Center Of Plot Research Articles

The Magic Realist Unconscious: Twain, Yamashita and Jackson

The literary topic of Siamese twins is not unfamiliar. American literary history tells us of the genealogy from Mark Twain’s pseudo-antebellum story The Tragedy of Pudd’nhead Wilson and the Comedy Those Extraordinary Twins (1894), Karen Tei Yamashita’s postmodern metafiction “Siamese Twins and Mongoloids: Cultural Appropriation and the Deconstruction of Stereotype via the Absurdity of Metaphor” (1999), down to Shelley Jackson’s James Tiptree, Jr. award winner Half-Life (2006). Rereading these works, we are easily invited to notice the political unconscious hidden deep within each plot: Twain’s selection of the Italian Siamese twins based upon Chang and Eng Bunker, antebellum stars of the Barnum Museum, cannot help but recall the ideal of the post-Civil War world uniting the North and the South; Yamashita’s figure of the conjoined twins Heco and Okada derives from Hikozo Hamada, an antebellum Japanese who made every effort to empower the bond between Japan and the United States, and John Okada, the Japanese American writer well known for his masterpiece No No Boy (1957); and Jackson’s characterization of the female conjoined twins Nora and Blanche Olney represents a new civil rights movement in the post-Cold War age in the near future, establishing a close friendship between the humans and the post-humans. This literary and cultural context should convince us that Yamashita’s short story “Siamese Twins and Mongoloids” serves as a kind of singularity point between realist twins and magic realist twins. Influenced by Twain’s twins, Yamashita paves the way for the re-figuration of the conjoined twins not only as tragi-comical freaks in the Gilded Age but also as representative men of magic realist America in our Multiculturalist Age. A Close reading of this metafiction composed in a way reminiscent of Jorge Luis Borges, Stanislaw Lem and Bruce Sterling will enable us to rediscover not only the role conjoined twins played in cultural history, but also the reason why Yamashita had to feature them once again in her novel I Hotel (2010) whose plot centers around the Asian American civil rights movement between the 1960s and the 1970s. Accordingly, an Asian American magic realist perspective will clarify the way Yamashita positioned the figure of Siamese Twins as representing legal and political double standards, and the way the catachresis of Siamese Twins came to be naturalized, questioned and dismissed in American literary history from the 19th century through the 21st century.

Ecology of Persian Walnut (Juglans regia L.) in Western Bhutan

In Bhutan the Persian Walnut (Juglans regia L.) is highly valued for its timber and is listed under special class in Royalty on Forest Products of Bhutan. Possessing high timber and other medicinal values, the ecology of the species in the country was poorly understood. The study aimed to understand the ecological requirements and habitat modeling of the species in Bhutan. A purposive non-probability sampling was adopted in natural habitats of the species in four districts (Gasa, Punakha, Wangdue Phodrang, and Dagana) of the country. Plot size of 20 m X 20 m (major plot) for tree and understory and 2 m X 2 m for ground cover were used to collect vegetation data. Soil samples were collected from the center of the major plot at a depth of 25 - 30 cm. A total of 163 plant species belonging to 74 families were recorded from the study plots. Pearson and Kendal correlation of CCA Ordination showed moderate influence of slope (r = .66) followed by altitude (r =.55). Annual mean temperature and rainfall showed moderately negative correlation with the growth and distribution of J. regia (r =. -54 and -.64) in the study area. Despite, scattered distribution of J. regia in the country an area of 7146.53 km2 which accounts for 18.61% of the country’s total area was found to be suitable for the growth and development of the species which can be used for protection and management of species in future.

