Inferred history of a boreal pond from sediment and vegetation characteristics

2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 335-347 ◽  
Author(s):  
B. J. Nicholson ◽  
S. E. Bayley ◽  
H. E. Whitehouse
Keyword(s):  
Physical Structure ◽  
Carbon Stocks ◽  
Water Levels ◽  
Spatial Changes ◽  
C Stocks ◽  
History Of ◽  
Shallow Ponds ◽  
Vegetation Characteristics ◽  
Forested Bog ◽  
Peat Stratigraphy

Shallow ponds associated with peatlands in boreal Alberta contain large quantities of stored carbon in their peaty sediments, and exhibit spatial changes in response to dry or wet conditions. Peatland ponds around Utikuma Lake experienced a partial to nearly complete drawdown in 2002, in response to drought. A fourfold investigation was begun to assess the natural drought and flood cycles, assess the current C stocks along the shore, determine what species were colonizing the newly exposed shorelines, and to place the magnitude of the current drought into historical perspective. Ten vegetation communities were found to have colonized the exposed sediments. Paleostratigraphy shows that the surface communities differ markedly from paleocommunities. Stratigraphy of the wetland sediments demonstrates that only two changes occurred, one a successional switch from a sedge-dominated marsh to a forested bog, the other a much more recent disturbance that caused water levels near the pond to rise. No evidence of constantly changing paleocommunities was found, suggesting that previous droughts have not left a visible paleorecord. The more recent disturbance has likely redistributed peat into the pond basins and subsequently it has broken down to detritial peat, altering its physical structure, and perhaps its rate of decomposition. Continued exposure of the peat is likely to enhance decomposition. In this study both flooding and drought may have impacted the wetland in ways likely to result in higher rates of decomposition and enhanced CO2 emissions under global warming. Key words: Peat stratigraphy, Holocene climate, thermokarst melting, detrital peat, carbon stocks

Spatial changes and driving variables of topsoil organic carbon stocks in Chinese croplands under different fertilization strategies

2020 ◽  
pp. 144350
Author(s):  
Fengling Ren ◽  
T.H. Misselbrook ◽  
Nan Sun ◽  
Xubo Zhang ◽  
Shuxiang Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Stocks ◽  
Spatial Changes

scholarly journals Allometric Equations for Estimating Biomass and Carbon Stocks in Afforested Open Woodlands with Black Spruce and Jack Pine, in the Eastern Canadian Boreal Forest

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Olivier Fradette ◽  
Charles Marty ◽  
Pascal Tremblay ◽  
Daniel Lord ◽  
Jean-François Boucher
Keyword(s):  
Large Scale ◽  
Ad Hoc ◽  
Black Spruce ◽  
Tree Height ◽  
Jack Pine ◽  
Carbon Stocks ◽  
Allometric Equations ◽  
C Stocks ◽  
The Difference ◽  
Canadian Boreal Forest

Allometric equations use easily measurable biometric variables to determine the aboveground and belowground biomasses of trees. Equations produced for estimating the biomass within Canadian forests at a large scale have not yet been validated for eastern Canadian boreal open woodlands (OWs), where trees experience particular environmental conditions. In this study, we harvested 167 trees from seven boreal OWs in Quebec, Canada for biomass and allometric measurements. These data show that Canadian national equations accurately predict the whole aboveground biomass for both black spruce and jack pine trees, but underestimated branches biomass, possibly owing to a particular tree morphology in OWs relative to closed-canopy stands. We therefore developed ad hoc allometric equations based on three power models including diameter at breast height (DBH) alone or in combination with tree height (H) as allometric variables. Our results show that although the inclusion of H in the model yields better fits for most tree compartments in both species, the difference is minor and does not markedly affect biomass C stocks at the stand level. Using these newly developed equations, we found that carbon stocks in afforested OWs varied markedly among sites owing to differences in tree growth and species. Nine years after afforestation, jack pine plantations had accumulated about five times more carbon than black spruce plantations (0.14 vs. 0.80 t C·ha−1), highlighting the much larger potential of jack pine for OW afforestation projects in this environment.

scholarly journals Carbon stocks of homestead forests have a mitigation potential to climate change in Bangladesh

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tarit Kumar Baul ◽  
Tajkera Akhter Peuly ◽  
Rajasree Nandi ◽  
Lars Holger Schmidt ◽  
Shyamal Karmakar
Keyword(s):  
Species Diversity ◽  
Stand Structure ◽  
Diversity Index ◽  
Carbon Stocks ◽  
Small Scale ◽  
Species Diversity Index ◽  
C Stocks ◽  
Homestead Forests ◽  
C Stock ◽  
Low Altitude

