Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for ...Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for this most important forest region in China. Accordingly, the objective of this study is to develop a first comprehensive system for estimating the wood production for the five dominant forest types.Methods: Based on a network of 384 field plots and using the state-space approach, we develop a system of dynamic stand models, for each of the five main forest types. Four models were developed and evaluated, including a base model and three extended models which include the effects of dominant height and climate variables. The four models were fitted, and their predictive strengths were tested, using the "seemingly unrelated regression"(SUR) technique.Results: All three of the extended models increased the accuracy of the predictions at varying degrees for the five major natural forest types of northeastern China. The inclusion of dominant height and two climate factors(precipitation and temperature) in the base model resulted in the best performance for all the forest types. On average, the root mean square values were reduced by 13.0% when compared with the base model.Conclusion: Both dominant height and climate factors were important variables in estimating forest production. This study not only presents a new method for estimating forest production for a large region, but also explains regional differences in the effect of site productivity and climate.展开更多
Background:Estimation of tree diversity at broader scale is important for conservation planning.Tree diversity should be measured and understood in terms of diversity and evenness,two integral components to describe t...Background:Estimation of tree diversity at broader scale is important for conservation planning.Tree diversity should be measured and understood in terms of diversity and evenness,two integral components to describe the structure of a biological community.Variation of the tree diversity and evenness with elevation,topographic relief,aspect,terrain shape,slope,soil nutrient,solar radiation etc.are well documented.Methods:Present study explores the variation of tree diversity(measured as Shannon diversity and evenness indices)of Majella National Park,Italy with five available forest types namely evergreen oak woods,deciduous oak woods,black/aleppo pine stands,hop-hornbeam forest and beech forest,using satellite,environmental and field data.Results:Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even.Diversity and evenness of forest types were concurrent to each other i.e.forest type which was more diverse was also more even.As a broad pattern,majority portion of the study area belonged to medium diversity and high evenness class.Conclusions:Satel ite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types.Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majel a.展开更多
The species diversities of rust fungus in live forest types was investigated and discussed according to the methods of fungi taxonomy and foresny ecology in Maorshan area. The results show the speies diversity index o...The species diversities of rust fungus in live forest types was investigated and discussed according to the methods of fungi taxonomy and foresny ecology in Maorshan area. The results show the speies diversity index of rust fungus is the highest in the mixed forest type, mendiun in Birch-poplar forest, Larch plantation and Korean pine plantation, and the lowest in Oak forest. The results also show that the vegetation succession can cause the fungus population succession.展开更多
To understand soil N2O fluxes from temperate forests in a climate-sensitive transitional zone,N2O emissions from three temperate forest types(Pinus tabulaeformis,PTT;Pinus armandii,PAT;and Quercus aliena var.acuteserr...To understand soil N2O fluxes from temperate forests in a climate-sensitive transitional zone,N2O emissions from three temperate forest types(Pinus tabulaeformis,PTT;Pinus armandii,PAT;and Quercus aliena var.acuteserrata,QAT)were monitored using the static closed-chamber method from June 2013 to May 2015 in the Huoditang Forest region of the Qinling Mountains,China.The results showed that these three forest types acted as N2O sources,releasing a mean combined level of 1.35±0.56 kg N2O ha^-1 a^-1,ranging from0.98±0.37 kg N2O ha^-1 a^-1 in PAT to 1.67±0.41 kg N2O ha^-1 a^-1 in QAT.N2O emission fluctuated seasonally,with highest levels during the summer for all three forest types.N2O flux had a significantly positive correlation with soil temperature at a depth of 5 cm or in the water-filled pore space,where the correlation was stronger for temperature than for the water-filled pore space.N2O flux was positively correlated with available soil nitrogen in QAT and PAT.Our results indicate that N2O flux is mainly controlled by soil temperature in the temperate forest in the Qinling Mountains.展开更多
