Total Litterfall Research Articles

Responses of aboveground litterfall respiration to unexpected snowfall events in Ailao subtropical forests in Southwest China

Soil respiration, the second largest CO2 flux in terrestrial ecosystems, involves the microbial respiration of litter from aboveground sources, belowground litter and root respiration, from rhizodeposition. In the subtropical forests of the Ailao Mountain, a chamber with automated CO2 efflux was set up with two treatments: a control treatment with litterfall to measure the total soil respiration (RT) and a litter removal treatment to measure aboveground litterfall respiration (RL). This study aimed to examine the responses of RL to unexpected heavy snowfall events and soil temperature (ST), soil moisture (SM), rainfall (RF), total litterfall (TL), litter water content (LWC), nitrate nitrogen (NO3−-N), and ammonium nitrogen (NH4+-N). The period of the study was divided into two: before the heavy snowfall event (BS) and during and after the heavy snowfall event (AS). The rate of RL was slightly decreased in AS (1.18 ± 0.03 μmol CO2 m−2 s−1) compared with that in BS (1.19 ± 0.02 μmol CO2 m−2 s−1). The relationships between RL and ST, SM, RF, and LWC, respectively, were all statistically significant (p < 0.05) in both periods. However, the relationships between RL and TL and NH4+-N, respectively, were not statistically significant for either period. The relationship between RL and NO3−-N was statistically significant for AS but not for BS. The relationship between RL and RF was statistically significant from 2011 to 2018. The temperature dependence of soil respiration was higher in BS than in AS, and the effect of litter removal was 2.55 % and 2.32 % for AS and BS respectively. The results indicate that current global terrestrial models underestimate RL trends for the feedback of global climate change in subtropical forests.

Pore Water Chemical Variability and Its Effect on Phenological Production in Three Mangrove Species under Drought Conditions in Southeastern Mexico

Mangrove forests have proven to be resilient to most environmental change, surviving catastrophic climate events over time. Our study aimed to evaluate the chemical variability of pore water and its effect on phenological production in three mangrove species (Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa) along the coast of the state of Campeche during a year of severe drought (2009) and a year of average precipitation (2010). Pore water salinity and redox potential were measured monthly in a mangrove forest in 2009 and 2010. Litterfall production and reproductive phenology was measured monthly. We determined the relationships among litterfall production, reproductive phenology, pore water chemistry and precipitation of three species between years. Precipitation, pore water salinity and redox potential significantly differed among years, seasons and sites, and also showed significant interaction between years and seasons (p &lt; 0.05). Significant variation was observed in litterfall production, propagules, flowers, and leaf litter among sites (p &lt; 0.05). A significant change was observed in propagules and flowers among years, and in total litterfall and leaf litter between seasons and species (p &lt; 0.05). Under severe drought, salinity had the strongest effect on total litterfall and propagules in R. mangle, while A. germinans, had the strongest effect on propagule/flower precipitation. Both A. germinans and L. racemosa showed higher resilience than R. mangle at all sites under severe drought conditions. These findings can support activity allocation for mangrove conservation and restoration by providing the tolerance thresholds of the three species that dominate in the regional area of Campeche state. Likewise, this research provides knowledge to the Intergovernmental Experts Group on climate change about drought intensity and its magnitude of impact on mangrove productivity, reproduction and integrity.

Variations in Litterfall Dynamics, C:N:P Stoichiometry and Associated Nutrient Return in Pure and Mixed Stands of Camphor Tree and Masson Pine Forests

