scholarly journals Distribution and altitudinal patterns of carbon and nitrogen storage in various forest ecosystems in the central Yunnan Plateau, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jianqiang Li ◽  
Qibo Chen ◽  
Zhuang Li ◽  
Bangxiao Peng ◽  
Jianlong Zhang ◽  
...  
Keyword(s):  
Forest Ecosystems ◽  
Sustainable Forest Management ◽  
Carbon And Nitrogen ◽  
Pinus Yunnanensis ◽  
Yunnan Plateau ◽  
Baseline Information ◽  
C And N ◽  
Quercus Semecarpifolia ◽  
Management Policies

AbstractThe carbon (C) pool in forest ecosystems plays a long-term and sustained role in mitigating the impacts of global warming, and the sequestration of C is closely linked to the nitrogen (N) cycle. Accurate estimates C and N storage (SC, SN) of forest can improve our understanding of C and N cycles and help develop sustainable forest management policies in the content of climate change. In this study, the SC and SN of various forest ecosystems dominated respectively by Castanopsis carlesii and Lithocarpus mairei (EB), Pinus yunnanensis (PY), Pinus armandii (PA), Keteleeria evelyniana (KE), and Quercus semecarpifolia (QS) in the central Yunnan Plateau of China, were estimated on the basis of a field inventory to determine the distribution and altitudinal patterns of SC and SN among various forest ecosystems. The results showed that (1) the forest SC ranged from 179.58 ± 20.57 t hm−1 in QS to 365.89 ± 35.03 t hm−1 in EB. Soil, living biomass and litter contributed an average of 64.73%, 31.72% and 2.86% to forest SC, respectively; (2) the forest SN ranged from 4.47 ± 0.94 t ha−1 in PY to 8.91 ± 1.83 t ha−1 in PA. Soil, plants and litter contributed an average of 86.88%, 10.27% and 2.85% to forest SN, respectively; (3) the forest SC and SN decreased apparently with increasing altitude. The result demonstrates that changes in forest types can strongly affect the forest SC and SN. This study provides baseline information for forestland managers regarding forest resource utilization and C management.

scholarly journals Long-term Carbon and Nitrogen Dynamics at SPRUCE Revealed through Stable Isotopes in Peat Profiles

2016 ◽  
Author(s):  
Erik A. Hobbie ◽  
Janet Chen ◽  
Paul J. Hanson ◽  
Colleen M. Iversen ◽  
Karis J. Mcfarlane ◽  
...  
Keyword(s):  
Industrial Revolution ◽  
Continuous Variables ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Dynamics ◽  
Aerobic Decomposition ◽  
C And N ◽  
C And N Cycling ◽  
Δ15n And Δ13c ◽  
Forested Bog

Abstract. We used δ15N and δ13C patterns from 16 peat depth profiles to interpret changes in C and N cycling in the Marcell S1 forested bog in northern Minnesota over the past ~ 10 000 years. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, C / N, %N, and each other. Continuous variables in the regression model mainly reflected 13C and 15N fractionation accompanying N and C losses, with an estimated 40 % of fractionations involving C-N bonds. In contrast, nominal variables such as plot, depth, and vegetation cover reflected peatland successional history and climate. Higher δ15N and lower δ13C in plots closer to uplands may reflect distinct hydrology and accompanying shifts in C and N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ13CO2 since the Industrial Revolution) and aerobic decomposition lowered δ13C in recent surficial samples. A decrease of 1 ‰ in the depth coefficient for δ15N from −35 cm to −25 cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland. Low δ13C at −213 cm and −225 cm (~ 8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage, whereas higher δ13C thereafter reflected subsequent cooling. Because of multiple potential mechanisms influencing δ13C, there was no clear evidence for the influence of methanogenesis or methane oxidation on bulk δ13C.

