Carbon and nitrogen accumulation and decomposition from coarse woody debris in a naturally regenerated Korean red pine (pinus densiflora S. et Z.) forest

The contribution of coarse woody debris (CWD) to forest carbon (C) and nitrogen (N) dynamics is poorly quantified. This study quantified total C and N content in CWD and estimated the decomposition rates of CWD at different decay stages in a 70-year-old naturally regenerated Korean red pine forest (Pinus densiflora S. et Z.). The N concentration in CWD varied among species and decay classes (from 0.15% to 0.82%), and exhibited a decreasing pattern in C:N ratios with increasing decay class. Total CWD amounts of 4.84 Mg C ha−1, dominated by pine logs (45.4%) and decay class III (40.0%), contained total N of 20.48 kg N ha−1, which was approximately nine times the N input from annual tree mortality. In addition, this study demonstrated that the decay constant rate k was 0.2497 for needle litter, whereas k values were 0.0438, 0.0693, 0.1054, and 0.1947 for red pine CWD of decay class I, II, III, and IV, respectively. The decay rates were significantly related to wood density, N concentration, and C:N ratio across the decay classes of CWD. The results suggest that the C:N ratio of CWD is a key factor affecting its decomposition

Interactions between topsoil properties and ecophysiological responses of mangroves (Avicennia marina) along the tidal gradient in an arid region in Qatar

This study investigated the interactions between topsoil properties and ecophysiological responses of Avicennia marina along the tidal gradient in an arid region in Qatar. In February 2017, three plots were established, each at a distance of 0 m (D0), 50 m (D50), and 100 m (D100) from the inland boundary of a mangrove forest. Soil samples were collected at 0–10-cm depth in each plot to determine the chemical properties, and the density of seedlings, saplings, and trees was measured. Moreover, above- (AGB) and below-ground biomass (BGB) were calculated using an allometric equation for A. marina with the measured diameter at breast height in February 2017. As an indicator of salt stress, chlorophyll fluorescence parameters were measured in October 2017. Salinity (45.60 ppt) and exchangeable sodium percentage (ESP; 29.02%) at D100 were significantly highest. AGB was higher at D100 (41.44 Mg ha–1) than at D0 (0 Mg ha–1) and D50 (7.33 Mg ha–1), and BGB was higher at D100 (44.91 Mg ha–1) than only at D0 (0 Mg ha–1). There was no significant difference in the density of seedlings, saplings, or trees or the chlorophyll fluorescence parameters among the plots. Salt stress was not induced despite the hypersalinity at this site, since A. marina growing in an arid climate can endure strong salinity. Soil pH was highest at D0, followed by at D50 and D100. Organic matter, total nitrogen, available phosphorus, and cation exchange capacity were significantly higher at D100 than at D0 and D50. Higher concentrations of nutrients on the seaward side might result from the tidal gradient and a large input of organic matter and low soil alkalinity.Qatar University Grant (QUUG-CAS-DBES-15/16-5); the Biodiversity Conservation Fund of Kazakhstan (Q1727701); the Korean Ministry of Environment (2014001310008

Effect of soil moisture on the response of soil respiration to open-field experimental warming and precipitation manipulation

Soil respiration (RS, Soil CO2 efflux) is the second largest carbon (C) flux in global terrestrial ecosystems, and thus, plays an important role in global and regional C cycling; moreover, it acts as a feedback mechanism between C cycling and global climate change. RS is highly responsive to temperature and moisture, factors that are closely related to climate warming and changes in precipitation regimes. Here, we examined the direct and interactive effects of climate change drivers on RS of Pinus densiflora Sieb. et Zucc. seedlings in a multifactor climate change experiment involving atmospheric temperature warming (+3 °C) and precipitation manipulations (-30% and +30%). Our results indicated that atmospheric temperature warming induced significant changes in RS (p < 0.05), enhancing RS by an average of 54.6% and 59.7% in the control and elevated precipitation plots, respectively, whereas atmospheric temperature warming reduced RS by 19.4% in plots subjected to lower rates of precipitation. However, the warming effect on RS was influenced by soil moisture. On the basis of these findings, we suggest that atmospheric temperature warming significantly influenced RS, but the warming effect on RS may be weakened by warming-induced soil drying in water-limited environments