Litterfall, directly and indirectly, affects the soil physicochemical properties, microbial activity, and diversity of soil fauna and flora by adding organic matter and nutrients to the soil. This study explores litterfall dynamics such as litterfall production, litter decomposition rate, and associated nutrient return in three forest types, that is, camphor tree forest (CTF), Masson pine forest (MPF), and camphor tree and Masson pine mixed forest (CMF), in subtropical China. Results showed that CMF had the highest mean annual litterfall production (4.30 ± 0.22 t ha−1), which was significantly higher than that of MPF (3.41 ± 0.25 t ha−1) and CTF (3.26 ± 0.17 t ha−1). Leaf represented the major fraction of litterfall, constituting over 71% of the total litterfall mass in the three forest types. The contribution of branch litter was 16.3, 8.9, and 16.9%, and miscellaneous litter was 12.6, 18.9, and 11.1% in CTF, MPF, and CMF, respectively. The concentration of macronutrients ranked as N &amp;gt; Ca &amp;gt; K &amp;gt; Mg &amp;gt; P in all litter fractions. The total annual macronutrient return to the soil from the litterfall was in order as CTF (74.2 kg ha−1‧yr−1) &amp;gt; CMF (70.7 kg ha−1‧yr−1) &amp;gt; MPF (33.6 kg ha−1‧yr−1). The decomposition rate was higher in leaf litter than in branch litter throughout the three forests. Among the forest types, the leaf and branch decomposition rates were in a pattern: CTF &amp;gt; CMF &amp;gt; MPF. The ratio of C/N in both leaf and branch litters was significantly higher in MPF than in CTF and CMF, while no significant differences in N/P ratio were found in these litters among the three forests. The high N:P ratios in leaf litter (23/30) and the branch (24/32) litter indicated the high N returning and low nutrient returning to the soil. Our results suggested that the broadleaved forests have faster litter decomposition and higher macronutrient returns than conifer forests. Moreover, the litter decomposition rate was mainly associated with litterfall quality and chemical composition. The introduction of broadleaved trees into monoculture coniferous stands could increase litter production nutrients return, and thus, it had advantages in soil nutrients restoration and sustainable forest management.

Linking soil phosphorus with forest litterfall resistance and resilience to cyclone disturbance: A pantropical meta-analysis.

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.

Reduced litterfall and decomposition alters nutrient cycling following conversion of tropical natural forests to rubber plantations

Natural tropical landscapes have been continuously altered by land use change and other climate factors. Forest management practices have transformed massive tropical forests into rubber plantations throughout mainland Southeast Asia and Southwest China. However, the effect of the forest-to-plantation conversion on ecosystem functions associated with plant litter is limited. Here, we compare litterfall production, decomposition, nutrient return and nutrient use efficiency between a tropical natural forest (TNF) and a monoculture rubber plantation (MRP) in Xishuangbanna (China) over three years. Annual mean litterfall production was significantly higher in TNF (10.92 Mg ha−1 yr−1) than in MRP (5.23 Mg ha−1 yr−1). Production of leaf litter was positively correlated to that of total litterfall, suggesting that leaf litter could be reliably estimated from total litterfall. Temperature and solar radiation are dominant drivers of seasonal variation of litterfall production. The litterfall production was more sensitive to climate variables in MRP. The average stand litter and the decomposition quotient were 1.8 and 1.2 times greater in TNF than in MRP, respectively. The total nutrient return to the forest floor was 2.1 times higher in TNF (5.66 Mg ha−1 yr−1) than in MRP (2.76 Mg ha−1 yr−1); the return of each mineral element was significantly lower in MRP relative to TNF. The nutrient return preferentially occurred during the cold and dry seasons, which was consistent with the trend of litterfall. Relatively high N, P, Ca, and Mg use efficiencies were observed in MRP in line with their deficiency in the present tropical soils, indicating that rubber trees likely possess an efficient nutrient uptake mechanism to facilitate their adaption to oligotrophic habitats. Our results suggest that the large scale transformation of tropical forests to rubber plantations could alter the biogeochemical cycles related to litterfall, and thus possibly affect the resilience of ecosystems to climate variation. An increasing organic matter input in rubber monoculture may favor the sustainable development of rubber cultivation.

