scholarly journals Quantification of One-Year Gypsy Moth Defoliation Extent in Wonju, Korea, Using Landsat Satellite Images

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 545
Author(s):  
Won-IL Choi ◽  
Eun-Sook Kim ◽  
Soon-Jin Yun ◽  
Jong-Hwan Lim ◽  
Ye-Eun Kim
Keyword(s):  
Gypsy Moth ◽  
Satellite Images ◽  
Canopy Cover ◽  
Japanese Larch ◽  
Forest Damage ◽  
Larix Kaempferi ◽  
Moisture Index ◽  
Landsat Images ◽  
Host Preferences ◽  
Landsat Satellite

We quantified the extent and severity of Asian gypsy moth (Lymantria dispar) defoliation in Wonju, Korea, from May to early June in 2020. Landsat images were collected covering Wonju and the surrounding area in June from 2017 to 2020. Forest damage was evaluated based on differences between the Normalized Difference Moisture Index (NDMI) from images acquired in 8 June 2020 and the prior mean NDMI estimated from images in June from 2017 to 2019. The values of NDMI ranged from −1 to 1, where values closer to 1 meant higher canopy cover. The NDMI values for 7825 ha of forests were reduced by more than 0.05 compared to the mean NDMI values for the prior 3 years (2017 to 2019). The NDMI values of 1350 ha of forests were reduced by >0.125 to 0.2, and the NDMI values for another 656 ha were reduced by more than 0.2. A field survey showed that these forests were defoliated by gypsy moth and that forests with NDMI reductions of more than 0.2 were heavily defoliated by gypsy moth. A 311 ha area of Japanese larch (Larix kaempferi) was severely damaged by gypsy moth and the proportion of larch damaged was higher than that of other tree species. This intense damage to larch suggests that gypsy moths preferentially attack Japanese larch in Wonju. Our study shows that the use of NDMI values to detect areas defoliated by gypsy moth from satellite images is effective and can be used to measure other characteristics of gypsy moth defoliation events, such as host preferences under field conditions.

scholarly journals Snow Cover and Snow Persistence Changes in the Mocho-Choshuenco Volcano (Southern Chile) Derived From 35 Years of Landsat Satellite Images

2021 ◽  
Vol 9 ◽  
Author(s):  
Roberto O. Chávez ◽  
Verónica F. Briceño ◽  
José A. Lastra ◽  
Daniel Harris-Pascal ◽  
Sergio A. Estay
Keyword(s):  
Snow Cover ◽  
Satellite Images ◽  
Remote Sensing Data ◽  
Landsat Images ◽  
Microbial Composition ◽  
Mountain Areas ◽  
Pixel Resolution ◽  
Temperature Changes ◽  
Soil Microbial ◽  
Landsat Satellite

Mountain regions have experienced above-average warming in the 20th century and this trend is likely to continue. These accelerated temperature changes in alpine areas are causing reduced snowfall and changes in the timing of snowfall and melt. Snow is a critical component of alpine areas - it drives hibernation of animals, determines the length of the growing season for plants and the soil microbial composition. Thus, changes in snow patterns in mountain areas can have serious ecological consequences. Here we use 35 years of Landsat satellite images to study snow changes in the Mocho-Choshuenco Volcano in the Southern Andes of Chile. Landsat images have 30 m pixel resolution and a revisit period of 16 days. We calculated the total snow area in cloud-free Landsat scenes and the snow frequency per pixel, here called “snow persistence” for different periods and seasons. Permanent snow cover in summer was stable over a period of 30 years and decreased below 20 km2 from 2014 onward at middle elevations (1,530–2,000 m a.s.l.). This is confirmed by negative changes in snow persistence detected at the pixel level, concentrated in this altitudinal belt in summer and also in autumn. In winter and spring, negative changes in snow persistence are concentrated at lower elevations (1,200–1,530 m a.s.l.). Considering the snow persistence of the 1984–1990 period as a reference, the last period (2015–2019) is experiencing a −5.75 km2 reduction of permanent snow area (snow persistence > 95%) in summer, −8.75 km2 in autumn, −42.40 km2 in winter, and −18.23 km2 in spring. While permanent snow at the high elevational belt (>2,000 m a.s.l.) has not changed through the years, snow that used to be permanent in the middle elevational belt has become seasonal. In this study, we use a probabilistic snow persistence approach for identifying areas of snow reduction and potential changes in alpine vegetation. This approach permits a more efficient use of remote sensing data, increasing by three times the amount of usable scenes by including images with spatial gaps. Furthermore, we explore some ecological questions regarding alpine ecosystems that this method may help address in a global warming scenario.

