Warming and nitrogen(N)deposition are two important drivers of global climate changes.Coarse woody debris(CWD)contains a large proportion of the carbon(C)in the total global C pool.The composition of soil microbial co...Warming and nitrogen(N)deposition are two important drivers of global climate changes.Coarse woody debris(CWD)contains a large proportion of the carbon(C)in the total global C pool.The composition of soil microbial communities and environmental changes(i.e.,N deposition and warming)are the key drivers of CWD decomposition,but the interactive impact between N deposition and warming on the composition of soil microbial communities and CWD decomposition is still unclear.In a laboratory experiment,we study and simulate respiration during decomposition of the CWD(C 98)of Cryptomeria japonica(CR)and Platycarya strobilacea(PL)in response to warming and N deposition over 98 days.Resuts show that either warming or N addition signifi cantly accelerated the C 98 of the two tree species by altering the soil microbial community(bacterial:fungi and G+:G–).The combined treatment(warming+N)resulted in a decomposition eff ect equal to the sum of the individual eff ects.In addition,the species composition of bacteria and fungi was obviously aff ected by warming.However,N deposition had a remarkable infl uence on G+:G–.Our results indicated that N deposition and warming will observably alter the composition and growth of the microbial community and thus work synergistically to accelerate CWD decomposition in forest ecosystems.We also present evidence that N deposition and warming infl uenced the composition and balance of soil microbial communities and biogeochemical cycling of forest ecosystems.展开更多
This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river chan...This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest.展开更多
Coarse woody debris is an important structure and function unit in forest ecosystem.This review analyzed the ecological functions of coarse woody debris in forest ecosystem and introduced several hotspots and existing...Coarse woody debris is an important structure and function unit in forest ecosystem.This review analyzed the ecological functions of coarse woody debris in forest ecosystem and introduced several hotspots and existing problems in coarse woody debris research field. It is suggested that quantitative research should be intensified in theintensified in the ecological demands of coarse woody debris for providing a technical guidelines in management of productivity, biodiversity and other ecologicalprocesses.展开更多
Coarse woody debris （CWD） is an important and particular component of forest ecosystems and is extremely important to forest health. This review describes the decomposition process, decomposition model and influence...Coarse woody debris （CWD） is an important and particular component of forest ecosystems and is extremely important to forest health. This review describes the decomposition process, decomposition model and influence factors. CWD decomposition is a complex and continuous process and characterizes many biological and physical processes, including biological respiration, leaching, and fragmentation. All these processes have closed relationships between each other and work synergistically. During decomposition, there are many controlling factors mainly including site conditions （temperature, humidity, and OJCO2concentration）, woody substrate quality （diameter, species and compound） and organism in CWD. The decomposition rate is generally expresses through a constant k which indicate the percent mass, volume or density loss over time, and can be determined by long-term monitoring, chronosequence approach and the radio between input and the total mass. Now using mathematical models to simulate decomposition patterns and estimate the decomposition rate is widely applied, especially the exponential model. We brought forward that managing and utilizing for the CWD in forest was a primary objective on all forest lands. And it is should be intensified to integrate many related research subjects and to carry a comprehensive, long-term and multi-scale research which mainly focus on seven sections.展开更多
A rapid assessment on the status and distribution patterns of coarse woody debris （CWD） was conducted by laying five curvilinear transects （transects A, B, C, D and E; major trails）, along an altitudinal gradient ...A rapid assessment on the status and distribution patterns of coarse woody debris （CWD） was conducted by laying five curvilinear transects （transects A, B, C, D and E; major trails）, along an altitudinal gradient starting from 900 to 2 600 m, in three major watersheds （Charigad, Dogarhigad and upper Gosigad） of Goriganga catchment in Askot Wildlife Sanctuary, India. At every 100 m rise in altitude a hectare plot （100 m x 100 m） was selected. Results showed that the percentage contribution by different succession phases was in the decreasing order： phase I 〉 phase II 〉 phase IV 〉 phase III for snags, and phase III〉 phase II 〉 phase IV 〉 phase I for logs. Snag density in chir pine forest was high in transect A （11 snags＇ha^-1） at 1 500 m, and the value in rianj oak forest was high in transect B （10 snags.ha-l） at 2 300 m. The total available mass of snags and logs in chit pine forest was 13.9 t, of which snags mass accounted for 41% of the total mass and logs mass for 59%. While the total value was 5.6 t in rianj oak forest, of which snags and logs accounted for 60% and 40% of the total mass, respectively. Moreover, the presence of CWD in the study area if not harvested, would provide a great opportunity to the orchids in future to flourish by providing protection. The high densities of snags and logs in chir pine forest at mid-altitudinal zone led to less species richness and lower density of ground flora as the zone receives more light, accompanying with lower soil moisture, and thus only the dominant species occupy the habitat.展开更多