Structure and functioning of Coriaria nepalensis dominated shrublands in degraded hills of Kumaun Himalaya. I. Dry matter dynamics

AbstractIn Kumaun Himalaya, the shrublands dominated by Coriaria nepalensis are present in patches and due to their facilitative nature enhance the restoration of degraded hills. This study deals with the dry matter dynamics of C. nepalensis shrublands. The equation for C. nepalensis was developed to measure the biomass and to understand the dry matter dynamics through compartmental models. Total biomass of tree, shrub and herb varied from 71.66 to 217.40 t ha−1, 43.65 to 77.55 t ha−1 and 11.11 to 64.55 t ha−1, respectively. The biomass of herbs was higher during monsoon and lowest during the summer season. Litter fall varied from 1.02–1.70 t ha−1 yr−1 and the highest value of litter fall was recorded during winter (52%) followed by rainy (29%) and summer season (19%). Order of contribution of different components to total litter fall was: foliage (45.32%–50.33%) &gt; twigs (36.80%–42.22%) &gt; miscellaneous litter (4.62%–6.97%) &gt; Bark (3.56%–5.47%) &gt; reproductive parts (2.13%–3.57%). Shrub floor biomass was recorded maximum during the rainy season (11.32–37.55 t ha−1) followed by the winter season (13.03–25.36 t ha−1) and minimum in the summer season (6.83–12.80 t ha−1). Net primary productivity in trees, shrubs and sapling was ranged from 0.94 to 11.01, 1.83 to 4.88 and 0.55 to 0.87, respectively. Due to less canopy cover, the litter fall was less than from the majority of the forest types of the region. Thus, proper conservation and management measures must be designed to improve the structural components and functional traits of the shrubland ecosystem to enhance the ecological services on sustained basis.

Effects of Forest Thinning on Soil Litter Input Nutrients in Relation to Soil CO2, CH4, and N2O Fluxes in Greece

The contribution of litterfall (dead leaves, twigs, etc., fallen to the ground) and forest floor (organic residues such as leaves, twigs, etc., in various stages of decomposition, on the top of the mineral soil) is fundamental in both forest ecosystem sustainability and soil greenhouse gases (GHG) exchange system with the atmosphere. The effect of different thinning treatments (control-no thinning, traditional-low thinning, selective-intense thinning) on litterfall and forest floor nutrients, in relation to soil GHG fluxes, is analyzed. After one year of operations, thinning had a significant seasonal effect on both litterfall and forest floor, and on their nutrient concentrations. The intense (selective) thinning significantly affected the total litterfall production and conifer fractions, reducing them by 46% and 48%, respectively, compared with the control (no thinning) sites. In the forest floor, thinning was able to significantly increase the Fe concentration intraditional thinning by 59%, and Zn concentration in the intense thinning by 55% (compared with control). Overall, litterfall acted as a bio-filter of the gasses emitting from the forest floor, acting as a GHG regulator.

Influence of input litter quality and quantity on carbon storage in post-mining forest soil after 14 years of reclamation

Reclamation of post mining soils by planting trees is of great research interest due to its potential to stabilize mine soils and sequester atmospheric carbon (C). However there are knowledge gaps regarding the effect of different litter quality and biomass on the C sequestration vis-à-vis molecular characterization of soil organic carbon (SOC) in reclaimed mine soils. Hence, an experiment was conducted to determine the effect of litter quality, quantity, and leaf litter decomposition rate on the quality and quantity of carbon sequestered after 14 years of restoration by three representative plant species (Azadirachta indica, Dalbergia sissoo, and Gmelina arborea) which have been frequently used for revegetation of post-mining sites in India. Results indicate that significant amounts of carbon accumulated under different tree species (47.44, 42.34, and 20.17 Mg C ha−1 under A. indica, D. sissoo, and G. arborea plantations resepctively) as compared to recent dump. Decomposition rate constant had a significant relationship with C/N ratio and nitrogen (N) content and therefore tree species (A. indica) with high C/N, lignin/N ratios, and low N content had a significantly lower decomposition rate constant thereby sequestering more carbon, making it the tree species of choice. Among the three tree species studied, G. arborea witnessed the highest litterfall (4635 kg ha−1 yr−1) but had the lowest SOC stock due to the highest decomposition rate constant (0.00229), which established the fact that composition of leaf litter rather than total litterfall played a significant role in carbon sequestration. Furthermore, spectroscopic methods (UV–vis and FTIR) could clearly distinguish differences in functional groups and molecularity of the humic acids derived from plant species of different resource quality and hence can be effectively used in studying the quality of C sequestered.