scholarly journals A aplicação de imagens LANDSAT e magnetometria como suporte a estudos geocronológicos dos terrenos Paleo e Mesoproterozóicos do SW do craton Amazônico.

2020 ◽  
Vol 13 (2) ◽  
pp. 798
Author(s):  
Armando Dias Tavares Jr. ◽  
Mauro César Geraldes ◽  
Neivaldo Castro ◽  
Miguel Angelo Mane ◽  
Marcelo Dos Santos Salomão ◽  
...  
Keyword(s):  
Satellite Images ◽  
Image Interpretation ◽  
Geological Mapping ◽  
Vegetation Coverage ◽  
Landsat Images ◽  
Intrusive Rocks ◽  
Amazonian Craton ◽  
Age Appropriate ◽  
Landsat Satellite

O relevo é a base onde todas as populações vivem e desenvolvem suas atividades, derivando dessa relação vantagens e desvantagens, daí a importância de conhecê-lo através do estudo de suas diferentes formas e elementos. Nesse contexto insere-se a importância de metodologias para o seu estudo, sendo que atualmente vivencia-se a expressividade de dados disponíveis para aplicação de geoprocessamento. A partir das geotecnologias pode-se empreender diversas análises sobre o relevo, destacando-se nesse contexto, a proposta dos geomorphons a qual foi aplicada na bacia hidrográfica do arroio Pantanoso. O objetivo da pesquisa é a identificação e análise dos elementos do relevo definido por geomorphons, quais sejam: 1) Planos, 2) Picos, 3) Cristas, 4) Ressaltos, 5) Crista secundária, 6) Encostas, 7) Escavado, 8) Base de encosta, 9) Vales e 10) Fosso. A determinação dos geomorphons foi a partir do processamento em ambiente SIG do Modelo Digital de Elevação (MDE) do Shuttle Radar Topograph Mission (SRTM) com resolução espacial 3 arcsec (90 metros), “L” Lookup (distância em metros) definiu-se como de 20 pixels (1800 metros) e o “T” Theresholdt (nivelamento em graus) definiu-se em 2º. Para visualização do comportamento dos elementos do relevo na área de estudo realizaram-se trabalhos de campo, o que contribuiu para evidenciar a padronização desses elementos. Os quatro elementos geomorphons mais representativos são encostas, vales, cristas e planos.Palavras–Chave: SIG; Geomorphons; Canguçu-RS; Relevo  The application of LANDSAT images and magnetometry as support for geochronological studies of paleo and mesoproterozoic terrains of the SW of the Amazonian craton A B S T R A C TThematic compositions obtained from LANDSAT satellite images were used together magnetometric survey to support the geochronology and paleogeography in the SW region of the Amazon craton. The elaboration of thematic images with characterization of homologous zones allowed the correlation of these areas with terranes with geological evolution previously characterized by U-Pb and Sm-Nd methods.The delimitation of the terranes allowed the planning of sampling of selected form between central and bordering areas of the lands. In this way the thermochronological studies allow the identification of the ages of cooling and collision between these lands. In addition, the identification of structures generated by intrusive rocks in sediments of the Aguapeí Group allowed the location of sampling points of age - appropriate mafic rocks for paleogeographic studies on Amazon craton at the end of Mesoproterozoic.The multi-band LANDSAT images combined with magnetometry proved to be a useful tool in geological research in regions with difficult access and extensive vegetation coverage such as the Amazon craton. In this sense, the elaboration of images in the scale 1: 50,000 was adequate with the resolution (pixel) of 30 meters which can be used as support basic geological mapping as reported in this work.Keywords: Satellite images, image interpretation, geochronology, magnetometry 

scholarly journals EVALUATING GLACIER DYNAMICS USING TEMPORAL REMOTE SENSING IMAGES: A CASE STUDY OF HUNZA VALLEY, NORTHERN PAKISTAN