AbstractA total of 176 homestead forests at three altitudes in the Chittagong Hill Tracts, Bangladesh were randomly surveyed to estimate carbon (C) stocks and how stand structure affects the biomass C. All woody vegetations were measured, and litter and soil (0–30 cm depth) were sampled. The tree biomass C stock in the top two altitude forests was up to 37–48% higher than in low altitude, owing to significantly higher tree density and species diversity. An increase in species diversity index by one unit increased the biomass stock by 23 Mg C ha−1. The C stock of litterfall in low altitude forests was 22–28% higher than in the top two altitude due to the deposition of litters downslope and deliberate use of mulch for soil improvement and conservation, resulting in up to 5% higher total soil C. The topsoil C was 10–25% higher than the deeper soil, depending on the altitude. The forest stored 89 Mg C ha−1, indicating a potential for C sequestration in trees outside forest. This study would help policymakers to strengthen the recognition of small-scale forests for mitigation in REDD + (reducing emissions from deforestation and forest degradation, the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks) and support owners through C credits from sustainably managed forests.

scholarly journals Agro-forestry Systems as a Means to Achieve Carbon Co-benefits in Nepal

2016 ◽  
Vol 13 (1) ◽  
pp. 59-68
Author(s):  
Roshan M. Bajracharya ◽  
Him Lal Shrestha ◽  
Ramesh Shakya ◽  
Bishal K. Sitaula
Keyword(s):  
Organic Carbon ◽  
Soil Properties ◽  
Soil Carbon ◽  
Bulk Density ◽  
Agricultural Land ◽  
Carbon Stocks ◽  
Community Forests ◽  
C Stocks ◽  
Soil Carbon Stocks ◽  
Agro Forestry

Land management regimes and forest types play an important role in the productivity and accumulation of terrestrial carbon pools. While it is commonly accepted that forests enhance carbon sequestration and conventional agriculture causes carbon depletion, the effects of agro-forestry are not well documented. This study investigated the carbon stocks in biomass and soil, along with the selected soil properties in agro-forestry plots compared to community forests (CF) and upland farms in Chitwan, Gorkha and Rasuwa districts of Central Nepal during the year 2012-2013. We determined the total above ground biomass carbon, soil organic carbon (SOC) stocks and soil properties (bulk density, organic carbon per cent, pH, total nitrogen (TN), available phosphorus (P), exchangeable potassium (K), and cation exchange capacity (CEC)) on samples taken from four replicates of 500 m2 plots each in community forests, agro-forestry systems and agricultural land. The soil was sampled in two increments at 0-15 cm and 15-30 cm depths and intact cores removed for bulk density and SOC determination, while loose samples were separately collected for the laboratory analysis of other soil properties. The mean SOC percent and corresponding soil carbon stocks to 30 cm depth were generally highest in CF (3.71 and 3.69 per cent, and 74.98 and 76.24 t ha-1, respectively), followed by leasehold forest (LHF) (2.26 and 1.13 per cent and 40.72 and 21.34 t ha-1, respectively) and least in the agricultural land (3.05 and 1.09 per cent, and 63.54 and 19.42 t ha-1, respectively). This trend was not, however, observed in Chitwan, where agriculture (AG) had the highest SOC content (1.98 per cent) and soil carbon stocks (42.5 t ha-1), followed by CF (1.8 per cent and 41.2 t ha-1) and leasehold forests (1.56 per cent and 35.3 t ha-1) although the differences were not statistically significant. Other soil properties were not significantly different among land use types with the exceptions of pH, total N, available P and CEC in the Chitwan plots. Typically, SOC and soil carbon stocks (to 30cm depth) were positively correlated with each other and with TN and CEC. The AGB-C was expectantly highest in Rasuwa district CF (ranging from 107.3 to 260.3 t ha-1) due to dense growth and cool climate, followed by Gorkha (3.1 to 118.4 t ha-1), and least in Chitwan (17.6 to 95.2 t ha-1). The highest C stocks for agro-forestry systems in both above ground and soil were observed in Rasuwa, followed by Chitwan district. Besides forests, agro-forestry systems also hold good potential to store and accumulate carbon, hence they have scope for contributing to climate change mitigation and adaptation with co-benefits.Journal of Forest and Livelihood 13(1) May, 2015, page: 56-68

scholarly journals Biochar Effects on Carbon Stocks in the Coffee Agroforestry Systems of the Himalayas