Litterfall and Accumulated Nutrients in Pinus taeda Plantation and Native Forest in Southern Brazil

The dynamics of the production, chemical composition, and accumulated nutrients in litterfall are essential to understand the availability of nutrients and, consequently, possible gains in productivity in different forest types. Thus, the objective of the present study was to evaluate the litterfall and the accumulated nutrients in litterfall in a Pinus taeda plantation and native forest from southern Brazil. Two forest types: (i) an eight-year-old Pinus taeda L. plantation; and (ii) a native forest fragment, located in southern Brazil, were studied for four years. The monthly and annual litterfall production, chemical composition, accumulated nutrients, and nutrient use efficiency of the litterfall were evaluated. The Pinus taeda plantation showed higher values of leaves/needles litterfall and N, P, K, Ca and Mg use efficiency. This demonstrates that Pinus taeda plantations have a high production of needle biomass, which, in turn, has increased cell division, favoring the entry of these nutrients into the soil via decomposition. Our results show that total litterfall production did not significantly influence the accumulated nutrient and nutrient efficiency of litterfall, demonstrating that evaluating litterfall fractionation, such as leaves/needles, twigs and miscellaneous, is essential to understand the quantity and quality of litterfall and, thus, the nutrient cycling, which can contribute to possible silvicultural practices to be implemented, which can provide growth gains in forest types.

Temperature and Precipitation Diversely Control Seasonal and Annual Dynamics of Litterfall in a Temperate Mixed Mature Forest, Revealed by Long‐Term Data Analysis

AbstractLitterfall is a good indicator of overall forest functions in forest ecosystems. Globally, forest litterfall has been extensively investigated, however, there is a lack of long‐term data analysis to show the various litterfall components in relation to environmental factors on the monthly and yearly scales. Here, monthly (May–October) and annual (1981–2018) litterfall including leaves, twigs, bark, reproductive, and miscellaneous fractions were collected in a mixed mature Pinus koraiensis forest on Changbai Mountain in Northeast, China, across 30 years. Based on these long‐term litterfall data, we analyzed the seasonal and annual variations in different litterfall fractions and the internal/external drivers. We observed that both the leaf and total litterfall exhibited a strong, similar seasonal pattern, with the highest levels between September and October, and the annual litterfall had an “S‐shaped” increasing pattern from 1981 to 2018. The other litterfall fractions showed distinct monthly and yearly fluctuations across the 30 years. Mean monthly evapotranspiration and temperature (minimum and maximum) were the best predictors for monthly litterfall. By contrast, the models that best predicted the annual litterfall production included mean annual precipitation and mean monthly precipitation and temperature in May and October. Our study, using a unique dataset of detailed long‐term litterfall dynamics, has potentially major significance for enhancing our understanding of the role of climatic factors controlling forest litterfall amount and seasonality in temperate mixed mature forests. This insight is of paramount importance for modeling and estimating soil carbon sequestration and nutrient cycling of temperate forests under climate change.

