Litter Production Rate Research Articles

Comparison of the Potential of Mangrove Forests as an Estimate of Carbon Stocks : A Review

Global warming is an increase in carbon dioxide gas (CO2) and other gases in the earth's atmosphere, which will make the earth's atmosphere retain more heat coming from the sun. This study aimed to determine the highest carbon stock ratio from various areas with mangrove forest areas. This research was conducted using the grid route method by collecting data from a literature study from different locations in the mangrove forest. The research results obtained that the highest average carbon stock in various regions of Indonesia which has the highest mangrove forest conservation is the Mangrove Area in Pasar Banggi Rembang Village of 737.2 tons/ha with three stations whose species names consist of Rhizophora apiculata, Rhizophora stylosa, and Rhizophora mucronata. High and low carbon content, density, and mangrove species in mangrove leaf litter were influenced by the rate of litter production. This production rate will later affect the high low carbon content in mangrove leaf litter.

Analysis of mangrove litter production and carbon stock in Sukamandi Village, Belitung Timur Regency

This study examined the litter production and carbon stock in the mangrove forest of Sukamandi Village in Belitung Timur Regency. The research identified 10 mangrove species in the area and found that the highest litter biomass was recorded at 6x10-8 ton/ha in station III. The organic material content varied across stations, with the highest value observed in station III. The carbon content of mangrove litter was relatively low due to its composition. The study emphasizes the significance of mangrove ecosystems in carbon sequestration and underscores the need for conservation efforts in Sukamandi Village. The variations in leaf litter production in the mangrove forest are influenced by factors such as mangrove density, plant age, and fertility. Leaf litter production is higher in areas with greater tree density and varies among different mangrove species. Natural factors like weather conditions, wind direction and speed, and movements of living organisms can also impact leaf litter production. The average leaf litter production rate in Sukamandi Village is 258.81 gr/m2/month or 8.62 gr/m2/day. The carbon content in mangrove leaf litter is relatively low due to its composition, which primarily consists of water and mineral nutrients.

Analisis Produksi Serasah Mangrove pada Hutan Mangrove Desa Kurau Timur, Kabupaten Bangka Tengah, Bangka Belitung

Mangrove forests have many ecological functions such as retaining and trapping sediments, dampening waves, providing protection for fish and other biota, and assimilating nutrients. Most of the nutrients returned to the forest floor are in the form of litter. Litter has an important role for the soil and the microorganisms in it. This study aims to measure the productivity of mangrove litter in the mangrove forest of Kurau Timur Village, Central Bangka Regency, Bangka Belitung. The method used to measure litter production is litter storage using a 1m x 1m litter trap with litter collection every 7 days for 3 months. Environmental parameter data analysis was performed by PCA (Principal Component Analysis). The rate of litter production in the mangrove forest of East Kurau Village is with a dry weight of 2.72 gr/m2/day. The components that make up litter are grouped into 3 components, namely leaves (66%), stems (18%), and flowers/fruits (16%). The litter layer on the mangrove forest floor of Kurau Timur Village is with an average dry weight of 69.02 grams, a water content of 40.73%, and an estimated average biomass of 3.08 tons/ha.

Litter production in two mangrove forests along the coast of Ghana

Litter production is an important component of mangrove primary productivity and has been widely used as a measure of productivity. During the past years, studies have been carried out on aspects of mangrove ecology and biodiversity in Ghana. These lay the foundations for surveys in ecological processes including productivity. This study was aimed at evaluating the production of litter within the mangrove forests at the Kakum and Pra estuaries. Four 0.25 ha study plots were demarcated in each mangrove forest, within which litter production and mangrove structural parameters were measured. Records on meteorological parameterss surrounding the study areas were obtained from Tutiempo Network. It was observed that annual litter production rate varied significantly (t = 2.91, P < 0.05) between the two mangrove forests - Kakum mangrove forest recorded 9.60 t ha−1 y−1 while Pra mangrove forest recorded 10.72 t ha−1 y−1. Litter production also varied significantly within the sampling months and study plots (P < 0.05). Leaf litter accounted for 61.26–99.45% of litterfall in both forests. Mean DBH and height of mangrove trees per study plot ranged from 3.05 cm to 3.39 cm and 3.20 m to3.92 m respectively for the Kakum mangrove forest, while that of the Pra mangrove forests ranged between 3.12 cm and 4.06 cm, and 3.58m and 4.44 m respectively. It was observed that the meteorological and structural parameters explained very little of the litter variability within the two mangrove forests. Hence, other factors such as growth cycles, senescence and age might have influenced mangrove litter production more than those measured in this study. This calls for more studies into litter production in mangrove ecosystems in Ghana, to ascertain the various factors that contribute to litter production. This will help emphasise the importance of mangrove litter productivity and the need to restore and conserve our mangrove ecosystems.