Woody debris(WD) is an important par of natural Pinus tabulaeformis mixed stands, and i affects the forest ecosystem stability and developmen The WD spatial patterns are especially importan structural characteristics ...Woody debris(WD) is an important par of natural Pinus tabulaeformis mixed stands, and i affects the forest ecosystem stability and developmen The WD spatial patterns are especially importan structural characteristics that can provide insights into forest dynamics. In this paper, the WD storage WD spatial patterns and WD associations among the main species were examined in the natural secondary forest on Loess Plateau in northwest China. Data were collected in a 1 ha(100 m × 100 m) permanent plot and all the trees with a diameter at breast height o more than 3 cm were measured and stem-mapped Ripley's K functions from the spatial-point-pattern analysis method were used to analyze the spatia distribution and associations. The results showed tha(1) The total storage of WD was 10.73 t/ha, fallen wood was the main source of WD, and the majority diameters were greater than 20 cm, and in intermediate levels of decay;(2) The overall spatia pattern was closely related to the spatial scale, which exhibited an aggregated pattern on a small scale, and a random pattern on a large scale. The spatia patterns of coarse woody debris also gradually transitioned from an aggregated pattern in fine scales to a random pattern in broader spatial scales, which matched the overall spatial pattern. The spatial intensity was gradually decreased with the increasing diameters, and increased with the decomposition classes;(3) The WD of Pinus tabulaeformis species was negatively associated with Betula platyphylla and Populus davidiana on a small scale but positively associated with these species on a large scale. The spatial pattern and interspecies relations were the results of long-term interactions between the natural secondary forest community and the surrounding natural environment. These findings would provide a scientific basis for the sustainable management and protection of natural secondary forest ecosystems on Loess Plateau.展开更多
CWD （coarse woody debris） plays an important role in nutrient cycling, habitat for species and more recently carbon accounting in forest ecosystems. LiDAR （light detection and ranging） technology has demonstrated ...CWD （coarse woody debris） plays an important role in nutrient cycling, habitat for species and more recently carbon accounting in forest ecosystems. LiDAR （light detection and ranging） technology has demonstrated utility in capturing forest structure information. This paper proposes an indirect method of assessing downed CWD using LiDAR derived forest structure variables. Fieldwork was conducted to measure CWD volume in an Eucalyptus forest in Tasmania. A GLM （generalized linear model） to statistically estimate CWD volume in the Eucalyptus forest was developed using a LiDAR derived FCS （forest characterisation scheme）： the openings above the ground, low and medium vegetation, canopy cover, presence of understorey and mid-storey vegetation and high trees, and the vertical canopy density of high trees. Five structural variables were selected for the best model based on AIC （Akaike＇s Information Criterion） by stepwise selection. The applicability of the model was then compared to the outcome of model using field derived variables such as diameter at breast height of trees. The results show that the model using LiDAR derived variables better estimated the amount of CWD. It is concluded that LiDAR derived forest structural variables has the potential to predict the amount of downed CWD in Eucalyptus forest.展开更多
A rapid assessment on the status and distribution patterns of coarse woody debris (CWD) was conducted by laying five curvilinear transects (transects A, B, C, D and E; major trails), along an altitudinal gradient star...A rapid assessment on the status and distribution patterns of coarse woody debris (CWD) was conducted by laying five curvilinear transects (transects A, B, C, D and E; major trails), along an altitudinal gradient starting from 900 to 2 600 m, in three major watersheds (Charigad, Dogarhigad and upper Gosigad) of Goriganga catchment in Askot Wildlife Sanctuary, India. At every 100 m rise in altitude a hectare plot (100 m x 100 m) was selected. Results showed that the percentage contribution by different succession phases was in the decreasing order: phase I > phase II > phase IV > phase III for snags, and phase III > phase II > phase IV > phase I for logs. Snag density in chir pine forest was high in transect A (11 snags·ha-1) at 1 500 m, and the value in rianj oak forest was high in transect B (10 snags·ha-1) at 2 300 m. The total available mass of snags and logs in chir pine forest was 13.9 t, of which snags mass accounted for 41% of the total mass and logs mass for 59%. While the total value was 5.6 t in rianj oak forest, of which snags and logs accounted for 60% and 40% of the total mass, respectively. Moreover, the presence of CWD in the study area if not harvested, would provide a great opportunity to the orchids in future to flourish by providing protection. The high densities of snags and logs in chir pine forest at mid-altitudinal zone led to less species richness and lower density of ground flora as the zone receives more light, accompanying with lower soil moisture, and thus only the dominant species occupy the habitat.展开更多
The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coa...The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coarse woody debris decomposition is complex and the results from different regions vary considerably.It is not clear which factors affect decay rate(k),especially at different decomposition stages.In this study,a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains.The results show that the decay rate of coarse woody debris was positively correlated to decay class.The average decomposition rate was 0.019,and 41 years and 176 years are needed for a 50%and 95%mass loss,respectively.CWD nutrient content,density,and water content could explain the variance in the decay rate(~42%)of the decay factors such as amount of leaching,degree of fragmentation,respiration of the debris,and biotransformation,and varied significantly between different decay classes.Using the space-time substitution method,this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process.It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents.This paper quantifies the indicators affecting CWD decay to explain the decomposition process.展开更多
In Yingzuijie National Nature Reserve, Pinus massoniana forest, mixed broadleaf-coniferous forest and evergreen broad-leaf forest were investigated to study the changing characteristics of woody debris （WD） during v...In Yingzuijie National Nature Reserve, Pinus massoniana forest, mixed broadleaf-coniferous forest and evergreen broad-leaf forest were investigated to study the changing characteristics of woody debris （WD） during various succession stages o1 evergreen broad-leaf forest. The results showed that during various succession stages of evergreen broad-leaf forest in Yingzuijie National Nature Reserve, WD storage of each forest ranged from 1.26 to 8.82 t/hm^2, with the order of P. massoniana forest 〈 mixed broadleaf-coniferous forest 〈 evergreen broad-leaf forest, that is, it increased from early to late stages of the succession. At different succession stages, coarse woody debris （CWD） storage was 2 -9 times more than fine woody debris （FWD） storage, revealing that CWD was dominant in WD of each forest. CWD biomass accounted for 0.66% -2.21% of arbor biomass, so the forests were at the developmental stage.展开更多
Coarse woody debris (CWD) has unique ecological function, historical value and cultural connotation in urban ecosystem, the application prospect of CWD in urban greening was discussed and forecasted.