Cycling and retention of nitrogen in European beech (&amp;lt;i&amp;gt;Fagus sylvatica&amp;lt;/i&amp;gt; L.) ecosystems under elevated fructification frequency

Abstract. Atmospheric deposition of nitrogen (N) has exceeded its demand for plant increment in forest ecosystems in Germany. High N inputs increased plant growth, the internal N cycling within the ecosystem, the retention of N in soil and plant compartments, and the N output by seepage water. But the processes involved are not fully understood, notably the effect of fructification in European beech (Fagus sylvatica L.) on N fluxes. The frequency of fructification has increased together with air temperature and N deposition, but its impact on N fluxes and the sequestration of carbon (C) and N in soils have been hardly studied. A field experiment using 15N-labeled leaf litter exchange was carried out over a 5.5-year period at seven long-term European beech (Fagus sylvatica L.) monitoring sites to study the impact of current mast frequency on N cycling. Mean annual leaf litterfall contained 35 kg N ha−1, but about one-half of that was recovered in the soil 5.5 years after the establishment of the leaf litter 15N exchange experiment. In these forests, fructification occurred commonly at intervals of 5 to 10 years, which has now changed to every 2 years as observed during this study period. Seed cupules contributed 51 % to the additional litterfall in mast years, which creates a high nutrient demand during their decomposition due to the very high ratios of C to N and C to phosphorus (P). Retention of leaf litter 15N in the soil was more closely related to the production of total litterfall than to the leaf litterfall, indicating the role of seed cupules in the amount of leaf N retained in the soil. Higher mast frequency increased the mass of mean annual litterfall by about 0.5 Mg ha−1 and of litterfall N by 8.7 kg ha−1. Mean net primary production (NPP) increased by about 4 %. Mean total N retention in soils calculated by input and output fluxes was unrelated to total litterfall, indicating that mast events were not the primary factor controlling total N retention in soils. Despite reduced N deposition since the 1990s, about 5.7 out of 20.7 kg N ha−1 deposited annually between 1994 and 2008 was retained in soils, notably at acid sites with high N/P and C/P ratios in the organic layers and mineral soils, indicating P limitation for litter decomposition. Trees retained twice as much N compared to soils by biomass increment, particularly in less acidic stands where the mineral soils had low C/N ratios. These results have major implications for our understanding of the C and N cycling and N retention in forest ecosystems. In particular the role of mast products in N retention needs more research in the future.

Decline in nutrient inputs from litterfall following forest plantation in subtropical China

The rapid conversion of natural broadleaved forests to plantations (mainly Cunninghamia lanceolata and Pinus massoniana) in subtropical China has resulted in a substantial decline in soil fertility, but the biogeochemical mechanism behind this decline remains not fully understood. Litterfall is an important source of nutrients that are returned to soils through litter deposition and decomposition. We assessed various types of litterfall (leaves, twigs, flowers, fruits and unidentified litter) monthly and their carbon (C), nitrogen (N), phosphorus (P) and potassium (K) inputs to soils in a natural broadleaved forest (Castanopsis carlesii) and in P. massoniana and C. lanceolata plantations over 10 years. The total litterfall was 21–25% lower in plantations than in the C. carlesii forest, resulting in much lower C (−17% and −14%), N (−62% and −52%), P (−24% and −32%) and K (−53% and −40%) inputs from litterfall in the P. massoniana and C. lanceolata plantations. Leaves accounted for 72–76% of the total litterfall, so we compiled available data on the nutrient release from the three foliar litters during the 1st year of decomposition throughout subtropical China. The decomposition rates of P. massoniana and C. lanceolata needle litter were only half that of C. carlesii leaf litter, and the lower initial quality of P. massoniana and C. lanceolata needle litter relative to C. carlesii leaf litter resulted in significantly lower amounts of N (−95% and −76%) and P (−48% and −25%) being released. These results suggest that low nutrient (N, P and K) inputs due to low litter production and slow nutrient release due to slow litter decomposition are two important biogeochemical reasons for the decline in soil fertility in plantations in subtropical China.