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 1781-1785
Author(s):  
M. Shafique ◽  
B. Faiz ◽  
A. Bacha
Keyword(s):  
Satellite Images ◽  
Temporal Dynamics ◽  
Drainage Network ◽  
Northern Pakistan ◽  
Remote Sensing Images ◽  
Landsat Images ◽  
Glacier Dynamics ◽  
Landsat Satellite ◽  
The Impact

<p><strong>Abstract.</strong> Glaciers are the major source of water for drainage network. Northern Pakistan is hosting some of the largest and longest glaciers. Studies evaluating the temporal dynamics of glaciers in Pakistan shows contradictory results of retreat, stable of advancing behavior. Aim of the present study is to evaluate the temporal dynamics in three glaciers in northern Pakistan, using Landsat satellite images. The Landsat images for the years of 1977, 1999, 2001, 2007, 2009 and 2014 shows retreat in selected Hispar, Birpu and Bualtar glaciers. To evaluate the impact of weather indicators of the glaciers dynamics, the temporal glaciers inventories were compared with the rainfall and temperature for the corresponding years. This study should assist to understand the glaciers dynamics and future climate of the region.</p>

scholarly journals Forest Degradation Associated with Logging Frontier Expansion in the Amazon: The BR-163 Region in Southwestern Pará, Brazil

2016 ◽  
Vol 20 (17) ◽  
pp. 1-26 ◽  
Author(s):  
T. F. Pinheiro ◽  
M. I. S. Escada ◽  
D. M. Valeriano ◽  
P. Hostert ◽  
F. Gollnow ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Forest Fire ◽  
Forest Fires ◽  
Canopy Cover ◽  
Degradation Process ◽  
Forest Degradation ◽  
Selective Logging ◽  
Forest Damage ◽  
Landsat Images ◽  
Logged Forest

Abstract Forest degradation is the long-term and gradual reduction of canopy cover due to forest fire and unsustainable logging. A critical consequence of this process is increased atmospheric carbon emissions. Although this issue is gaining attention, forest degradation in the Brazilian Amazon has not yet been properly addressed. The claim here is that this process is not constant throughout Amazonia and varies according to colonization frontiers. Moreover, the accurate characterization of degradation requires lengthy observation periods to track gradual forest changes. The forest degradation process, the associated timeframe, spatial patterns, trajectories, and extent were characterized in the context of the Amazon frontiers of the 1990s using 28 years (1984–2011) of annual Landsat images. Given the large database and the characteristic of logging and burning, this study used data mining techniques and cell approach classification to analyze the spatial patterns and to construct associated trajectories. Multitemporal analysis indicated that forest degradation in the last two decades has caused as many interannual landscape changes as have clear-cuts. In addition, selective logging, as a major aspect of forest degradation, affected a larger amount of forest land than did forest fire. Although a large proportion of logged forest was deforested in the following years, selective logging did not always precede complete deforestation. Instead, the results indicate that logged forests were abandoned for approximately 4 years before clearance. Throughout the forest degradation process, there were no recurrent forest fires, and loggers did not revisit the forest. Forest degradation mostly occurred as a result of a single selective logging event and was associated with low-intensity forest damage.

scholarly journals Icings of the Indigirka river basin according to the recent Landsat satellite images and historical data

2019 ◽  
Vol 59 (2) ◽  
pp. 201-212 ◽  
Author(s):  
О. M. Makarieva ◽  
A. N. Shikhov ◽  
A. A. Ostashov ◽  
N. V. Nesterova
Keyword(s):  
River Basin ◽  
Satellite Images ◽  
Historical Data ◽  
No Reduction ◽  
Landsat Images ◽  
The Past ◽  
North East ◽  
The North ◽  
Left Tributary ◽  
Landsat Satellite