Litter production and leaf litter decomposition rate in secondary peat swamp forests in Central Kalimantan, Indonesia

Peat swamp forest is an important ecosystem in global climate change through its high carbon content and role as a carbon sink. In peat swamp forest, there is a near-closed cycle of nutrients including carbon. In order to better understand the rate of plant litter production and decomposition, a study was carried out in three secondary peat swamp forests in Central Kalimantan, Indonesia. Litterfall collection was undertaken using a litter trap with samples collected every month in the first year and every two months thereafter between June 2018 and June 2021. The rate of litter decomposition was assessed by measuring the reduction in dry weight of litter at 3, 6, 12 and 24 months. At each of three study sites, two sets of recently fallen litterfall were placed in 25cm x 25cm mesh bags on the peat soil surface to assess decomposition rates under aerobic conditions, and another two sets of litter were placed at a depth of 40 cm to assess decomposition rates under anaerobic conditions. Dry weight of fresh litterfall and decomposed litter samples was determined at 3, 6, 12 and 24 months, and total carbon content was analyzed using the loss of ignition method. The results showed that litterfall production in secondary peat swamp forests was about 9.52 ± 3.57 t ha−1 and it followed a seasonal pattern, with higher production in the dry season. The rate of litter decomposition was exponential and faster under aerobic conditions.

Wind disturbance on litter production affects soil carbon accumulation in degraded sandy grasslands in semi-arid sandy grassland

Plant litter derived from the living biomass is the primary source of soil carbon (C). However, the contribution and the mechanism of plant litter production to soil C remains uncertain in aeolian regions. In this study, the relationship between plant biomass, litter mass, and soil C content was analyzed after a spatial field investigation in Horqin sandy land, northeast China. Long-term monitoring of wind speed and plant litter production was also conducted in three habitats (mobile dune, semi-fixed dune, and fenced grassland). The soil C content was significantly affected by belowground biomass and belowground litter mass but not aboveground biomass and aboveground litter. The litter production in the desertified habitat (mobile dune and semi-fixed dune) significantly differed with that of the undesertified habitat (fixed dune and fenced grassland). In mobile dune, 38% of the aboveground primary production was lost, while there was a distinct enrichment of plant litter in semi-fixed dune and fenced grassland. Wind events (wind speeds of 7 and 8 m s−1) at the end of the growing season significantly affected litter production rate, and wind was a major driver for litter transportation between habitats. In summary, plant litter production can be affected by wind events, and this influence differs among habitats in degraded grassland, leading to spatial heterogeneity of soil C accumulation. These results can strengthen the understanding of the relationship between soil properties and plant litter production in aeolian regions and furthermore, can provide information for ecological restoration of different types of desertified land, especially for the soil C accumulation.

Beryllium cycling through deciduous trees and implications for meteoric 10Be systematics

