12 treatment plots for three years. In the laboratory, dry weight measurements and analyses of carbon and macro–micro nutrient elements (N, P, K, Ca, Mg, S, Na, Fe, Cu, Zn, and Mn) were performed on litterfall samples taken from the field. Differences between treatments in terms of litterfall and the amount of carbon and nutrient elements entering the ecosystem were evaluated through variance analysis and the Duncan test. According to the findings, the quantity of litterfall input into the forest floor was highest in the control treatment, at 6,543 kg ha−1 year−1 and lowest in the heavy treatment, at 4,378 kg ha−1 year−1, showing a significant variation in litterfall quantity. The input of C to the soil ranged between 2,233 kg ha−1 year−1 and 3,347 kg ha−1 year−1 depending on thinning treatment. Although thinning treatment reduced C input to the soil, there was no significant difference among treatments. This also applied to nutrient elements such as N, P, K, Mg, and S. Needles constituted the majority of litterfall components (60%) and had the highest C density among all components, at 51.2%. The weighted carbon ratio for litterfall was calculated at 50.8%. Considering carbon-focused planning, performing moderate thinning interventions in the study area or similar pine-afforested areas may be a suitable option for maintaining the sustainability and health of the forest. [ABSTRACT FROM AUTHOR]

We present a meta-analysis of mangrove litterfall across 58 sites in the American Pacific, exploring its variability among geoforms, ecoregions, and provinces. This study contributes to filling the information gap on litter-based primary productivity in American mangroves at the ecoregional level and directly examines the effects of geomorphological and biogeographic factors on mangrove productivity. The objective was to evaluate how geoform, ecoregion, and province factors, along with eight environmental variables, influence litterfall-based primary productivity. Each site was categorized according to its landform through the analysis of satellite images obtained from various sensors on the Google Earth Pro v. 7.3.6 platform. Additionally, it was categorized according to its ecoregion and province by analyzing the occurrence of the sites on biogeographic unit coverage in ArcMap 10.4.1. We then analyzed the effect of each factor and the efficiency of categorization using multivariate methods. Our results showed significant differences in litterfall among the geoforms, with estuaries exhibiting higher litterfall production (11.90 Mg ha−1 year−1) compared to lagoons (7.49 ± 4.13 Mg ha−1 year−1). Differences were also observed among provinces, with the highest average in the Tropical Eastern Pacific (11.19 ± 3.63 Mg ha−1 year−1) and the lowest in the Warm Temperate Northeast Pacific (7.34 ± 4.28 Mg ha−1 year−1). Allocation success analyses indicated that sites classified by dominant species and province were more predictable (>60.34%) for litterfall production. Additionally, the maximum temperature and the precipitation of the wettest month and the driest month explained 34.13% of the variability in mangrove litter-based primary productivity. We conclude that mangrove litterfall production is influenced by coastal geomorphic characteristics and biogeography, which are, in turn, affected by latitude-induced climate variation. [ABSTRACT FROM AUTHOR]

In this study, we investigated the distribution and abundance of macrobenthos, particularly tanaids, in the Kadalundi Estuary, southwest coast of India, across three seasons. Tanaids were found to be the dominant macrobenthic group, with a strong preference for clayey mangrove habitats. The study highlights the vital role of mangroves in supporting macrobenthic communities and emphasizes the importance of conserving these habitats. Litterfall was identified as a crucial factor in nutrient cycling within the mangrove ecosystem. Sandbar formation near the estuary mouth poses a significant threat to mangrove ecosystems and associated fauna. This research contributes valuable insights for informed conservation strategies and ecosystem management. [ABSTRACT FROM AUTHOR]

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Tropical forest productivity represents an important global carbon sink, but many tropical forests grow on infertile soils. Efficient nutrient cycling by litterfall has long been assumed to maintain tropical tree growth, but there is no direct evidence that the nutrients cycled in litterfall are essential for tropical forest productivity.To test whether nutrient cycling by litterfall maintains tropical forest above‐ground productivity, we established large‐scale long‐term litter removal (L−) and litter addition (L+) treatments in a mature lowland tropical forest. We hypothesised that the removal of nutrients in litter would reduce tree growth, survival and litter production in L− plots. By contrast, the addition of nutrients in litter would enhance tree growth, survival and litter production in L+ plots. To test our hypotheses, we recorded tree growth and survival every 2 years, and measured litterfall monthly during 17 years of treatments.Tree growth and litterfall declined over time in L− plots, with consistently lower growth rates compared to controls after 8 years, and lower litter production after 4 years of treatments. By contrast, although litterfall was higher in the L+ plots relative to the controls, there was only a minor transient increase in tree growth immediately after the start of treatments. Tree survival declined over time in all treatments but was not affected by litter manipulation.The long‐term decline in tree growth and litterfall in the L− plots provides the first empirical evidence that nutrient cycling by litterfall plays a key role in maintaining above‐ground productivity in this tropical forest. By contrast, the transient increase in growth in the L+ plots can be attributed to the large inputs of nutrients with the addition of the entire litter standing crop at the start of treatments. The addition of nutrients in litter over the long term was nonetheless sufficient to enhance litter production, possibly by accelerating leaf turnover.Synthesis: Efficient nutrient cycling by litterfall makes an important contribution to the annual nutrient requirements of mature tropical forest trees, compensating for infertile soils. Disturbances that disrupt this finely balanced cycle could therefore reduce biomass carbon sequestration in tropical forests. [ABSTRACT FROM AUTHOR]

