Clearcut Edges Research Articles

Structure of Ground Vegetation and Natural Regeneration of Tree Species in 12- to 15-Year-Old Bilberry Pine Forest-Clear-cut Complex of Middle Taiga Subzone.

Logging in mature stands where part of the forest is harvested in one or several cuts and part is retained (clearcutting and alternate strip cutting) results in the formation of an ecotone complex (EC), which includes a forest (F) zone, a forest edge (FE) as a transition from the forest to the clear-cut under the canopy, a clear-cut edge (CE) as a transition from the forest to the clear-cut outside of the canopy, and the clear-cut proper (C). The composition and structure of ground vegetation and natural regeneration of woody species (Pinus sylvestris L., Picea abies (L.) H. Karst., Betula sp., Populus tremula L., Sorbus aucuparia L., and Juniperus communis L.) were studied in a bilberry pine forest-clear-cut ecotone complex 12-15 years after stand removal. Specific structural features of ground vegetation and undergrowth (including tree regeneration) were observed in each of the four zones of the ecotone complex formed after logging of the mature forest. Atypical forest habitat (zone F) showed a minimum number of young regeneration of Pinus sylvestris, Picea abies, Betula sp., Populus tremula, and Sorbus aucuparia and the highest abundance of the lingonberry V. vitis-idaea L. and bilberry Vaccinium myrtillus L. with a maximum height and a maximum yield of bilberry plants. The amount of tree regeneration in the FE zone was much the same as in the F zone. The projective cover, maximum shoot height, and yield of bilberry and the maximum shoot height of lingonberry in the FE zone were significantly lower than in the F zone. The transitional zone on the clear-cut side (CE) and the clear-cut proper (C) strikingly differed from the forest (F and FE) zones of the ecotone complex by a greater number of deciduous and pine regeneration and a low abundance of dwarf shrubs. The clear-cut proper (C) differed from the CE zone by a higher abundance of grasses and forbs and an established tree regeneration layer composed of pine, birch, and aspen.

Climatic and management‐related drivers of endemic European spruce bark beetle populations in boreal forests

Abstract Climate change is already reducing carbon sequestration in Central European forests dramatically through extensive droughts and bark beetle outbreaks. Further warming may threaten the enormous carbon reservoirs in the boreal forests in northern Europe unless disturbance risks can be reduced by adaptive forest management. The European spruce bark beetle (Ips typographus) is a major natural disturbance agent in spruce‐dominated forests and can overwhelm the defences of healthy trees through pheromone‐coordinated mass‐attacks. We used an extensive dataset of bark beetle trap counts to quantify how climatic and management‐related factors influence bark beetle population sizes in boreal forests. Trap data were collected during a period without outbreaks and can thus identify mechanisms that drive populations towards outbreak thresholds. The most significant predictors of bark beetle population size were the volume of mature spruce, the extent of newly exposed clearcut edges, temperature and soil moisture. For clearcut edge, temperature and soil moisture, a 3‐year time lag produced the best model fit. We demonstrate how a model incorporating the most significant predictors, with a time lag, can be a useful management tool by allowing spatial prediction of future beetle population sizes. Synthesis and Applications: Some of the population drivers identified here, i,e., spruce volume and clearcut edges, can be targeted by adaptive management measures to reduce the risk of future bark beetle outbreaks. Implementing such measures may help preserve future carbon sequestration of European boreal forests.

Spatially-explicit effects of small-scale clear-cutting on soil fungal communities in Pinus sylvestris stands

Clear-cutting is a common silvicultural practice. Although temporal changes in the soil fungal community after clear-cutting have been widely investigated, little is known about stand-level variations in the spatial distribution of soil fungi, particularly at the clear-cut edge. We performed spatial soil sampling in three clear-cuts (0.5 ha), edge habitats, and surrounding forests 8 years after clear-cutting to examine the impact of clear-cutting on the soil fungal community (diversity, composition, guilds, and biomass) and soil properties in a managed Pinus sylvestris forest in northern Spain. Our analyses showed small differences in the composition of the soil fungal community between edge, forest, and clear-cut zones, with <4 % of the species strictly associated with one or two zones. The richness, diversity, and evenness of the fungal community in the edge zone was not significantly different to that in the forest or clear-cut zones, although the clear-cut core had approximately a third fewer ectomycorrhizal species than the edge or the forest. Saprotrophic fungi were widespread across the clear-cut–forest gradient. Soil fungal biomass varied significantly between zones, ranging from 4 to 5 mg g−1 dry soil in the forest and at the forest edge to 1.7 mg g−1 dry soil in the clear-cut area. Soil organic matter, pH, nitrogen, and phosphorus did not differ significantly between edge, forest, and clear-cutting zones and were not significantly related to the fungal community composition. Overall, our study showed that small-scale clear-cut treatments are optimal to guarantee, in the medium-term, soil fungal communities within harvested areas and at the forest edge that are comparable to soil fungal communities in the forest, even though the amount of fungal biomass in the clear-cut zone is lower than at the forest edge or in the forest.

