The role of forest litter as an acid-base buffering system was assessed by litter from plantation and natural forests in South China. Samples were either extracted with acid solutions or titrated with acid or base sol...The role of forest litter as an acid-base buffering system was assessed by litter from plantation and natural forests in South China. Samples were either extracted with acid solutions or titrated with acid or base solutions. Litter was found to be a strong acid-base buffering system. Two legume species, Acacia mangium Willd and A. auriculaiformis A. Cunn, had very high litter pH values of around 6, which was 2 pH units higher than that of the soil where they grew. Litter of all other plantation species had litter pH of around 4, similar to that of the soil. Both legume species have high potential to neutralize soil acidity and the litter layer could act to shield soil against acid rain. The current stand of two legume species was estimated to be able to raise rain acidity by 0.1 to 0.4 pH units. Inorganic ions did not fully explain the pH pattern of different litter extracts, but high sodium and low nitrate partly accounted for the high pH of the two legume species. Some natural forest species had extremely low pH. As a whole, the litter of the natural climax forest was the driving force of soil acidification. Although plant residues are strong acid-base buffering system and able to adjust acidity of environment, only a few species can be expected to make soil more acid or alkaline through this mechanism since most species have litter pH values similar to those of soil where they grow.展开更多
The effects of nitrogen （N） availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment. Fresh lit...The effects of nitrogen （N） availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment. Fresh litter samples including needle litter （Pinus koraiensis） and two types of broadleaf litters （Quercus mongolica and Tilia amurensis） were collected from a broadleaf-korean pine mixed forest in the northern slope of Changbai Mountain （China）. Different doses of N （equal to 0, 30 and 50 kg.ha^-1yr^-1, respectively, as NH4NO3） were added to litter during the experiment period. The litter decomposition rate expressed as mass loss and respiration rate increased significantly with increasing N availability. The mass loss and cumulative CO2-C emission were higher in leaf litter compared to that in needle litter. The dis- solved organic Carbon （DOC） concentrations in litter leachate varied widely between the species, but were not greatly affected by N treatments. Regardless of the N addition rate, both N treatments and species had no significant effect on dissolved organic N （DON） concentrations in litter leachate. About 52-78% of added N was retained in the litter. The percentage of N retention was positively correlated （R^2=0.9 1, p〈0.05） with the litter mass loss. This suggested that a forest floor with easily decomposed litter might have higher potential N sink strength than that with more slowly decomposed litter.展开更多
Larch (Larix olgensis), Manchurian ash (Fraxinus mandshurica), Korean pine (Pinus koraiensis) and White birch (Betula platyphylla) are the major planting species in northeast China. The samples of forest litters were ...Larch (Larix olgensis), Manchurian ash (Fraxinus mandshurica), Korean pine (Pinus koraiensis) and White birch (Betula platyphylla) are the major planting species in northeast China. The samples of forest litters were collected from the stands of the above 4 species in Laoyeling and Jianlagou experiment stations of Maorshan Exp. Forest Farm (45?2-45?0N, 127?0-127?8E), Northeast Forestry University, in early October 2002. Quantitative analysis and qualitative analysis were carried out on the organic acids existing in freshly fallen litters (L layer) and hemi-decomposed litters (F layer) of the four forest species by using Gas Chromatogram system. A wide variety of organic acids were identified, including oxalic, malonic, fumaric, succinic, maleic, malic, citric, C16:0, C18:0, C18:1, C18:2, C18:3 and C20:0 acids. In respect of L litters of all samples, the oxalic acid content (over 30 mg/g) was the highest of the seven low-molecular-weight organic acids identified, while the content of oleic or linoleic (above 40 mg/g) was found to be highest among the six high aliphatic acids identified. As to F litters, oxalic acid content was also the highest, followed by linoleic and oleic. For the same tree species or the same forest, the kinds and contents of organic acids in L litters were more abundant than that in F litters.展开更多
The effects of nitrogen(N)availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment.Fresh litter s...The effects of nitrogen(N)availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment.Fresh litter samples including needle litter(Pinus koraiensis)and two types of broadleaf litters(Quercus mongolica and Tilia amurensis)were collected from a broadleaf-korean pine mixed forest in the northern slope of Changbai Mountain(China).Different doses of N(equal to 0,30 and 50 kg·ha-1yr-1,respectively,as NH4NO3)were added to litter during the experiment period.The litter decomposition rate expressed as mass loss and respiration rate increased significantly with increasing N availability.The mass loss and cumulative CO_(2)-C emission were higher in leaf litter compared to that in needle litter.The dissolved organic Carbon(DOC)concentrations in litter leachate varied widely between the species,but were not greatly affected by N treatments.Regardless of the N addition rate,both N treatments and species had no significant effect on dissolved organic N(DON)concentrations in litter leachate.About 52?78%of added N was retained in the litter.The percentage of N retention was positively correlated(R2=0.91,p<0.05)with the litter mass loss.This suggested that a forest floor with easily decomposed litter might have higher potential N sink strength than that with more slowly decomposed litter.展开更多