It is recognised that the blockage of culverts by woody debris can result in an increased risk of infrastructure damage and flooding.To date,debris transport analysis has focused on regional fluvial systems and large ...It is recognised that the blockage of culverts by woody debris can result in an increased risk of infrastructure damage and flooding.To date,debris transport analysis has focused on regional fluvial systems and large woody debris,both in flume and field experiments.Given the social and economic risk associated with urban flooding,and as urban drainage design shifts away from subsurface piped network reliance,there is an increasing need to understand debris movement in urban watercourses.The prediction of urban watercourse small woody debris(SWD)movement,both quantity and risk,has undergone only limited analysis predominantly due to lack of field data.This paper describes the development of a methodology to enable the collection of accurate and meaningful SWD residency and transportation data from watercourses.The presented research examines the limitations and effective function of PIT tag technology to collect SWD transport data in the field appropriate for risk and prediction analysis.Passive integrated transponder(PIT)technology provides a method to collect debris transport data within the urban environment.In this study,the tags are installed within small woody debris and released at known locations into a small urban natural watercourse enabling monitoring of movement and travel time.SWD velocity and detention are collated with solute time of travel,watercourse and point flow characteristics to identify the relationships between these key variables.The work presented tests three hypotheses:firstly,that the potential for unobstructed or un-detained SWD movement increases with flow velocity and water level.Secondly,that SWD travel distance,and the resistance forces along this travel path,influence SWD transport potential.Thirdly,the relationship between SWD and channel dimensions is examined with the aim of advancing representative debris transport prediction modelling.展开更多
Coarse woody debris(CWD)is generally considered as dead woody materials in various stages of decomposition,including sound and rotting logs,snags,and large branches.CWD is an important functional and structural compon...Coarse woody debris(CWD)is generally considered as dead woody materials in various stages of decomposition,including sound and rotting logs,snags,and large branches.CWD is an important functional and structural component of forested ecosystems and plays an important role in nutrient cycling,long-term carbon storage,tree regeneration,and maintenance of heterogeneous environmental and biological diversity.However,the definition and classification of CWD have been the subject of a long debate in forest ecology.CWD has not been precisely defined.Recently,with the rapid development of landscape ecology in CWD,the USDA Forest Service and the Long Term Ecological Research(LTER)have provided a standardized definition and classification for CWD,which makes data comparison in landscape scale possible.Important characteristics of their definition include:(1)a minimum diameter(or an equivalent crosssection)of CWD≥10 cm at the widest point(the woody debris with a diameter from 1 to 10 cm should be defined as fine woody debris,and the rest is litterfall);and(2)sound and rotting logs,snags,stumps,and large branches(located above the soil),and coarse root debris(larger than 1 cm in diameter).This classification has greatly facilitated CWD studies.Therefore,it has been widely applied in some countries(particularly in North America).However,this classification has long been a source of confusion for forest ecologists in China.Furthermore,different definitions and criteria are still adopted in individual studies,which makes the interpretation and generalization of their work difficult.This article reviewed recent progress in classifying CWD,with an emphasis on introducing the classification system of the USDA Forest Service and the LTER.It is expected that this review will help facilitate the development of standardized definition and classification suitable to forest ecosystems in China.展开更多
Decaying wood is an essential element of forest ecosystems and it affects its other components.The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in ...Decaying wood is an essential element of forest ecosystems and it affects its other components.The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in the gaps formed in the montane forest stands.The research was carried out in the Babiog orski National Park.The research plots were marked out in the gaps of the stands,which were formed as a result of bark beetle gradation.Control plots were located in undisturbed stands.The research covered wood of two species–spruce and beech in the form of cubes with dimensions of 50 mm×50 mm×22 mm.Wood samples were placed directly on the soil surface and subjected to laboratory analysis after 36 months.A significant influence of the wood species and the study plot type on the physicochemical properties of the tested wood samples was found.Wood characteristics strongly correlated with soil moisture.A significantly higher mass decline of wood samples was recorded on the reference study plots,which were characterized by more stable moisture conditions.Poorer decomposition of wood in the gaps regardless of the species is related to lower moisture.The wood species covered by the study differed in the decomposition rate.Spruce wood samples were characterized by a significantly higher decomposition rate compared to beech wood samples.Our research has confirmed that disturbances that lead to the formation of gaps have a direct impact on the decomposition process of deadwood.展开更多
Deadwood plays a key role for biodiversity in forests.A significant number of beetles from this group are currently listed as endangered in the Red List.In addition to other management recommendations,there have been ...Deadwood plays a key role for biodiversity in forests.A significant number of beetles from this group are currently listed as endangered in the Red List.In addition to other management recommendations,there have been recent efforts to enrich stands with dead wood to promote biodiversity.An important parameter for forestry enterprises is the optimization of these interventions.The study investigated the abundance,species richness,gamma diversity,conservation value and biomass of saproxylic beetles in natural forests using window traps.A total of 89traps were used for saproxylic beetle monitoring,of which 29 were placed on lying logs,30 on snags and 30 as controls in forest stand space.A total of 35,011 beetles were recorded in 564 species(61 families).Notably,20,515 of these belong to saproxylic beetles(59%)in 311 species(55%),with 62 classified as Red-List species(20%).In the group of'all saproxylic beetles',the results indicate that a diversity and y diversity(q=0)remain consistent across various deadwood types,whileβdiversity showed significant differences.Significant differences were found in the Red-List species group,where a diversity and y diversity differed,with higher values observed in snags.Rarefaction based total species richness of site was estimated to be 391 species,including 74 Red-Listed species.Comparing the sample coverage of the studied stand categories showed that all saproxylic species exhibit a pronounced preference for inhabiting areas featuring lying logs.Conversely,Red-List species mainly inhabit snags,withβdiversity being more similar to snags and forest stand space.Notably,both the conservation value(weighted average by conservation status)and beetle biomass are significantly highest in snags,whereas stand space shows the lowest values across all measured saproxylic beetle indices.Furthermore,the use of traps set on the poles in forest stand space resulted in an underestimation of the actual stand richness by 20%-25%.Our results support the conclusion that snags are indispensable features in beech forests,playing a key role in promoting high species diversity,especially among Red-List species,and supporting the biomass of saproxylic beetles.Consequently,it becomes crucial to incorporate a higher percentage of standing deadwood in managed forests or actively create equivalent environments by introducing high stumps.展开更多
Fxcessive forest exploitation significantly contributes to land degradation and the creation of human-made deadwood.Stumps are sometimes ignored in studies on the biodiversity of coarse woody debris.We investigated wh...Fxcessive forest exploitation significantly contributes to land degradation and the creation of human-made deadwood.Stumps are sometimes ignored in studies on the biodiversity of coarse woody debris.We investigated whether the type of stump,i.e.broken stumps(naturally created)and cut stumps(formed during forestry operations)had an impact on the species composition and species diversity as well as due to this fact they can be characterized by plant indicators.The research covered 728 spruce stumps(287 broken and 441 cut stumps)that were inhabited by lichens,liverworts,mosses and vascular plants in mountain forest belt(Karkonosze Mts.,Poland).The following types of microhabitats were included in the research:the upper surface and the lateral surface of a stump with both bark and wood.There are statistically significant compositional differences between the two types of stumps,which was demonstrated by ordination analyses and indicator species analysis.According to the generalized linear models,the probability of occurrence increases in cut stumps in case of liverworts and vascular plants and also along the decomposition stages.The generalized linear mixed-effects model showed that there was a higher species richness of liverworts,mosses and vascular plants on the cut stumps and less drier but the reverse situation was in lichens.The generalized additive models for their cover showed similar trends.Almost all of the taxonomic groups were affected by altitude both in terms of species composition and total cover on the stumps.We concluded that cut stumps are an important type of deadwood for biodiversity and provide a convenient habitat,especially for many lichens and bryophytes.展开更多