Characterization of the CZTS (Cu2ZnSnS4) thin film for solar cell absorber layer synthesized from the nitrate-based sol-gel precursor solution

Manufacture of eco-friendly CZTS (Cu2ZnSnS4) thin film absorption layer of pure keserite structure for solar cell is far-reaching. We have manufactured the CZTS thin films by sol-gel dip-coating means from the nitrate-based chemicals. After hardening at 550°C in vacuum condition, we characterize the films by UV–vis spectroscopy, X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) methods. The CZTS films provided high optical absorption coefficient (2.92x104cm-1) and average band gap energy (1.58 eV). X-ray diffraction analysis proved the kesterite structure of films. The surface morphology analysis proved the deposition of crammed, condensed and granulated CZTS films. The thin films have intermittent disposal of agglomerated particles with clear-cut edges. The energy dispersive X-ray spectroscopy analysis conferred stoichiometric ratio as Cu: Zn: Sn: S= 2.1: 1.3: 1: 5.2. DUJASE Vol. 7 (2) 1-7, 2022 (July)

Structure of the Ground Vegetation and Natural Regeneration of Tree Species in a 12–15-Year-Old Bilberry Pine Forest–Clear-Cut Ecotone Complex in the Middle Taiga Subzone

Abstract—Logging in mature stands, where part of the forest is harvested in one or several cuts and part is retained (clear-cutting and alternate strip cutting) results in the formation of an ecotone complex: forest (F), transition from forest to clear-cut under the canopy (forest edge – FE), transition from forest to clear-cut outside of the canopy (clear-cut edge – CE), and the clear-cut itself (C). Strips 8 m wide on each side of the mature forest/clear-cut site border form the transitional zone. We studied the ground vegetation composition and structure, and the natural regeneration of woody species (Pinus sylvestris L., Picea abies (L.) H. Karst., Betula sp., Populus tremula L., Sorbus aucuparia L., Juniperus communis L.) in the bilberry pine forest – clear-cut ecotone complex 12–15 years after the stand removal. The studies demonstrate that each of the four zones of the ecotone complex formed after logging of the mature forest has its own structural features of ground vegetation and undergrowth (including tree regeneration). The typical forest (F) habitat is characterized by the minimum number of young regeneration of Pinus sylvestris, Picea abies, Betula sp., Populus tremula, and Sorbus aucuparia and, on the contrary, by the highest abundance of lingonberry V. vitis-idaea L. and bilberry Vaccinium myrtillus L., and the maximum height of bilberry plants and their yield. The amount of tree regeneration in the FE is almost the same as in the F zone. The projective cover, maximum shoot height and yield of bilberry, and maximum shoot height of lingonberry in the FE zone are reliably lower than in the F zone. The transitional zone on the clear-cut side (CE) and the clear-cut itself (C) are distinguished from the forest sections of the ecotone complex (F and FE zones) by a greater number of deciduous and pine regeneration and the low abundance of dwarf shrubs. The clear-cut itself (C) differs from the CE by the higher abundance of grasses and forbs and an established tree regeneration layer composed of pine, birch, and aspen.