In order to explore a technology for producing organic fertilizer by composting urban forest litter and river sediment passivated by fly ash,an experiment was conducted to study dynamic changes of several parameters i...In order to explore a technology for producing organic fertilizer by composting urban forest litter and river sediment passivated by fly ash,an experiment was conducted to study dynamic changes of several parameters including temperature,pH,organic matter,C/N and germination index(GI)during high-temperature composting of urban forest litter and river sediment at five different proportions(1:1(Ⅰ),1:2(Ⅱ),1:3(Ⅲ),2:1(Ⅳ)and 3:1(Ⅴ)).Results showed that the temperature and pH increased first and then decreased;at the proportion of 3:1,the temperature increased rapidly and the high-temperature duration was longest(5 d);at the end of the composting,all the treatments reached the decomposed status,the pH ranged from 7.47 to 8.87,and the organic matter content was reduced by 36%,38%,42%,33%and 29%,respectively,indicating that increasing the proportion of urban forest litter was conducive to reducing the loss of organic matter.Due to low C/N ratio of river sediment,increasing the proportion of urban forest litter was helpful to improve the efficiency of composting.The GI of treatments I,IV and V reached 80%on day 26,18 and 19 respectively,but the GI of treatments II and III did not reach this level until the end of composting.Considering the quality of fertilizer and efficiency of composting for large-scale production,the proportion between urban forest litter and river sediment is suitable to be set as 3:1 for production of organic fertilizer.展开更多
Based on the introduction of concept of forest litter, changes in the amount of forest litter with climate zone, elevation, forest type and age of stand were analyzed, and then the decomposition of forest litter was d...Based on the introduction of concept of forest litter, changes in the amount of forest litter with climate zone, elevation, forest type and age of stand were analyzed, and then the decomposition of forest litter was discussed.展开更多
This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided...This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling(SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance(harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.展开更多
We used a litterbag method to investigate litter decomposition and related soil degradative enzyme activities across four seasons in a broad-leaved forest and a coniferous forest on Zijin Mountain in sub-tropical Chin...We used a litterbag method to investigate litter decomposition and related soil degradative enzyme activities across four seasons in a broad-leaved forest and a coniferous forest on Zijin Mountain in sub-tropical China. Across four seasons, we quantified litter mass losses, soil pH values, and related soil degradative enzyme activities. Litter decomposition rates differed significantly by season. Litter decomposi- tion rates of broadleaf forest leaves were higher than for coniferous for- ests needles across four seasons, and maximal differences in litter de- composition rates between the two litter types were found in spring.展开更多
To study the role of leaf litter in the mercury （Hg） cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf...To study the role of leaf litter in the mercury （Hg） cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing. The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g, with an average （avg） of （49.7 ± 36.9） ng/g. The average Hg concentration in evergreen broadleaf forest leaf litter （50.8 ± 39.4） ng/g was higher than that in deciduous broadleaf forest leaf litter （25.8 ± 10.1） ng/g. The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/（ha·yr）, respectively. The Hg concentration in organic horizons （O horizons） （（263.1 ± 237.2） ng/g） was higher than that in eluvial horizons （A horizons） （（83.9 ± 52.0） ng/g）. These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests. For urban forests in Beijing, the Hg concentrations in leaf litter ranged from 8.8–119.0 （avg 28.1 ± 16.6） ng/g, with higher concentrations at urban sites than at suburban sites for each tree. The Hg concentrations in surface soil in Beijing were 32.0–25300.0 ng/g and increased from suburban sites to urban sites, with the highest value from Jingshan （JS） Park at the centre of Beijing. Therefore, the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.展开更多
The effects of extraction fluids from the leaf litter from different dominant tree species on the functional characteristics of the soil microbial community were studied to understand how changes in soil quality and s...The effects of extraction fluids from the leaf litter from different dominant tree species on the functional characteristics of the soil microbial community were studied to understand how changes in soil quality and synergism between plants and soil contribute to the process of forest succession. Leaf litter from dominant tree species at different stages of succession were collected and extracted with sterile deionized water. After treating the soil of abandoned land with the different extraction fluids, we analyzed changes in carbon utilization of the soil microbial community in Biolog EcoPlates, then considered these results with those of our previous study on forest vegetation succession in the Malan forest. The leaf litter enhanced the metabolic capacity and functional diversity of the soil microbes, especially in the following combinations： the leaf litter of Quercus liaotungensis-Pinus tabulae- formis, P. tabulaeformis-Betula platyphylla, Q. liaotun- gensis and P. tabulaeformiss. Second, when litter from onespecies evaluated, the species enhanced metabolism and diversity in the order of their successional relationship： B. Platyphylla 〈 P. tabulaeformis 〈 Q. liaotungensis. After soils were treated with different leaf litters at 25 ℃ for 7 days, the sorting pattern of the PCA values, based on the similarity of carbon source utilization by the soil microbes, corresponded to the successional pattern on the basis of the similarity of community composition of forest plants. Thus, changes in soil properties caused by leaf litter from different dominant trees probably play a unique role in the successional pattern of a forest community. We thus pro- pose a successional mechanism that underlies the natural succession process within the Malan forest region. When the dominant forest species of the climax successional stage develops during the early successional stages, its forest litter probably alters soil properties such that the soil becomes unsuitable for the gradual growth and regenera- tion of the original dominant tree species but promotes the growth and establishment of later-invasive plants. In this way, the originally dominant species is replaced by the newly dominant tree species during forest succession.展开更多