Aims A lack of explicit information on differential controls on net primary productivity(NPP)across regions and ecosystem types is largely responsible for uncertainties in global trajectories of terrestrial carbon bal...Aims A lack of explicit information on differential controls on net primary productivity(NPP)across regions and ecosystem types is largely responsible for uncertainties in global trajectories of terrestrial carbon balance with changing environment.The objectives of this study were to determine how NPP of different forest types would respond to inter-annual variability of climate and to examine the responses of NPP to future climate change scenarios across contrasting forest types in northern China.Methods We investigated inter-annual variations of NPP in relation to climate variability across three forest types in northern China,including a boreal forest dominated by Larix gmelinii Rupr.,and two temperate forests dominated by Pinus tabulaeformis Carr.and Quercus wutaishanica Mayr.,respectively,and studied the responses of NPP in these forests to predicted changes in climate for the periods 2011–40,2041–70 and 2070–100 under carbon emission scenarios A2 and B2 of Intergovernmental Panel on Climate Change.We simulated the responses of NPP to predicted changes in future climate as well as inter-annual variability of the present climate with the Biome-BGC version 4.2 based on site-and species-specific parameters.The modeled forest NPP data were validated against values in literature for similar types of forests and compared with inter-annual growth variations reflected by tree-ring width index(RWI)at the study sites.Important Findings Inter-annual variations in modeled NPP during the period 1960–06 were mostly consistent with the temporal patterns in RWI.There were contrasting responses of modeled NPP among the three forest types to inter-annual variability of the present climate as well as to predicted changes in future climate.The modeled NPP was positively related to annual mean air temperature in the L.gmelinii forest(P<0.001),but negatively in the P.tabulaeformis forest(P=0.05)and the Q.wutaishanica forest(P=0.03),while the relationships of modeled NPP with annual precipitation for the three forest types were all positive.Multiple stepwise regression analyses showed that temperature was a more important constraint of NPP than precipitation in the L.gmelinii forest,whereas precipitation appeared to be a prominent factor limiting the growth in P.tabulaeformis and Q.wutaishanica.Model simulations suggest marked,but differential increases in NPP across the three forest types with predicted changes in future climate.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 >shrub forest >mixed broad leaf-conifer forest >coniferous forest. The order of natural water holding capacity was mixed broad leafconifer forest > coniferous forest > grass slope > 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 > mixed broad leafconifer forest > grass slope > coniferous forest. The maximum precipitation interception amount of litter presented the order of shrub forest > grass slope > mixed broad leafconifer forest > coniferous forest. Effective impounding capacity of litter presented the order of shrub forest > mixed broad leafconifer forest > grass slope > coniferous forest. [Conclusion]The research could provide support for the construction of water conservation forest in Caohai basin.展开更多
Climate is a critical factor affecting forest ecosystems and their capacity to produce goods and services. Effects of climate change on forests depend on ecosystem-specific factors including dimensions of climate (tem...Climate is a critical factor affecting forest ecosystems and their capacity to produce goods and services. Effects of climate change on forests depend on ecosystem-specific factors including dimensions of climate (temperature, precipitation, drought, wind etc.). Available information is not sufficient to support a quantitative assessment of the ecological, social and economic consequences. The present study assessed shifts in forest cover types of Western Himalayan Eco-region (700?4500 m). 100 randomly selected samples (75 for training and 25 for testing the model), genetic algorithm of rule set parameters and climatic envelopes were used to assess the distribution of five prominent forest cover types (Temperate evergreen, Tropical semi-evergreen, Temperate conifer, Subtropical conifer, and Tropical moist deciduous forests). Modelling was conducted for four different scenarios, current scenario, changed precipitation (8% increase), changed temperature (1.07°C increase), and both changed temperature and precipitation. On increasing precipitation a downward shift in the temperate evergreen and tropical semi-evergreen was observed, while sub-tropical conifer and tropical moist-deciduous forests showed a slight upward shift and temperate conifer showed no shift. On increasing temperature, an upward shift in all forest types was observed except sub-tropical conifer forests without significant changes. When both temperature and precipitation were changed, the actual distribution was maintained and slight upward shift was observed in all the forest types except sub-tropical conifer. It is important to understand the likely impacts of the projected climate change on the forest ecosystems, so that better management and conservation strategies can be adopted for the biodiversity and forest dependent community. Knowledge of impact mechanisms also enables identification and mitigation of some of the conditions that increase vulnerability to climate change in the forest sector.展开更多
Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura.Overall 10,957 individual trees belonging t...Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura.Overall 10,957 individual trees belonging to 46 family,103 genera and 144 species were counted at ≥30 cm DBH(diameter at breast height) using 28 permanent belt transects with a size of 1 ha(10 m × 1000 m).Four different tree communities were identified.The primary forests was dominated by Shorea robusta(mean density 464.77 trees ha-1,105 species) and Schima wallichii(336.25 trees ha-1,82 species),while the secondary forests was dominated by Tectona grandis(333.88 trees ha-1,105 species) and Hevea brasiliensis(299.67 trees ha-1,82 species).Overall mean basal area in this study was 18.01m 2 ·ha-1 ;the maximum value was recorded in primary Shorea forest(26.21 m 2 ·ha-1).Mean density and diversity indices were differed significantly within four different communities.No significant differences were observed in number of species,genera,family and tree basal cover area.Significant relationships were found between the species richness and different tree population groups across the communities.Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumulation of native oligarchic small tree species.Seventeen species were recorded with <2 individuals of which Saraca asoka(Roxb.) de Wilde and Entada phaseoloides(L.) Merr.etc.extensively used in local ethno-medicinal formulations.The present S.robusta Gaertn dominated forest was recorded richer(105 species) than other reported studies.Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests.Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur.The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T.grandis L.dominated community.展开更多
The purpose of this study was to classify current forest cover types,and to investigate stand development patterns for natural forests in six areas in northern Baekdudaegan,South Korea.Twenty-eight independent forest ...The purpose of this study was to classify current forest cover types,and to investigate stand development patterns for natural forests in six areas in northern Baekdudaegan,South Korea.Twenty-eight independent forest communities were aggregated into eight forest cover types by species composition in the overstory of each forest community.The forest cover types were of mixed mesophytic,‘‘others' ' deciduous,Quercus mongolica dominant,Q.mongolica pure,Pinus densiflora–Q.mongolica,P.densiflora,Betula ermanii,and Q.mongolica–P.koraiensis.The ecological information was organized by importance value and species diversity for each forest type.Based on the correlation between species diversity index and the abundance of Q.mongolica plus P.densiflora for corresponding forest cover types,we compared the developmental process and approximate successional pathway between each cover type.The P.densiflora forest cover type changes into the P.densiflora–Q.mongolica cover type,followed by the Q.mongolica dominant cover type through continuous invasion of the oak trees.Furthermore,the Q.mongolica pure cover type would spread toward the Q.mongolica dominant cover type with a mixture of various deciduous tree species.The Q.mongolica dominant cover type progresses through the other deciduous cover types to the mixed mesophytic cover type with diversified composition and structure.On the mid to lower slopes,with loamy soils and good moisture conditions,various deciduous forest types should progress,by ecological succession,toward the mixed mesophytic cover type without any further disturbance.展开更多
This paper quantifies the relationships among community type, peat layer thickness and habitat age of the mangrove forests in Pohnpei Island, Micronesia and provides a discussion concerning the primary succession and ...This paper quantifies the relationships among community type, peat layer thickness and habitat age of the mangrove forests in Pohnpei Island, Micronesia and provides a discussion concerning the primary succession and the belowground carbon storage of the main mangrove community types. The ages of the habitat were estimated from a relationship between the thickness of the mangrove peat layer and the formative period, which was decided by calibrated radiocarbon ages. Mangrove communities in the coral reef type habitat were generally arranged in the following order, from seaward to landward: 1) the Rhizophora stylosa or Sonneratia alba community (I or II communities), 2) the typical subunit of the S. alba subcommunity of the Rhizophora apiculata— Bruguiera gymnorrhiza community (III(2)a subunit) and 3) the Xylocarpus granatum subunit of the same subcommunity of the same community (III(2)b subunit). Their habitat ages were estimated to be younger than 460 years, between 360 and 1070 years and between 860 and 2300 years, respectively. Based on these results and other evidences such as photosynthetic characteristics and pollen analysis derived from the previous studies, the primary succession was inferred to have progressed in the order mentioned above. Belowground stored carbon for the main community types in the coral reef type habitat were estimated to be less than 370 t C ha-1 for the I and the II communities, between 290 and 860 t C ha-1 for the III(2)a subunit and between 700 and 1850 t C ha-1 for the III(2)b subunit.展开更多