Changes in the Contribution of Termites to Mass Loss of Dead Wood among Three Tree Species during 23 Months in a Lowland Tropical Rainforest

This study investigated the contribution of termites to mass loss of dead wood (Macaranga bancana, Elateriospermum tapos, and Dillenia beccariana) in a lowland tropical rainforest, Brunei Darussalam. Mesh bag method was used to exclude termites, and the mass remaining was monitored after 3, 7, 13, and 23 months. C/N ratio of the samples was analyzed after 13 and 23 months. Initial wood density was 0.63, 0.92, and 1.02 g/cm3 for M. bancana, E. tapos, and D. beccariana, respectively, and the termite contribution to mass loss was an average (range) of 13.05±5.68 (4.17-29.59%), 3.48±1.13 (2.20-6.49), and 3.40±1.92% (0.74-10.78), respectively. Until 7 months, termites contributed highly to mass loss, given the low initial wood density, and interaction effect of species and treatment was significant. After 7 months, the contribution decreased in M. bancana and E. tapos, whereas it increased consistently in D. beccariana. The interaction effect was not significant, whereas differences in C/N ratio among the species were significant, with a lower C/N ratio in M. bancana and E. tapos than in D. beccariana. After 23 months, the differences in C/N ratio were not significant, and ants were present at 40% of control samples in M. bancana and E. tapos. Our results suggest that the contribution of termites to mass loss varies by dead wood species and is temporally variable. Initial wood traits could affect the termite feeding in the beginning, however, termites thereafter could forage in response to the varying C/N ratio among species and predators

Contributing to sustainability education of east asian university students through a field trip experience: A social-ecological perspective

This study reports the effects of a field trip environmental education program with a social-ecological perspective on the experience and learning of university students from China, Japan, South Korea and Vietnam. The students visited Jeju Island, the SaemangeumSeaDike, theDemilitarized Zone and Seoul, South Korea. Their experiences and learning about social-ecological interactions were analyzed using the new environmental paradigmtest, an evaluation questionnaire, group presentations and individual reports. Across demographic characteristics, the participants believed the program fairly presented the concept of social-ecological systems. Some developed new ideas of social-ecological systems through interpreting, transforming and contextualizing their field trip experience based on prior knowledge bases; others compared the sites to case studies. They preferred the sites where social-ecological issues were clearly presented by well-preserved landscapes, successful environmental management or environmental conflict. The results show the need for an advanced multi-dimensional methodology to evaluate students' learning through constructive processes. The program design of this study from planning to field trip and evaluation, the field site design in which regional site resources were organized in a social-ecological context and the analysis of participants' learning and experiences could contribute to attempts to couple the social-ecological perspective with the practice of sustainability and environmental education in field trip design.We appreciate the anonymous private environmental foundation that organized and supported the field trip program. We also appreciate the passionate NGO directors and activists who devoted themselves to helping and guiding the field trip in Jeju, Saemangeum and the DMZ. This study was supported by research grants from the National Research Foundation of Korea (2015R1A6A3A01058445) and the Korea Forest Service (S211216L030120).Scopu

Early growth responses of Larix kaempferi (Lamb.) Carr. seedling to short-term extreme climate events in summer

Abstract: Extreme climate events such as heat waves, drought, and heavy rainfall are occurring more frequently and are more intense due to ongoing climate change. This study evaluated the early growth performance of one-year-old Larix kaempferi (Lamb.) Carr. seedlings under open-field extreme climate conditions including experimental warming and different precipitation regimes. We recorded the survival rate, root collar diameter, height, biomass, shoot-to-root ratio, and seedling quality index using nine treatments (three temperature levels, i.e., control, warming by 3 ◦C and by 6 ◦C, × three precipitation levels, i.e., control, drought, and heavy rainfall) in July and August 2020. The survival rate of seedlings did not differ between treatments, showing high values exceeding 94% across treatments. The measured shoot height was largest under warming by 3 ◦C and high rainfall, indicating that moderate warming increased seedling height growth in a moist environment. Heavy rainfall decreased stem volume by 21% and 25% under control and warming by 6 ◦C treatments, respectively. However, drought manipulation using rain-out shelters did not decrease the growth performance. Overall, extreme climate events did not affect the survival rate, biomass, shoot-to-root ratio, and seedling quality index of L. kaempferi. We thus conclude that, regarding growth responses, L. kaempferi seedlings may be resistant to short-term extreme warming and drought events during summer