Biotic and climatic controls on the interannual variation in canopy litterfall of a deciduous broad-leaved forest

Canopy litterfall is an important component of net primary productivity (NPP) in forests, but the climatic and biotic controls on its interannual fluctuation remain poorly understood. In this study, we quantified the interannual variation in and the influencing factors of the canopy litterfall with 45 litter traps in nine plots for 12 years (2008 − 2019) in a temperate deciduous broad-leaved forest in Northeast China. The coefficients of interannual variation in the total (7.3%) and leaf (5.6%) litterfall were substantially lower than those in the basal area (BA) increment (21.0%) and gross primary productivity (10.2%). Climatic (i.e., air temperature, thermal time, precipitation, and radiation) and biotic (i.e., BA and species richness) factors jointly controlled the annual production of litterfall for individual plots and species. Significant climate legacy effects were detected in all components of the litterfall, with the strongest in woody tissue component that contributed to 58.9% of the total litterfall variability. The most important factor driving the variability of the total litterfall and its non-leaf components was climate legacy effect (67.2% to 86.6%), while those for the leaf litterfall were BA (40.4%) and species richness (38.3%). We conclude that high species richness of the deciduous forest increases the temporal stability of canopy productivity, and leaf productivity is much more stable than wood productivity as indicated by BA increament. These findings provide insight into spatiotemporal dynamics in the litterfall and canopy NPP in temperate deciduous forests.

Carbon Storage of Single Tree and Mixed Tree Dominant Species Stands in a Reserve Forest—Case Study of the Eastern Sub-Himalayan Region of India

In recent decades, carbon (C) management is an important point on the agenda to identify the best viable mitigation strategies for its reduction. The study was conducted at Jaldapara National Park located in the Eastern Himalayan region of India. The study quantified litter production, decomposition, periodic nutrient release, soil fertility status, and soil organic carbon (SOC) of five major forest stands i.e., Tectona grandis (TGDS), Shorea robusta (SRDS), Michelia champaca (MCDS), Lagerstroemia parviflora (LPDS) and miscellaneous stand (MS). A stratified random nested quadrate method was adopted for sample collection. Results reveal that the greatest amount of litter production and decomposition was under MCDS followed by MS, LPDS, SRDS, and the smallest under TGDS. The material annual turnover through litter decomposition in all the stands varies between 96.46% and 99.34%. The content and amount of the available nutrients in litter varied significantly among the stands. Moreover, release of these nutrients was nearly equal to the amount available in the initial litter mass. In general, the magnitude of the total nutrient return was in the same order as the total litter fall and the nutrient availability was more closely related to litter nutrient content and soil organic carbon. The range of pH (4.86–5.16), EC (0.34–0.50), soil moisture (27.01–31.03) and available primary nutrients (N: (0.21–0.26 Mg/ha), P: (0.09–0.12 Mg/ha), K: (0.13–0.14 Mg/ha)) also varied significantly among the stands. Significant positive correlations were observed between SOC, N and K. Both the fertility indices exhibited no definite pattern in the stands but a significant correlation between the two indicates the healthy soil fertility status of the stands. SOC varies significantly under different forest stands, but the greatest content was found under MS. The estimated SOC ranges between 75.9 and 107.7 Mg ha−1 up to 60 cm and is reported to be below the Indian average of 182.94 Mg ha−1. The present study strongly recommends that Tectona grandis, Shorea robusta, Michelia champaca, and Lagerstroemia parviflora should be the important commercial timbers of the Eastern Himalayan region because they may help further to increase the C sink in agricultural and degraded landscapes.

Change of the litter fall, decomposition, and nutrient release in cork oak forest after anthropogenic disturbances in North West of Tunisia.