Snow/wind damage is one of the important natural disturbances in forest ecosystems,especially in a montane secondary forest.However,the effects of snow/wind damage remain unclear which affects the management of these ...Snow/wind damage is one of the important natural disturbances in forest ecosystems,especially in a montane secondary forest.However,the effects of snow/wind damage remain unclear which affects the management of these forests.Therefore,we investigated the responses of species,individual tree traits and stand structure to snow/wind damage in a montane secondary forest.Results show that,amongst the canopy trees,Betula costata exhibited the most uprooting,bending and overall damage ratio(the number of damaged stems to the total number of stems in a plot); Quercus mongolica showed the highest breakage ratio and Fraxinus mandshurica and Juglans mandshurica the least overall damage ratios.Among the subcanopy trees,Carpinus cordata,Acer mono,Acer tegmentosum and Acer pseudo-sieboldianum showed the least uprooting and breakage,and the most bending damage.A.pseudo-sieboldianum demonstrated the lowest breakage and highest bending damage ratios.Thesefindings indicate that different species have various sensitivities to snow/wind damage.Larger trees(taller,wider crowns) tend to break and become uprooted,while smaller trees are bent or remain undamaged,suggesting that tree characteristics significantly influence the types of damage from snow and wind.Stands of Q.mongolica and B.costata had the highest damage ratios,whereas A.pseudosieboldianum had the lowest snapping ratio.In summary,the severity and type of snow/wind damage are related to individual tree attributes and stand-level characteristics.Therefore,selection of suitable species(e.g.,shorter,smaller with deep root systems,hard wood,bending resistance and compression resistance) and appropriate thinning are recommended for planting in the montane secondary forests.展开更多
Using plant community analysis methods, we analyzed the floristic characteristics, species composition, community structure, population structure, and spatial distribution patterns of a Betula dahurica forest on the ...Using plant community analysis methods, we analyzed the floristic characteristics, species composition, community structure, population structure, and spatial distribution patterns of a Betula dahurica forest on the “1238” mountain of Badaling in Beijing, China. The results show that: 1) There are 33 plant species in the B. dahurica community, including 18 woody plant spe- cies. The B. dahurica forest is a monodominant community with 75.9% dominance. 2) Based on diameter at breast height (DBH) size class distribution, the population structure of B. dahurica and Acer mono—two heliophyllous and pioneer tree species—is cascade-type, with both in an increasing stage. The population structure of Tilia mandshurica and T. mongolica, two shade-tolerant tree species, is inverse-J type, and they have more young seedling individuals and regenerate more stably. They are associated species of the pioneer tree species. The population structure of Quercus mongolica, as the associated species of climax species in the community, is sporadic, and its regeneration is fluctuating and random. Fraxinus rhynchophylla is a shade-tolerant tree species which has a unibar population structure and climax characteristics of pioneer tree species. The relative frequency of young seedlings reached 0.4. 3) The dominant species B. dahurica is still in an increasing stage, and the regeneration of other species is steady or partly influences the community, putting the community in the pioneer species stage. From the population structure and distribution frequency of F. rhynchophylla, the B. dahurica forest will approach to a climax state in the future.展开更多
5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content ...5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content of degraded red soil region in subtropics. The soil heavy metal pollution degree was evaluated by national environmental quality standard (II class). The results showed that three soil metals of P. massoniana × S. superba were the highest, and the soil metals enrichment ability was strong. The order of single factor pollution index of metal elements was Cu (1.38) > Cr (0.81) > Zn (0.42), and moderately pollution, pollution warning and no pollution, respectively. There was no significant correlation between three soil heavy metals and soil total carbon (TC), total nitrogen (TN) and total phosphorus (TP). These results suggested that the accumulation of heavy metal elements was not derived from the parent material of soil. There was a significant positive correlation between the three metal elements which indicated that the sources of the three elements were similar. The structural equation model showed that the direct and indirect effects among the influencing factors ultimately affected the activity of heavy metals by cascade effects.展开更多