Effect of Forest Management on Carbon Stock of Tropical Moist Afromontane Forest

Moist tropical forests have a significant role in provisioning and regulating ecosystem services. However, these forests are under threat of deforestation and forest degradation. In Ethiopia, the moist evergreen Afromontane forests have the potential for carbon storage and support a high diversity of plant species. However, it is under severe threat of deforestation and degradation.This investigation was conducted to obtain adequate information on the carbon stock potential of the moist Afromontane forest of southwestern Ethiopia. A comparison of carbon stock was conducted between disturbed and undisturbed forests. A systematic sampling design was applied for recording woody species and soil data. A total of 100 main plots of 400 m2 were laid to record trees and shrubs with a diameter at breast height (DBH) ≥ 5 cm. The soil data were collected from 1 m2 subplots established at the four corners and the center of each main plot. The DBH and height were measured to calculate the aboveground carbon of trees and shrubs with DBH ≥ 5 cm. A total of 68 tree and shrub species belonging to 59 genera and 33 families were recorded. The mean carbon stock density was 203.80 ± 12.38 t·ha–1 (aboveground carbon stock) and 40.76 ± 2.47 t·ha–1 (belowground carbon stock). The highest proportion of aboveground carbon (t·ha–1) (42.34%) was contributed by a few tree individuals with DBH > 70 cm. The soil organic carbon stock (SOCS) (t·ha–1) for the depth of 0–30 cm is ranging from 58.97 to 198.33 across plots; the mean is 117.16 ± 3.15. The carbon stored in the moist Afromontane forest indicates its huge potential for climate change mitigation. Therefore, for the enhancement of forest biodiversity and carbon sequestration effective conservation measure and sound management approach is essential.

Segmentation of conifer tree crowns from terrestrial laser scanning point clouds in mixed stands of Scots pine and Norway spruce

Terrestrial laser scanning of conifer tree crowns is challenged by occlusion problems causing sparse point clouds for many trees. Automatic segmentation of conifer tree crowns from sparse point clouds is a task that has only recently been addressed and not solved in a way that all trees can be segmented automatically without assignment errors. We developed a new segmentation algorithm that is based on region growing from seeds in voxelized 3D laser point clouds. In our data, field measured tree positions and diameters were available as input data to estimate crown cores as seeds for the region growing. In other applications, these seeds can be derived from the laser point cloud. Segmentation success was judged visually in the 3D voxel clouds for 1294 tree crowns of Norway spruce and Scots pine on 24 plots in six mixed species stands. Only about half of the tree crowns had only minor or no segmentation errors allowing to fit concentric crown models. Segmentation errors were most often caused by unsegmented neighbors at the edge of the sample plots. Wrong assignments of crown parts were also more frequent in dense groups of trees and for understory trees. For some trees, point clouds were too sparse to describe the crown. Segmentation success rates were considerably higher for dominant trees in the plot center. Despite the incomplete automatic segmentation of tree crowns, metrics describing crown size and crown shape could be derived for a large number of sample trees. A description of the irregular shape of tree crowns was not possible for most trees due to the sparse point clouds in the upper crown of most trees.

Using an unmanned aerial system to analyse environmental impacts of charcoal production on tropical savanna ecosystems in northwestern Kenya

In many regions of Sub-Saharan Africa, charcoal plays an important role as energy source but is widely perceived as a major driver of deforestation and forest degradation. This narrative, however, is mostly based on research within primary production regions. Though space-borne remote sensing applications can be useful in monitoring such large-scale production modes, environmental effects of household-level production are less easy to assess. Therefore, the present study employs an unmanned aerial system (UAS) to assess the impact of small-scale charcoal production on the vegetation density in the immediate vicinity of production sites. The UAS data was complemented by field measurements and very high-resolution WordView-2 satellite imagery. This approach revealed only small differences between charcoal production sites and reference plots which were usually evened out after 20–25-m distance to the plot centre using a concentric ring analysis. Results further show that a distinction between different land-use practices is difficult, even with the high spatial resolution provided by a UAS. Thus, more research and new approaches are needed to evaluate the role of small-scale charcoal production in deforestation and forest degradation processes against the background of other human activities. However, to exploit the full potential of UAS for monitoring environmental effects in charcoal producing areas, official regulations need to be clearer and more reliable.

Diversity and species composition of ants at coffee agroforestry systems in East Java, Indonesia: Effect of habitat condition and landscape composition