[Objective]The research aimed to understand water conservation capacity of litter from different forest types in Caohai basin. [Method] Current storage amount,water holding capacity and precipitation interception abil...[Objective]The research aimed to understand water conservation capacity of litter from different forest types in Caohai basin. [Method] Current storage amount,water holding capacity and precipitation interception ability of litter from 4 types of forest were investigated and studied. [Result]The order of exist litter amount was grass slope ＆gt;shrub forest ＆gt;mixed broad leaf-conifer forest ＆gt;coniferous forest. The order of natural water holding capacity was mixed broad leafconifer forest ＆gt; coniferous forest ＆gt; grass slope ＆gt; shrub forest. The relevance between water holding capacity of litter and soaking time was in line with this formula： y = kln（ x） ＋ b. During 0-120 min of litter soaking,water holding capacity increased rapidly. After 120 min,the increasing trend remained flat until closing to the maximum water holding capacity. The relevance between water absorption rate of litter and soaking time was in line with this formula： y = a ＋ bx-1. In the beginning of soaking,water absorption rates of litter from different woodlands showed great difference. As soaking time went by,water absorption rates of litter from different woodlands all declined sharply. During 0-120 min,declining velocity of water absorption rate was quicker. After 120 min,the declining trend tended to be slow. The maximum water holding capacity of litter presented the order of shrub forest ＆gt; mixed broad leafconifer forest ＆gt; grass slope ＆gt; coniferous forest. The maximum precipitation interception amount of litter presented the order of shrub forest ＆gt; grass slope ＆gt; mixed broad leafconifer forest ＆gt; coniferous forest. Effective impounding capacity of litter presented the order of shrub forest ＆gt; mixed broad leafconifer forest ＆gt; grass slope ＆gt; coniferous forest. [Conclusion]The research could provide support for the construction of water conservation forest in Caohai basin.展开更多
Litter is an important source of easily mineralizable C, N, and P for microbial metabolism in forest ecosystems;however, its decomposition is dependent upon a variety of biotic and abiotic factors, including litter ch...Litter is an important source of easily mineralizable C, N, and P for microbial metabolism in forest ecosystems;however, its decomposition is dependent upon a variety of biotic and abiotic factors, including litter chemical composition and plant specie, soil properties, and climate. We investigated C, N, and P mineralization patterns of pine litter, oak and a mixture of various species commonly found in wetland landscape position. Litter species were incubated (alone and with soils) under laboratory conditions in the dark for 120 days. Samples were leached weekly and the leachates were analyzed for pH, E4:E6 ratio, dissolved organic carbon (DOC), total N, NO3, NH4, soluble reactive P, and total P. CO2 effluxes during the 120-d incubation period were measure using NaOH traps. Carbon loss was calculated as the sum of DOC and CO2 effluxes. Results indicated that patterns of C and N release varied with litter species and soil type. Mix species treatment resulted in larger DOC and N pulses compared to pine and oak treatments. The majority of the DOC, N, and P leached was retained by the soils. When litters were added to the soils, a greater proportion of the C was lost as CO2, while litter incubated alone lost more C as DOC. This result demonstrated the importance of the soil microbial community affecting the patterns of litter mineralization. Total N concentration and C:N ratio of the litter species were significantly correlated to C loss.展开更多
As an important part in forest ecosystems, the arthropod communities in the forest litter are closely related to forest health.Based on the ecological function,community structure and biology of the arthropods,we disc...As an important part in forest ecosystems, the arthropod communities in the forest litter are closely related to forest health.Based on the ecological function,community structure and biology of the arthropods,we discuss the theoretical basis for the selection of particular groups of arthropods as bio-indicators in this paper,and suggest that the evenness and richness of Collembola(Collembolan), Coleoptera(Beetle) and Hymenoptera(Ant) can serve as forest health indicators.In terms of the relationship between forest litter arthropods and forest health,we summarize the main groups of forest litter arthropods suitable as bio-indicators and their ecological functions in forest ecosystems,and subsequently introduce a simple and accurate new method for selecting forest health indicator species by comparing the frequencies of the various species in different habitats.This method was tested with a real case using forest litter arthropods as a bio- indicator to evaluate rain forest health.Finally,the problems in using forest litter arthropods to evaluate and monitor forest habitat health are discussed and the use of multiple bio-indicator species in order to establish a balanced index system is recommended.展开更多
Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The ob...Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The objective of this research was to assess litterfall production,the potential deposition of macro and micronutrients through leaf and twig fall as well as macronutrient—use efficiency in three forest ecosystems at different altitudes： a pine forest mixed with deciduous species（S1）; a Quercus spp.forest（S2）; and,a Tamaulipan thornscrub forest（S3）.Total annual litterfall deposition was 594,742 and 533 g m^（-2） for S1,S2 and S3.Leaf litter was higher （68%） than twigs（18%）,reproductive structures（8%） or miscellaneous material（6%）.Micronutrient leaf deposition was higher for Fe followed by Mn,Zn and Cu.Macronutrient leaf deposition was higher for Ca followed by K,Mg and P.Even though P deposition in leaves and twigs was lower than other macronutrients,its nutrient use efficiency was higher than Ca,Mg or K.Altitude and species composition determine litter and nutrient deposition,with higher values at mid-altitudes（550 m）.Altitude is an important factor to consider when analyzing litter production as well as nutrient deposition as shown in this study.Litter production and nutrient deposition are expected to change in a scenario of global warming.展开更多
