Spatiotemporal approach for estimating potential CO2 sequestration by reforestation in the Korean Peninsula

A forest is one of the carbon sinks in the terrestrial ecosystem; it is a major target for securing CO2 sequestration to achieve carbon neutrality. Reforestation is a forest management method that could attain carbon fixation and forest degradation recovery at the same time, but quantitative research has not been actively conducted. The purpose of this study is to identify the target areas for reforestation through changes in land cover in the Korean Peninsula and to quantify the potential CO2 sequestration effect of reforestation. According to the land cover change through satellite imagery, the area of settlements in the Republic of Korea (ROK) was the most dominant (+3,371 km2), and the main change occurred from cropland to settlements. The forest area increased by +1,544 km2 from 68,264 km2 in the 1980s to 69,809 km2 in the late 2010s. The forest decreased by 7,526 km2, accounting for 5.68% of the entire land area of the Democratic People's Republic of Korea (DPRK), and cropland increased by 5,222 km2 which is 5.12%. Assuming that the target of reforestation is an area whose land cover was a forest in the past and then converted to cropland, wetland, or bare ground, the area of the target decreased as the reference period was applied more recently. As a result of comparing the late 2000s to the late 2010s, the ROK's annual net carbon sequestration due to reforestation is predicted to be 10,833,600 Mg CO2 yr−1 in 2050 and 20,919,200 Mg CO2 yr−1 in 2070. In the DPRK, 14,236,800 Mg CO2 yr−1 in 2050 and 27,490,400 Mg CO2 yr−1 in 2070 were predicted. Reforestation in the Korean Peninsula was analyzed to have sufficient potential to secure a carbon sink, and the DPRK in particular was analyzed to be able to play a role in overseas reforestation

Hydrological response of dry Afromontane forest to changes in land use and land cover in northern Ethiopia

This study analyzes the impact of land use/land cover (LULC) changes on the hydrology of the dry Afromontane forest landscape in northern Ethiopia. Landsat satellite images of thematic mapper (TM) (1986), TM (2001), and Operational Land Imager (OLI) (2018) were employed to assess LULC. All of the images were classified while using the maximum likelihood image classification technique, and the changes were assessed by post-classification comparison. Seven LULC classes were defined with an overall accuracy 83-90% and a Kappa coefficient of 0.82-0.92. The classification result for 1986 revealed dominance of shrublands (48.5%), followed by cultivated land (42%). Between 1986 and 2018, cultivated land became the dominant (39.6%) LULC type, accompanied by a decrease in shrubland to 32.2%, as well as increases in forestland (from 4.8% to 21.4%) and bare land (from 0% to 0.96%). The soil conservation systems curve number model (SCS-CN) was consequently employed to simulate forest hydrological response to climatic variations and land-cover changes during three selected years. The observed changes in direct surface runoff, the runoff coefficient, and storage capacity of the soil were partially linked to the changes in LULC that were associated with expanding bare land and built-up areas. This change in land use aggravates the runoff potential of the study area by 31.6 mm per year on average. Runoff coefficients ranged from 25.3% to 47.2% with varied storm rainfall intensities of 26.1-45.4 mm/ha. The temporal variability of climate change and potential evapotranspiration increased by 1% during 1981-2018. The observed rainfall and modelled runoff showed a strong positive correlation (R-2 = 0.78; p < 0.001). Regression analysis between runoff and rainfall intensity indicates their high and significant correlation (R-2 = 0.89; p < 0.0001). Changes were also common along the slope gradient and agro-ecological zones at varying proportions. The observed changes in land degradation and surface runoff are highly linked to the change in LULC. Further study is suggested on climate scenario-based modeling of hydrological processes that are related to land use changes to understand the hydrological variability of the dry Afromontane forest ecosystems

Measurement of the nuclear modification factor for muons from charm and bottom hadrons in Pb+Pb collisions at 5.02 TeV with the ATLAS detector