2018 ◽  
Vol 7 (4) ◽  
pp. 103 ◽  
Author(s):  
Ngamindra Dahal ◽  
Roshan Man Bajracharya ◽  
Lal Mani Wagle
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Low Income ◽  
Smallholder Farmers ◽  
Carbon Stocks ◽  
Agricultural Practice ◽  
Coffee Agroforestry ◽  
Incremental Change ◽  
C Stocks ◽  
Soc Stocks

Coffee agroforestry is an emerging agricultural practice in the mid hills of Nepal. Smallholder farmers of low-income strata have progressively adopted coffee as a perennial crop over seasonal crops. A multi-year study was conducted to test effects of locally produced biochar derived from coffee wastes, e.g., pulp and husks, on carbon stocks of: i) coffee trees, and, ii) soil organic carbon (SOC) in selected coffee growing pockets. We conducted on-farm experimental trials in three different physiographical locations of the Nepal mid-hills, namely, Chandanpur (Site I at 1475masl), Panchkhal (Site II at 1075masl), and Talamarang (Site III at 821masl) where smallholders grow coffee together with other cereal crops and vegetables. We applied biochar to the soil at a rate of 5 Mgha-1, then, monitored the SOC and biomass growth of the coffee trees in the three treatment plots at sites I, II and III over two years beginning in 2013. The average stocks of aboveground carbon in coffee trees increased from 6.2±4.3 Mgha-1 to 9.1±5.2 Mgha-1 over the trial period of two years in biochar treated plots. The same in control plots increased from 5.6±2.8 Mgha-1 to 6.7±4.7 Mgha-1. In the biochar plots, the average increments of ABG carbon was 0.73 Mgh-1 while in the control it was 0.29 Mgh-1. Analysis of soil organic carbon of the plots indicated overall incremental change in carbon stocks in the coffee farms. During the base year, the average SOC stocks in the top 0-15cm layer of the soil at sites I, II, and III were estimated 74.88 ± 15.93; 63.96 ±16.71 and 33.05 ±4.42 Mgha-1 respectively. Although both the biochar treated and control plot registered incremental change in SOC stocks, the volumes were remarkably higher in the former than the latter. Compared to the baseline data, the changes in SOC stocks in the three biochar treated plots were 19.8, 49.8 and 45.3 Mgha-1, respectively, whereas in the control plots these were 8.3, 29.3 and 11.3 Mgha-1, respectively. The higher incremental rates of C-stocks in all the biochar treated plots in comparison to the corresponding control plots of the coffee agroforestry implies that application of biochar can enhance accumulation of carbon in the form of aboveground biomass and soil organic carbon.

scholarly journals Uncertainties in the land-use flux resulting from land-use change reconstructions and gross land transitions

2017 ◽  
Vol 8 (1) ◽  
pp. 91-111 ◽  
Author(s):  
Anita D. Bayer ◽  
Mats Lindeskog ◽  
Thomas A. M. Pugh ◽  
Peter M. Anthoni ◽  
Richard Fuchs ◽  
...  
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Land Use Changes ◽  
Terrestrial Ecosystem ◽  
Grid Cell ◽  
Carbon Stocks ◽  
Dynamic Global Vegetation Model ◽  
Soil C ◽  
Tropical Regions ◽  
C Stocks