In Mediterranean forests, anthropogenic disturbances received little interest in regards to their shrub layer induced enlargement. We studied in the cork oak forest of Beni Métir and in undisturbed and disturbed sites, the relative contribution of the tree (LT, DLT) and shrub (LS, DLS) layers to litter fall, litter decomposition, and nutrients dynamic. Our results showed that disturbance significantly (p < 0.001) reduced (-43%) total litter fall in DS in comparison with S (583 g m-2 year-1); the increased (+ 54%) shrub layer contribution to site litter fall did not counterbalance the decreased input by the tree layer. Leaf litter decomposition was negatively affected (p < 0.001) by disturbance, the remaining mass value being after 2 years, approximately 14 and 33%, respectively, for S and DS. This resulted into a gain of above ground soil organic matter 1.3 higher in DS than it was in S whereas the shrub layer contribution to litter fall increased by 50%. The prevailing driver of decomposition was very probably not related to litter quality but rather site-dependent. Indeed, layers of the same site shared the same remaining mass in spite of significant differences (p < 0.05) in initial content of minerals (N, Ca, and Mn) implicated in biological decomposition. In the disturbed site, the nutrient input by the shrub layer increased by more than double, but its low nutrient quality drastically impaired litter decomposition and mineral return at the site level. In conclusion, this study highlighted the importance of shrub layer which must be taken into account when considering any disturbance assessment and management of Mediterranean forests.

Estimation of the soil and plant nutrient budget of the traditional Eucalyptus based agroforestry system in different spacing

Traditional tree-integrated farming systems are adopted for the security of food, fodder and fuelwood. Therefore, investigations were carried out to study the leaf litter, wood litter, miscellaneous litter and total litterfall in Eucalyptus based agri-silvicultural system. It was further observed from the analysis of the data that leaf component was the main contributor to the total above-ground biomass in all the planting spacings followed by woody and miscellaneous. The major nutrient pool was in leaves, branches and miscellaneous matter types of litter. The total return of nutrients during both the years study period was in6×1.5 m spacing returned the highest amount of N (54.04 kg/ha) through leaf litter followed by 3×3 m spacing (53.05 kg/ha), 17×1×1 m spacing (52.85 kg/ha) in 2014-15. Out of which the total amount of these nutrients used by the intercrops was 44.01 (kg/ha) of nitrogen, 9.96 (kg/ha) phosphorus and 68.65 (kg/ha) of potassium. Hence the remaining amount 45.31 (kg/ha) of nitrogen and 7.05 (kg/ha) of phosphorus. Which was ultimately left unused in the soil during seven and eighth year of Eucalyptus planted at 3×3 m spacing the farmers can take barley as an intercrop with the Eucalypts terticornis with a spacing of 3×3 m without adding any additional amount of nitrogen and phosphorus into the system. Hence can save some additional cost of fertilizer, which otherwise they have to add to raise intercrops with Eucalyptus.

Site quality and vegetation biomass in the tropical Sal mixed deciduous forest of Central India

Tropical Sal forests are gaining wide recognitions due to its multifarious significance. An estimation of vegetational structure and biomass would be helpful for evaluating both productivity and sustainability of the forest ecosystems. Information regarding vegetational biomass, litter mass and fine root biomass, and overall dry matter dynamics are very limited. Therefore, the present work deals the vegetation biomass influenced by four different site quality of Sal dominating tropical deciduous forest of Chhattisgarh, India. The current study provides a framework under which all vegetational attributes can be quantified under varying site quality which is modified by different seasons. Our study revealed a significant increase in vegetational attributes and biomass as per increasing quality of sites. The density value (individuals/ha) and basal area (m2/ha) of tree, sapling and seedling in different sites were ranged from 710 to 1010, 2000 to 2500, 9750 to 14,500 and 33.5 to 46.8, 0.32 to 0.33, 17.96 to 21.43, respectively. The total biomass varied from 187.39 to 383.46 t ha−1. The fine root and forest floor biomass varied between 2.44 and 4.20 t ha−1, and 2.32 and 2.83 t ha−1, respectively among different sites and seasons. The total litter fall varied from 4.18 to 5.69 t ha−1 yr−1 across the site quality. It reflected that highest value of forest floor, litter floor and fine root biomass were seen in site quality (SQ) SQ-I followed by SQ-II, SQ-III and SQ-IV, respectively in different seasons. A great synergy exists among site quality, stand structure and biomass which surely affect ecosystem structure and its functions. Seasonal impacts are another factor that regulates vegetational statistics, forest floor, fine roots and pattern of litterfall in varying site qualities. Thus, a management implication is needed to understand site quality variation which entirely affects vegetational structure and biomass pattern that would help in strengthening sustainable forest management program.