Application of meteoric 10Be inventories and 10Be/9Be ratios to determine surface ages, erosion rates, and denudation rates requires understanding the conditions under which meteoric 10Be functions as an open vs. closed system near the Earth's surface. Here, we investigate biologically mediated beryllium isotope mobility in an oak-hickory forest in eastern North America. We report meteoric 10Be and 9Be concentrations in soils, roots, and leaves of four deciduous tree species. The data show that beryllium is readily taken-up from the soil by roots, cycled through leaves, and redeposited on the forest floor with autumn leaf abscission. Hickory (genus Carya) dominates beryllium cycling with a spatially averaged annual 10Be flux to the soil surface through litterfall that is four times higher than the atmospheric 10Be deposition rate. Biocycling may thus modulate the shape of meteoric 10Be concentration and 10Be/9Be ratio depth profiles in soils. We present a biocycling model that describes beryllium uptake by roots, redeposition on the surface through litterfall, and retention according to an exponential adsorption rule. This model reproduces the observed form of meteoric 10Be and 9Be depth profiles and the beryllium isotope ratio in foliage at the study site. The model also indicates that both declining and bulge-type meteoric 10Be depth profiles may result from biocycling, even where beryllium loss by leaching is significant, implying that declining meteoric 10Be depth profiles may not be indicative of quantitative 10Be retention. We recommend that biocycling be considered in models of beryllium isotope systematics where hickory or other beryllium accumulating taxa are present and where litter production rates are high.

Primary production in forests of the mangrove palm Nypa fruticans

We investigated the forest structure, leaf demography, leaf allometry and growth of the erect canopy of the mangrove palm Nypa fruticans in four river systems distributed over 10 degrees of latitude in the tropics of northeast Australia and Papua New Guinea to obtain estimates of aboveground biomass (AGB) and annual aboveground net primary production (ANPP). In the four river sites Nypa mean leaf and tree densities ranged from 6538 to 12,200 leaves ha−1, and 1526 to 3550 trees ha-1 and differed significantly among sites, with the lowest densities at the lowest latitude site. AGB ranged from 36.5 to 55.7 Mg ha−1 and also differed among sites with the lowest AGB at the lowest latitude site. The mean plastochron increased with increasing periods of cooler air temperatures. Mean litter production per tree (range, 6.0–16.2 kg year−1) was least in the low latitude site and mean total productivity per tree (range, 13.9–25.1 kg year−1) did not differ significantly across sites. ANPP was lowest in the low latitude site and ranged from 23.8 to 60.9 Mg ha−1 year−1. This placed Nypa forests in the mid to high range of global estimates of ANPP. Rates of litter production at three sites (range, 25.7–37.5 Mg ha−1 year−1) was much greater than for litterfall in any other mangrove forest. ANPP estimated using a combination of demographic data and leaf allometry compares well with previous estimates using a light interception method to predict productivity. The complex pattern of differences in forest structure, growth and ANPP across latitudes likely represent differences in catchment land use, successional stages of forests, river discharge and variation in the length of the dry season.

Impacts of prescribed burnings on litter production, nitrogen concentration, δ13C and δ15N in a suburban eucalypt natural forest of subtropical Australia

Prescribed burning is projected to be adopted more frequently with intensifying climate change; thus, a long-term study is necessary to understand the burning impacts on forest productivity and carbon (C) and nitrogen (N) cycling. Litter fall production rate can be used to indicate burning impacts on forest productivity, whereas N concentration, and C and N isotope composition (δ13C and δ15N) can be used to infer burning impacts on C and N cycling in plant-soil system. In this study, the impacts of low-intensity prescribed burning on litter production, N concentration, and C and N isotope compositions were continuously investigated for 6 years at five study sites in a natural eucalypt forest of subtropical Australia. Higher leaf litter production rate, N concentration and δ15N, and lower δ13C could be seen shortly after prescribed burning. The higher leaf litter N concentration and lower δ13C were likely due to the ease of competition for soil N and moisture from understory vegetation in the short term by prescribed burning. Leaf δ15N and N concentration were closely correlated, and seasonal changes in leaf litter production rate, δ13C and δ15N were observed. Burning season and related severity might determine the suppression degree of understory vegetation. Time since fire (TSF) was a significant impact factor influencing the litter fall production rate, N concentration, δ13C and δ15N of leaf litter fall for a decade following prescribed burning. However, monthly rainfall and temperature were less consistent in their impacts. Nitrogen limitation was enhanced by prescribed burning through the removal of litter and understory vegetation in the N poor forest and might be responsible for the long-term burning impacts. Low-intensity prescribed burning might have a long-lasting impact on forest litter productivity in nutrient poor forests in subtropical Australia.