Forests and grasslands in arid and semi-arid regions receive high-intensity ultraviolet（UV） radiation year-round. However, how the UV radiation affects the litter decomposition on the forest floor remains unclear. H...Forests and grasslands in arid and semi-arid regions receive high-intensity ultraviolet（UV） radiation year-round. However, how the UV radiation affects the litter decomposition on the forest floor remains unclear. Here, we conducted a field-based experiment in 2011 in the southeastern Horqin Sandy Land, Northeast China, to investigate the effects of UV radiation, litter layer thickness, and their interaction on the mass loss and chemical properties of decomposing litter from Xiaozhuan poplar（Populus × xiaozhuanica） and Mongolian pine（Pinus sylvestris var. mongolica） plantation trees. We found that UV radiation accelerated the decomposition rates of both the Xiaozhuan poplar litter and Mongolian pine litter. For both species, the thick-layered litter had a lower mass loss than the thin-layered litter. The interaction between UV radiation and litter layer thickness significantly affected the litter mass loss of both tree species. However, the effects of UV radiation on the chemical properties of decomposing litter differed between the two species, which may be attributed to the contrasting initial leaf litter chemical properties and morphology. UV radiation mostly had positive effects on the lignin concentration and lignin/N ratio of Xiaozhuan poplar litter, while it had negative effects on the N concentration of Mongolian pine litter. Moreover, litter layer thickness and its interaction with UV radiation showed mostly positive effects on the N concentration and lignin/N ratio of Xiaozhuan poplar litter and the ratios of C/N and lignin/N of Mongolian pine litter, and mostly negative effects on the C/N ratio of Xiaozhuan poplar litter and the N concentration of Mongolian pine litter. Together, these results reveal the important roles played by UV radiation and litter layer thickness in the process of litter decomposition in this semi-arid region, and highlight how changes in the litter layer thickness can exert strong influences on the photodegradation of litter in tree plantations.展开更多
Abstract Forests have been expanding over typical savanna sites for the past 3000 years in the Neotropics. Such invasion can produce a series of environmental modifications on typical savanna; however, it remains uncl...Abstract Forests have been expanding over typical savanna sites for the past 3000 years in the Neotropics. Such invasion can produce a series of environmental modifications on typical savanna; however, it remains unclear how modifications in soil properties, caused by the encroachment of woody species, facilitate the expansion of forest ecosystems under dystrophic conditions. Here we examined chemical and microbiological changes associ- ated with tree encroachment in oxisols of a Neotropical Savanna at Assis Ecological Station, Southeastern Brazil. We predicted that tree encroachment caused by typical forest species would cause significant changes in the chemical and microbiological properties of savanna soils. Soils were sampled at Assis Ecological Station, from savanna sites differing in tree encroachment （typical, dense and forested savanna） caused by decades of fire exclusion. We analysed vegetation leaf area index and leaf litter volume deposited in the studied plots and chemical （pH,organic matter, P, K, Ca, Mg, A1, NO3-, NH4＋） and microbiological （microbial C biomass and dehydrogenase activity） properties of soils under distinct encroachment conditions. Most soil chemical properties did not change along the tree encroachment gradient; however, total P, soil organic matter, soil microbial C and dehydrogenase activity increased from typical savanna to forested savanna. The changes in soil organic matter and dehydrogenase activity were correlated with the values of leaf area index and litter volume along the encroachment gradient. Our results demonstrate that forest species can increase carbon and phosphorus supplies in tropical savanna soils.展开更多
Forest l itter is the physical makeu p part of forest ecosystem．The rate o f decompositi on of forest litter is low in temperate and cool temperate zones．There is impor tant signific ance to search and utilize the f...Forest l itter is the physical makeu p part of forest ecosystem．The rate o f decompositi on of forest litter is low in temperate and cool temperate zones．There is impor tant signific ance to search and utilize the functi on of soil animals，in order to probe the material circulation and energy flow in forest ecosystem．We selec ted three kin ds of mesh bag with different mesh size，in which，large pore mesh bag is large enough to permit the activities of all kinds of soil animals，medi um mesh bag is designed to exclude the function of soil macrofauna，while small mesh bag is small enough to exclude the effects o f any kind of soil animals as far as possible．The decomposition time is thr ee years．The studying results sh ow that：the decomposing speed of the bags with big meshes，under functions of a ll kinds of soil animals，faster than the bags with medium meshes，under functio ns of medium and small soil animals，as well as the bags with small meshes that exc luding all possibility of functions of soil animals；in the process of dec o mposition of litter，relationship of the litte r lost weight with number of soil anim als is not obvious clearly；the degre e of functions of soil animals to so ft litter higher than hard litter；according to the an alysis of diversity index ，no regula r changes will happen to the diversity of soil anima ls as the time of decomposing samples lengthen．展开更多
文摘The role of forest litter as an acid-base buffering system was assessed by litter from plantation and natural forests in South China. Samples were either extracted with acid solutions or titrated with acid or base solutions. Litter was found to be a strong acid-base buffering system. Two legume species, Acacia mangium Willd and A. auriculaiformis A. Cunn, had very high litter pH values of around 6, which was 2 pH units higher than that of the soil where they grew. Litter of all other plantation species had litter pH of around 4, similar to that of the soil. Both legume species have high potential to neutralize soil acidity and the litter layer could act to shield soil against acid rain. The current stand of two legume species was estimated to be able to raise rain acidity by 0.1 to 0.4 pH units. Inorganic ions did not fully explain the pH pattern of different litter extracts, but high sodium and low nitrate partly accounted for the high pH of the two legume species. Some natural forest species had extremely low pH. As a whole, the litter of the natural climax forest was the driving force of soil acidification. Although plant residues are strong acid-base buffering system and able to adjust acidity of environment, only a few species can be expected to make soil more acid or alkaline through this mechanism since most species have litter pH values similar to those of soil where they grow.