Abstract. Muhammad FN, Rizali A, Rahardjo BT. 2022. Diversity and species composition of ants at coffee agroforestry systems in East Java, Indonesia: Effect of habitat condition and landscape composition. Biodiversitas 23: 3313-3321. Habitat condition and landscape composition are the main factors that shape biodiversity in agroecosystems. However, information on the effect of habitat conditions and landscape composition on biodiversity in agroforestry systems is lacking. Agroforestry systems possess habitats that are characterized by a high diversity of vegetation, that can support biodiversity both on the field or landscape scale. This research aimed to study the diversity and species composition of ants in coffee (Coffea spp.) agroforestry systems, and to investigate the effects of habitat conditions and landscape composition on ant communities. Field research was conducted in twelve coffee agroforestry systems in East Java, Indonesia. Ants were sampled with the fogging method for canopy ants and pitfall traps for ground-dwelling ants in 40 m x 30 m plots. In each location, habitat conditions aspects (such as cultural technique and tree age) were identified by interviews with farmers and vegetation observation. Meanwhile, landscape composition was characterized by ground checking and mapping the land-use type within a 500 m radius from plot centers. This research recorded 35 species and 4,622 individuals of ants from all coffee plantations. Dolichoderus thoracicus was the most dominant canopy ant, while Pheidole sp.2 was the most dominant ground-dwelling ant in all plantations. Based on the GLM analysis, different responses were found between canopy and ground-dwelling ants in relation to habitat conditions and landscape composition. Canopy and ground-dwelling ants were affected by habitat conditions (such as tree age and canopy cover). The species composition of ground-dwelling ants was also affected by habitat conditions. In conclusion, habitats in coffee plantations can affect ant communities with ground-dwelling ants being more sensitive than canopy ants. Meanwhile, landscape composition can affect the species richness of all ants and not affect each stratum (canopy and ground-dwelling ants).

Density effect on decline of Cedrus atlantica Manetti Ex Carriere in national park of Theniet El Had, Algeria

This study focuses on the study of the causal factors of Atlas cedar decline in the Theniet el Had national park, once classified as the first park in Algeria and the most beautiful cedar forest in northern Africa. Although severalstudies have been done on the causative agent of decline, none of them have confirmed the predisposing factors, thus weakening its vigor. Therefore, in this study, the search for possible relationship between dieback and ecological, dendrometric characteristics as well as the spatial distribution of trees were taken into consideration. 40 concentric circular plots of 200, 400, 500 and 1,000 m² were installed in the northern part of the park for dendrometric and edaphic surveys, in addition to rectangular plots of 200 m2 installed in the center of the concentric plots were measured of distance between trees and of the four radii of the crown. The results obtained showed that the circumference in the reduced areas (the circular plots of 200m²) declined significantly. The spatial distribution of the trees, schematized by the AutoCAD software, was chaotic and the crowns showed deterioration influenced by their overlapping. In 76% of the rectangular plots, the maximum area of the crowns had an overlap of more than 90%. The application of Schütz's inter-individual competition index also indicated that competition between trees was very important. This situation only explains the chaotic distribution of the trees, due to the lack of forestry work, imposes a competition between the trees causing, thus, the weakening of their vigor. Therefore, the establishment of a short- and longterm Atlas cedar decline management plan is of high recommended importance, in which adjusting the spatial distribution can promote the future strength and vitality of Atlas cedars.

Diversity and Seasonal Occurrence of Native and Nonnative Ants (Hymenoptera: Formicidae) in Long-Term Experimental Chinese Privet (Lamiales: Oleaceae) Plots in Georgia, USA

Diversity and Seasonal Occurrence of Native and Nonnative Ants (Hymenoptera: Formicidae) in Long-Term Experimental Chinese Privet (Lamiales: Oleaceae) Plots in Georgia, USA

First occurrence of <i>Halyomorpha halys</i> in Bordeaux vineyards

Here we report the first detection of Halyomorpha halys (Stål, 1855) in Bordeaux vineyards. The species is native to Eastern Asia and was introduced to France in 2012. Halyomorpha halys is highly polyphagous and causes significant damage to various crops, including grapevines. From 2018 to 2020, Pentatomidae species were collected in vineyards in the Bordeaux region. In 2020, the first nymphs and adults of H. halys were identified in the plot centres. The study emphasizes the need for field population monitoring in risk assessment and, consequently, risk management.

Distribution analysis of wild medicinal plants in Ada'a District, Ethiopia: A means to identify most prior species for conservation