Tropical peat swamp forests are major global carbon (C) stores highly vulnerable to human intervention. In Peruvian Amazonia, palm swamps, the prevalent peat ecosystem, have been severely degraded through recurrent cutting of Mauritia flexuosa palms for fruit harvesting. While this can transform these C sinks into significant sources, the magnitude of C fluxes in natural and disturbed conditions remains unknown. Here, we estimated emissions from degradation along a gradient comprising undegraded (Intact), moderately degraded (mDeg) and heavily degraded (hDeg) palm swamps. C stock changes above- and below-ground were calculated from biomass inventories and peat C budgets resulting from the balance of C outputs (heterotrophic soil respiration (Rh), dissolved C exports), C inputs (litterfall, root mortality) and soil CH4 emissions. Fluxes spatiotemporal dynamics were monitored (bi)monthly over 1–3 years. The peat budgets (Mg C ha−1 year−1) revealed that medium degradation reduced by 88% the soil sink capacity (from − 1.6 ± 1.3 to − 0.2 ± 0.8 at the Intact and mDeg sites) while high degradation turned the soil into a high source (6.2 ± 0.7 at the hDeg site). Differences stemmed from degradation-induced increased Rh (5.9 ± 0.3, 6.2 ± 0.3, and 9.0 ± 0.3 Mg C ha−1 year−1 at the Intact, mDeg, and hDeg sites) and decreased C inputs (8.3 ± 1.3, 7.1 ± 0.8, and 3.6 ± 0.7 Mg C ha−1 year−1 at the same sites). The large total loss rates (6.4 ± 3.8, 15.7 ± 3.8 Mg C ha−1 year−1 under medium and high degradation), originating predominantly from biomass changes call for sustainable management of these peatlands. [ABSTRACT FROM AUTHOR]

Background: Tropical savannas represent a large proportion of the area burnt each year globally, with growing evidence that management to curtail fire frequency and intensity in some of these regions can contribute to mitigation of climate change. Approximately 25% of Australia's fire-prone tropical savanna region is currently managed for carbon projects, contributing significantly to Australia's National Greenhouse Gas Inventory. Aims: To improve the accuracy of Australia's national carbon accounting model (FullCAM) for reporting of fire emissions and sequestration of carbon in savanna ecosystems. Methods: Field data from Australian savannas were collated and used to calibrate FullCAM parameters for the prediction of living biomass, standing dead biomass and debris within seven broad vegetation types. Key results: Revised parameter sets and improved predictions of carbon stocks and fluxes across Australia's savanna ecosystems in response to wildfire and planned fire were obtained. Conclusions: The FullCAM model was successfully calibrated to include fire impacts and post-fire recovery in savanna ecosystems. Implications: This study has expanded the capability of FullCAM to simulate both reduced emissions and increased sequestration of carbon in response to management of fire in tropical savanna regions of Australia, with implications for carbon accounting at national and project scales. Savanna fire management has proved to be an effective mechanism for reducing greenhouse gas emissions and increasing carbon storage in ecosystems. In this study, we calibrate the FullCAM carbon accounting model with extensive field data to improve the model's representation of fire impacts and carbon dynamics in Australian savannas, and to facilitate carbon accounting at project to national scales. [ABSTRACT FROM AUTHOR]

Mangroves are one of the most carbon‐dense forests on the Earth and have been highlighted as key ecosystems for climate change mitigation and adaptation. Hundreds of studies have investigated how mangroves fix, transform, store, and export carbon. Here, we review and synthesize the previously known and emerging carbon pathways in mangroves, including gains (woody biomass accumulation, deadwood accumulation, soil carbon sequestration, root and litterfall production), transformations (food web transfer through herbivory, decomposition), and losses (respiration as CO2 and CH4, litterfall export, particulate and dissolved carbon export). We then review the technologies available to measure carbon fluxes in mangroves, their potential, and their limitations. We also synthesize and compare mangrove net ecosystem productivity (NEP) with terrestrial forests. Finally, we update global estimates of carbon fluxes with the most current values of fluxes and global mangrove area. We found that the contributions of recently investigated fluxes, such as soil respiration as CH4, are minor (<1 Tg C year−1), while the contributions of deadwood accumulation, herbivory, and lateral export are significant (>35 Tg C year−1). Dissolved inorganic carbon exports are an order of magnitude higher than the other processes investigated and were highly variable, highlighting the need for further studies. Gross primary productivity (GPP) and ecosystem respiration (ER) per area of mangroves were within the same order of magnitude as terrestrial forests. However, ER/GPP was lower in mangroves, explaining their higher carbon sequestration. We estimate the global mean mangrove NEP of 109.1 Tg C year−1 (7.4 Mg C ha−1 year−1) or through a budget balance, accounting for lateral losses, a global mean of 66.6 Tg C year−1 (4.5 Mg C ha−1 year−1). Overall, mangroves are highly productive, and despite losses due to respiration and tidal exchange, they are significant carbon sinks. [ABSTRACT FROM AUTHOR]

The quantification of carbon (C) storage of different stand types is a key component for understanding forest C cycles and potential climate change. This study evaluated the effects of stand types on litterfall, litter decomposition, and forest C storage in Pinus densiflora S. et Z. and Quercus variabilis Blume stands in southern Korea. The aboveground C storage by tree biomass was not affected (P > 0.05) by stand types (P. densiflora: 79.49 Mg C ha–1; Q. variabilis: 96.37 Mg C ha–1). However, total C inputs by litterfall were significantly higher for the P. densiflora (4,473 kg C ha–1 year–1) than for the Q. variabilis (2,633 kg C ha–1 year–1) stands. Organic C over litter decomposition processes was more rapidly mineralized in the leaf litter of Q. variabilis than in needle litter of P. densiflora, but C storage on the forest floor was not affected by different stand types. Total soil C storage was not significantly different between the Q. variabilis (55.71 Mg C ha–1) and P. densiflora (80.49 Mg C ha–1), whereas the C concentrations at each soil depth were significantly higher in the P. densiflora than in the Q. variabilis stands, except for the subsurface depth (30–50 cm). These results indicate that the distribution of C storage in P. densiflora and Q. variabilis stands is less susceptible to interspecific differences, such as litterfall inputs and decomposition rates.