Effect of leaching and clay content on carbon and nitrogen mineralisation in maize and pasture soils

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 535 ◽  
Author(s):  
R. L. Parfitt ◽  
G. J. Salt ◽  
S. Saggar
Keyword(s):  
Clay Content ◽  
N Mineralisation ◽  
Incubation Experiment ◽  
Nitrogen Mineralisation ◽  
Total N ◽  
Carbon And Nitrogen ◽  
Maize Sample ◽  
C Mineralisation ◽  
C And N

We conducted a 7-week laboratory incubation experiment to evaluate the effect of leaching on net C and N mineralisation in soils. The soils were collected from adjacent fields of long-term pasture and maize, where each field contained an Inceptisol and an Andisol. The concentration of clay mineral was 200 g/kg halloysite in the Inceptisol and 120 g/kg allophane in the Andisol. Half the samples were leached weekly with 0.002 M CaCl2 at a suction of 20 kPa to remove soluble products, and half were not leached. Carbon mineralisation was determined from CO2-C evolved each week. Net N mineralisation was measured for the leached samples from the NH4-N and NO3-N in the CaCl2 extracts, and for the batch of non-leached samples by extraction in 0.5 M K2SO4. Carbon and net N mineralisation were greater in the soils under pasture than in soils under maize. The proportion of total C mineralised as CO2-C, and of total N mineralised as NH4-N and NO3-N, followed the order Inceptisol-pasture > Inceptisol-maize > Andisol-pasture > Andisol-maize, suggesting that allophane and Al ions reduced net mineralisation. Dissolved organic carbon (DOC) produced during incubation, as a proportion of total C, was greatest for the Inceptisol-maize sample and least for the Andisol-pasture sample. Non-leaching resulted in the accumulation of acids and solutes, and decreased C mineralisation for the Inceptisol samples.

scholarly journals Fire in lichen-rich subarctic tundra changes carbon and nitrogen cycling between ecosystem compartments but has minor effects on stocks

2021 ◽  
Author(s):  
Ramona Julia Heim ◽  
Andrey Yurtaev ◽  
Anna Bucharova ◽  
Wieland Heim ◽  
Valeriya Kutskir ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Ambient Air ◽  
Fire Effects ◽  
Long Term Effects ◽  
Fire Scars ◽  
Microbial Decomposition ◽  
Carbon And Nitrogen ◽  
Arctic Regions ◽  
C And N

Abstract. Fires are predicted to increase in Arctic regions due to ongoing climate change. Tundra fires can alter carbon and nutrient cycling and release a substantial amount of greenhouse gases with global consequences. Yet, the long-term effects of tundra fires on carbon (C) and nitrogen (N) stocks and cycling are still unclear. Here we used a space-for-time approach to investigate the long-term fire effects on C and N stocks and cycling in soil and aboveground living biomass. We collected data from three large fire scars (> 44, 28 and 12 years old) and corresponding control areas and used linear mixed-effects models in a Bayesian framework to analyse how the stocks and cycling were influenced by fire. We found that tundra fires did not affect total C and N stocks because a major part of the stocks was located belowground in soils, which were largely unaltered by fire. However, fire had a strong effect on stocks in the aboveground vegetation, mainly due to the reduction of the lichen layer. Fire reduced N concentrations in graminoids and herbs on the younger fire scars, which affected respective C / N ratios and indicated an increased post-fire competition between vascular plants. Aboveground plant biomass was depleted in 13C in all three fire scars. This could be related to a lower 13C abundance in CO2 in the ambient air because of increased post-fire decomposition, providing a source of 13C-depleted CO2. In soil, the relative abundance of 13C changed with time after fire because of the combined effects of microbial decomposition and plant-related fractionation processes. Our results indicate that in lichen-rich subarctic tundra ecosystems, the contribution of fires to the release of additional carbon to the atmosphere might be relatively small as soil stocks appear to be resilient.

Four centuries of soil carbon and nitrogen change after stand-replacing fire in a forest landscape in the western Cascade Range of Oregon

2008 ◽  
Vol 38 (9) ◽  
pp. 2455-2464 ◽  
Author(s):  
T. W. Giesen ◽  
S. S. Perakis ◽  
K. Cromack
Keyword(s):  
Pacific Northwest ◽  
Forest Floor ◽  
Mineral Soil ◽  
Douglas Fir ◽  
Cascade Range ◽  
Carbon And Nitrogen ◽  
The Pacific ◽  
C And N ◽  
Mineral Soils