Background:As a structurally and functionally important component in forest ecosystems,plant debris plays a crucial role in the global carbon cycle.Although it is well known that plant debris stocks vary greatly with ...Background:As a structurally and functionally important component in forest ecosystems,plant debris plays a crucial role in the global carbon cycle.Although it is well known that plant debris stocks vary greatly with tree species composition,forest type,forest origin,and stand age,simultaneous investigation on the changes in woody and non-woody debris biomass and their carbon stock with forest succession has not been reported.Therefore,woody and non-woody debris and carbon stocks were investigated across a subalpine forest successional gradient in Wanglang National Nature Reserve on the eastern Qinghai-Tibet Plateau.Results:Plant debris ranged from 25.19 to 82.89 Mg∙ha−1 and showed a global increasing tendency across the subalpine forest successional series except for decreasing at the S4 successional stage.Accordingly,the ratios of woody to non-woody debris stocks ranged from 26.58 to 208.89,and the highest and lowest ratios of woody to non-woody debris stocks were respectively observed in mid-successional coniferous forest and shrub forest,implying that woody debris dominates the plant debris.In particular,the ratios of coarse to fine woody debris stocks varied greatly with the successional stage,and the highest and lowest ratios were found in later and earlier successional subalpine forests,respectively.Furthermore,the woody debris stock varied greatly with diameter size,and larger diameter woody debris dominated the plant debris.Correspondingly,the carbon stock of plant debris ranged from 10.30 to 38.87 Mg∙ha−1 across the successional series,and the highest and lowest values were observed in the mid-coniferous stage and shrub forest stage,respectively.Most importantly,the carbon stored in coarse woody debris in later successional forests was four times higher than in earlier successional forests.Conclusions:The stock and role of woody debris,particularly coarse woody debris,varied greatly with the forest successional stage and dominated the carbon cycle in the subalpine forest ecosystem.Thus,preserving coarse woody debris is a critical strategy for sustainable forest management.展开更多
Background： After their death, Scots pine trees can remain standing for decades and sometimes up to 200 years,forming long-lasting and ecologically important structures in boreal forest landscapes. Standing dead pine...Background： After their death, Scots pine trees can remain standing for decades and sometimes up to 200 years,forming long-lasting and ecologically important structures in boreal forest landscapes. Standing dead pines decay very slowly and with time develop into ‘kelo＇ trees, which are characterized by hard wood with silvery-colored appearance. These kelo trees represent an ecologically important, long lasting and visually striking element of the structure of natural pine-dominated forests in boreal Fennoscandia that is nowadays virtually absent from managed forest landscapes.Methods： We examined and mapped the amount, structural features, site characteristics and spatial distribution of dead standing pine trees over a ten hectare area in an unmanaged boreal forest landscape in the Kalevala National Park in Russian Viena Karelia.Results： The mean basal area of dead standing pine trees in the forested part of the landscape was 1.7 m^2·ha^-1 and the estimated volume 12.7 m^3·ha^-1. From the total number of standing dead pine trees 65% were kelo trees, with a basal area of 1.1 m^2·ha^-1 and volume of 8.0 m^3·ha^-1, the remainder consisting of standing dead pines along the continuum between a recently dead tree and a kelo tree. Overall, standing dead pines were distributed throughout the study area, but there was a tendency towards spatial clustering up to 〈100 m distances. Standing dead pines were most commonly situated on flat ground or in the mid slope in the local topography.In addition, standing dead pines contributed to substrate diversity also by commonly having charred wood and broken tops. Based on the presence of dead pine snags in different stage of transition from a recently dead pine to a kelo with silvery surface, it seems evident that the process of kelo recruitment was continuously in action in the studied landscape.Conclusions： Kelo trees are an omnipresent feature in natural pine-dominated forest landscapes with important contribution to forest structural and substrate diversity. Because of their longevity and extremely slow turnover dynamics and importance for biodiversity, protection of vulnerable kelo tree populations, and ensuring their continuous recruitment, should be of high priority in forest restoration and sustainable management.展开更多
Background:Deadwood and the associated epixylic vegetation influence nutrient cycles in forest ecosystems.Open canopies strongly regulate deadwood decomposition and disrupt epixylic vegetation on logs.However,it is un...Background:Deadwood and the associated epixylic vegetation influence nutrient cycles in forest ecosystems.Open canopies strongly regulate deadwood decomposition and disrupt epixylic vegetation on logs.However,it is unclear how the forest canopy density and epixylic vegetation growth affect the nutrient concentrations in deadwood.Methods:We measured the concentrations of nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),sodium(Na),magnesium(Mg),and manganese(Mn)in experimentally exposed decaying logs placed in gaps,at the edge of gaps,and under the closed canopy during a four-year decomposition experiment in a Subalpine Faxon fir forest(Abies fargesii var.faxoniana)on the eastern Qinghai-Tibetan Plateau,China.To assess the effect of the epixylic vegetation,we experimentally removed it from half of the logs used in the study.Results:Under open canopy conditions in the gap and at the edge,the concentrations for most of the nutrients in the bark and the highly decayed wood were lower than under the closed canopy.The effect of the epixylic treatment on nutrient concentrations for all but K and Na in barks varied with the decay classes.Significantly lower concentrations of N,P,Ca,and Mn following the removal of epixylic vegetation were observed in the wood of decay class IV.Epixylic vegetation significantly increased most nutrient concentrations for decaying barks and wood under open canopy conditions.In contrast,epixylic vegetation had no or minimal effects under the closed canopy.Conclusions:Forest canopy density and epixylic vegetation significantly alter the nutrient concentrations in decaying logs.Open canopies likely accelerate the rate of nutrient cycling between the epixylic vegetation and decaying logs in subalpine forests.展开更多
We investigated the relationships between dehydrogenase activity and the physicochemical properties of mountain soils over three and five years from Norway spruce(Picea abies L. Karst) logging residue spot burning and...We investigated the relationships between dehydrogenase activity and the physicochemical properties of mountain soils over three and five years from Norway spruce(Picea abies L. Karst) logging residue spot burning and the occurrence of epigeic carabid beetles. Six study sites were utilised, including18 study plots(nine plots in a mixed coniferous mountain forest site and nine plots in a mixed broadleaf mountain forest site), with five replicate pitfall traps at each site located in southern Poland.Soil samples from the organic horizon were taken for p H, organic carbon, nitrogen, base cation content,acidity and dehydrogenase activity determination.Carabid beetles were monitored in weekly intervals during the period of July to August 2016. The burning of logging residues led to modified soil properties,especially the dehydrogenase activity. In all the tested variants, the activity was higher in soil samples after the burning in comparison to the control variants. We show no positive correlation between dehydrogenase activity and the number of carabid specimens. The preferences of dominant predatory hygrophilous carabids to acid habitats with weakly decomposed organic matter were proven. Simultaneously, the soil organic matter content was positively related to the carabid abundance. The significant impact of forest site conditions and the date of logging residue burning on the number of caught specimens were confirmed. In contrast, no relationships between the species richness, species diversity, mean individual biomass and spot burning effect were found. This work supports the recommendation of spruce fine woody debris utilisation by spot burning on mountain regions with rich habitats presenting moderate wet conditions and small land falls.展开更多
基金supported by the National Natural Science Foundation of China(3196140162).