The paper presents methods and results of creation of the digital catalogue of aufeises for the Indigirka river basin made on the basis of Landsat images and historical data. The region under study is the basin before the hydrometric section of GMS Vorontsovo, its area is about 305 000 km2. Historical data were taken from the Inventory of naleds of the North-East of the USSR territory published in 1958 and topographic maps. It includes the estimated coordinates and characteristics of 897 aufeises with total area of 2064 km2. The Landsatbased identification of aufeises for 2013–2017 allowed making description of 1213 aufeises over a total area of 1287 km2. The integrated digital catalogue of the aufeises for the Indigirka river basin based on combination of the above two sources is available at https://issues.pangaea.de/browse/PDI-17699. 10% of the largest aufeises make up about 60% of the total area of all aufeises according to both sources. The largest number of aufeises is at altitudes of 900–1300 m. The interannual variability of area of the aufeises for the period 2001-2016 was estimated by the example of the Bolshaya Momskaya naled and the group of large aufeises in the basin of the Syuryukty River which is the left tributary of the Indigirka. The conclusions cannot be considered unambiguous due to certain limitations of the imagery data but the results of the analysis is indicative of a tendency to decreasing in the area of the Bolshaya Momskaya naled in recent years, while no reduction in the aufeis area is noted in the basin of the Syuryukty River. The main results of this work are the new geodatabase of the aufeises in the Indigirka river basin, and also the comparison of the satellite observations with historical data performed for two major naleds. It is established that the satellite-estimated total area of aufeises is 1.6 times less than in the Cadastre (1958). At the same time, it was found that more than 600 aufeises recognized by the Landsat images were absent in the Cadastre of 1958. This may suggest that either the Cadastre data is incomplete or that conditions of the aufeis can be significantly changed over the past 50 years.

Multitemporal distribution analysis of Dodonaea viscosa (L.) Jacq. by remote sensing in Durango, Mexico

2020 ◽  
Vol 13 (8) ◽  
Author(s):  
Marco, A. Márquez-Linares ◽  
Jonathan G. Escobar--Flores ◽  
Sarahi Sandoval- Espinosa ◽  
Gustavo Pérez-Verdín
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Design Methodology ◽  
Supervised Classification ◽  
Satellite Images ◽  
Ground Cover ◽  
Distribution Analysis ◽  
Dodonaea Viscosa ◽  
Artificial Neural ◽  
Landsat Satellite

Objective: to determine the distribution of D. viscosa in the vicinity of the Guadalupe Victoria Dam in Durango, Mexico, for the years 1990, 2010 and 2017.Design/Methodology/Approach: Landsat satellite images were processed in order to carry out supervised classifications using an artificial neural network. Images from the years 1990, 2010 and 2017 were used to estimate ground cover of D. viscosa, pastures, crops, shrubs, and oak forest. This data was used to calculate the expansion of D. viscosa in the study area.Results/Study Limitations/Implications: the supervised classification with the artificial neural network was optimal after 400 iterations, obtaining the best overall precision of 84.5 % for 2017. This contrasted with the year 1990, when overall accuracy was low at 45 % due to less training sites (fewer than 100) recorded for each of the land cover classes.Findings/Conclusions: in 1990, D. viscosa was found on only five hectares, while by 2017 it had increased to 147 hectares. If the disturbance caused by overgrazing continues, and based on the distribution of D. viscosa, it is likely that in a few years it will have the ability to invade half the study area, occupying agricultural, forested, and shrub areas

scholarly journals Complete Chloroplast Genome of Japanese Larch (Larix kaempferi): Insights into Intraspecific Variation with an Isolated Northern Limit Population