While tropical cyclone regimes are shifting with climate change, the mechanisms underpinning the resistance (ability to withstand disturbance-induced change) and resilience (capacity to return to pre-disturbance reference) of tropical forest litterfall to cyclones remain largely unexplored pantropically. Single-site studies in Australia and Hawaii suggest that litterfall on low-phosphorus (P) soils is more resistant and less resilient to cyclones. We conducted a meta-analysis to investigate the pantropical importance of total soil P in mediating forest litterfall resistance and resilience to 22 tropical cyclones. We evaluated cyclone-induced and post-cyclone litterfall mass (g/m2 /day), and P and nitrogen (N) fluxes (mg/m2 /day) and concentrations (mg/g), all indicators of ecosystem function and essential for nutrient cycling. Across 73 case studies in Australia, Guadeloupe, Hawaii, Mexico, Puerto Rico, and Taiwan, total litterfall mass flux increased from ~2.5 ± 0.3 to 22.5 ± 3 g/m2 /day due to cyclones, with large variation among studies. Litterfall P and N fluxes post-cyclone represented ~5% and 10% of the average annual fluxes, respectively. Post-cyclone leaf litterfall N and P concentrations were 21.6 ± 1.2% and 58.6 ± 2.3% higher than pre-cyclone means. Mixed-effects models determined that soil P negatively moderated the pantropical litterfall resistance to cyclones, with a 100 mg P/kg increase in soil P corresponding to a 32% to 38% decrease in resistance. Based on 33% of the resistance case studies, total litterfall mass flux reached pre-disturbance levels within one-year post-disturbance. A GAMM indicated that soil P, gale wind duration and time post-cyclone jointly moderate the short-term resilience of total litterfall, with the nature of the relationship between resilience and soil P contingent on time and wind duration. Across pantropical forests observed to date, our results indicate that litterfall resistance and resilience in the face of intensifying cyclones will be partially determined by total soil P.

Native grasslands in the Pampas of South America are increasingly being replaced by Eucalyptus and Pinus stands. The short rotation regimes used for the stands require high nutrient levels, with litterfall being a major source of nutrient return. To model the litterfall production using climatic variables and assess the nutrient return in 14-year-old Eucalyptusgrandis and Pinustaeda stands, we measured litter production over 2 years, using conical litter traps, and monitored climatic variables. Mean temperature, accumulated precipitation, and mean maximum vapor pressure deficit at the seasonal level influenced litterfall production by E.grandis; seasonal accumulated precipitation and mean maximum temperature affected litterfall by P.taeda. The regression tree modeling based on these climatic variables had great accuracy and predictive power for E.grandis (N = 33; MAE (mean absolute error) = 0.65; RMSE (root mean square error) = 0.91; R2 = 0.71) and P.taeda (N = 108; MAE = 1.50; RMSE = 1.59; R2 = 0.72). The nutrient return followed a similar pattern to litterfall deposition, as well as the order of importance of macronutrients (E.grandis: Ca > N > K > Mg > P; P.taeda: N > Ca > K > Mg > P) and micronutrients (E.grandis and P.taeda: Mn > Fe > Zn > Cu) in both species. This study constitutes a first approximation of factors that affect litterfall and nutrient return in these systems. [ABSTRACT FROM AUTHOR]

Montane cloud forests (MCFs) are ecosystems frequently immersed in fog and are vital for the terrestrial hydrological cycle and biodiversity hotspots. However, the potential impacts of climate change, particularly intensified droughts and typhoons, on the persistence of ecosystems remain unclear. Our study conducted cross‐scale assessments using 6‐year (2016–2021) ground litterfall and 21‐year (2001–2021) satellite greenness data (the Enhanced Vegetation Index [EVI] and the EVI anomaly change [ΔEVI%]), gross primary productivity anomaly change (ΔGPP%), and meteorological variables (the standardized precipitation index [SPI] and wind speed). We found a positive correlation between summer EVI and ΔGPP% with the SPI‐3 (3‐month time scale), while winter litterfall showed a negative correlation. Maximum typhoon daily wind speed was negatively correlated with summer and the monthly ΔEVI% and ΔGPP%. These findings suggest vegetation damage and productivity loss were related to drought and typhoon intensities. Furthermore, our analysis highlighted that chronic seasonal droughts had more pronounced impacts on MCFs than severe typhoons, implying that high precipitation and frequent fog immersion do not necessarily mitigate the ramifications of water deficit on MCFs but might render MCFs more sensitive and vulnerable to drought. A significant negative correlation between the summer and winter ΔEVI% and ΔGPP% of the same year, suggesting disturbance severity during summer may facilitate vegetation regrowth and carbon accumulation in the subsequent winter. This finding may be attributed to the ecological resilience of MCFs, which enables them to recover from the previous summer. In the long‐term, our results indicated an increase in vegetation resilience over two decades in MCFs, likely driven by rising temperatures and elevated carbon dioxide levels. However, the enhancement of resilience might be overshadowed by the potential intensified droughts and typhoons in the future, potentially causing severe damage and insufficient recovery times for MCFs, thus raising concerns about uncertainties regarding their sustained resilience. [ABSTRACT FROM AUTHOR]

Poplar plantations growing in short rotation are a crucial biomass source of raw material for bioenergy and/or bioproducts, making an important contribution towards achieving a low-carbon bioeconomy. To optimize yield predictions of poplar plantations, this study aims to adapt the foliar variables of the process-based model 3-PG (Physiological Principles Predicting Growth) to a deciduous species like poplar. A total of 138 trees were sampled from a poplar plantation of the highly productive hybrid P. x canadensis ('AF2') over a first rotation at a planting density of 10 000 trees ha−1. Two irrigation scenarios, full soil field capacity (FC) and 50% FC, were considered to take into account the impact of climate change in the context of irrigation restrictions. Based on this information, the objectives were not only to determine the required species-specific foliar parameters but also to adapt the 3-PG model architecture to a pattern of variation along each growing season and identify the foliar parameters which present a significant response to restrictive irrigation. For this, specific leaf area (SLA) changes were modelled and the litterfall rate (⁠|${\gamma}_F$|⁠), and maximum canopy quantum efficiency (⁠|${\alpha}_{Cx}$|⁠) were calculated. SLA follows a similar dynamic in terms of water availability and year, with SLA for mature leaves being 19.9 m2 kg−2 and the SLA at the beginning of the growing season 10.4 m2 kg2. Leaf litter season begins in late August and lasts until early December, with 26 per cent litterfall by October. Additionally, the highly sensitive parameter |${\alpha}_{Cx}$| was calibrated and a proposed value of 0.093 molC mol PAR−1 was used. The validation of the proposed parameterization showed realistic estimates of the changes of leaf biomass and LAI during the growing season. These results will enable improved 3-PG-based estimations of the real variation along the growing season of variables such as Net Primary Productivity, leaf litterfall or analysis of the soil–plant nutrient cycle. [ABSTRACT FROM AUTHOR]