In Ethiopia, traditional medicinal plants have been in use since time immemorial and they were the only existing means for health care of the people before the introduction of allopathic medicine. The majority of these plants are originated from wild habitats. By now these medicinal species are highly degraded due to environmental degradation, agricultural expansion, deforestation, and over-harvesting of species. There is a need to practice conservation activities on target species at the local and/or district level to ensure the continuity of medicinal plants. One possible way for achieving this is through distribution analysis of species, which is a central concept in conservation management. Distribution analysis addresses identifying species in a community; how abundant and frequent is each species? And how do the species interact? The present study aimed to assess the degree of occurrences and spatial distribution of the medicinal plants in Ada'a District. A total of 59 study plots with the size of 20 × 20 m were laid randomly on the different land-use types of the District for collecting tree medicinal species. A sub-plot of 5 × 5 m was located in the center of each plot for recording shrubby medicinal plants whereas five 1 × 1 m subplots, four of which were on the corners and one in the center of the main plots were used for recording herbaceous medicinal plant species. The density of each plant species was recorded by counting the number of individuals. Frequency was calculated as the percentage of sub-plots that included the target species. Frequency, abundance, density, and abundance-frequency (AB/F) ratio were estimated. Sorensen similarity index was applied to quantify the floristic similarity of the study area with the other areas in Ethiopia. Results showed that most of the medicinal plants (82%) are locally rare; therefore they need to be domesticated. Moreover, some of these locally species are found only in Ethiopia (i.e. endemic species), thus they registered in the IUCN Red List of Ethiopia. They are highly endangered species that must be among the top priority for conservation urgency in this district.

Metabarcoding of canopy arthropods reveals negative impacts of forestry insecticides on community structure across multiple taxa

Abstract Insecticides used to combat outbreaks of forest defoliators can adversely affect non‐target arthropods. Forestry insecticides typically suppress Lepidoptera larvae which are the cornerstone of the canopy community of deciduous oak forests. The abrupt removal of this dominant component of the food web could have far‐reaching implications for forest ecosystems, yet it is rarely investigated in practice owing to several methodological shortcomings. The taxonomic impediment and the biased nature of arthropod sampling techniques particularly impede the assessment of insecticide impacts on diverse communities. To tackle this issue, we propose an experimental approach combining sampling by pyrethrum knockdown and species determination via DNA metabarcoding, using community subsampling to derive estimates of species abundances. We applied this protocol to investigate the short‐term effects of the insecticides diflubenzuron (DFB) and Bacillus thuringiensis var. kurstaki (BTK) on canopy‐dwelling arthropod communities in German oak woodlands. Our approach allowed us to detect most of the diversity and integrate species abundances in our analyses. By classifying arthropod species into assemblages based on their expected sensitivity rather than coarse taxonomic groupings, we could unveil substantial effects of DFB across multiple taxa 5 weeks after application. Although strong effects on single species appear related to direct toxicity, substantial impacts of DFB on parasitoids and xylophagous beetles suggest that anti‐defoliator treatments can have previously unsuspected indirect effects on some components of forest arthropod communities. The impacts of BTK on community structure were consistent with that of DFB though much weaker. Synthesis and applications. Comparing diversity patterns in the arthropod communities of sprayed and unsprayed oak canopies, our results show that selective insecticides can alter species diversity in presumably non‐sensitive taxa. Even though the ecological significance of these impacts has yet to be assessed in an operational setting, their existence calls for increased regulatory scrutiny on indirect effects. As community approaches become more attainable with the rapid development of DNA metabarcoding, we suggest the inclusion of community‐level end points as regulatory requirements for the approval of forest‐use insecticides.

A Semi-Automatic Workflow to Extract Irregularly Aligned Plots and Sub-Plots: A Case Study on Lentil Breeding Populations

Plant breeding experiments typically contain a large number of plots, and obtaining phenotypic data is an integral part of most studies. Image-based plot-level measurements may not always produce adequate precision and will require sub-plot measurements. To perform image analysis on individual sub-plots, they must be segmented from plots, other sub-plots, and surrounding soil or vegetation. This study aims to introduce a semi-automatic workflow to segment irregularly aligned plots and sub-plots in breeding populations. Imagery from a replicated lentil diversity panel phenotyping experiment with 324 populations was used for this study. Image-based techniques using a convolution filter on an excess green index (ExG) were used to enhance and highlight plot rows and, thus, locate the plot center. Multi-threshold and watershed segmentation were then combined to separate plants, ground, and sub-plot within plots. Algorithms of local maxima and pixel resizing with surface tension parameters were used to detect the centers of sub-plots. A total of 3489 reference data points was collected on 30 random plots for accuracy assessment. It was found that all plots and sub-plots were successfully extracted with an overall plot extraction accuracy of 92%. Our methodology addressed some common issues related to plot segmentation, such as plot alignment and overlapping canopies in the field experiments. The ability to segment and extract phenometric information at the sub-plot level provides opportunities to improve the precision of image-based phenotypic measurements at field-scale.