基金supported by the Key Project of National Key Research and Development Plan(No.2017YFC0504104)the Program of National Natural Science Foundation of China(No.31670643)
文摘Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for this most important forest region in China. Accordingly, the objective of this study is to develop a first comprehensive system for estimating the wood production for the five dominant forest types.Methods: Based on a network of 384 field plots and using the state-space approach, we develop a system of dynamic stand models, for each of the five main forest types. Four models were developed and evaluated, including a base model and three extended models which include the effects of dominant height and climate variables. The four models were fitted, and their predictive strengths were tested, using the "seemingly unrelated regression"(SUR) technique.Results: All three of the extended models increased the accuracy of the predictions at varying degrees for the five major natural forest types of northeastern China. The inclusion of dominant height and two climate factors(precipitation and temperature) in the base model resulted in the best performance for all the forest types. On average, the root mean square values were reduced by 13.0% when compared with the base model.Conclusion: Both dominant height and climate factors were important variables in estimating forest production. This study not only presents a new method for estimating forest production for a large region, but also explains regional differences in the effect of site productivity and climate.
文摘Background:Estimation of tree diversity at broader scale is important for conservation planning.Tree diversity should be measured and understood in terms of diversity and evenness,two integral components to describe the structure of a biological community.Variation of the tree diversity and evenness with elevation,topographic relief,aspect,terrain shape,slope,soil nutrient,solar radiation etc.are well documented.Methods:Present study explores the variation of tree diversity(measured as Shannon diversity and evenness indices)of Majella National Park,Italy with five available forest types namely evergreen oak woods,deciduous oak woods,black/aleppo pine stands,hop-hornbeam forest and beech forest,using satellite,environmental and field data.Results:Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even.Diversity and evenness of forest types were concurrent to each other i.e.forest type which was more diverse was also more even.As a broad pattern,majority portion of the study area belonged to medium diversity and high evenness class.Conclusions:Satel ite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types.Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majel a.
文摘The species diversities of rust fungus in live forest types was investigated and discussed according to the methods of fungi taxonomy and foresny ecology in Maorshan area. The results show the speies diversity index of rust fungus is the highest in the mixed forest type, mendiun in Birch-poplar forest, Larch plantation and Korean pine plantation, and the lowest in Oak forest. The results also show that the vegetation succession can cause the fungus population succession.
基金financially supported by the Program for Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20120204110011)
文摘To understand soil N2O fluxes from temperate forests in a climate-sensitive transitional zone,N2O emissions from three temperate forest types(Pinus tabulaeformis,PTT;Pinus armandii,PAT;and Quercus aliena var.acuteserrata,QAT)were monitored using the static closed-chamber method from June 2013 to May 2015 in the Huoditang Forest region of the Qinling Mountains,China.The results showed that these three forest types acted as N2O sources,releasing a mean combined level of 1.35±0.56 kg N2O ha^-1 a^-1,ranging from0.98±0.37 kg N2O ha^-1 a^-1 in PAT to 1.67±0.41 kg N2O ha^-1 a^-1 in QAT.N2O emission fluctuated seasonally,with highest levels during the summer for all three forest types.N2O flux had a significantly positive correlation with soil temperature at a depth of 5 cm or in the water-filled pore space,where the correlation was stronger for temperature than for the water-filled pore space.N2O flux was positively correlated with available soil nitrogen in QAT and PAT.Our results indicate that N2O flux is mainly controlled by soil temperature in the temperate forest in the Qinling Mountains.
基金Public Welfare Forestry of the State Forestry Administration of China(201104008)Beijing Municipal Commission of Education for development of Key Laboratory for Silviculture and Conservation.