Innutrient dynamics, an extremely valuable resource is litterfall. It is crucial to the dynamics of soil nutrients, the characteristics of soil, and the transfer of energy. In an agroforestry system, decomposition and litter fall are the two key processes that contribute to soil enrichment. In addition to affecting soil characteristics and ecology, litter fall in soil has a significant impact on carbon sequestration. The type of tree, the management methods, and the quantity and quality of litter all affect how much the soil is enriched. The complicated ecophysiological process of litterfall is influenced by both internal and external variables. Other significant causes of leaf fall include variations in weather and photoperiod as well as internal plant characteristics like age of leaf or potential endogenous rhythams. Nutrients are converted as a result of decomposition of different components of litter, and their release is influenced by the content of the litter, moisture, activity of microbes, C:N, temperature, and other variables. Litterfall therefore contributes to the long-term maintenance of nutrient levels in forest ecosystems and has been a primary research focus for a better understanding of soil fertility, site productivity, and forest services. [ABSTRACT FROM AUTHOR]

Abstract Mangroves are one of the most carbon‐dense forests on the Earth and have been highlighted as key ecosystems for climate change mitigation and adaptation. Hundreds of studies have investigated how mangroves fix, transform, store, and export carbon. Here, we review and synthesize the previously known and emerging carbon pathways in mangroves, including gains (woody biomass accumulation, deadwood accumulation, soil carbon sequestration, root and litterfall production), transformations (food web transfer through herbivory, decomposition), and losses (respiration as CO2 and CH4, litterfall export, particulate and dissolved carbon export). We then review the technologies available to measure carbon fluxes in mangroves, their potential, and their limitations. We also synthesize and compare mangrove net ecosystem productivity (NEP) with terrestrial forests. Finally, we update global estimates of carbon fluxes with the most current values of fluxes and global mangrove area. We found that the contributions of recently investigated fluxes, such as soil respiration as CH4, are minor (35 Tg C year−1). Dissolved inorganic carbon exports are an order of magnitude higher than the other processes investigated and were highly variable, highlighting the need for further studies. Gross primary productivity (GPP) and ecosystem respiration (ER) per area of mangroves were within the same order of magnitude as terrestrial forests. However, ER/GPP was lower in mangroves, explaining their higher carbon sequestration. We estimate the global mean mangrove NEP of 109.1 Tg C year−1 (7.4 Mg C ha−1 year−1) or through a budget balance, accounting for lateral losses, a global mean of 66.6 Tg C year−1 (4.5 Mg C ha−1 year−1). Overall, mangroves are highly productive, and despite losses due to respiration and tidal exchange, they are significant carbon sinks.

Innutrient dynamics, an extremely valuable resource is litterfall. It is crucial to the dynamics of soil nutrients, the characteristics of soil, and the transfer of energy. In an agroforestry system, decomposition and litter fall are the two key processes that contribute to soil enrichment. In addition to affecting soil characteristics and ecology, litter fall in soil has a significant impact on carbon sequestration. The type of tree, the management methods, and the quantity and quality of litter all affect how much the soil is enriched. The complicated ecophysiological process of litterfall is influenced by both internal and external variables. Other significant causes of leaf fall include variations in weather and photoperiod as well as internal plant characteristics like age of leaf or potential endogenous rhythams. Nutrients are converted as a result of decomposition of different components of litter, and their release is influenced by the content of the litter, moisture, activity of microbes, C:N, temperature, and other variables. Litterfall therefore contributes to the long-term maintenance of nutrient levels in forest ecosystems and has been a primary research focus for a better understanding of soil fertility, site productivity, and forest services.

Bamboo invasion into broadleaf forests is a common phenomenon in karst areas; however, the effect of bamboo invasion on soil organic carbon (SOC) in karst areas and the mechanism of the effect are not clear. We selected the study site with broad-leaved forests (BF), mixed forests (MF), and pure bamboo (Indosasa shibataeoides McClure) forests (IF). Furthermore, we sampled the soil from 0 cm to 20 cm and 20 cm to 40 cm layers in the region and investigated the soil properties, organic carbon fractions, and microbial communities. At the same time, we sampled the litterfall layer of different stands and determined the biomass. The results showed that bamboo invasion increased the litterfall biomass per unit area of karst forest, increased the bulk weight of the 0–20 cm soil layer, and lowered the soil pH in the 0–20 cm and 20–40 cm soil layers, bamboo invasion consistently increased the content of soil AN and AK, whereas the content of AP was significantly reduced after bamboo invasion. Both active organic carbon groups (MBC, DOC, and EOC) and passive organic carbon groups (Fe/Al-SOC and Ca-SOC) increased significantly after bamboo invasion. The bamboo invasion increased the diversity of soil microorganisms and bacterial communities; the relative abundance of Actinobacteriota increased in MF and IF, while the relative abundance of Firmicutes decreased in IF. The structure of fungal communities was altered during the bamboo invasion, with an increase in the relative abundance of Mortierellomycota and a decrease in the relative abundance of Basidiomycota at the level of fungal phyla. Partial least squares path modeling analysis identified bamboo invasion enhanced SOC sequestration mainly by increasing litterfall biomass and altering the structure of the fungal community, and the effect of bacteria on SOC was not significant. Our study suggests that bamboo invasion of broadleaf forests is more favorable to soil organic carbon sequestration in karst areas. [ABSTRACT FROM AUTHOR]