Production, decomposition and nutrient contents of litter in subtropical broadleaved forest surpass those in coniferous forest, Meghalaya

Litter plays a crucial role in forest ecosystem functioning as its production and decomposition govern the pools and fluxes of forest nutrient cycling. The release of nutrients through litterfall and decomposition influences forest productivity. Therefore, these two factors are considered to be important indicators of forest ecosystem health. Such processes vary across different ecosystem types because of natural as well as anthropogenic factors. Hence, studying such processes would help in better understanding and management of forest ecosystems. Litter production and decomposition rates between a broadleaved and a coniferous forest ecosystem of Meghalaya in Northeast India were compared. We selected six subtropical broadleaved forest stands in Muthlong, Ialong, Nongbah, Mukhla, Nongkrem and Mawnai, and six adjacent coniferous forest stands dominated by pine. We estimated leaf litter production, decomposition and nutrient release, and analyzed the nitrogen and phosphorus contents in the litter of both the forest types. The study revealed that litter production and decomposition rates, and the litter nitrogen and phosphorous contents were significantly higher in the broadleaved forest compared to the pine forest. The variability in the litter characteristics was greater in the broadleaved forest compared to the coniferous forest indicating that the former is functionally more dynamic than the latter. Such dynamism in the broadleaved forest could be an important factor for providing greater ecological services compared to the coniferous forest, which nevertheless requires an in-depth study.

Leaf litter contributes more to soil organic carbon than fine roots in two 10-year-old subtropical plantations

Although many reports assume a strong relationship between plant litter inputs and soil organic carbon (SOC) accumulation, there is limited experimental evidence in support of this relationship. The Detritus Input and Removal Transfer (DIRT) experiment was conducted in two subtropical plantations, an Acacia crassicarpa monoculture (AC) and a Eucalyptus urophylla monoculture (EU), to assess the importance of leaf litter and fine roots for SOC content over a 6-year period. The SOC content in 0–10 cm soil layer was significantly reduced by litter removal (NL) or by removal of both litter and roots (NI), but the influence of root removal (NR) was only marginal. The AC forest had a much higher annual rate of litter production and a lower decomposition rate than the EU forest, but carbon release from plant litter did not significantly differ between the two forests. These results help explain why the SOC content did not differ between the two forests. Our findings suggest that plant leaf litter is more important than roots in maintaining the balance of the SOC pool in subtropical forest plantations.

Pervasively high mangrove productivity in a major tropical delta throughout an ENSO cycle (Southern Caribbean, Colombia)

Rhizophora mangle is a mangrove forest foundation species that can create vegetated habitat, support entire animal and plant communities, and modulate ecosystem processes. Changes in freshwater subsidies over space and time may alter the performance of mangrove foundation species, presumably resulting in disproportionally large effects on energy flow. Yet the linkages between above-ground biomass and below-ground carbon reservoirs across freshwater-subsidy gradients remain poorly understood in many regions. We assessed the dynamics of litterfall production and breakdown of leaf material in a monospecific Rhizophora mangle forest thriving in a small bay in the Atrato River Delta (Southern Caribbean coast of Colombia), during a major El Niño to La Niña transition (from July 2015 to October 2016). Although parameters varied at different spatial scales within the bay, the mean annual total litter production (55 ± 15 g m−2 day−1 or 20 ± 5 Mg ha−1 yr−1) and the mean mass loss of leaf litter (1.0% and 1.7% day−1, above- and below-ground, respectively) are the highest reported for R. mangle-dominated forests worldwide. Total litter production and mass loss rates did not vary significantly over time. The lack of temporal effect was counterintuitive, because these rates typically show strong seasonal variation in mangroves elsewhere in the tropics. We concluded that mangroves in this area constitute a primary productivity hotspot (leaf fall carbon spatio-temporal range: 0.81–1.30 g C m−2 d−1). Based on a comparison of our results and data from the literature, we hypothesize that high freshwater input from the Atrato River subsidizes mangrove plants settled on the deltaic front, which sustain pervasively high litterfall rates. The high mass loss rates of leaf litter observed in this study demonstrate the importance of carbon vertical fluxes across the forest floor in fringing mangroves for carbon sinking.