文摘Warming and nitrogen(N)deposition are two important drivers of global climate changes.Coarse woody debris(CWD)contains a large proportion of the carbon(C)in the total global C pool.The composition of soil microbial communities and environmental changes(i.e.,N deposition and warming)are the key drivers of CWD decomposition,but the interactive impact between N deposition and warming on the composition of soil microbial communities and CWD decomposition is still unclear.In a laboratory experiment,we study and simulate respiration during decomposition of the CWD(C 98)of Cryptomeria japonica(CR)and Platycarya strobilacea(PL)in response to warming and N deposition over 98 days.Resuts show that either warming or N addition signifi cantly accelerated the C 98 of the two tree species by altering the soil microbial community(bacterial:fungi and G+:G–).The combined treatment(warming+N)resulted in a decomposition eff ect equal to the sum of the individual eff ects.In addition,the species composition of bacteria and fungi was obviously aff ected by warming.However,N deposition had a remarkable infl uence on G+:G–.Our results indicated that N deposition and warming will observably alter the composition and growth of the microbial community and thus work synergistically to accelerate CWD decomposition in forest ecosystems.We also present evidence that N deposition and warming infl uenced the composition and balance of soil microbial communities and biogeochemical cycling of forest ecosystems.
基金This paper was supported by the Chinese Academy of Sciences (KZCX2-406) and National Natural Science Foundation of China (NSFC39970123) and Changbai Mountain Open Research Station.
文摘This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest.
基金This work was supported by National Natural Science Foundation of China（No.30370293）,0pen Fund for the Research Station of Changbai Mountain Forest Ecosystem.Chinese Academy of Sciences, and Science Frontiers Project of Institute of Applied Ecology, Chinese Academy of Sciences.
文摘Coarse woody debris is an important structure and function unit in forest ecosystem.This review analyzed the ecological functions of coarse woody debris in forest ecosystem and introduced several hotspots and existing problems in coarse woody debris research field. It is suggested that quantitative research should be intensified in theintensified in the ecological demands of coarse woody debris for providing a technical guidelines in management of productivity, biodiversity and other ecologicalprocesses.
基金This research was supported by National Natural Science Foundation of China (No.30470302&70373044)Overseas Scholar Funding from Chinese Academy of Science (C13HU&C13HK).
文摘Coarse woody debris （CWD） is an important and particular component of forest ecosystems and is extremely important to forest health. This review describes the decomposition process, decomposition model and influence factors. CWD decomposition is a complex and continuous process and characterizes many biological and physical processes, including biological respiration, leaching, and fragmentation. All these processes have closed relationships between each other and work synergistically. During decomposition, there are many controlling factors mainly including site conditions （temperature, humidity, and OJCO2concentration）, woody substrate quality （diameter, species and compound） and organism in CWD. The decomposition rate is generally expresses through a constant k which indicate the percent mass, volume or density loss over time, and can be determined by long-term monitoring, chronosequence approach and the radio between input and the total mass. Now using mathematical models to simulate decomposition patterns and estimate the decomposition rate is widely applied, especially the exponential model. We brought forward that managing and utilizing for the CWD in forest was a primary objective on all forest lands. And it is should be intensified to integrate many related research subjects and to carry a comprehensive, long-term and multi-scale research which mainly focus on seven sections.
文摘A rapid assessment on the status and distribution patterns of coarse woody debris （CWD） was conducted by laying five curvilinear transects （transects A, B, C, D and E; major trails）, along an altitudinal gradient starting from 900 to 2 600 m, in three major watersheds （Charigad, Dogarhigad and upper Gosigad） of Goriganga catchment in Askot Wildlife Sanctuary, India. At every 100 m rise in altitude a hectare plot （100 m x 100 m） was selected. Results showed that the percentage contribution by different succession phases was in the decreasing order： phase I 〉 phase II 〉 phase IV 〉 phase III for snags, and phase III〉 phase II 〉 phase IV 〉 phase I for logs. Snag density in chir pine forest was high in transect A （11 snags＇ha^-1） at 1 500 m, and the value in rianj oak forest was high in transect B （10 snags.ha-l） at 2 300 m. The total available mass of snags and logs in chit pine forest was 13.9 t, of which snags mass accounted for 41% of the total mass and logs mass for 59%. While the total value was 5.6 t in rianj oak forest, of which snags and logs accounted for 60% and 40% of the total mass, respectively. Moreover, the presence of CWD in the study area if not harvested, would provide a great opportunity to the orchids in future to flourish by providing protection. The high densities of snags and logs in chir pine forest at mid-altitudinal zone led to less species richness and lower density of ground flora as the zone receives more light, accompanying with lower soil moisture, and thus only the dominant species occupy the habitat.
基金supported by the National Natural Science Foundation of China (Grant No. 31300538, 31400540 and 31170587)the Special Foundation of Basic Scientific Research Professional Expenses in Northwest A&F University (Grant No. QN2013082)the Youth development projects of the second basic scientific research business expenses of Northwest A&F University (Grant No. 2452015335)
文摘Woody debris(WD) is an important par of natural Pinus tabulaeformis mixed stands, and i affects the forest ecosystem stability and developmen The WD spatial patterns are especially importan structural characteristics that can provide insights into forest dynamics. In this paper, the WD storage WD spatial patterns and WD associations among the main species were examined in the natural secondary forest on Loess Plateau in northwest China. Data were collected in a 1 ha(100 m × 100 m) permanent plot and all the trees with a diameter at breast height o more than 3 cm were measured and stem-mapped Ripley's K functions from the spatial-point-pattern analysis method were used to analyze the spatia distribution and associations. The results showed tha(1) The total storage of WD was 10.73 t/ha, fallen wood was the main source of WD, and the majority diameters were greater than 20 cm, and in intermediate levels of decay;(2) The overall spatia pattern was closely related to the spatial scale, which exhibited an aggregated pattern on a small scale, and a random pattern on a large scale. The spatia patterns of coarse woody debris also gradually transitioned from an aggregated pattern in fine scales to a random pattern in broader spatial scales, which matched the overall spatial pattern. The spatial intensity was gradually decreased with the increasing diameters, and increased with the decomposition classes;(3) The WD of Pinus tabulaeformis species was negatively associated with Betula platyphylla and Populus davidiana on a small scale but positively associated with these species on a large scale. The spatial pattern and interspecies relations were the results of long-term interactions between the natural secondary forest community and the surrounding natural environment. These findings would provide a scientific basis for the sustainable management and protection of natural secondary forest ecosystems on Loess Plateau.