Forest ecosystems are critical for their carbon sequestration potential. Increasing tree diversity has been shown to enhance both forest productivity and litter decomposition. Litter diversity increases litter decomposability by increasing the diversity of substrates offered to decomposers. However, the relative importance of litter decomposability and decomposer community in mediating tree diversity effects on decomposition remains unknown. Moreover, tree diversity modulation of litterfall spatial distribution, and consequently litter decomposition, has rarely been tested. We studied tree diversity effects on leaf litter decomposition and its mediation by the amount of litterfall, litter species richness and decomposability, and soil microorganisms in a large‐scale tree diversity experiment in subtropical China. Furthermore, we examined how litter functional identity and diversity affect leaf litter decomposability. Finally, we tested how leaf functional traits, tree biomass, and forest spatial structure drive the litterfall spatial distribution. We found evidence that tree species richness increased litter decomposition by increasing litter species richness and the amount of litterfall. We showed that soil microorganisms in this subtropical forest perform 84–87% of litter decomposition. Moreover, changes in the amount of litterfall and microbial decomposition explained 19–37% of the decomposition variance. Additionally, up to 20% of the microbial decomposition variance was explained by litter decomposability, while litter decomposability itself was determined by litter functional identity, diversity, and species richness. Tree species richness increased litter species richness and the amount of litterfall (+200% from monoculture to eight‐species neighborhood). We further demonstrated that the amount of species‐specific litterfall increased with increasing tree proximity and biomass, and was modulated by leaf functional traits. These litterfall drivers increased the spatial heterogeneity of litter distribution, and thus litter decomposition. We highlighted multiple biomass‐ and diversity‐mediated effects of tree diversity on ecosystem properties driving forest nutrient cycling. We conclude that considering spatial variability in biotic properties will improve our mechanistic understanding of ecosystem functioning. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the importance of litterfall as a link in biogeochemical cycling of certain elements (C, N, P, K, Ca, Mg, Fe, Mn, Cu, and Zn) in silver birch stands growing on post-arable soils under temperate climatic conditions (Poland). The study covered three stands on sandy soils (21, 29, and 40 years old) and three on loamy soils (15, 33, and 41 years old). Litterfall was collected during 2020–2021 and analysed using standard procedures. Elemental contents were determined also in green leaves collected from the tree crowns in early summer to determine intensity of retranslocation. The total litterfall production varied from 2576 to 5293 kg ha−1, depending on the stand and year. These values are typical of temperate forests. Litterfall production was positively correlated with stand age. Leaves made up the major fraction, followed by twigs. Silver birch litterfall was generally rich in nutrients compared to many other tree species typical for temperate climatic zone. Nutrient fluxes to the soil were in the upper limits reported in the literature. It may partially be an effect of the post-arable history of these stands. Large fluxes of nutrients to the soil via litterfall are important in the context of the high nutritional demands of the studied tree species. This study also showed that silver birch strongly retranslocates N, P, and K from senescing leaves, whereas Ca, Mg, Fe, Mn, Cu, and Zn are accumulated in these organs. [ABSTRACT FROM AUTHOR]

Methylmercury in soils and vegetation from the Amazonian rainforest is still poorly studied. Hence, the aim of this work was to determine the total mercury [THg] and methylmercury [MeHg] concentrations in litter and surface soil, MeHg deposition via litterfall, and the MeHg fate during a forest fire in the Amazonian rainforest. Sampling of litter, soil (0-1, 1-2, and 2-5 cm), and ash was carried out before (BB) and after (AB) a prescribed forest fire. The results showed a low [THg] (34 ± 8 ng g-1) and [MeHg] (0.16 ± 0.03 ng g-1) value in litter, with a correspondingly low estimate of the MeHg litterfall flux (0.13 ± 0.03 µgm-2 yr-1) which has been probably underestimated due to potential losses during the field experiment. In ashes, [THg] and [MeHg] values were 23 ± 8 ng g-1 and 0.11 ± 0.04 ng g-1, respectively. Although a significant part of Hg contained in the biomass was lost during the fire, the [MeHg]/[THg] ratio was not affected by it and was the same in litterfall and ash (~0.5%). In soil, the average [THg] BB value was 149 ± 12 ng g-1 in the three layers and [MeHg] was between 0.8 and 1.0 ng g-1. The forest fire only affected the superficial soil, with a significant decrease of [THg] and [MeHg] in the 0-1 cm layer. Similarly, the decrease of the [MeHg]/[THg] ratio in the surface soil layer suggested that MeHg was more readily emitted or degraded than the other Hg species present. [ABSTRACT FROM AUTHOR]

Many degraded ecosystems have altered nutrient dynamics due to invaders' possessing a suite of traits that allow them to both outcompete native species and alter the environment. In ecosystems where invasive species have increased nutrient turnover rates, it can be difficult to reduce nutrient availability. This study examined whether a functional trait‐based restoration approach involving the planting of species with conservative nutrient‐use traits could slow rates of nutrient cycling and consequently reduce rates of invasion. We examined a functional trait restoration initiative in a heavily invaded lowland wet forest site in Hilo, Hawaiʻi. Native and introduced species were chosen to create four experimental hybrid forest communities, in comparison to the invaded forest, with a factorial design in which communities varied in rates of carbon turnover (slow or moderate [SLOW, MOD]), and in the relationship of species in trait space (redundant or complementary [RED, COMP]). After the first 5 years, we evaluated community‐level outcomes related to nutrient cycling: carbon (C), nitrogen (N), and phosphorus (P) via litterfall, litter decomposition, and outplant productivity and rates of invasion. We found that (1) regardless of treatment, the experimental communities had low rates of nutrient cycling through litterfall relative to the invaded reference forest, (2) the MOD communities had greater nutrient release via litterfall than the SLOW communities, (3) introduced species had greater nutrient release than native species in the two MOD experimental communities, and (4) within treatments, there was a positive relationship between nutrient levels and outplant basal area, but outplant basal area was negatively associated with rates of invasion. The negative relationships among basal area and weed invasion, particularly for the two COMP treatments, suggest species existing in different parts of trait space may help confer some degree of invasion resistance. The diversification of trait space was facilitated by the use of introduced species, a new concept in Hawaiian forest management. Although challenges remain in endeavors to restore this heavily degraded ecosystem, this study provides evidence that functional trait‐based restoration approaches using carefully crafted hybrid communities can reduce rates of nutrient cycling and invasion in order to reach management goals. [ABSTRACT FROM AUTHOR]