文摘Aims A lack of explicit information on differential controls on net primary productivity(NPP)across regions and ecosystem types is largely responsible for uncertainties in global trajectories of terrestrial carbon balance with changing environment.The objectives of this study were to determine how NPP of different forest types would respond to inter-annual variability of climate and to examine the responses of NPP to future climate change scenarios across contrasting forest types in northern China.Methods We investigated inter-annual variations of NPP in relation to climate variability across three forest types in northern China,including a boreal forest dominated by Larix gmelinii Rupr.,and two temperate forests dominated by Pinus tabulaeformis Carr.and Quercus wutaishanica Mayr.,respectively,and studied the responses of NPP in these forests to predicted changes in climate for the periods 2011–40,2041–70 and 2070–100 under carbon emission scenarios A2 and B2 of Intergovernmental Panel on Climate Change.We simulated the responses of NPP to predicted changes in future climate as well as inter-annual variability of the present climate with the Biome-BGC version 4.2 based on site-and species-specific parameters.The modeled forest NPP data were validated against values in literature for similar types of forests and compared with inter-annual growth variations reflected by tree-ring width index(RWI)at the study sites.Important Findings Inter-annual variations in modeled NPP during the period 1960–06 were mostly consistent with the temporal patterns in RWI.There were contrasting responses of modeled NPP among the three forest types to inter-annual variability of the present climate as well as to predicted changes in future climate.The modeled NPP was positively related to annual mean air temperature in the L.gmelinii forest(P<0.001),but negatively in the P.tabulaeformis forest(P=0.05)and the Q.wutaishanica forest(P=0.03),while the relationships of modeled NPP with annual precipitation for the three forest types were all positive.Multiple stepwise regression analyses showed that temperature was a more important constraint of NPP than precipitation in the L.gmelinii forest,whereas precipitation appeared to be a prominent factor limiting the growth in P.tabulaeformis and Q.wutaishanica.Model simulations suggest marked,but differential increases in NPP across the three forest types with predicted changes in future climate.
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 >shrub forest >mixed broad leaf-conifer forest >coniferous forest. The order of natural water holding capacity was mixed broad leafconifer forest > coniferous forest > grass slope > 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 > mixed broad leafconifer forest > grass slope > coniferous forest. The maximum precipitation interception amount of litter presented the order of shrub forest > grass slope > mixed broad leafconifer forest > coniferous forest. Effective impounding capacity of litter presented the order of shrub forest > mixed broad leafconifer forest > grass slope > coniferous forest. [Conclusion]The research could provide support for the construction of water conservation forest in Caohai basin.
文摘Climate is a critical factor affecting forest ecosystems and their capacity to produce goods and services. Effects of climate change on forests depend on ecosystem-specific factors including dimensions of climate (temperature, precipitation, drought, wind etc.). Available information is not sufficient to support a quantitative assessment of the ecological, social and economic consequences. The present study assessed shifts in forest cover types of Western Himalayan Eco-region (700?4500 m). 100 randomly selected samples (75 for training and 25 for testing the model), genetic algorithm of rule set parameters and climatic envelopes were used to assess the distribution of five prominent forest cover types (Temperate evergreen, Tropical semi-evergreen, Temperate conifer, Subtropical conifer, and Tropical moist deciduous forests). Modelling was conducted for four different scenarios, current scenario, changed precipitation (8% increase), changed temperature (1.07°C increase), and both changed temperature and precipitation. On increasing precipitation a downward shift in the temperate evergreen and tropical semi-evergreen was observed, while sub-tropical conifer and tropical moist-deciduous forests showed a slight upward shift and temperate conifer showed no shift. On increasing temperature, an upward shift in all forest types was observed except sub-tropical conifer forests without significant changes. When both temperature and precipitation were changed, the actual distribution was maintained and slight upward shift was observed in all the forest types except sub-tropical conifer. It is important to understand the likely impacts of the projected climate change on the forest ecosystems, so that better management and conservation strategies can be adopted for the biodiversity and forest dependent community. Knowledge of impact mechanisms also enables identification and mitigation of some of the conditions that increase vulnerability to climate change in the forest sector.