文摘CWD （coarse woody debris） plays an important role in nutrient cycling, habitat for species and more recently carbon accounting in forest ecosystems. LiDAR （light detection and ranging） technology has demonstrated utility in capturing forest structure information. This paper proposes an indirect method of assessing downed CWD using LiDAR derived forest structure variables. Fieldwork was conducted to measure CWD volume in an Eucalyptus forest in Tasmania. A GLM （generalized linear model） to statistically estimate CWD volume in the Eucalyptus forest was developed using a LiDAR derived FCS （forest characterisation scheme）： the openings above the ground, low and medium vegetation, canopy cover, presence of understorey and mid-storey vegetation and high trees, and the vertical canopy density of high trees. Five structural variables were selected for the best model based on AIC （Akaike＇s Information Criterion） by stepwise selection. The applicability of the model was then compared to the outcome of model using field derived variables such as diameter at breast height of trees. The results show that the model using LiDAR derived variables better estimated the amount of CWD. It is concluded that LiDAR derived forest structural variables has the potential to predict the amount of downed CWD in Eucalyptus forest.
文摘A rapid assessment on the status and distribution patterns of coarse woody debris (CWD) was conducted by laying five curvilinear transects (transects A, B, C, D and E; major trails), along an altitudinal gradient starting from 900 to 2 600 m, in three major watersheds (Charigad, Dogarhigad and upper Gosigad) of Goriganga catchment in Askot Wildlife Sanctuary, India. At every 100 m rise in altitude a hectare plot (100 m x 100 m) was selected. Results showed that the percentage contribution by different succession phases was in the decreasing order: phase I > phase II > phase IV > phase III for snags, and phase III > phase II > phase IV > phase I for logs. Snag density in chir pine forest was high in transect A (11 snags·ha-1) at 1 500 m, and the value in rianj oak forest was high in transect B (10 snags·ha-1) at 2 300 m. The total available mass of snags and logs in chir pine forest was 13.9 t, of which snags mass accounted for 41% of the total mass and logs mass for 59%. While the total value was 5.6 t in rianj oak forest, of which snags and logs accounted for 60% and 40% of the total mass, respectively. Moreover, the presence of CWD in the study area if not harvested, would provide a great opportunity to the orchids in future to flourish by providing protection. The high densities of snags and logs in chir pine forest at mid-altitudinal zone led to less species richness and lower density of ground flora as the zone receives more light, accompanying with lower soil moisture, and thus only the dominant species occupy the habitat.
基金This research was funded by the National Key Research and Development Projects,Grant Number 2018YFE0207800the National Natural Science Foundation of China,Grant Number 41871103.
文摘The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coarse woody debris decomposition is complex and the results from different regions vary considerably.It is not clear which factors affect decay rate(k),especially at different decomposition stages.In this study,a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains.The results show that the decay rate of coarse woody debris was positively correlated to decay class.The average decomposition rate was 0.019,and 41 years and 176 years are needed for a 50%and 95%mass loss,respectively.CWD nutrient content,density,and water content could explain the variance in the decay rate(~42%)of the decay factors such as amount of leaching,degree of fragmentation,respiration of the debris,and biotransformation,and varied significantly between different decay classes.Using the space-time substitution method,this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process.It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents.This paper quantifies the indicators affecting CWD decay to explain the decomposition process.
基金Supported by the International Science and Technology Cooperation Program of China(2011DFA90740)Science and Technology Cooperation Program between Ministry of Science and Technology of China and European Union(0906)+1 种基金Research and Innovation Foundation for Young Scholars of Hunan Academy of Forestry(2013LQJ08)Forestry Science and Technology Program of Hunan Province,China(XLK201417)
文摘In Yingzuijie National Nature Reserve, Pinus massoniana forest, mixed broadleaf-coniferous forest and evergreen broad-leaf forest were investigated to study the changing characteristics of woody debris （WD） during various succession stages o1 evergreen broad-leaf forest. The results showed that during various succession stages of evergreen broad-leaf forest in Yingzuijie National Nature Reserve, WD storage of each forest ranged from 1.26 to 8.82 t/hm^2, with the order of P. massoniana forest 〈 mixed broadleaf-coniferous forest 〈 evergreen broad-leaf forest, that is, it increased from early to late stages of the succession. At different succession stages, coarse woody debris （CWD） storage was 2 -9 times more than fine woody debris （FWD） storage, revealing that CWD was dominant in WD of each forest. CWD biomass accounted for 0.66% -2.21% of arbor biomass, so the forests were at the developmental stage.
文摘Coarse woody debris (CWD) has unique ecological function, historical value and cultural connotation in urban ecosystem, the application prospect of CWD in urban greening was discussed and forecasted.
基金supported by the Engineering and Physical Sciences Research Council(Grant Nos.EPSRC EP/J501335/1 and EP/K50337X/1)the Heriot-Watt University School of the Built Environment
文摘It is recognised that the blockage of culverts by woody debris can result in an increased risk of infrastructure damage and flooding.To date,debris transport analysis has focused on regional fluvial systems and large woody debris,both in flume and field experiments.Given the social and economic risk associated with urban flooding,and as urban drainage design shifts away from subsurface piped network reliance,there is an increasing need to understand debris movement in urban watercourses.The prediction of urban watercourse small woody debris(SWD)movement,both quantity and risk,has undergone only limited analysis predominantly due to lack of field data.This paper describes the development of a methodology to enable the collection of accurate and meaningful SWD residency and transportation data from watercourses.The presented research examines the limitations and effective function of PIT tag technology to collect SWD transport data in the field appropriate for risk and prediction analysis.Passive integrated transponder(PIT)technology provides a method to collect debris transport data within the urban environment.In this study,the tags are installed within small woody debris and released at known locations into a small urban natural watercourse enabling monitoring of movement and travel time.SWD velocity and detention are collated with solute time of travel,watercourse and point flow characteristics to identify the relationships between these key variables.The work presented tests three hypotheses:firstly,that the potential for unobstructed or un-detained SWD movement increases with flow velocity and water level.Secondly,that SWD travel distance,and the resistance forces along this travel path,influence SWD transport potential.Thirdly,the relationship between SWD and channel dimensions is examined with the aim of advancing representative debris transport prediction modelling.
基金supported by the National Natural Science Foundation of China (no.30130060).