Are litterfall and litter decomposition processes indicators of forest regeneration in the neotropics? Insights from a case study in the Brazilian Amazon

Litterfall plays an important role in nutrient cycling and maintenance of soil fertility in terrestrial ecosystems. We gauged the effects of anthropogenic impacts on the production, decomposition and seasonality of litterfall in primary and secondary forests within a tropical landscape of the Brazilian Amazon. We hypothesized that leaf litter quantity and quality would differ in line with forest disturbance and that these changes would translate into dissimilar decomposition rates. If proved, these processes could be used as surrogates for indentifying the ecological status of forest habitats. The obtained results have shown that, in the study area litterfall is reduced and litter decomposition is braked in disturbed habitats when compared with primary and recovered secondary forests. Also, within similar climatic conditions, the litter production and decomposition rates begin to stabilize in mature secondary forests. Our results represent a useful contribution to understand the dynamics of the litterfall and litter decomposition processes in the neotropics. Both processes were correlated and sensitive to disturbance gradients and should used as forest recovery indicators in ecological monitoring and ecological restoration studies.

间伐和改变凋落物输入对华北落叶松人工林土壤呼吸的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 间伐和改变凋落物输入对华北落叶松人工林土壤呼吸的影响 DOI: 10.5846/stxb201703160449 作者: 作者单位: 北京林业大学林学院 北京 100083,北京林业大学林学院 北京 100083,北京林业大学林学院 北京 100083,北京林业大学林学院 北京 100083,北京林业大学林学院 北京 100083,北京林业大学林学院 北京 100083 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划（2016YFD0600205） Thinning treatment and litterfall changes influence soil respiration in a Larix principis-rupprechtii plantation Author: Affiliation: Forestry College of Beijing Forestry University,Forestry College of Beijing Forestry University,Forestry College of Beijing Forestry University,Forestry College of Beijing Forestry University,Forestry College of Beijing Forestry University,Forestry College of Beijing Forestry University Fund Project: National Key R&D Plan 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:作为森林生态系统的第二大碳通量，土壤呼吸在全球碳循环和气候变化中发挥着重要作用。通过探究土壤呼吸对间伐和改变凋落物的响应规律以及响应之间的联系，能够为准确评价森林碳循环提供依据。针对不同强度（对照、轻度、中度、重度）间伐后的华北落叶松人工林，2016年5月至10月采用LI-8100土壤碳通量测量系统对其原状、凋落物去除、凋落物加倍的土壤呼吸进行观测。结果表明：土壤呼吸在生长季的8月份达到最高值，呈现出明显的季节动态。不同林分间伐处理下，中度间伐显著促进了土壤呼吸，使平均土壤呼吸速率升高了15.66%，轻度间伐和重度间伐对土壤呼吸的影响不显著；不同凋落物处理下，去除凋落物使平均土壤呼吸速率降低了40.16%，加倍凋落物使平均土壤呼吸速率升高了16.06%。中度间伐使土壤呼吸生长季通量增加了55.06 g C/m2；去除凋落物使土壤呼吸生长季通量减少了153.48 g C/m2，加倍凋落物使土壤呼吸生长季通量增加了79.87 g C/m2。土壤呼吸速率与土壤温度呈显著指数相关，而与土壤湿度无显著相关。不同林分间伐处理下，土壤呼吸的温度敏感性指数（Q10）为2.36-3.46，轻度间伐下Q10值最高；凋落物去除和加倍均降低了土壤呼吸的温度敏感性。土壤温湿度对土壤呼吸存在着显著影响，能够解释土壤呼吸28.7%-62.3%的季节变化。研究结果表明间伐和凋落物处理对华北落叶松人工林土壤CO2释放的影响表现出一定的交互作用，中度间伐和加倍凋落物的交互作用对土壤呼吸的促进作用显著大于单一因子。可见，间伐作业通过改变土壤微环境和凋落物量，对土壤呼吸以及森林生态系统碳循环产生着重要影响。 Abstract:Soil respiration (Rs), the second largest site of carbon flow in the forest ecosystem carbon budget, plays an important role in the global carbon (C) cycle and climate change. Understanding the effects of forest management practices (e.g. thinning) on Rs is crucial for the accurate estimation of forest carbon cycling. Simultaneously, aboveground litter management practices (removal, addition, and so on) can also influence Rs. However, little is known about the response of Rs to thinning and its relationship with the changes in litter production induced by thinning. We aimed to quantify the response of Rs rate to different thinning intensities and to explore the relationships between Rs and soil temperature and moisture as a result of different litter management practices. A thinning manipulation experiment was conducted in a Larix principis-rupprechtii plantation in Shanxi province, China, with the following treatments:heavy thinning, moderate thinning, low thinning and no thinning. In addition, three treatments-litterfall removal, litter addition and normal litterfall-were applied to analyze the relationship between differences in litter input and Rs. Rates of soil respiration were measured twice a month using the LI-8100 Automated Soil CO2 Flux System from May to October 2016, while soil temperature and moisture at a depth of 5 cm were measured using temperature and moisture probes and data loggers. A significant difference was noted in Rs among the different thinning treatments (P < 0.05). Clear monthly variations in Rs were noted in the growing season, and Rs reached its peak value in August. Overall, moderate thinning increased Rs rate during the growing season by 15.7% from that of the no-thinning treatment. During the growing season, the Rs rate was lower by 40.16% with litterfall removal than that of normal litterfall; however, Rs rate was higher by 16.06% with litter addition than that of normal litterfall. Moderate thinning increased accumulative Rs by 55.06 g C/m2 during the growing season. Under litter removal conditions, accumulative Rs decreased by 153.48 g C/m2 during the growing season, while accumulative Rs increased with litter addition by 79.87 g C/m2. During the growing season, Rs exhibited significant exponential relationships with soil temperature, while there were no significant differences in soil moisture among the various treatments. Temperature sensitivity (Q10) values of Rs ranged from 2.36 to 3.46 in the various thinning intensities, with the highest Q10 value in the low thinning stand. The Q10 value were lower with the litter removal and litter addition treatments than those of normal litterfall. The interaction of soil temperature and moisture had a significant effect on Rs. The best fitting model with temperature and moisture explained 28%-62% of the variation in Rs. The results indicated that the interaction between thinning treatments and litter changes has a significant effect on the Rs in L. principis-rupprechtii plantations. The compound effect of moderate thinning and litter addition on Rs is significantly greater than that of any single factor. In conclusion, thinning played a considerable role in altering Rs and carbon cycle in forest ecosystems by influencing the soil micro-environment and litter production rates. 参考文献 相似文献 引证文献