Heavy-flavour hadron production provides information about the transport properties and microscopic structure of the quark-gluon plasma created in ultra-relativistic heavy-ion collisions. A measurement of the muons from semileptonic decays of charm and bottom hadrons produced in Pb+Pb and pp collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV with the ATLAS detector at the Large Hadron Collider is presented. The Pb+Pb data were collected in 2015 and 2018 with sampled integrated luminosities of 208 mu b(-1) and 38 mu b(-1), respectively, and pp data with a sampled integrated luminosity of 1.17 pb(-1) were collected in 2017. Muons from heavy-flavour semileptonic decays are separated from the light-flavour hadronic background using the momentum imbalance between the inner detector and muon spectrometer measurements, and muons originating from charm and bottom decays are further separated via the muon track's transverse impact parameter. Differential yields in Pb+Pb collisions and differential cross sections in pp collisions for such muons are measured as a function of muon transverse momentum from 4 GeV to 30 GeV in the absolute pseudorapidity interval vertical bar eta vertical bar &lt; 2. Nuclear modification factors for charm and bottom muons are presented as a function of muon transverse momentum in intervals of Pb+Pb collision centrality. The bottom muon results are the most precise measurement of b quark nuclear modification at low transverse momentum where reconstruction of B hadrons is challenging. The measured nuclear modification factors quantify a significant suppression of the yields of muons from decays of charm and bottom hadrons, with stronger effects for muons from charm hadron decays

A search for an unexpected asymmetry in the production of e+μ− and e−μ+ pairs in proton-proton collisions recorded by the ATLAS detector at root s = 13 TeV

This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for e(+)mu(-) and e(-)mu(+) pairs to constrain physics processes beyond the Standard Model. It uses 139 fb(-1) of proton-proton collision data recorded at root s = 13 TeV at the LHC. Targeting sources of new physics which prefer final states containing e(+)mu(-) and e(-)mu(+), the search contains two broad signal regions which are used to provide model-independent constraints on the ratio of cross sections at the 2% level. The search also has two special selections targeting supersymmetric models and leptoquark signatures. Observations using one of these selections are able to exclude, at 95% confidence level, singly produced smuons with masses up to 640 GeV in a model in which the only other light sparticle is a neutralino when the R-parity-violating coupling lambda(23)(1)' is close to unity. Observations using the other selection exclude scalar leptoquarks with masses below 1880 GeV when g(1R)(eu) = g(1R)(mu c) = 1, at 95% confidence level. The limit on the coupling reduces to g(1R)(eu) = g(1R)(mu c) = 0.46 for a mass of 1420 GeV

A Study on the Genetic Variations and Germination Characteristics of <i>Rhododendron sobayakiense</i> to Prepare for Climate Change Threat

Rhododendron sobayakiense is an endemic and near-threatened species (Korean Red List, NT) found in the alpine regions of South Korea that requires conservation. This study investigated the species’ genetic variations and seed germination characteristics and predicted its potential habitat change according to climate change scenarios. The genetic diversity of R. sobayakiense at the species level (P = 88.6%; S.I. = 0.435; h = 0.282) was somewhat similar to that observed for the same genus. The inter-population genetic differentiation was 19% and revealed a relatively stable level of gene exchange at 1.22 in each population. The main cause of gene flow and genetic differentiation was presumed to be the Apis mellifera pollinator. Seed germination characteristics indicated non-deep physiological dormancy, with germination at ≥10 °C and the highest percent germination (PG) of ≥60% at 15–25 °C, while the PG was ≥50% at 30 °C. The PG increased at constant temperature than at variable temperatures; the mean germination time decreased as temperature increased. The climate scenarios SSP3 and SSP5 were analyzed to predict future R. sobayakiense habitat changes. The variables of the main effects were Identified as follows: elevation > temperature seasonality > mean diurnal range

The Effects of Stand Density Control on Carbon Cycle in Chamaecyparis obtusa (Siebold and Zucc.) Endl. Forests