基金supported by DBT Network Project (BT/PR7928/NDB/52/9/2006)Department of Biotechnology(DBT),Govt. of India
文摘Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura.Overall 10,957 individual trees belonging to 46 family,103 genera and 144 species were counted at ≥30 cm DBH(diameter at breast height) using 28 permanent belt transects with a size of 1 ha(10 m × 1000 m).Four different tree communities were identified.The primary forests was dominated by Shorea robusta(mean density 464.77 trees ha-1,105 species) and Schima wallichii(336.25 trees ha-1,82 species),while the secondary forests was dominated by Tectona grandis(333.88 trees ha-1,105 species) and Hevea brasiliensis(299.67 trees ha-1,82 species).Overall mean basal area in this study was 18.01m 2 ·ha-1 ;the maximum value was recorded in primary Shorea forest(26.21 m 2 ·ha-1).Mean density and diversity indices were differed significantly within four different communities.No significant differences were observed in number of species,genera,family and tree basal cover area.Significant relationships were found between the species richness and different tree population groups across the communities.Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumulation of native oligarchic small tree species.Seventeen species were recorded with <2 individuals of which Saraca asoka(Roxb.) de Wilde and Entada phaseoloides(L.) Merr.etc.extensively used in local ethno-medicinal formulations.The present S.robusta Gaertn dominated forest was recorded richer(105 species) than other reported studies.Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests.Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur.The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T.grandis L.dominated community.
基金support of ‘Forest Science&Technology Projects(Project No.S211012L030110)’ provided by Korea Forest Service
文摘The purpose of this study was to classify current forest cover types,and to investigate stand development patterns for natural forests in six areas in northern Baekdudaegan,South Korea.Twenty-eight independent forest communities were aggregated into eight forest cover types by species composition in the overstory of each forest community.The forest cover types were of mixed mesophytic,‘‘others' ' deciduous,Quercus mongolica dominant,Q.mongolica pure,Pinus densiflora–Q.mongolica,P.densiflora,Betula ermanii,and Q.mongolica–P.koraiensis.The ecological information was organized by importance value and species diversity for each forest type.Based on the correlation between species diversity index and the abundance of Q.mongolica plus P.densiflora for corresponding forest cover types,we compared the developmental process and approximate successional pathway between each cover type.The P.densiflora forest cover type changes into the P.densiflora–Q.mongolica cover type,followed by the Q.mongolica dominant cover type through continuous invasion of the oak trees.Furthermore,the Q.mongolica pure cover type would spread toward the Q.mongolica dominant cover type with a mixture of various deciduous tree species.The Q.mongolica dominant cover type progresses through the other deciduous cover types to the mixed mesophytic cover type with diversified composition and structure.On the mid to lower slopes,with loamy soils and good moisture conditions,various deciduous forest types should progress,by ecological succession,toward the mixed mesophytic cover type without any further disturbance.
文摘This paper quantifies the relationships among community type, peat layer thickness and habitat age of the mangrove forests in Pohnpei Island, Micronesia and provides a discussion concerning the primary succession and the belowground carbon storage of the main mangrove community types. The ages of the habitat were estimated from a relationship between the thickness of the mangrove peat layer and the formative period, which was decided by calibrated radiocarbon ages. Mangrove communities in the coral reef type habitat were generally arranged in the following order, from seaward to landward: 1) the Rhizophora stylosa or Sonneratia alba community (I or II communities), 2) the typical subunit of the S. alba subcommunity of the Rhizophora apiculata— Bruguiera gymnorrhiza community (III(2)a subunit) and 3) the Xylocarpus granatum subunit of the same subcommunity of the same community (III(2)b subunit). Their habitat ages were estimated to be younger than 460 years, between 360 and 1070 years and between 860 and 2300 years, respectively. Based on these results and other evidences such as photosynthetic characteristics and pollen analysis derived from the previous studies, the primary succession was inferred to have progressed in the order mentioned above. Belowground stored carbon for the main community types in the coral reef type habitat were estimated to be less than 370 t C ha-1 for the I and the II communities, between 290 and 860 t C ha-1 for the III(2)a subunit and between 700 and 1850 t C ha-1 for the III(2)b subunit.