基金Foundation project： This work was supported by the Knowledge Innova- tion Project of the Chinese Academy of Sciences （KZCX2-YW-416） and the National Natural Science Foundation （90411020）
文摘The effects of nitrogen （N） availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment. Fresh litter samples including needle litter （Pinus koraiensis） and two types of broadleaf litters （Quercus mongolica and Tilia amurensis） were collected from a broadleaf-korean pine mixed forest in the northern slope of Changbai Mountain （China）. Different doses of N （equal to 0, 30 and 50 kg.ha^-1yr^-1, respectively, as NH4NO3） were added to litter during the experiment period. The litter decomposition rate expressed as mass loss and respiration rate increased significantly with increasing N availability. The mass loss and cumulative CO2-C emission were higher in leaf litter compared to that in needle litter. The dis- solved organic Carbon （DOC） concentrations in litter leachate varied widely between the species, but were not greatly affected by N treatments. Regardless of the N addition rate, both N treatments and species had no significant effect on dissolved organic N （DON） concentrations in litter leachate. About 52-78% of added N was retained in the litter. The percentage of N retention was positively correlated （R^2=0.9 1, p〈0.05） with the litter mass loss. This suggested that a forest floor with easily decomposed litter might have higher potential N sink strength than that with more slowly decomposed litter.
基金This paper is supported by National Natural Science Foundation of China (30170768)
文摘Larch (Larix olgensis), Manchurian ash (Fraxinus mandshurica), Korean pine (Pinus koraiensis) and White birch (Betula platyphylla) are the major planting species in northeast China. The samples of forest litters were collected from the stands of the above 4 species in Laoyeling and Jianlagou experiment stations of Maorshan Exp. Forest Farm (45?2-45?0N, 127?0-127?8E), Northeast Forestry University, in early October 2002. Quantitative analysis and qualitative analysis were carried out on the organic acids existing in freshly fallen litters (L layer) and hemi-decomposed litters (F layer) of the four forest species by using Gas Chromatogram system. A wide variety of organic acids were identified, including oxalic, malonic, fumaric, succinic, maleic, malic, citric, C16:0, C18:0, C18:1, C18:2, C18:3 and C20:0 acids. In respect of L litters of all samples, the oxalic acid content (over 30 mg/g) was the highest of the seven low-molecular-weight organic acids identified, while the content of oleic or linoleic (above 40 mg/g) was found to be highest among the six high aliphatic acids identified. As to F litters, oxalic acid content was also the highest, followed by linoleic and oleic. For the same tree species or the same forest, the kinds and contents of organic acids in L litters were more abundant than that in F litters.
基金supported by the Knowledge Innova-tion Project of the Chinese Academy of Sciences(KZCX2-YW-416)the National Natural Science Foundation(90411020)
文摘The effects of nitrogen(N)availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment.Fresh litter samples including needle litter(Pinus koraiensis)and two types of broadleaf litters(Quercus mongolica and Tilia amurensis)were collected from a broadleaf-korean pine mixed forest in the northern slope of Changbai Mountain(China).Different doses of N(equal to 0,30 and 50 kg·ha-1yr-1,respectively,as NH4NO3)were added to litter during the experiment period.The litter decomposition rate expressed as mass loss and respiration rate increased significantly with increasing N availability.The mass loss and cumulative CO_(2)-C emission were higher in leaf litter compared to that in needle litter.The dissolved organic Carbon(DOC)concentrations in litter leachate varied widely between the species,but were not greatly affected by N treatments.Regardless of the N addition rate,both N treatments and species had no significant effect on dissolved organic N(DON)concentrations in litter leachate.About 52?78%of added N was retained in the litter.The percentage of N retention was positively correlated(R2=0.91,p<0.05)with the litter mass loss.This suggested that a forest floor with easily decomposed litter might have higher potential N sink strength than that with more slowly decomposed litter.