Abstract. Land-use and land-cover (LUC) changes are a key uncertainty when attributing changes in measured atmospheric CO2 concentration to its sinks and sources and must also be much better understood to determine the possibilities for land-based climate change mitigation, especially in the light of human demand on other land-based resources. On the spatial scale typically used in terrestrial ecosystem models (0.5 or 1°) changes in LUC over time periods of a few years or more can include bidirectional changes on the sub-grid level, such as the parallel expansion and abandonment of agricultural land (e.g. in shifting cultivation) or cropland–grassland conversion (and vice versa). These complex changes between classes within a grid cell have often been neglected in previous studies, and only net changes of land between natural vegetation cover, cropland and pastures accounted for, mainly because of a lack of reliable high-resolution historical information on gross land transitions, in combination with technical limitations within the models themselves. In the present study we applied a state-of-the-art dynamic global vegetation model with a detailed representation of croplands and carbon–nitrogen dynamics to quantify the uncertainty in terrestrial ecosystem carbon stocks and fluxes arising from the choice between net and gross representations of LUC. We used three frequently applied global, one recent global and one recent European LUC datasets, two of which resolve gross land transitions, either in Europe or in certain tropical regions. When considering only net changes, land-use-transition uncertainties (expressed as 1 standard deviation around decadal means of four models) in global carbon emissions from LUC (ELUC) are ±0.19, ±0.66 and ±0.47 Pg C a−1 in the 1980s, 1990s and 2000s, respectively, or between 14 and 39 % of mean ELUC. Carbon stocks at the end of the 20th century vary by ±11 Pg C for vegetation and ±37 Pg C for soil C due to the choice of LUC reconstruction, i.e. around 3 % of the respective C pools. Accounting for sub-grid (gross) land conversions significantly increased the effect of LUC on global and European carbon stocks and fluxes, most noticeably enhancing global cumulative ELUC by 33 Pg C (1750–2014) and entailing a significant reduction in carbon stored in vegetation, although the effect on soil C stocks was limited. Simulations demonstrated that assessments of historical carbon stocks and fluxes are highly uncertain due to the choice of LUC reconstruction and that the consideration of different contrasting LUC reconstructions is needed to account for this uncertainty. The analysis of gross, in addition to net, land-use changes showed that the full complexity of gross land-use changes is required in order to accurately predict the magnitude of LUC change emissions. This introduces technical challenges to process-based models and relies on extensive information regarding historical land-use transitions.

The developmental history of peatlands at Muskiki and Marguerite lakes, Alberta

1989 ◽  
Vol 67 (12) ◽  
pp. 3534-3544 ◽  
Author(s):  
Helen Kubiw ◽  
Michael Hickman ◽  
Dale F. Vitt
Keyword(s):  
Species Composition ◽  
Radiocarbon Dating ◽  
Environmental Changes ◽  
Warm Period ◽  
Vegetation Changes ◽  
Developmental History ◽  
Peat Accumulation ◽  
Fire Activity ◽  
History Of ◽  
Peat Stratigraphy

The peat stratigraphy of fens at Muskiki Lake (52°50′N, 116°51′W) and Marguerite Lake (54°38′N, 110°43′W) in central Alberta was examined to determine the developmental history of the fens on the basis of radiocarbon dating and bryophyte macrofossil analyses. Peat accumulation at Muskiki Lake peatland began about 9000 years BP via lake filling. Expansion of the peatland by paludification and vegetation changes, including string and flark formation, are secondary occurrences, the latter occurring subsequent to environmental changes, including mid-Holocene thermal events. Peat inception at Marguerite Lake began about 2400 years BP via paludification. This delay, relative to Muskiki Lake peatland, may be related to the mid-Holocene warm period. Fire activity and increased wetness, as well as autogenic successional processes, altered species composition and abundance.

scholarly journals Caracterización físico-espacial de las promociones de nuevos barrios durante la República de Weimar (1919-1933): estudio de casos en las ciudades alemanas de Berlín, Frankfurt y Hamburgo

2017 ◽  
pp. 55
Author(s):  
Yeimis Milton Palomino Pichihua
Keyword(s):  
Urban Form ◽  
Physical Structure ◽  
Urban Morphology ◽  
Physical Analysis ◽  
Social Changes ◽  
Political Factors ◽  
Palabras Clave ◽  
German Model ◽  
History Of ◽  
Historical Accounts