文摘Coarse woody debris(CWD)is generally considered as dead woody materials in various stages of decomposition,including sound and rotting logs,snags,and large branches.CWD is an important functional and structural component of forested ecosystems and plays an important role in nutrient cycling,long-term carbon storage,tree regeneration,and maintenance of heterogeneous environmental and biological diversity.However,the definition and classification of CWD have been the subject of a long debate in forest ecology.CWD has not been precisely defined.Recently,with the rapid development of landscape ecology in CWD,the USDA Forest Service and the Long Term Ecological Research(LTER)have provided a standardized definition and classification for CWD,which makes data comparison in landscape scale possible.Important characteristics of their definition include:(1)a minimum diameter(or an equivalent crosssection)of CWD≥10 cm at the widest point(the woody debris with a diameter from 1 to 10 cm should be defined as fine woody debris,and the rest is litterfall);and(2)sound and rotting logs,snags,stumps,and large branches(located above the soil),and coarse root debris(larger than 1 cm in diameter).This classification has greatly facilitated CWD studies.Therefore,it has been widely applied in some countries(particularly in North America).However,this classification has long been a source of confusion for forest ecologists in China.Furthermore,different definitions and criteria are still adopted in individual studies,which makes the interpretation and generalization of their work difficult.This article reviewed recent progress in classifying CWD,with an emphasis on introducing the classification system of the USDA Forest Service and the LTER.It is expected that this review will help facilitate the development of standardized definition and classification suitable to forest ecosystems in China.
基金financed by the National Science Centre,Poland:decision no.DEC 2020/39/B/NZ9/00372 and decision no.DEC-2021/43/O/NZ9/00066。
文摘Decaying wood is an essential element of forest ecosystems and it affects its other components.The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in the gaps formed in the montane forest stands.The research was carried out in the Babiog orski National Park.The research plots were marked out in the gaps of the stands,which were formed as a result of bark beetle gradation.Control plots were located in undisturbed stands.The research covered wood of two species–spruce and beech in the form of cubes with dimensions of 50 mm×50 mm×22 mm.Wood samples were placed directly on the soil surface and subjected to laboratory analysis after 36 months.A significant influence of the wood species and the study plot type on the physicochemical properties of the tested wood samples was found.Wood characteristics strongly correlated with soil moisture.A significantly higher mass decline of wood samples was recorded on the reference study plots,which were characterized by more stable moisture conditions.Poorer decomposition of wood in the gaps regardless of the species is related to lower moisture.The wood species covered by the study differed in the decomposition rate.Spruce wood samples were characterized by a significantly higher decomposition rate compared to beech wood samples.Our research has confirmed that disturbances that lead to the formation of gaps have a direct impact on the decomposition process of deadwood.
基金supported by the Ministry of Agriculture of the Czech Republic(Grant No.QK23020008)。
文摘Deadwood plays a key role for biodiversity in forests.A significant number of beetles from this group are currently listed as endangered in the Red List.In addition to other management recommendations,there have been recent efforts to enrich stands with dead wood to promote biodiversity.An important parameter for forestry enterprises is the optimization of these interventions.The study investigated the abundance,species richness,gamma diversity,conservation value and biomass of saproxylic beetles in natural forests using window traps.A total of 89traps were used for saproxylic beetle monitoring,of which 29 were placed on lying logs,30 on snags and 30 as controls in forest stand space.A total of 35,011 beetles were recorded in 564 species(61 families).Notably,20,515 of these belong to saproxylic beetles(59%)in 311 species(55%),with 62 classified as Red-List species(20%).In the group of'all saproxylic beetles',the results indicate that a diversity and y diversity(q=0)remain consistent across various deadwood types,whileβdiversity showed significant differences.Significant differences were found in the Red-List species group,where a diversity and y diversity differed,with higher values observed in snags.Rarefaction based total species richness of site was estimated to be 391 species,including 74 Red-Listed species.Comparing the sample coverage of the studied stand categories showed that all saproxylic species exhibit a pronounced preference for inhabiting areas featuring lying logs.Conversely,Red-List species mainly inhabit snags,withβdiversity being more similar to snags and forest stand space.Notably,both the conservation value(weighted average by conservation status)and beetle biomass are significantly highest in snags,whereas stand space shows the lowest values across all measured saproxylic beetle indices.Furthermore,the use of traps set on the poles in forest stand space resulted in an underestimation of the actual stand richness by 20%-25%.Our results support the conclusion that snags are indispensable features in beech forests,playing a key role in promoting high species diversity,especially among Red-List species,and supporting the biomass of saproxylic beetles.Consequently,it becomes crucial to incorporate a higher percentage of standing deadwood in managed forests or actively create equivalent environments by introducing high stumps.
基金supported by the Statutory Funds of the Institute of Environmental Protection and Engineering of the University of Bielsko-Biala and the Department of Geobotany and Plant Ecologythe University of Lodz,Lodz,Poland。
文摘Fxcessive forest exploitation significantly contributes to land degradation and the creation of human-made deadwood.Stumps are sometimes ignored in studies on the biodiversity of coarse woody debris.We investigated whether the type of stump,i.e.broken stumps(naturally created)and cut stumps(formed during forestry operations)had an impact on the species composition and species diversity as well as due to this fact they can be characterized by plant indicators.The research covered 728 spruce stumps(287 broken and 441 cut stumps)that were inhabited by lichens,liverworts,mosses and vascular plants in mountain forest belt(Karkonosze Mts.,Poland).The following types of microhabitats were included in the research:the upper surface and the lateral surface of a stump with both bark and wood.There are statistically significant compositional differences between the two types of stumps,which was demonstrated by ordination analyses and indicator species analysis.According to the generalized linear models,the probability of occurrence increases in cut stumps in case of liverworts and vascular plants and also along the decomposition stages.The generalized linear mixed-effects model showed that there was a higher species richness of liverworts,mosses and vascular plants on the cut stumps and less drier but the reverse situation was in lichens.The generalized additive models for their cover showed similar trends.Almost all of the taxonomic groups were affected by altitude both in terms of species composition and total cover on the stumps.We concluded that cut stumps are an important type of deadwood for biodiversity and provide a convenient habitat,especially for many lichens and bryophytes.
基金supported by the National Nature Science Foundation of China(32071554,31570445).