PRODUÇÃO E DECOMPOSIÇÃO DE SERAPILHEIRA EM POVOAMENTOS DE TECA NO ESTADO DE MATO GROSSO, BRASIL

O presente estudo teve como objetivos estimar a produção, a taxa de decomposição, o tempo médio de renovação e decomposição da serapilheira em povoamentos da espécie Tectona grandis Linn. F. (Teca). O estudo foi realizado em três povoamentos de teca localizados no município de Nossa Senhora do Livramento - MT. Para as coletas da serapilheira foi delimitada uma área de 1 (um) ha em cada talhão com idades de cinco, seis e sete anos, na qual foram distribuídos, aleatoriamente, 20 coletores de madeira suspensos e vazados, com área de 0, 64 m2. O material vegetal depositado nos coletores foi recolhido a cada 30 dias, durante 12 meses, levado ao laboratório separando-se folhas, ramos (menores que um centímetro de diâmetro) e miscelânea, e depois de secos foram pesados. A serapilheira produzida nos talhões com sete, seis e cinco anos de idade foi, respectivamente, 7.280,25; 6.739,42 e 6.419,61 kg ha-1. As folhas representaram 86% do total de serapilheira depositada, os ramos, 4%, e as miscelâneas, 10%. As constantes de decomposição da serapilheira (K) nas árvores com cinco, seis e sete anos de idade foram, respectivamente, de 0,54; 0,60 e 0,58. O tempo médio de renovação, em anos, foi de 1,84 (671 dias) aos cinco anos, 1,67 (609 dias) aos seis anos e 1,71 (624 dias) aos sete anos. Para que ocorresse a decomposição de 50% da serapilheira, o tempo médio estimado foi de 1,28 anos (467 dias), 1,15 anos (419 dias) e 1,19 anos (434 dias) para as árvores com cinco, seis e sete anos, respectivamente. Para a decomposição de 95% da serapilheira, o tempo médio estimado foi de 5,53 anos (2.018 dias), 5,00 anos (1.825 dias) e 5,14 anos (1.876 dias) para a mesma sequência das idades.