文摘In order to explore a technology for producing organic fertilizer by composting urban forest litter and river sediment passivated by fly ash,an experiment was conducted to study dynamic changes of several parameters including temperature,pH,organic matter,C/N and germination index(GI)during high-temperature composting of urban forest litter and river sediment at five different proportions(1:1(Ⅰ),1:2(Ⅱ),1:3(Ⅲ),2:1(Ⅳ)and 3:1(Ⅴ)).Results showed that the temperature and pH increased first and then decreased;at the proportion of 3:1,the temperature increased rapidly and the high-temperature duration was longest(5 d);at the end of the composting,all the treatments reached the decomposed status,the pH ranged from 7.47 to 8.87,and the organic matter content was reduced by 36%,38%,42%,33%and 29%,respectively,indicating that increasing the proportion of urban forest litter was conducive to reducing the loss of organic matter.Due to low C/N ratio of river sediment,increasing the proportion of urban forest litter was helpful to improve the efficiency of composting.The GI of treatments I,IV and V reached 80%on day 26,18 and 19 respectively,but the GI of treatments II and III did not reach this level until the end of composting.Considering the quality of fertilizer and efficiency of composting for large-scale production,the proportion between urban forest litter and river sediment is suitable to be set as 3:1 for production of organic fertilizer.
基金Supported by the National Key Technology R&D Program(2013BAC04B01)Research and Demonstration of Restoration Technology of Typical Degraded Ecosystems in Tibet Plateau
文摘Based on the introduction of concept of forest litter, changes in the amount of forest litter with climate zone, elevation, forest type and age of stand were analyzed, and then the decomposition of forest litter was discussed.
文摘This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling(SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance(harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.
基金supported by the National Natural Science Foundation of China(30870419,40971151)Strategic Priority Research Program Climate Change:Carbon Budget and Related Issues of the Chinese Academy of Sciences(XDA05050204)
文摘We used a litterbag method to investigate litter decomposition and related soil degradative enzyme activities across four seasons in a broad-leaved forest and a coniferous forest on Zijin Mountain in sub-tropical China. Across four seasons, we quantified litter mass losses, soil pH values, and related soil degradative enzyme activities. Litter decomposition rates differed significantly by season. Litter decomposi- tion rates of broadleaf forest leaves were higher than for coniferous for- ests needles across four seasons, and maximal differences in litter de- composition rates between the two litter types were found in spring.
基金supported by the National Natural Science Foundation of China (No. 40803033, 41073092)
文摘To study the role of leaf litter in the mercury （Hg） cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing. The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g, with an average （avg） of （49.7 ± 36.9） ng/g. The average Hg concentration in evergreen broadleaf forest leaf litter （50.8 ± 39.4） ng/g was higher than that in deciduous broadleaf forest leaf litter （25.8 ± 10.1） ng/g. The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/（ha·yr）, respectively. The Hg concentration in organic horizons （O horizons） （（263.1 ± 237.2） ng/g） was higher than that in eluvial horizons （A horizons） （（83.9 ± 52.0） ng/g）. These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests. For urban forests in Beijing, the Hg concentrations in leaf litter ranged from 8.8–119.0 （avg 28.1 ± 16.6） ng/g, with higher concentrations at urban sites than at suburban sites for each tree. The Hg concentrations in surface soil in Beijing were 32.0–25300.0 ng/g and increased from suburban sites to urban sites, with the highest value from Jingshan （JS） Park at the centre of Beijing. Therefore, the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.
基金supported by the National Key Basic Research Program of China(2002 CB111505)Natural Science Basic Research Project in Shaanxi Province(2011 JM3003)Project PCSIRT(No.IRT1035)
文摘The effects of extraction fluids from the leaf litter from different dominant tree species on the functional characteristics of the soil microbial community were studied to understand how changes in soil quality and synergism between plants and soil contribute to the process of forest succession. Leaf litter from dominant tree species at different stages of succession were collected and extracted with sterile deionized water. After treating the soil of abandoned land with the different extraction fluids, we analyzed changes in carbon utilization of the soil microbial community in Biolog EcoPlates, then considered these results with those of our previous study on forest vegetation succession in the Malan forest. The leaf litter enhanced the metabolic capacity and functional diversity of the soil microbes, especially in the following combinations： the leaf litter of Quercus liaotungensis-Pinus tabulae- formis, P. tabulaeformis-Betula platyphylla, Q. liaotun- gensis and P. tabulaeformiss. Second, when litter from onespecies evaluated, the species enhanced metabolism and diversity in the order of their successional relationship： B. Platyphylla 〈 P. tabulaeformis 〈 Q. liaotungensis. After soils were treated with different leaf litters at 25 ℃ for 7 days, the sorting pattern of the PCA values, based on the similarity of carbon source utilization by the soil microbes, corresponded to the successional pattern on the basis of the similarity of community composition of forest plants. Thus, changes in soil properties caused by leaf litter from different dominant trees probably play a unique role in the successional pattern of a forest community. We thus pro- pose a successional mechanism that underlies the natural succession process within the Malan forest region. When the dominant forest species of the climax successional stage develops during the early successional stages, its forest litter probably alters soil properties such that the soil becomes unsuitable for the gradual growth and regenera- tion of the original dominant tree species but promotes the growth and establishment of later-invasive plants. In this way, the originally dominant species is replaced by the newly dominant tree species during forest succession.