文摘Background:As a structurally and functionally important component in forest ecosystems,plant debris plays a crucial role in the global carbon cycle.Although it is well known that plant debris stocks vary greatly with tree species composition,forest type,forest origin,and stand age,simultaneous investigation on the changes in woody and non-woody debris biomass and their carbon stock with forest succession has not been reported.Therefore,woody and non-woody debris and carbon stocks were investigated across a subalpine forest successional gradient in Wanglang National Nature Reserve on the eastern Qinghai-Tibet Plateau.Results:Plant debris ranged from 25.19 to 82.89 Mg∙ha−1 and showed a global increasing tendency across the subalpine forest successional series except for decreasing at the S4 successional stage.Accordingly,the ratios of woody to non-woody debris stocks ranged from 26.58 to 208.89,and the highest and lowest ratios of woody to non-woody debris stocks were respectively observed in mid-successional coniferous forest and shrub forest,implying that woody debris dominates the plant debris.In particular,the ratios of coarse to fine woody debris stocks varied greatly with the successional stage,and the highest and lowest ratios were found in later and earlier successional subalpine forests,respectively.Furthermore,the woody debris stock varied greatly with diameter size,and larger diameter woody debris dominated the plant debris.Correspondingly,the carbon stock of plant debris ranged from 10.30 to 38.87 Mg∙ha−1 across the successional series,and the highest and lowest values were observed in the mid-coniferous stage and shrub forest stage,respectively.Most importantly,the carbon stored in coarse woody debris in later successional forests was four times higher than in earlier successional forests.Conclusions:The stock and role of woody debris,particularly coarse woody debris,varied greatly with the forest successional stage and dominated the carbon cycle in the subalpine forest ecosystem.Thus,preserving coarse woody debris is a critical strategy for sustainable forest management.
基金the EBOR-project funded by the Academy of Finland (proj.no.276255)
文摘Background： After their death, Scots pine trees can remain standing for decades and sometimes up to 200 years,forming long-lasting and ecologically important structures in boreal forest landscapes. Standing dead pines decay very slowly and with time develop into ‘kelo＇ trees, which are characterized by hard wood with silvery-colored appearance. These kelo trees represent an ecologically important, long lasting and visually striking element of the structure of natural pine-dominated forests in boreal Fennoscandia that is nowadays virtually absent from managed forest landscapes.Methods： We examined and mapped the amount, structural features, site characteristics and spatial distribution of dead standing pine trees over a ten hectare area in an unmanaged boreal forest landscape in the Kalevala National Park in Russian Viena Karelia.Results： The mean basal area of dead standing pine trees in the forested part of the landscape was 1.7 m^2·ha^-1 and the estimated volume 12.7 m^3·ha^-1. From the total number of standing dead pine trees 65% were kelo trees, with a basal area of 1.1 m^2·ha^-1 and volume of 8.0 m^3·ha^-1, the remainder consisting of standing dead pines along the continuum between a recently dead tree and a kelo tree. Overall, standing dead pines were distributed throughout the study area, but there was a tendency towards spatial clustering up to 〈100 m distances. Standing dead pines were most commonly situated on flat ground or in the mid slope in the local topography.In addition, standing dead pines contributed to substrate diversity also by commonly having charred wood and broken tops. Based on the presence of dead pine snags in different stage of transition from a recently dead pine to a kelo with silvery surface, it seems evident that the process of kelo recruitment was continuously in action in the studied landscape.Conclusions： Kelo trees are an omnipresent feature in natural pine-dominated forest landscapes with important contribution to forest structural and substrate diversity. Because of their longevity and extremely slow turnover dynamics and importance for biodiversity, protection of vulnerable kelo tree populations, and ensuring their continuous recruitment, should be of high priority in forest restoration and sustainable management.
基金jointly funded by the following grants:The National Natural Science Foundation of China(Nos.32071554,31870602,31901295)the National Key R&D Program of China(No.2017YFC0503906)the Program of Sichuan Excellent Youth Sci-Tech Foundation(No.2020JDJQ0052).
文摘Background:Deadwood and the associated epixylic vegetation influence nutrient cycles in forest ecosystems.Open canopies strongly regulate deadwood decomposition and disrupt epixylic vegetation on logs.However,it is unclear how the forest canopy density and epixylic vegetation growth affect the nutrient concentrations in deadwood.Methods:We measured the concentrations of nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),sodium(Na),magnesium(Mg),and manganese(Mn)in experimentally exposed decaying logs placed in gaps,at the edge of gaps,and under the closed canopy during a four-year decomposition experiment in a Subalpine Faxon fir forest(Abies fargesii var.faxoniana)on the eastern Qinghai-Tibetan Plateau,China.To assess the effect of the epixylic vegetation,we experimentally removed it from half of the logs used in the study.Results:Under open canopy conditions in the gap and at the edge,the concentrations for most of the nutrients in the bark and the highly decayed wood were lower than under the closed canopy.The effect of the epixylic treatment on nutrient concentrations for all but K and Na in barks varied with the decay classes.Significantly lower concentrations of N,P,Ca,and Mn following the removal of epixylic vegetation were observed in the wood of decay class IV.Epixylic vegetation significantly increased most nutrient concentrations for decaying barks and wood under open canopy conditions.In contrast,epixylic vegetation had no or minimal effects under the closed canopy.Conclusions:Forest canopy density and epixylic vegetation significantly alter the nutrient concentrations in decaying logs.Open canopies likely accelerate the rate of nutrient cycling between the epixylic vegetation and decaying logs in subalpine forests.
基金financed by the Ministry of Science and Higher Education, Republic of Poland
文摘We investigated the relationships between dehydrogenase activity and the physicochemical properties of mountain soils over three and five years from Norway spruce(Picea abies L. Karst) logging residue spot burning and the occurrence of epigeic carabid beetles. Six study sites were utilised, including18 study plots(nine plots in a mixed coniferous mountain forest site and nine plots in a mixed broadleaf mountain forest site), with five replicate pitfall traps at each site located in southern Poland.Soil samples from the organic horizon were taken for p H, organic carbon, nitrogen, base cation content,acidity and dehydrogenase activity determination.Carabid beetles were monitored in weekly intervals during the period of July to August 2016. The burning of logging residues led to modified soil properties,especially the dehydrogenase activity. In all the tested variants, the activity was higher in soil samples after the burning in comparison to the control variants. We show no positive correlation between dehydrogenase activity and the number of carabid specimens. The preferences of dominant predatory hygrophilous carabids to acid habitats with weakly decomposed organic matter were proven. Simultaneously, the soil organic matter content was positively related to the carabid abundance. The significant impact of forest site conditions and the date of logging residue burning on the number of caught specimens were confirmed. In contrast, no relationships between the species richness, species diversity, mean individual biomass and spot burning effect were found. This work supports the recommendation of spruce fine woody debris utilisation by spot burning on mountain regions with rich habitats presenting moderate wet conditions and small land falls.