IntroductionRiverine forests in the Himalaya represent a biodiverse, dynamic, and complex ecosystem that offers numerous ecosystem services to local and downstream communities and also contributes to the regional carbon cycle. However, these forests have not been assessed for their contribution to dry matter dynamics and carbon flux. We studied these parameters along three classes of riverine forests in eastern Uttarakhand, dominated by Macaranga, Alnus, and Quercus-Machilus forest.MethodsUsing volume equations, we assessed tree biomass, carbon storage, and sequestration in the study area.ResultsThe total standing tree biomass in Macaranga, Alnus, and Quercus-Machilus forest ranged from 256.6 to 558.1 Mg ha−1, 460.7 to 485.8 Mg ha−1, and 508.6 to 692.1 Mg ha−1, respectively. A total of 77.6–79.6% of vegetation biomass was stored in the aboveground biomass and 20.4–22.4% in belowground plant parts across the riverine forests. The carbon stock in Macaranga forest ranged from 115.5 to 251.1 Mg ha−1, in Alnus forest from 207.3 to 218.6 Mg ha−1, and in Quercus-Machilus forest from 228.9 to 311.4 Mg ha−1. The mean annual litterfall was accounted maximum for Quercus-Machilus forest (5.94 ± 0.54 Mg ha−1 yr.−1), followed by Alnus (5.57 ± 0.31 Mg ha−1 yr.−1) and Macaranga forest (4.67 ± 0.39 Mg ha−1 yr.−1). The highest value of litterfall was recorded during summer (3.40 ± 0.01 Mg ha−1 yr.−1) and the lowest in winter (0.74 ± 0.01 Mg ha−1 yr.−1). The mean value of net primary productivity and carbon sequestration was estimated to be highest in Quercus-Machilus forest (15.8 ± 0.9 Mg ha−1 yr.−1 and 7.1 ± 0.9 Mg C ha−1 yr.−1, respectively) and lowest in Alnus forest (13.9 ± 0.3 Mg ha−1 yr.−1 and 6.1 ± 0.3 Mg C ha−1 yr.−1, respectively).DiscussionThe results highlight that riverine forests play a critical role in providing a large sink for atmospheric CO2. To improve sustainable ecosystem services and climate change mitigation, riverine forests must be effectively managed and conserved in the region.

Methylmercury in soils and vegetation from the Amazonian rainforest is still poorly studied. Hence, the aim of this work was to determine the total mercury [THg] and methylmercury [MeHg] concentrations in litter and surface soil, MeHg deposition via litterfall, and the MeHg fate during a forest fire in the Amazonian rainforest. Sampling of litter, soil (0–1, 1–2, and 2–5 cm), and ash was carried out before (BB) and after (AB) a prescribed forest fire. The results showed a low [THg] (34 ± 8 ng g-1) and [MeHg] (0.16 ± 0.03 ng g-1) value in litter, with a correspondingly low estimate of the MeHg litterfall flux (0.13 ± 0.03 μgm-2 yr-1) which has been probably underestimated due to potential losses during the field experiment. In ashes, [THg] and [MeHg] values were 23 ± 8 ng g-1 and 0.11 ± 0.04 ng g-1, respectively. Although a significant part of Hg contained in the biomass was lost during the fire, the [MeHg]/[THg] ratio was not affected by it and was the same in litterfall and ash (∼0.5%). In soil, the average [THg] BB value was 149 ± 12 ng g-1 in the three layers and [MeHg] was between 0.8 and 1.0 ng g-1. The forest fire only affected the superficial soil, with a significant decrease of [THg] and [MeHg] in the 0-1 cm layer. Similarly, the decrease of the [MeHg]/[THg] ratio in the surface soil layer suggested that MeHg was more readily emitted or degraded than the other Hg species present.

[Objective] The aim of this study is to explore the carbon sink function of different forest types in subtropical China and better guide significance in tree species selection for forest management and coniferous forest transformation. [Methods] Based on monthly dynamic observation, the dynamic changes of litterfall and carbon (C) and nitrogen (N) return in three forest types including evergreen broad-leaved forest (the Castanopsis carlesii forest), evergreen and deciduous broad-leaved mixed forest (the Betula fujianensis and Phoebe bournei mixed forest) and coniferous forest (the Pinus massoniana forest) in Luoboyan Nature Reserve were studied from September 2018 to August 2019. [Results] The annual litterfall was highest in Pinus massoniana forest [9 815 kg/ (hm²·a)], followed by Betula fujianensis and Phoebe bournei mixed forest [9 207 kg/ (hm²·a)], and lowest in Castanopsis carlesii forest [8 083 kg/ (hm²·a)]. In terms of litter composition, the leaflitter of Betula fujianensis and Phoebe bournei mixed forest and Pinus massoniana forest was relatively high, while other components such as debris in Castanopsis carlesii forest accounted for the highest, followed by leaflitter. The monthly dynamics of total litterfall, leaf litter, flower, fruit and other components of three forests all showed double peak curve, and the peak appeared from November to December and from April to May in the next year, respectively. The range of litter C return was Pinus massoniana forest [4 970 kg/ (hm²·a)]＞Betula fujianensis and Phoebe bournei mixed forest [4 458 kg/ (hm²·a)]＞Castanopsis carlesii forest [3 804 kg/ (hm²·a)], and the range of litter N return was Betula fujianensis and Phoebe bournei mixed forest [160 kg/ (hm²·a)]＞Pinus massoniana forest [128 kg/ (hm²·a)]＞Castanopsis carlesii forest [113 kg/ (hm²·a)]. The dynamic characteristics of litter C and N return of the three forests was consistent with that of total litterfall. Significant differences were observed in litter quality among three forests, and the litter C∶N ratio was highest in Pinus massoniana forest, and lowest in Betula fujianensis and Phoebe bournei mixed forest, the litter lignin concentration was highest in Betula fujianensis, and the litter lignin: cellulose value was highest in Phoebe bournei and Pinus massoniana, and lowest in Castanopsis carlesii. [Conclusion] The Betula fujianensis and Phoebe bournei mixed forest has higher annual litterfall and faster potential decomposition rate, which can supplement nutrients more continuously and quickly. [ABSTRACT FROM AUTHOR]

Nitrogen deposition has a considerable impact on biogeochemical cycling in terrestrial ecosystems. However, how litter production and element return respond to N addition remains poorly understood in nitrogen-rich subtropical regions. In this study, a 4-year nitrogen addition experiment explored its effects on foliar litter production and carbon, nitrogen and phosphorus in a subtropical Michelia wilsonii forest. A clear seasonal pattern in foliar litterfall was observed, regardless of nitrogen treatments, with a peak in spring and a smaller one in autumn. Foliar litter increased with increasing nitrogen but did not affect litter carbon concentrations and often decreased nitrogen and phosphorous concentrations. The effect of nitrogen addition was dependent on time (month/year). Carbon, nitrogen and phosphorous return showed similar bimodal seasonal patterns. Nitrogen addition increased carbon and nitrogen return but did not affect phosphorous. Our results suggest that the addition of nitrogen stimulates carbon and nutrient return via litterfall. [ABSTRACT FROM AUTHOR]