Forest structure and carbon dynamics of an intact lowland mixed dipterocarp forest in Brunei Darussalam

Tropical forests play a critical role in mitigating climate change because they account for large amount of terrestrial carbon storage and productivity. However, there are many uncertainties associated with the estimation of carbon dynamics. We estimated forest structure and carbon dynamics along a slope (17.3°–42.8°) and to assess the relations between forest structures, carbon dynamics, and slopes in an intact lowland mixed dipterocarp forest, in Kuala Belalong, Brunei Darussalam. Living biomass, basal area, stand density, crown properties, and tree family composition were measured for forest structure. Growth rate, litter production, and litter decomposition rates were also measured for carbon dynamics. The crown form index and the crown position index were used to assess crown properties, which we categorized into five stages, from very poor to perfect. The living biomass, basal area and stand density were 261.5–940.7 Mg ha−1, 43.6–63.6 m2 ha−1 and 6,675–8400 tree ha−1, respectively. The average crown form and position index were 4, which means that the crown are mostly symmetrical and sufficiently exposed for photosynthesis. The mean biomass growth rate, litter production, litter decomposition rate were estimated as 11.9, 11.6 Mg ha−1 a−1, and 7.2 g a−1, respectively. Biomass growth rate was significantly correlated with living biomass, basal area, and crown form. Crown form appeared to strongly influence living biomass, basal area and biomass growth rate in terms of light acquisition. However, basal area, stand density, crown properties, and biomass growth rate did not vary by slope or tree family composition. The results indicate that carbon accumulation by tree growth in an intact lowland mixed dipterocarp forest depends on crown properties. Absence of any effect of tree family composition on carbon accumulation suggests that the main driver of biomass accumulation in old-growth forests of Borneo is not species-specific characteristics of tree species.

Effect of Different genetic and non-genetic factors on Pre weaninglitter and growth performance of pigs

The study was carried out on two different genetic groups of pig viz. Duroc and Hampshire maintained at pig breeding farm of National Research Centre on Pig, Guwahati. Effect of different genetic group and non-genetic factors (year and season of farrowing and parity) were estimated by least squares analysis of variance for different litter production, weight and pre weaning growth rate. Genetic group and parity revealed highly significant (P less than 0.01) effect on all the traits under study. However, effect of year and season of birth was non significant in most of the cases. The pre weaning mortality of Hampshire pigs was found to be less than Duroc. The performance of litter production and weight traits of Hampshire pigs were found to be better than Duroc pigs in the farm.

Forest soil carbon stock estimates in a nationwide inventory: evaluating performance of the ROMULv and Yasso07 models in Finland

Abstract. Dynamic soil models are needed for estimating impact of weather and climate change on soil carbon stocks and fluxes. Here, we evaluate performance of Yasso07 and ROMULv models against forest soil carbon stock measurements. More specifically, we ask if litter quantity, litter quality and weather data are sufficient drivers for soil carbon stock estimation. We also test whether inclusion of soil water holding capacity improves reliability of modelled soil carbon stock estimates. Litter input of trees was estimated from stem volume maps provided by the National Forest Inventory, while understorey vegetation was estimated using new biomass models. The litter production rates of trees were based on earlier research, while for understorey biomass they were estimated from measured data. We applied Yasso07 and ROMULv models across Finland and ran those models into steady state; thereafter, measured soil carbon stocks were compared with model estimates. We found that the role of understorey litter input was underestimated when the Yasso07 model was parameterised, especially in northern Finland. We also found that the inclusion of soil water holding capacity in the ROMULv model improved predictions, especially in southern Finland. Our simulations and measurements show that models using only litter quality, litter quantity and weather data underestimate soil carbon stock in southern Finland, and this underestimation is due to omission of the impact of droughts to the decomposition of organic layers. Our results also imply that the ecosystem modelling community and greenhouse gas inventories should improve understorey litter estimation in the northern latitudes.