This study was conducted to quantify the carbon storage in each pool (including trees, forest floor, and soil) and to analyze the carbon cycle in a Chamaecyparis obtusa (Siebold and Zucc.) Endl. forest according to different thinning intensities. The study site was located in Gochang-gun, Jeollabuk-do, and the treatments consisted of a control (Con), a light thinning (LT), and a heavy thinning (HT), based on 3000 trees originally planted per hectare. As stand density decreased, total C storage decreased, and the annual C storage of trees and C released through soil respiration significantly increased. Net ecosystem production (NEP; Mg&middot;C&middot;ha&minus;1&middot;year&minus;1), as the difference between net primary production and microbial respiration, was 1.95, 2.49, and 2.11 in the Con, LT, and HT treatments, respectively; i.e., the LT stimulated greater NEP than the Con and HT treatments. While these results show that thinning decreases total C storage of forests, proper thinning enhances carbon uptake capacity. In addition, this study can be a basic reference for the effects of thinning on forest carbon cycles. Repeated measurements of each C pool should be performed over multiple years to see the exact movement patterns of forest carbon in the future

Effects of Forest and Agriculture Land Covers on Organic Carbon Flux Mediated through Precipitation

Carbon stored on land is discharged into rivers through water flow, which is an important mechanism for energy transfer from land to river ecosystems. The goal of this study was to identify the relationship between land cover and carbon flux mediated through precipitation. In order to clarify the general relationship, research was conducted on a range of national scales. Eighty-two watershed samples from an area where the urban land cover area was less than 10% and with a water-quality measurement point at an outlet were delineated. Carbon flux and soil organic carbon of the watershed was estimated using the Soil and Water Assessment Tool model, Forest Biomass and Dead Organic Matter Carbon model, and other data. Finally, the data were analyzed to determine the relationship between soil organic carbon and carbon flux. As a result, it was concluded that the carbon flux of the watershed increased with increasing area of the watershed. Under the same area condition, it was revealed that the greater the forest soil organic carbon, the less the carbon flux released from the watershed. Through this study, it was observed that as the above-ground biomass of forest increased, the carbon flux from watershed to river outlet decreased logarithmically

Restoration Plan for Degraded Forest in The Democratic People’s Republic of Korea Considering Suitable Tree Species and Spatial Distribution

The ecosystem across the Democratic People’s Republic of Korea (DPRK) is threatened by deforestation. However, there is very little attention being given to government efforts for afforestation and rehabilitation plan. The most significant barriers to addressing this problem are technique limitations, availability of information, and lack of a stepwise forest management plan. This study identifies spatially suitable tree species, and establishes a stepwise restoration plan to support decision making for restoring degraded forest in the DPRK throughout a suitable restoration map. First off, target species were chosen from reference data, and spatial distribution maps for each tree species were prepared based on social needs as well as natural conditions in the DPRK. The suitable restoration map was calculated by two priorities in a weighting method; suitable priority, and distributional clustering level. Finally, the 23 afforestation species were selected for the suitable restoration map, including 11 coniferous and 12 deciduous tree species. We introduced a stepwise afforestation/restoration plan of degraded forest in the DPRK; general (long-term), detailed (medium-term), implementation (short-term) plans. Maps with different spatial resolutions were prepared for each of the plans. A restoration map with 12.5 km spatial resolution can be used for the general plan at the national level, and maps with 5 km and 1 km spatial resolutions can be used for detailed plan at the local level and implementation plan at the site level, respectively

Observation of photon-induced W+W??? production in pp collisions at TeV using the ATLAS detector

This letter reports the observation of photon-induced production of W -boson pairs, γγ→WW . The analysis uses 139 fb −1 of LHC proton–proton collision data taken at s=13 TeV recorded by the ATLAS experiment during the years 2015–2018. The measurement is performed selecting one electron and one muon, corresponding to the decay of the diboson system as WW→e±νμ∓ν final state. The background-only hypothesis is rejected with a significance of well above 5 standard deviations consistent with the expectation from Monte Carlo simulation. A cross section for the γγ→WW process of 3.13±0.31(stat.)±0.28(syst.) fb is measured in a fiducial volume close to the acceptance of the detector, by requiring an electron and a muon of opposite signs with large dilepton transverse momentum and exactly zero additional charged particles. This is found to be in agreement with the Standard Model prediction