[Objective] The present study focused on the litterfall accumulation and decomposition dynamics of natural and artificial forests in coastal sandy land, and provided theoretical references for the protection and reconstruction of coastal shelterbelt systems. [Method] According to the time dynamic analysis method, two natural forests of Ficus altissima/Sterculia lanceolate natural forests (FS) and Syzygium hancei natural forests (SH), and Acacia mangium plantation pure forest (AM) were selected in the southern subtropical coastal sandy area.The collection net and decomposition bag were used to determine the amount of litterfall accumulation, the residual amount and the initial content of litterfall C, N and P, and to analyze the monthly dynamic change, decomposition rate and the proportion of leaves, branches, flowers+fruits and scraps in each stand.The Olson model and correlation analysis were used to analyze the turnover period and the correlation between decomposition rate and initial nutrients of litterfall. [Result] In the study, the annual litterfall of the three forest types was between 8645.74-23 404.07 kg/hm~2, and the order was FS ＞ SH ＞ AM.Leaf litter was the dominant component in the total litterfall and contributed about 84.24% to 94.98%.There was a significant difference between the foliage litter amount of AM and FS and SH (P＜0.05,the same as below).The total litter and the litter of each component were higher in two natural forests than in artificial forests.The monthly dynamics of annual volume in the three kinds of forests showed three peaks, appearing in May, August and October or November, respectively, and reached the highest annual litter amount in May as a whole, but the specific fluctuation amplitude was different.The decomposition rate of litters showed that FS and SH were both fast at first and then slow, and AM was slow-fast-slow.At the end of the experiment, the order of dry matter residue was AM (66.30%) ＞ SH (46.90%) ＞ FS (23.90%). Litter decomposition conformed to Olson model, and the predicted half-life of decomposition was between 0.423-1.472 a, the litterfall decomposition cycle was AM (6.360 a) ＞ SH (4.016 a) ＞ FS (1.827 a).The decomposition rate of litter showed a very significant negative correlation with the initial C content (P＜0.01), and a significant negative correlation with C/N. [Conclusion] The FS and SH natural forests in coastal sandy land have a large amount of annual litterfall, a fast decomposition rate and a short turnover period, which can improve the soil structure and maintain soil fertility in coastal sandy land.When constructing vegetation restoration and shelter forest system in coastal sandy land, should select group species and associated tree species from local natural forests priorly, to build a near-natural mixed forest or a multi-layer forest.It will increase the biodiversity of the forest and the complexity of litter composition, also increase the contribution rate of the forest to soil nutrients.And it has great significance to the sustainable protection and management of coastal ecosystem. [ABSTRACT FROM AUTHOR]

The interplay between long‐term environmental variability and litterfall is complex and through this study, we quantified the response of peak leaf, flower, and fruit litterfall production to such variability in a lower montane evergreen forest located in Doi Suthep‐Pui National Park, Thailand. We observed seasonality in litterfall accumulation with peak leaf and flower litterfalls occurring mostly during the cool and hot dry seasons, while fruit litterfall occurs mostly during the wet season. Probable associations with environmental drivers (barometric pressure, temperature, relative humidity, number of sunlight hours, evaporation, wind speed, and vapor pressure deficit) were tested on a 5‐year litter trap dataset using superposed epoch analysis and Granger causality tests. The tests indicated that significant deviations in barometric pressure, maximum temperature, maximum relative humidity, and wind speed were the most plausible precursors to peak litter production of all components. Additionally, we observed a lag in peak litterfall production relative to climate variability by up to 4 months for most of the climate variables. Changing environmental conditions can affect both the timing and amount of litterfall production, which in turn can alter the nutrient recycling rate and other essential ecosystem services of such forests. [ABSTRACT FROM AUTHOR]

The concentrations of Co were determined in the hydrological cycle (in maquis and fir forests), litterfall and soils in maquis, oak, beech and fir forests. The concentrations in the hydrological cycle were characterized by high variability. The concentrations in soil solution were much higher than those in the bulk deposition and throughfall. The contribution of the earth’s’ crust in the bulk deposition enrichment with Co was not high but some minor quantities of Co can be considered to be transported in long distances. The concentrations of Co in litterfall were high in the fraction composed of lichens, flowers and mosses, especially in the fir forest. The total content of Co was significantly higher in the soils derived from mica schist than those in the flysch. The residence time of Co in the forest floor was rather long. This is an indication that weathering in the mineral layers plays an important role in providing Co for plant uptake.

Recent studies demonstrate a short 3–6-month atmospheric lifetime for mercury (Hg). This implies Hg emissions are predominantly deposited within the same hemisphere in which they are emitted, thus placing increasing importance on considering Hg sources, sinks and impacts from a hemispheric perspective. In the absence of comprehensive Hg data from the Southern Hemisphere (SH), estimates and inventories for the SH have been drawn from data collected in the NH, with the assumption that the NH data are broadly applicable. In this paper, we centre the uniqueness of the SH in the context of natural biogeochemical Hg cycling, with focus on the midlatitudes and tropics. Due to its uniqueness, Antarctica warrants an exclusive review of its contribution to the biogeochemical cycling of Hg and is therefore excluded from this review. We identify and describe five key natural differences between the hemispheres that affect the biogeochemical cycling of Hg: biome heterogeneity, vegetation type, ocean area, methylation hotspot zones and occurence of volcanic activities. We review the current state of knowledge of SH Hg cycling within the context of each difference, as well as the key gaps that impede our understanding of natural Hg cycling in the SH. The differences demonstrate the limitations in using NH data to infer Hg processes and emissions in the SH. [ABSTRACT FROM AUTHOR]