The Residual Copper and Zinc in Tropical Soil over 21 Years after Amendment with Heavy Metal Containing Waste, Lime, and Compost

This research aimed to evaluate the residual Cu and Zn in tropical soil over 21 years after amendment with industrial waste, lime, and compost. Soil samples were collected from a well-maintained experimental field amended one time with industrial waste high in Cu and Zn set in 1998 at about 1.5–20 years after amendment. Treatments were arranged in a randomized block design with a metal-wares industrial waste at rates 0, 15, and 60 Mg·ha−1, lime at 0 and 5 Mg·ha−1, and compost at 0 and 5 Mg·ha−1. Soil samples were also taken vertically in the exact plot centers at depths of 0–75 cm of plots not amended with lime and compost and also from topsoils (0–15 cm) at 90 points with distances 50 cm between each other in each of the respective plots 21 years after amendment. Significant increases in Cu and Zn caused by waste were observed over 21 years. The increase in soil pH by lime was observed over 10 years but its effect in decreasing Cu and Zn was observed only at 1.5 years, particularly in topsoils. However, the effect of lime in lowering Cu and Zn was observed over 20 years when waste and/or compost were also given. Similarly, the effect of compost was absent over 20 years but significant when waste and/or lime were also given. The relative concentration of Cu and Zn in the 60 Mg waste ha−1 plots decreased over 20 years to 17–53% for Cu and to 12–33% for Zn; their concentrations were, in general, lower with lime and/or compost addition. The relative concentrations of Cu and Zn significantly decreased over 21 years in plots with 15 or 60 Mg·ha−1 and increased in the control plots. Heavy metals moved in soil significantly through soil tillage and erosion and partially by leaching.

Effect of Tillage on Agro-morphological Parameters and Yield of Cassava (Manihot esculenta crantz) in Abongoua, East-Central Côte d'Ivoire

The objective of this work is to improve the production and yield of cassava cultivated by tillage. The experiment was conducted in the field for 13 months (June 2019-july 2020) in Abongoua in the department of Bongouanou (East-central Côte d'Ivoire). After the cleaning of a 900 m2 surface of a fallow of more than 5 years, and cleared of all plant debris, soil samples were taken with an auger in the 40 cm surface in each corner and in the center of the experimental plot to constitute the composite sample for laboratory analysis. The trials were conducted in a randomized complete block design with four replicates in which four elementary plots were distributed. Three treatments T1 (tilled soil), T2 (mounded soil) and T3 (ridged soil) compared to a control treatment T0 (no-till soil) were applied in each microplot. The cuttings were directly sown at a rate of 12 cuttings per treatment. The data of the different parameters collected underwent an analysis of variance (ANOVA) performed with SAS software version 9.4 and the means were separated using the Newman and Keuls test at the 5% probability threshold. The results showed an acidic soil with a sandy texture and a good supply of nutrients, particularly major elements, trace elements and clay-humus complex. Good growth and development of agro-morphological parameters as well as yield were obtained with treatments T3 (ridged soil), T2 (mounded soil) and T1 (tilled soil) in decreasing order of importance compared to the control treatment (T0). In conclusion, the study clearly showed that the type of tillage, particularly the ridged tillage technique, improves the agro morphological parameters, productivity and yield of cassava. What we recommend to farmers for a good yield of cassava in the area.

White Grub Adults1 Associated with Maize (Zea mays L.) at Zaachila, Oaxaca, Mexico

Results of a preliminary study on adult scarab beetles (Coleoptera: Scarabaeidae “Pleurosticti”) associated with maize (Zea mays L.) at the municipality of Villa de Zaachila, Oaxaca, Mexico are presented. The objective was to identify species of the white grub complex associated with the crop. Samples were collected each month from March through August 2018. A blacklight trap in the center of the maize plot was used from 1900 to 2300 hours during 3 nights of the new moon period. In total, 1,429 specimens were captured, belonging to 12 species, four genera, four tribes, and three subfamilies of Scarabaeidae. Abundance was greatest in April, coinciding with the start of the rainy season. The genus Anomala Samouelle with five species was most abundant. Anomala flavilla Bates, 1888 was the most abundant species and together with A. sticticoptera Blanchard, 1850 were reported for the first time in the State of Oaxaca. An annotated checklist with data on distribution, elevation, and associated crops was presented. A key was provided for taxonomic identification of the species studied.