ResumenLas primeras décadas del siglo XX mostraron al urbanismo en un proceso de redefinición disciplinar producto de los nuevos requerimientos de habitabilidad de las emergentes ciudades europeas. En este periodo sobresalieron los aportes de la República de Weimar, relacionados a la promoción de vivienda, que marcaron el inicio de las modernas políticas de vivienda social, al mismo tiempo que inauguraban un modelo de crecimiento suburbano. La importancia del modelo alemán de nuevos barrios radicó en la conjunción de factores disciplinares y políticos. Esta particularidad provocó un creciente interés por parte del mundo académico; no obstante, este derivaría hacia interpretaciones sociológicas, dejando de lado el análisis netamente físico. En respuesta, el presente artículo plantea un análisis enfocado en la forma urbana. Busca identificar las cualidades de estos nuevos espacios, atendiendo a indicadores morfológicos de superficie, ocupación, forma y distribución. Asimismo, el estudio coteja casos de promoción de vivienda, con formas tradicionales de ocupación residencial. Con la intención de obtener pruebas de la relación entre la estructura física y los intensos cambios sociales de la época. Confrontando resultados empíricos con relatos históricos vigentes, fortaleciendo así una visión crítica de los mismos. De este modo, cuestiona visiones generalizadoras de la historia del urbanismo, la misma que se reconoce fragmentaria y diversa. Palabras clave  Siedlungen, morfología urbana, historia del urbanismo, Berlín, Frankfurt, HamburgoAbstractFirst decades of the twentieth century, showed urbanism in a process of disciplinary redefinition. Result of the new requirements of habitability of emerging European cities. Period in which the contributions of the Weimar Republic, related to the promotion of housing were outstanding. These marked the beginning of modern policies of social housing, at the same time as they inaugurated a model of suburban growth. The relevance of the German model of neighborhoods lay in the conjunction of disciplinary and political factors. This particularity has produced a growing interest on the academic world. However, this has led to sociological interpretations, leaving aside the purely physical analysis. In response, the present article proposes an analysis focused on the urban form. It implies the identification of qualities of new spaces, in terms of morphological indicators like surface, occupation, form and distribution. The study compares cases of housing promotion, with traditional forms of residential occupation. In order to obtain evidence of the relation between the physical structure and intense social changes. Confronting empirical results with current historical accounts, strengthening a critical view of them. By this way, question generalizing visions of the history of urbanism, which is recognized fragmentary and diverse. KeywordsSiedlungen, urban morphology, urban history, Berlin, Frankfurt, Hamburg

scholarly journals WALKING WALKing walking: Action Recognition from Action Echoes

2017 ◽  
Author(s):  
Qianli Ma ◽  
Lifeng Shen ◽  
Enhuan Chen ◽  
Shuai Tian ◽  
Jiabing Wang ◽  
...  
Keyword(s):  
Time Series ◽  
Spatial Information ◽  
Multivariate Time Series ◽  
Learning Task ◽  
Physical Structure ◽  
Data Sets ◽  
Benchmark Data ◽  
Echo State Networks ◽  
History Of ◽  
Label Distribution

Recognizing human actions represented by 3D trajectories of skeleton joints is a challenging machine learning task. In this paper, the 3D skeleton sequences are regarded as multivariate time series, and their dynamics and multiscale features are efficiently learned from action echo states. Specifically, first the skeleton data from the limbs and trunk are projected into five high dimensional nonlinear spaces, that are randomly generated by five dynamic, training-free recurrent networks, i.e., the reservoirs of echo state networks (ESNs). In this way, the history of the time series is represented as nonlinear echo states of actions. We then use a single multiscale convolutional layer to extract multiscale features from the echo states, and maintain multiscale temporal invariance by a max-over-time pooling layer. We propose two multi-step fusion strategies to integrate the spatial information over the five parts of the human physical structure. Finally, we learn the label distribution using softmax. With one training-free recurrent layer and only layer of convolution, our Convolutional Echo State Network (ConvESN) is a very efficient end-to-end model, and achieves state-of-the-art performance on four skeleton benchmark data sets.

scholarly journals Review of the Methods for Strengthening and Retrofitting Cultural Heritage Structures

2020 ◽  
Vol 4 (6) ◽  
pp. 45-56
Author(s):  
Bira Wafaei Baneh ◽  
Koosha Wafaei Baneh
Keyword(s):  
Cultural Heritage ◽  
Construction Materials ◽  
Physical Structure ◽  
Shear Capacity ◽  
Historical Monuments ◽  
History Of ◽  
Historical Sites ◽  
Traditional Construction ◽  
Seismic Forces ◽  
Low Shear

Referring to the fact that the history of each country is the identity of its people and the preservation of originality and culture is also considered as a social value, the maintenance of valuable historical monuments, which indicates the path to the growth of human civilization, is of particular importance. Each country is trying to prevent the destruction of its historic buildings and cultural heritage by applying various methods of reparation and retrofitting. Iran, as a country with an ancient civilization, is a heritage of many valuable historical monuments. Traditional construction materials included masonry materials such as clay and mud, stone, wood and brick, and due to the weakness in physical structure and their low shear capacity and tensile strength, these materials do not have strength for example against strong forces from earthquakes and are suffered heavy damages. Unfortunately, in our country, fundamental work has not been performed on historical sites and complexes so far, and practically, the measures have been taken without any improvement in the structural performance of the buildings. Using special technical and specialized methods, the seismic behavior of such buildings could be enhanced against the seismic forces caused by the earthquake, and minimize the damage on the historical buildings to the least possible extent by strengthening historical monuments. In this paper, by separating the components, we examine a number of strengthening methods belonging to each of them.

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