Episodic stand-replacing wildfire is a significant disturbance in mesic and moist Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) forests of the Pacific Northwest. We studied 24 forest stands with known fire histories in the western Cascade Range in Oregon to evaluate long-term impacts of stand-replacing wildfire on carbon (C) and nitrogen (N) pools and dynamics within the forest floor (FF, Oe and Oa horizons) and the mineral soil (0–10 cm). Twelve of our stands burned approximately 150 years ago (“young”), and the other 12 burned approximately 550 years ago (“old”). Forest floor mean C and N pools were significantly greater in old stands than young stands (N pools: 1823 ± 132 kg·ha–1vs. 1450 ± 98 kg·ha–1; C pools: 62 980 ± 5403 kg·ha–1vs. 49 032 ± 2965 kg·ha–1, mean ± SE) as a result of significant differences in FF mass. Forest floor C and N concentrations and C/N ratios did not differ by time since fire, yet potential N mineralization rates were significantly higher in FF of old sites. Old and young mineral soils did not differ significantly in pools, concentrations, C/N ratios, or cycling rates. Our results suggest that C and N are sequestered in FF of Pacific Northwest Douglas-fir forests over long (∼400 year) intervals, but that shorter fire return intervals may prevent that accumulation.

scholarly journals Effects of long-term nitrogen addition on soil respiration and its components in a boreal forest

2020 ◽  
Author(s):  
Guancheng Liu ◽  
Tong Liu ◽  
Guoyong Yan ◽  
Lei Wang ◽  
Xiaochun Wang ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Boreal Forest ◽  
Forest Ecosystems ◽  
Nitrogen Addition ◽  
N Deposition ◽  
Microbial Biomass C ◽  
N Addition ◽  
Soil C ◽  
C And N

Abstract Background Atmospheric nitrogen (N) deposition in boreal forest ecosystems increased gradually with the development of industry and agriculture, but the effects of N input on soil CO2 fluxes in these ecosystems were rarely reported in previous studies. To evaluate the effect of N addition on soil respiration is of great significance for understanding the distribution of soil carbon (C) on the N gradient in forest ecosystems.Results In this study, four treatment levels of N addition (0, 25, 50, 75 kg N ha− 1 yr− 1) were applied to natural Larix gmelinii forest in Greater Khingan Mountains of northeast China. We focused mainly on the dynamics of soil respiration (Rs), heterotrophic respiration (Rh), autotrophic respiration (Ra), microbial biomass C and N (MBC and MBN) and fine root biomass (FRB) in a growing season. We found that low N addition significant increased Rs, Rh and Ra, but with the increase of N addition, the promotion effect was gradually weakened. Medium N increased the temperature sensitivity (Q10) of Rs and Rh components, while medium N and high N significantly reduced the Q10 of Ra. Ra was positively correlated with FRB; Rh was positively correlated with soil MBC and MBN; and RS was probably driven by Ra from May to July, while by Rh in August and September.Conclusions Long-term N addition alleviated microbial N limitation, promoted soil respiration and accelerated soil C and N cycle in boreal forest ecosystems.

On Climate Change Risks of Long-Term Socio-Economic Development in Russia

2019 ◽  
pp. 79-95
Author(s):  
N.E. Terentiev
Keyword(s):  
Climate Change ◽  
Economic Development ◽  
Technological Innovation ◽  
Global Climate Change ◽  
Global Climate ◽  
Climate Risk ◽  
Climate Change Risks ◽  
Socio Economic Development ◽  
Management Policies

Based on the latest data, paper investigates the dynamics of global climate change and its impact on economic growth in the long-term. The notion of climate risk is considered. The main directions of climate risk management policies are analyzed aimed, first, at reducing anthropogenic greenhouse gas emissions through technological innovation and structural economic shifts; secondly, at adaptation of population, territories and economic complexes to the irreparable effects of climate change. The problem of taking into account the phenomenon of climate change in the state economic policy is put in the context of the most urgent tasks of intensification of long-term socio-economic development and parrying strategic challenges to the development of Russia.

Concussion, neuroethics, and sport: Policies of the past do not suffice for the future

2017 ◽  
Author(s):  
Brad Partridge ◽  
Wayne Hall
Keyword(s):  
Mental Health ◽  
Head Trauma ◽  
Mental Health Problems ◽  
Ethical Issues ◽  
Cognitive Impairments ◽  
Concussion Management ◽  
Design And Implementation ◽  
The Past ◽  
Management Policies

Concussion management policies have become a major priority worldwide for sports that involve frequent collisions between participants because repeated head trauma has been associated with long-term cognitive impairments, mental health problems, and some forms of neurological degeneration. A number of concussion management policies have been developed by professional bodies and subsequently adopted by various sporting leagues. These have offered little guidance on how to navigate ethical issues in identifying and managing concussion. This chapter discusses ethical issues that arise in the diagnosis of concussion, debates about the longer-term consequences of repeated concussion injuries, and the design and implementation of policies that aim to prevent and manage concussion injuries in sporting matches.

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