The study of parent-regeneration relationships for wild cherry (Prunus avium L.) in Hyrcanian forests

The regeneration of forest trees is affected by the presence, dispersion pattern and specifications of parent trees. These effects were investigated and modelled in hardwood forests in the north of Iran. To do so, at first, fifty plots, each with a total area of 0.1 ha, were identified. Four subplots with a radius of two meters were then stabilized in each plot. The height and the root collar diameter of all the cherry seedlings were measured. Likewise, the diameter, basal area, and distance from the plot centre were appraised in the parent trees. The correlation and regression analyses were performed to evaluate the effects and to construct the models, respectively. The results showed that there was a positive and significant relationship between the presence, abundance, mean diameter, and total basal area of parent trees and the presence and abundance of seedlings. The logistic regression showed that the models based on the mean diameter of parent trees and abundance of parent trees could significantly predict the presence of regeneration. Only in 10% of the sample plots was the regeneration recorded without the presence of a parent tree. Due to the small number of established seedlings, while maintaining the existing parent trees, especially large trees, it is necessary to consider the proper management methods to promote and protect their regeneration. We recommend completing the natural regeneration of wild cherry by artificial regeneration and creating well-dimensioned canopy gaps.

Short-term impacts of winter bale grazing beef cows on forage production and soil nutrient status in the eastern Canadian Prairies

The impact of winter bale grazing on forage productivity and nutrient cycling was determined near Winnipeg, MB, Canada. Variable distribution of nutrients and forage yield within bale-grazed plots on a perennial grass–legume forage field was identified using an intensive grid sampling method. In bale-grazed plots, mean dry matter (DM) yield of forage decreased 68% in year 1 following bale grazing, with no difference in DM yield in year 2 following bale grazing, relative to an untreated control. Decreased yield was attributed to the large mass of waste feed and feces (21% of feed delivered) that remained at the centre of each bale-grazed plot, where each bale was placed. Concentrations of crude protein, total digestible nutrients, phosphorus (P), and potassium in forage increased in the first growing season following winter bale grazing compared with the control, particularly at the centre of each bale-grazed plot. Concentrations of residual nitrate-nitrogen and Olsen P in soil were 15 and 2.5 times greater, respectively, at the centre of the bale-grazed plots compared with untreated control plots. Dispersion of waste feed packs when bale grazing in subhumid climates on clay soils is recommended to minimize smothering and encourage rapid decomposition of waste feed and feces. Long-term studies are needed to determine the potential benefits and risks of bale grazing to forage productivity and soil nutrient status in the eastern Canadian Prairies.

Mathematically optimized trajectory for terrestrial close-range photogrammetric 3D reconstruction of forest stands

Terrestrial close-range photogrammetry offers a low-cost method of three-dimensional (3D) reconstruction of forest stands that provides automatically processable 3D data that can be used to evaluate inventory parameters of forest stands and individual trees. However, fundamental methodological problems in image acquisition and processing remain. This study enhances the methodology of photogrammetric Structure from Motion reconstruction of forest stands by determining the best photographer's trajectory for image acquisition. The study comprises 1) mathematical optimization of the route in a square grid using integer programming, 2) evaluation of point clouds derived from sequences of real photographs, simulating different trajectories, and 3) verification on real trajectories. In a forest research plot, we established a 1 m square grid of 625 (i.e., 25 × 25) photographic positions, and at each position, we captured 16 photographs in uniformly spaced directions. We adopted real tree positions and diameters, and the coordinates of the photographic positions, including orientation angles of captured images, were recorded. We then formulated an integer programming optimization model to find the most efficient trajectory that provided coverage of all sides of all trees with sufficient counts of images. Subsequently, we used the 10,000 captured images to produce image subsets simulating image sequences acquired during the photographer's movement along 84 different systematic trajectories of seven patterns based on either parallel lines or concentric orbits. 3D point clouds derived from the simulated image sequences were evaluated for their suitability for automatic tree detection and estimation of diameters at breast height. The results of the integer programming model indicated that the optimal trajectory consisted of parallel line segments if the camera is pointed forward – in the travel direction, or concentric orbits if the camera is pointed to a side – perpendicular to the travel direction. With point clouds derived from the images of the simulated trajectories, the best diameter estimates on automatically detected trees were achieved with trajectories consisting of parallel lines in two perpendicular directions where each line was passed in both opposite directions. For efficient image acquisition, resulting in point clouds of reasonable quality with low counts of images, a trajectory consisting of concentric orbits, including the plot perimeter with the camera pointed towards the plot center, proved to be the best. Results of simulated trajectories were verified with the photogrammetric reconstruction of the forest stand based on real trajectories for six patterns. The mathematical optimization was consistent with the results of the experiment, which indicated that mathematical optimization may represent a valid tool for planning trajectories for photogrammetric 3D reconstruction of scenes in general.