Effects of grazing intensity and grazing exclusion on litter decomposition in the temperate steppe of Nei Mongol, China

Aims Grazing intensity and grazing exclusion affect ecosystem carbon cycling by changing the plant community and soil micro-environment in grassland ecosystems. The aims of this study were: 1) to determine the effects of grazing intensity and grazing exclusion on litter decomposition in the temperate grasslands of Nei Mongol; 2) to compare the difference between above-ground and below-ground litter decomposition; 3) to identify the effects of precipitation on litter production and decomposition. Methods We measured litter production, quality, decomposition rates and soil nutrient contents during the growing season in 2011 and 2012 in four plots, i.e. light grazing, heavy grazing, light grazing exclusion and heavy grazing exclusion. Quadrate surveys and litter bags were used to measure litter production and decomposition rates. All data were analyzed with ANOVA and Pearson’s correlation procedures in SPSS. Important findings Litter production and decomposition rates differed greatly among four plots. During the two years of our study, above-ground litter production and decomposition in heavy-grazing plots were faster than those in light-grazing plots. In the dry year, below-ground litter production and decomposition in light-grazing plots were faster than those in heavy-grazing plots, which is opposite to the findings in the wet year. Short-term grazing exclusion could promote litter production, and the exclusion of light-grazing could increase litter decomposition and nutrient cycling. In contrast, heavy-grazing exclusion decreased litter decomposition. Thus, grazing exclusion is beneficial to the restoration of the light-grazing grasslands, and more human management measures 杨丽丽等: 内蒙古温带草原不同放牧强度和围栏封育对凋落物分解的影响 749 doi: 10.17521/cjpe.2016.0051 are needed during the restoration of heavy-grazing grasslands. Precipitation increased litter production and decomposition, and below-ground litter was more vulnerable to the inter-annual change of precipitation than above-ground litter. Compared to the light-grazing grasslands, heavy-grazing grasslands had higher sensitivity to precipitation. The above-ground litter decomposition was strongly positively correlated with the litter N content (R = 0.489, p < 0.01) and strongly negatively correlated with the soil total N content (R = 0.450, p < 0.01), but it was not significantly correlated with C:N and lignin:N. Below-ground litter decomposition was negatively correlated with the litter C (R = 0.263, p < 0.01), C:N (R = 0.349, p < 0.01) and cellulose content (R = 0.460, p < 0.01). Our results will provide a theoretical basis for ecosystem restoration and the research of carbon cycling.

High-Fat Diet Causes Subfertility and Compromised Ovarian Function Independent of Obesity in Mice.

Excess calorie consumption, particularly of a diet high in fat, is a risk factor for both obesity and reproductive disorders. Animal model studies indicate that elevated dietary fat can influence some reproductive functions independent of obesity. In the current study we sought to determine whether a high-fat diet (HFD) impacts ovarian function, long-term fertility, and local and systemic markers of inflammation independent of obesity. Five-week-old mice were fed either low-fat diet (control group-LF-Ln) or HFD for 10 wk and were divided based on body weight into high-fat obese (HF-Ob: >25 g) and high-fat lean (HF-Ln: <22 g). Ovaries were collected to assess ovarian follicles and to determine the degree of local inflammation. Serum proinflammatory cytokines were also measured. A group of animals was followed for breeding trials for 5 mo while being exposed to LFD or HFD. We found that both 10-wk and 32-wk exposure to HFD resulted in depleted primordial follicles regardless of obesity phenotype. Macrophage counts revealed increased tissue inflammation in the ovary independent of obesity. In addition, serum proinflammatory cytokines were increased in HF-Ln and HF-Ob in comparison to LF-Ln mice. Moreover, HFD had a sustained effect on litter production rate and number of pups per litter regardless of obese phenotype. This study describes for the first time that exposure to HFD causes significant reduction in primordial follicles, compromised fertility, produced higher proinflammatory cytokine levels, and increased ovarian macrophage infiltration, independent of obesity. The negative effects of HFD on primordial follicles may be mediated by increased tissue inflammation.