基金supported by the National Key Research and Development Program of China(2016YFC0500302)the National Nature Scientific Foundation Project of China(31200432)
文摘Snow/wind damage is one of the important natural disturbances in forest ecosystems,especially in a montane secondary forest.However,the effects of snow/wind damage remain unclear which affects the management of these forests.Therefore,we investigated the responses of species,individual tree traits and stand structure to snow/wind damage in a montane secondary forest.Results show that,amongst the canopy trees,Betula costata exhibited the most uprooting,bending and overall damage ratio(the number of damaged stems to the total number of stems in a plot); Quercus mongolica showed the highest breakage ratio and Fraxinus mandshurica and Juglans mandshurica the least overall damage ratios.Among the subcanopy trees,Carpinus cordata,Acer mono,Acer tegmentosum and Acer pseudo-sieboldianum showed the least uprooting and breakage,and the most bending damage.A.pseudo-sieboldianum demonstrated the lowest breakage and highest bending damage ratios.Thesefindings indicate that different species have various sensitivities to snow/wind damage.Larger trees(taller,wider crowns) tend to break and become uprooted,while smaller trees are bent or remain undamaged,suggesting that tree characteristics significantly influence the types of damage from snow and wind.Stands of Q.mongolica and B.costata had the highest damage ratios,whereas A.pseudosieboldianum had the lowest snapping ratio.In summary,the severity and type of snow/wind damage are related to individual tree attributes and stand-level characteristics.Therefore,selection of suitable species(e.g.,shorter,smaller with deep root systems,hard wood,bending resistance and compression resistance) and appropriate thinning are recommended for planting in the montane secondary forests.
文摘Using plant community analysis methods, we analyzed the floristic characteristics, species composition, community structure, population structure, and spatial distribution patterns of a Betula dahurica forest on the “1238” mountain of Badaling in Beijing, China. The results show that: 1) There are 33 plant species in the B. dahurica community, including 18 woody plant spe- cies. The B. dahurica forest is a monodominant community with 75.9% dominance. 2) Based on diameter at breast height (DBH) size class distribution, the population structure of B. dahurica and Acer mono—two heliophyllous and pioneer tree species—is cascade-type, with both in an increasing stage. The population structure of Tilia mandshurica and T. mongolica, two shade-tolerant tree species, is inverse-J type, and they have more young seedling individuals and regenerate more stably. They are associated species of the pioneer tree species. The population structure of Quercus mongolica, as the associated species of climax species in the community, is sporadic, and its regeneration is fluctuating and random. Fraxinus rhynchophylla is a shade-tolerant tree species which has a unibar population structure and climax characteristics of pioneer tree species. The relative frequency of young seedlings reached 0.4. 3) The dominant species B. dahurica is still in an increasing stage, and the regeneration of other species is steady or partly influences the community, putting the community in the pioneer species stage. From the population structure and distribution frequency of F. rhynchophylla, the B. dahurica forest will approach to a climax state in the future.
文摘5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content of degraded red soil region in subtropics. The soil heavy metal pollution degree was evaluated by national environmental quality standard (II class). The results showed that three soil metals of P. massoniana × S. superba were the highest, and the soil metals enrichment ability was strong. The order of single factor pollution index of metal elements was Cu (1.38) > Cr (0.81) > Zn (0.42), and moderately pollution, pollution warning and no pollution, respectively. There was no significant correlation between three soil heavy metals and soil total carbon (TC), total nitrogen (TN) and total phosphorus (TP). These results suggested that the accumulation of heavy metal elements was not derived from the parent material of soil. There was a significant positive correlation between the three metal elements which indicated that the sources of the three elements were similar. The structural equation model showed that the direct and indirect effects among the influencing factors ultimately affected the activity of heavy metals by cascade effects.