基金Supported by National "Twelfth Five-year"Science and Technology Support Plan,China(2011BAC02B02)Graduate Innovation Fund of Guizhou University,China
文摘[Objective]The research aimed to understand water conservation capacity of litter from different forest types in Caohai basin. [Method] Current storage amount,water holding capacity and precipitation interception ability of litter from 4 types of forest were investigated and studied. [Result]The order of exist litter amount was grass slope ＆gt;shrub forest ＆gt;mixed broad leaf-conifer forest ＆gt;coniferous forest. The order of natural water holding capacity was mixed broad leafconifer forest ＆gt; coniferous forest ＆gt; grass slope ＆gt; shrub forest. The relevance between water holding capacity of litter and soaking time was in line with this formula： y = kln（ x） ＋ b. During 0-120 min of litter soaking,water holding capacity increased rapidly. After 120 min,the increasing trend remained flat until closing to the maximum water holding capacity. The relevance between water absorption rate of litter and soaking time was in line with this formula： y = a ＋ bx-1. In the beginning of soaking,water absorption rates of litter from different woodlands showed great difference. As soaking time went by,water absorption rates of litter from different woodlands all declined sharply. During 0-120 min,declining velocity of water absorption rate was quicker. After 120 min,the declining trend tended to be slow. The maximum water holding capacity of litter presented the order of shrub forest ＆gt; mixed broad leafconifer forest ＆gt; grass slope ＆gt; coniferous forest. The maximum precipitation interception amount of litter presented the order of shrub forest ＆gt; grass slope ＆gt; mixed broad leafconifer forest ＆gt; coniferous forest. Effective impounding capacity of litter presented the order of shrub forest ＆gt; mixed broad leafconifer forest ＆gt; grass slope ＆gt; coniferous forest. [Conclusion]The research could provide support for the construction of water conservation forest in Caohai basin.
文摘Litter is an important source of easily mineralizable C, N, and P for microbial metabolism in forest ecosystems;however, its decomposition is dependent upon a variety of biotic and abiotic factors, including litter chemical composition and plant specie, soil properties, and climate. We investigated C, N, and P mineralization patterns of pine litter, oak and a mixture of various species commonly found in wetland landscape position. Litter species were incubated (alone and with soils) under laboratory conditions in the dark for 120 days. Samples were leached weekly and the leachates were analyzed for pH, E4:E6 ratio, dissolved organic carbon (DOC), total N, NO3, NH4, soluble reactive P, and total P. CO2 effluxes during the 120-d incubation period were measure using NaOH traps. Carbon loss was calculated as the sum of DOC and CO2 effluxes. Results indicated that patterns of C and N release varied with litter species and soil type. Mix species treatment resulted in larger DOC and N pulses compared to pine and oak treatments. The majority of the DOC, N, and P leached was retained by the soils. When litters were added to the soils, a greater proportion of the C was lost as CO2, while litter incubated alone lost more C as DOC. This result demonstrated the importance of the soil microbial community affecting the patterns of litter mineralization. Total N concentration and C:N ratio of the litter species were significantly correlated to C loss.
文摘As an important part in forest ecosystems, the arthropod communities in the forest litter are closely related to forest health.Based on the ecological function,community structure and biology of the arthropods,we discuss the theoretical basis for the selection of particular groups of arthropods as bio-indicators in this paper,and suggest that the evenness and richness of Collembola(Collembolan), Coleoptera(Beetle) and Hymenoptera(Ant) can serve as forest health indicators.In terms of the relationship between forest litter arthropods and forest health,we summarize the main groups of forest litter arthropods suitable as bio-indicators and their ecological functions in forest ecosystems,and subsequently introduce a simple and accurate new method for selecting forest health indicator species by comparing the frequencies of the various species in different habitats.This method was tested with a real case using forest litter arthropods as a bio- indicator to evaluate rain forest health.Finally,the problems in using forest litter arthropods to evaluate and monitor forest habitat health are discussed and the use of multiple bio-indicator species in order to establish a balanced index system is recommended.