Litterfall is the carrier of material and energy conversion between plants and soil, and an important link of the nutrient cycle in terrestrial ecosystem. In this paper, during the 2010 and 2011 growing seasons (May -- October), we studied the production, decomposition and turnover of the litterfall of two Reaumuria soongorica communities, located in the Sangong River basin with different growth, as well as their association with soil factors and responses. In the research process, we used the collector and decomposition bag method. The results showed that the monthly litterfall production of the two communities increased initially, and decreased thereafter with time. Their production reached the maximum value in July and August, respectively. The annual litterfall production of community 1 and community 2 was 25.42 g·m–2·a–1 and 34.05 g·m–2·a–1, respectively. The supplement amount of litterfall to soil organic carbon was 11.81 g·m–2·a–1 and 17.65 g·m–2·a–1, respectively. The residual rate was 71.81% and 75.60% after a year's decomposition in community 1 and community 2, respectively. When the litterfall decomposition reached 50% and 95%, it took 2.52 and 14.64 years for community 1 and 3.69 and 20.13 years for community 2, respectively. The turnover of litterfall in community 1 and community 2 was 1.21 times·a–1 and 0.98 times·a–1, respectively. Soil water content, pH and bulk density were the main factors affecting the decomposition of litterfall in the two communities. [ABSTRACT FROM AUTHOR]

Abstract The interplay between long‐term environmental variability and litterfall is complex and through this study, we quantified the response of peak leaf, flower, and fruit litterfall production to such variability in a lower montane evergreen forest located in Doi Suthep‐Pui National Park, Thailand. We observed seasonality in litterfall accumulation with peak leaf and flower litterfalls occurring mostly during the cool and hot dry seasons, while fruit litterfall occurs mostly during the wet season. Probable associations with environmental drivers (barometric pressure, temperature, relative humidity, number of sunlight hours, evaporation, wind speed, and vapor pressure deficit) were tested on a 5‐year litter trap dataset using superposed epoch analysis and Granger causality tests. The tests indicated that significant deviations in barometric pressure, maximum temperature, maximum relative humidity, and wind speed were the most plausible precursors to peak litter production of all components. Additionally, we observed a lag in peak litterfall production relative to climate variability by up to 4 months for most of the climate variables. Changing environmental conditions can affect both the timing and amount of litterfall production, which in turn can alter the nutrient recycling rate and other essential ecosystem services of such forests.

Litterfall may facilitate the outperformance of exotic species by inducing better resource acquisition and reproductive performance. However, the drivers that determine litterfall patterns in exotic and native species have remained insufficiently investigated due to the lack of long-term observations. Here, we employed empirical dynamic modeling on a two-decade-long litterfall observation (1999–2019) in a subtropical mangrove forest in Shenzhen, China, to evaluate the relative importance of environmental drivers on different species. We found that mangrove leaf litterfall in both exotic and native species was strongly altered by temperature, and the causal relationship was stronger in the dominant exotic species Sonneratia apetala compared to native species. However, the main driver of reproductive output differed largely between exotic and native species; temperature was the main cause of native reproduction, whereas coastal nutrients drove the reproductive output of exotic species. Our study highlighted that high nutrient availability in Shenzhen Bay in the past decade allowed the exotic species S. apetala to gain better reproductive output than native species. We imply that enriched nutrients in coastal water likely contributed to exotic dominance in China’s coastal mangrove forest.

The effective performance of ameliorative functions by water protection plantations is largely determined by the development of the forest litter, its structure, capacity, quality composition, and degree of mineralization. Therefore, the aim of the study was to identify the features of the formation of the forest litter of pine plantations of the Ukrainian interfluves of the Dnipro and Desna. The study of forest litter was carried out on the accounting sites in all age groups of plantations, in which 22 test plots were laid. Litter samples were taken in between rows and directly in rows of forest plantations. During the analysis of the qualitative composition of the forest litter of young plantations, the dominance of the upper horizon of the inactive fraction, which consisted mainly of needles and branches, was revealed. Here, the share of inactive litter in the conditions of moist poor pine site and moist relatively poor pine site was 8.13 t/ha or 85.1% and 12.54 t/ha or 92.1%, respectively. A large amount of dust, which forms the active fraction, was recorded in the lower horizon. Its stocks were 5.3-5.6 times higher than the reserves of inactive litter. In general, in young pine forests in the conditions of moist poor pine site, the stock of inactive litter is 15.10 t/ha (28.1%), while its presence in of moist poor pine site is 17.91 t/ha, 36.5%. In middle-aged pine forests, the share of the active litter fraction increases, which is a consequence of the active action of its decomposition processes. The share of active litter is 79.3% or 155.29 t/ha in mature stands of the conditions of moist poor pine site. This is evidence of the intensification of the processes of mineralization and activation of the circulation of substances. Three horizons are clearly distinguished in the litter of plantations of older age groups, with a strong connection between them. The lower layer of the forest litter of water conservation plantations is permeated with physiologically active roots, which forms its dense type of structure. Under such conditions, during the separation of the lower layer of litter from the upper one, it does not fall apart and its structure remains dense. The presence of strongly intertwined physiologically active roots in the third horizon of the litter is evidence of the activation of microbiological processes, which are also accelerated by the interception of moisture and the accumulation of humus particles of the soil by the lower layers of the forest litter. To prevent the development of flood processes, the effective performance of water regulation and water purification functions, it is recommended to create water conservation plantations with the formation of the identified type of forest litter

Stored carbon varies among wetlands, yet they rank among the highest carbon accumulating ecosystems. Leaf litter production and aboveground carbon storage are frequently used as proxies for estimating primary productivity, which can be affected by flooding, salinity and other environmental factors. The objective of this study was to quantify leaf litter production and soil carbon density in two coastal tropical wetland types, namely mangrove swamps and forested freshwater wetlands. Water and soil physicochemical properties, together with leaf litter production, were measured bimonthly between 2007 and 2009 in wetlands of both types, located on the coast of the Gulf of Mexico. The soils ranged from entirely mineral to entirely organic in the top metre. Mangrove sites had relatively uniform hydroperiods and moderately reductive soils, whereas forested freshwater wetlands had reducing conditions. Electrical conductivity was lower and pH less acidic in forested freshwater wetland soils. Litterfall was around 1000 g m-2 yr-1 and annual production did not differ significantly between wetlands, despite the presence of acidic soils with prolonged flooding and high salinity in the mangrove swamps. Also, there were no consistent differences in soil carbon density between the two wetland types. Some forested freshwater wetlands had low litter production and high soil carbon density, whereas some mangrove swamps had high litter production and low soil carbon density. We present information regarding aboveground biomass turnover and belowground carbon storage in coastal tropical forested wetlands which is greatly needed to support us in understanding, valuing and conserving these neglected ecosystems.