Ecological study of Sago Palm (Metroxylon sagu Rott ver molat (Becc.)) in the natural habitat at Malili District East Luwu South Sulawesi

Sago palm (Metroxylon sago), a tropical plant which mostly grows naturally and distributed in Eastern Part of Indonesia (including Wallacea Zone). However, currently the existing of sago palm is facing threats for food security in the future due to land conversion and life cycle of sago palm is a long term periode (10 – 15 years). The objective of this research were to: 1) Analyses of population structure of sago palm; 2) Regeneration potency of sago palm; and 3) describe habitat characteristic of sago palm. The research was conducted in April to August 2017 at Wewangriu Village Malili District. The circle plots (each 314 m2) were purpossively established in a lowland sago palm area based on growth phase of sago palm. The pole and tree diameter were measured at breast height (1.30 m) above the trunk, but sapling and seedling were only counted the number of individals. Moreover, environmental factors were measured directly at every center of plot. The result of research showed that population of sago palm in natural habitat was dominated by sapling with 226 individuals, then followed by seedling was 177 individuals. The regeneration potency of sago palm was categorized Fair based on relatif density and relatif frequency. Related to habitat characteristic or microclimate conditions, the temperature was hot and dry with ranged form 28.7°C to 29.5°C. Hydorology parameters such as water pH was about 6.0 to 7.9. Especially soil propeties was dominated by silty clay and clay with slightly acid condition (soil pH 6.2 and 6.3). Maintaining the existence of sago palm, it is necessary to protect and preserve it in the natural habitat.

Validation of a method for in situ determination of 137Cs soil contamination density in kitchen gardens using the portable spectrometer-dosimeter MKS AT6101D

The collection of representative soil samples in the territory of settlements and subsequent measurements of the content of radionuclides in these samples under laboratory conditions (the so-called “ex situ method”) is a generally accepted technology for determining the density of soil contamination with 137Cs in the populated areas contaminated due to the Chernobyl accident. Recently, as a supplement or alternative to the ex situ method, researchers are developing field (in situ) gamma-spectrometry methods. These methods allow determining the density of soil contamination with 137Cs directly on site, without soil sampling and laboratory analysis. At the same time, the in situ methodology has several limitations, the most important of which is a lack of generally recognized metrological basis for measurements and interpretation of results. Hence, before using a particular technique and measuring device for carrying out large-scale in situ measurements, it is necessary to validate (to assess the suitability) of the selected in situ method using an established ex situ method. The aim of this study was to validate the method for determining the density of 137Cs soil contamination in kitchen gardens using the MKS AT6101D spectrometer-dosimeter in situ. The method was recently presented by a Russian-Swedish-Belarusian group of researchers in an article published in the Journal of Environmental Radioactivity (https://doi.org/10.1016/j.jenvrad.2021.106562). To validate this method, we selected 10 representative kitchen garden plots. The plots were located in six settlements of the Bryansk region in Russia. The territory of the settlements had been heavily contaminated with 137Cs as a result of the Chernobyl accident: the officially established levels of the density of soil contamination by 137Cs ranged from 111 to 511 kBq/m2 in 2017. Field gamma-ray spectra were recorded at a height of 1 m above the ground in the center of kitchen garden plots using the MKS AT6101D device. The measurement duration was in the range of 1207–1801 s (the mean value = 1383 s). Samples of soil in the kitchen gardens were taken layer by layer (with a step of 5 cm) to a depth of 20 cm using a demountable cylindrical sampler. The 137Cs content in each soil layer was determined in the laboratory using a stationary semiconductor gamma spectrometer. The values of the 137Cs contamination density of the sampled soils ranged from 77 to 548 kBq/m2. It was found that the results of the ex situ analyzes of soil samples were in a good agreement with the contamination density values obtained with the in situ method. On average, the difference between two methodologies was 7% (a maximum of 20%). The results of the study confirm that the method proposed by the international group is suitable for determining the density of soil contamination by 137Cs in kitchen gardens in remote period after the Chernobyl accident.