The Contribution of Traditional Ecological Knowledge and Practices to Forest Management: The Case of Northeast Asia

This study aims to introduce the potential applicability of traditional ecological knowledge and community forestry in Northeast Asia, including China, Japan, and South Korea. In ancient Northeast Asia, forest policies and practices were based on Fengshui (an old Chinese concept regarding the flow of vital forces), with which forests were managed under community forestry. However, these traditional systems diminished in the twentieth century owing to the decline of traditional livelihood systems and extreme deforestation. Recently, legacies from traditional ecological knowledge and community forestry have been revisited and incorporated into forest policies, laws, and management practices because of growing needs for sustainable forest use in China, Japan, and Korea. This reevaluation of traditional ecological knowledge and community forestry has provided empirical data to help improve forestry systems. Although traditional ecological knowledge and community forestry in Northeast Asia have been scarcely theorized, they play a significant role in modifying forest management practices in the face of socioeconomic changes

Low Carbon Development Pathways in Indian Agriculture

Indian agriculture sector is a significant emitter of Green House Gas (GHG), which is projected to increase by 47% between 2011 and 2020. In response to this, India has committed itself to voluntarily reduce its emissions intensity (emissions per unit GDP) between 20 to 25 percent below 2005 levels by 2020. This would require rapid and significant scaling up of mitigation efforts including the agriculture sector, which remains a challenge, as mitigation is not a priority in Indian agriculture. The study found out that in-spite of numerous mitigation technologies that are readily available for takeoff, the scale of adoption and deployment is far from sufficient to meet the emission targets set by the Government of India, mainly due to lack of financial incentives, capacity building of farmers, and an enabling policy at different levels. This study identified a suite of feasible interventions for promoting low carbon agriculture such as: low tillage systems as it has negative costs due to savings on tillage and fuel; introduction of superior livestock breeds to reduce numbers (especially unproductive cattle) and increase yield; use of livestock wastes to produce energy for cooking and heating through bio-gas technology can not only reduce methane emission but also save electricity costs for the households and; introduction of carbon credits and exploration of domestic carbon markets. An enabling policy environment must be created for these interventions to take off

Short-Term Effects of Experimental Warming and Precipitation Manipulation on Soil Microbial Biomass C and N, Community Substrate Utilization Patterns and Community Composition

Soil microorganisms are major drivers of soil carbon (C) cycling; however, the response of these microorganisms to climate change remains unclear. In the present study, we investigated how 18 months of multifactor climate treatments (warmed air temperature by 3 °C and decreased or increased precipitation manipulation by 30%) affected soil microbial biomass C and nitrogen (N), community substrate utilization patterns, and community composition. Decreased and increased precipitation significantly reduced microbial biomass C by 13.5% and 24.9% and microbial biomass N by 22.9% and 17.6% in unwarmed plots, respectively (P < 0.01). Warming enhanced community substrate utilization by 89.8%, 20.4%, and 141.4% in the natural, decreased, and increased precipitation plots, respectively. Particularly, warming significantly enhanced the utilization of amine and carboxylic acid substrates among all precipitation manipulation plots. Compared with the natural air temperature with natural precipitation treatment, other treatments affected fungal community richness by −0.9% to 33.6% and reduced the relative abundance of the dominant bacterial and fungal groups by 0.5% to 6.8% and 4.3% to 10.7%, respectively. The warming and/or precipitation manipulation treatments significantly altered Zygomycota abundance (P < 0.05). Our results indicate that climate change drivers and their interactions may cause changes in soil microbial biomass C and N, community substrate utilization patterns, and community composition, particularly for the fungal community, and shifts in the microorganism community may further shape the ecosystems function.Scopu