基金supported by the PAICYT Grant CT259-15National Science and Technological Council(Grant250732)
文摘Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The objective of this research was to assess litterfall production,the potential deposition of macro and micronutrients through leaf and twig fall as well as macronutrient—use efficiency in three forest ecosystems at different altitudes： a pine forest mixed with deciduous species（S1）; a Quercus spp.forest（S2）; and,a Tamaulipan thornscrub forest（S3）.Total annual litterfall deposition was 594,742 and 533 g m^（-2） for S1,S2 and S3.Leaf litter was higher （68%） than twigs（18%）,reproductive structures（8%） or miscellaneous material（6%）.Micronutrient leaf deposition was higher for Fe followed by Mn,Zn and Cu.Macronutrient leaf deposition was higher for Ca followed by K,Mg and P.Even though P deposition in leaves and twigs was lower than other macronutrients,its nutrient use efficiency was higher than Ca,Mg or K.Altitude and species composition determine litter and nutrient deposition,with higher values at mid-altitudes（550 m）.Altitude is an important factor to consider when analyzing litter production as well as nutrient deposition as shown in this study.Litter production and nutrient deposition are expected to change in a scenario of global warming.
基金supported by the National Natural Science Foundation of China (31270668,41373038)the National Basic Research Program of China (2012CB416902)the China Postdoctoral Science Foundation (2016M601342)
文摘Forests and grasslands in arid and semi-arid regions receive high-intensity ultraviolet（UV） radiation year-round. However, how the UV radiation affects the litter decomposition on the forest floor remains unclear. Here, we conducted a field-based experiment in 2011 in the southeastern Horqin Sandy Land, Northeast China, to investigate the effects of UV radiation, litter layer thickness, and their interaction on the mass loss and chemical properties of decomposing litter from Xiaozhuan poplar（Populus × xiaozhuanica） and Mongolian pine（Pinus sylvestris var. mongolica） plantation trees. We found that UV radiation accelerated the decomposition rates of both the Xiaozhuan poplar litter and Mongolian pine litter. For both species, the thick-layered litter had a lower mass loss than the thin-layered litter. The interaction between UV radiation and litter layer thickness significantly affected the litter mass loss of both tree species. However, the effects of UV radiation on the chemical properties of decomposing litter differed between the two species, which may be attributed to the contrasting initial leaf litter chemical properties and morphology. UV radiation mostly had positive effects on the lignin concentration and lignin/N ratio of Xiaozhuan poplar litter, while it had negative effects on the N concentration of Mongolian pine litter. Moreover, litter layer thickness and its interaction with UV radiation showed mostly positive effects on the N concentration and lignin/N ratio of Xiaozhuan poplar litter and the ratios of C/N and lignin/N of Mongolian pine litter, and mostly negative effects on the C/N ratio of Xiaozhuan poplar litter and the N concentration of Mongolian pine litter. Together, these results reveal the important roles played by UV radiation and litter layer thickness in the process of litter decomposition in this semi-arid region, and highlight how changes in the litter layer thickness can exert strong influences on the photodegradation of litter in tree plantations.
文摘Abstract Forests have been expanding over typical savanna sites for the past 3000 years in the Neotropics. Such invasion can produce a series of environmental modifications on typical savanna; however, it remains unclear how modifications in soil properties, caused by the encroachment of woody species, facilitate the expansion of forest ecosystems under dystrophic conditions. Here we examined chemical and microbiological changes associ- ated with tree encroachment in oxisols of a Neotropical Savanna at Assis Ecological Station, Southeastern Brazil. We predicted that tree encroachment caused by typical forest species would cause significant changes in the chemical and microbiological properties of savanna soils. Soils were sampled at Assis Ecological Station, from savanna sites differing in tree encroachment （typical, dense and forested savanna） caused by decades of fire exclusion. We analysed vegetation leaf area index and leaf litter volume deposited in the studied plots and chemical （pH,organic matter, P, K, Ca, Mg, A1, NO3-, NH4＋） and microbiological （microbial C biomass and dehydrogenase activity） properties of soils under distinct encroachment conditions. Most soil chemical properties did not change along the tree encroachment gradient; however, total P, soil organic matter, soil microbial C and dehydrogenase activity increased from typical savanna to forested savanna. The changes in soil organic matter and dehydrogenase activity were correlated with the values of leaf area index and litter volume along the encroachment gradient. Our results demonstrate that forest species can increase carbon and phosphorus supplies in tropical savanna soils.
文摘Forest l itter is the physical makeu p part of forest ecosystem．The rate o f decompositi on of forest litter is low in temperate and cool temperate zones．There is impor tant signific ance to search and utilize the functi on of soil animals，in order to probe the material circulation and energy flow in forest ecosystem．We selec ted three kin ds of mesh bag with different mesh size，in which，large pore mesh bag is large enough to permit the activities of all kinds of soil animals，medi um mesh bag is designed to exclude the function of soil macrofauna，while small mesh bag is small enough to exclude the effects o f any kind of soil animals as far as possible．The decomposition time is thr ee years．The studying results sh ow that：the decomposing speed of the bags with big meshes，under functions of a ll kinds of soil animals，faster than the bags with medium meshes，under functio ns of medium and small soil animals，as well as the bags with small meshes that exc luding all possibility of functions of soil animals；in the process of dec o mposition of litter，relationship of the litte r lost weight with number of soil anim als is not obvious clearly；the degre e of functions of soil animals to so ft litter higher than hard litter；according to the an alysis of diversity index ，no regula r changes will happen to the diversity of soil anima ls as the time of decomposing samples lengthen．