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 884
Author(s):  
Shufen Chen ◽  
Wataru Ishizuka ◽  
Toshihiko Hara ◽  
Susumu Goto
Keyword(s):  
Chloroplast Genome ◽  
Intraspecific Variation ◽  
Japanese Larch ◽  
Monophyletic Group ◽  
Phylogenetic Position ◽  
Larix Kaempferi ◽  
Northern Limit ◽  
Complete Chloroplast Genome ◽  
Intraspecific Variations ◽  
Cpdna Markers

Research Highlights: The complete chloroplast genome for eight individuals of Japanese larch, including from the isolated population at the northern limit of the range (Manokami larch), revealed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed in Japanese larch. We detected intraspecific variation for possible candidate cpDNA markers in Japanese larch. Background and Objectives: The natural distribution of Japanese larch is limited to the mountainous range in the central part of Honshu Island, Japan, with an isolated northern limit population (Manokami larch). In this study, we determined the phylogenetic position of Manokami larch within Japanese larch, characterized the chloroplast genome of Japanese larch, detected intraspecific variation, and determined candidate cpDNA markers. Materials and Methods: The complete genome sequence was determined for eight individuals, including Manokami larch, in this study. The genetic position of the northern limit population was evaluated using phylogenetic analysis. The chloroplast genome of Japanese larch was characterized by comparison with eight individuals. Furthermore, intraspecific variations were extracted to find candidate cpDNA markers. Results: The phylogenetic tree showed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed, based on the complete chloroplast genome, with a bootstrap value of 100%. The value of nucleotide diversity (π) was calculated at 0.00004, based on SNP sites for Japanese larch, suggesting that sequences had low variation. However, we found three hyper-polymorphic regions within the cpDNA. Finally, we detected 31 intraspecific variations, including 19 single nucleotide polymorphisms, 8 simple sequence repeats, and 4 insertions or deletions. Conclusions: Using a distant genotype in a northern limit population (Manokami larch), we detected sufficient intraspecific variation for the possible candidates of cpDNA markers in Japanese larch.

scholarly journals Withdrawal Properties of Self-Tapping Screws in Japanese larch (Larix kaempferi (Lamb.) Carr.) Cross Laminated Timber

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 524
Author(s):  
Junhua Xu ◽  
Shuangbao Zhang ◽  
Guofang Wu ◽  
Yingchun Gong ◽  
Haiqing Ren
Keyword(s):  
Regression Model ◽  
Engineering Design ◽  
Wood Species ◽  
Japanese Larch ◽  
Effective Length ◽  
Larix Kaempferi ◽  
Cross Laminated Timber ◽  
The World ◽  
Different Types ◽  
Length Increment

With the increasing popularity of cross-laminated timber (CLT) constructions around the world, there have been attempts to produce CLT using local wood species in different countries, such as Japanese larch (Larix kaempferi (Lamb.) Carr.) in China. Thus, the need to investigate the connection performance also increases to support the design and construction of CLT buildings using local wood species. In this study, the withdrawal properties of three different types of self-tapping screws (STS), with a diameter of 6 mm, 8 mm, and 11 mm, were tested with Japanese larch CLT. The results revealed that the withdrawal strength of STS increased with increasing density and effective length, but decreased with an increasing diameter. With a density increment of 0.05 g/cm3, the withdrawal strength increased by an average of 9.4%. With an effective length increment of 24 mm, the withdrawal strength increased by an average of 1.4%. An empirical regression model was adopted to predict the withdrawal strength of Japanese larch CLT based on the results, which can be used for potential engineering design of CLT connections using STS.

EVALUATION OF A MODEL TO ESTIMATE NET RADIATION OVER A DRIP-IRRIGATED OLIVE ORCHARD USING LANDSAT SATELLITE IMAGES

2014 ◽  
pp. 309-314 ◽  
Author(s):  
S. Ortega-Farías ◽  
S. Ortega-Salazar ◽  
R. Aguilar ◽  
D. De la Fuente ◽  
F. Fuentes
Keyword(s):  
Satellite Images ◽  
Net Radiation ◽  
Olive Orchard ◽  
Landsat Satellite
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