Phenology and litter production in the mangrove genus Xylocarpus along rainfall and temperature gradients in tropical Australia

We investigated how variation in climate influences the timing and intensity of phenological events in two species of the mangrove genus Xylocarpus. Leaf fall in Xylocarpus granatum was continuous in high rainfall sites but was seasonal at sites with long dry seasons. Xylocarpus moluccensis is deciduous, and leaf shedding occurred over 1–2 months at different times in dry season months. Budding and flowering were tightly coupled in X. granatum and occurred in the wet season. At the highest rainfall site, flower fall in X. moluccensis occurred in the mid-wet season, but occurred 9 months later at other sites with protracted dry seasons. For X. moluccensis, the quantities of leaves, buds, flowers and total litter fall were negatively related to annual rainfall, whereas bud fall was negatively related to air temperature. Variations in the quantity of litter produced by X. granatum were not explained by the environmental variables considered. Mean litter production was significantly greater for X. moluccensis than X. granatum (5.16 v. 3.37Mgh–1 year–1 respectively). Mixed forest litter production was greater in forests containing X. moluccensis than X. granatum (7.86 v. 5.95Mgh–1 year–1 respectively). X. granatum has a more plastic response to environmental drivers of canopy production than X. moluccensis.

Litterfall production, carbon and nutrient return to the forest floor in Pinus brutia forests in Turkey

ABSTRACT In this study, we aimed at investigating carbon and nutrient concentration in litterfall components and calculating the weighted concentrations. Then, we estimated the annual carbon and nutrient return to the forest floor through litterfall. The study was carried out in even-aged stands of Pinus brutia in Antalya, in the South-Western part of Turkey. The litterfall samples were separated into five components, namely needles, bark, branches, cones, and “miscellaneous” which included flowers, buds, resins, etc. The amount of carbon and nutrients including N, P, K, Ca, Mg, Fe, Zn, Cu, Mn, and Na were determined for each component. Carbon and nutrient concentrations differed significantly among litterfall components. The mean annual carbon returned to the forest floor was found to be 1515.9 (kg ha−1yr−1), which corresponds to 51.62 % in total annual litterfall. The annual amounts of nutrients of N, Ca, K, Mg and P returned to the forest floor were calculated as 149.7, 36.9, 7.2, 6.6, and 2.1 (kg ha−1yr−1), respectively. The weighted C concentration calculated in this study can be used for more accurate national carbon sink reporting. In addition, information on nutrients returned to the forest floor via litterfall could be useful in various forest and watershed management activities.

Chinese privet (Ligustrum sinense Lour.) alters the timing of litterfall and nutrient quality of leaf litter inputs in invaded riparian forests

The invasive non-native shrub Chinese privet occupies riparian forests throughout the southeastern US however little is known regarding its ability to impact ecosystem processes. This study aimed to characterize phenological patterns of privet litterfall, litter chemistry, and changes in availability of mobile soil nutrients within riparian zones invaded by privet. Comparisons of native and invaded sites showed that privet invasion alters the timing but not quantity of litter deposition. In contrast to native species, total privet litterfall displayed little seasonal variation however invaded sites had similar total litter mass compared to native sites. Within invaded sites privet litter was 26% of total litterfall in spring. Privet leaf litter was seasonally enriched in nitrogen during winter as compared to fall and spring. Compared to native sites, invaded sites had significantly increased soil nitrate availability and decreased soil carbon:nitrogen ratios. In contrast, dissolved organic matter and dissolved nitrogen in soil solution was lower in invaded compared to native sites. Results suggest that privet enhances litter and inorganic nitrogen availability in ways that have potential to impact decomposer and detritovore communities in the riparian zone and adjacent aquatic systems.