The edges of galaxies: Tracing the limits of star formation

The outskirts of galaxies have been studied from multiple perspectives for the past few decades. However, it is still unknown if all galaxies have clear-cut edges similar to everyday objects. We address this question by developing physically motivated criteria to define the edges of galaxies. Based on the gas density threshold required for star formation, we define the edge of a galaxy as the outermost radial location associated with a significant drop in either past or ongoing in situ star formation. We explore ∼1000 low-inclination galaxies with a wide range in morphology (dwarfs to ellipticals) and stellar mass (107 M⊙ &lt; M⋆ &lt; 1012 M⊙). The location of the edges of these galaxies (Redge) were visually identified as the outermost cutoff or truncation in their radial profiles using deep multi-band optical imaging from the IAC Stripe82 Legacy Project. We find this characteristic feature at the following mean stellar mass density, which varies with galaxy morphology: 2.9 ± 0.10 M⊙ pc−2 for ellipticals, 1.1 ± 0.04 M⊙ pc−2 for spirals, and 0.6 ± 0.03 M⊙ pc−2 for present-day star-forming dwarfs. Additionally, we find that Redge depends on its age (colour) where bluer galaxies have larger Redge at a fixed stellar mass. The resulting stellar mass–size plane using Redge as a physically motivated galaxy size measure has a very narrow intrinsic scatter (≲0.06 dex). These results highlight the importance of new deep imaging surveys to explore the growth of galaxies and trace the limits of star formation in their outskirts.

A Critical Assessment of the Congruency between Environmental DNA and Palaeoecology for the Biodiversity Monitoring and Palaeoenvironmental Reconstruction.

The present study suggests that standardized methodology, careful site selection, and stratigraphy are essential for investigating ancient ecosystems in order to evaluate biodiversity and DNA-based time series. Based on specific keywords, this investigation reviewed 146 publications using the SCOPUS, Web of Science (WoS), PUBMED, and Google Scholar databases. Results indicate that environmental deoxyribose nucleic acid (eDNA) can be pivotal for assessing and conserving ecosystems. Our review revealed that in the last 12 years (January 2008–July 2021), 63% of the studies based on eDNA have been reported from aquatic ecosystems, 25% from marine habitats, and 12% from terrestrial environments. Out of studies conducted in aquatic systems using the environmental DNA (eDNA) technique, 63% of the investigations have been reported from freshwater ecosystems, with an utmost focus on fish diversity (40%). Further analysis of the literature reveals that during the same period, 24% of the investigations using the environmental DNA technique were carried out on invertebrates, 8% on mammals, 7% on plants, 6% on reptiles, and 5% on birds. The results obtained clearly indicate that the environmental DNA technique has a clear-cut edge over other biodiversity monitoring methods. Furthermore, we also found that eDNA, in conjunction with different dating techniques, can provide better insight into deciphering eco-evolutionary feedback. Therefore, an attempt has been made to offer extensive information on the application of dating methods for different taxa present in diverse ecosystems. Last, we provide suggestions and elucidations on how to overcome the caveats and delineate some of the research avenues that will likely shape this field in the near future. This paper aims to identify the gaps in environmental DNA (eDNA) investigations to help researchers, ecologists, and decision-makers to develop a holistic understanding of environmental DNA (eDNA) and its utility as a palaeoenvironmental contrivance.

Optical and Structural Study of the CZTS (Cu2ZnSnS4) Thin Film for Solar Cell Derived from the Chloride-Based sol-gel Precursor Solution

Fabrication of environmentally safe C2ZnSnS4 (CZTS) photovoltaic thin films of pure kesterite state is crucial. We have preparedCZTS thin films by sol-gel dip-coating process from chloride-based chemicals. After vacuum-annealed at 550°C, the optical andstructural characters of the films were further examined by UV–vis spectroscopy, X-ray diffraction (XRD), scanning electronmicroscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) methods. The CZTS films offered high optical absorption(0.4x104cm-1) and nearly optimum bandgap energy (1.65e V). X-ray diffraction examination confirmed the kesterite structure offilms. Scanning electron micrograph affirmed the creation of jam-packed, condensed and granulated CZTS films. The thin filmdisplayed intermittent disposal of agglomerated particles with clear-cut edges. The energy dispersive X-ray spectroscopy study gavethe stoichiometric ratio as Cu: Zn: Sn: S= 2.2: 1.4: 1: 5.1.&#x0D; Dhaka Univ. J. Sci. 70(1): 1-7, 2022 (January)

Forest logging is associated with shape of males and gynes in the wood ant Formica aquilonia

Environmental stress can affect individual development and fitness in insects. Forest logging is a serious environmental stress for forest-specialist insects, such as the mound-building wood ant Formica aquilonia Yarrow 1955, which builds its nests into forests and is dependent on the nutrition provided by the forest habitat. We studied whether the logging causes such a strong environmental stress that it would be visible in disproportionate growth and shape of young winged wood ant gynes (‘queens’) and males. We measured head width, thorax width and wing length of 144 gynes and 100 males from 12 nests from six clear-cut areas, 11 nests from unlogged forest stands and 10 nests in clear-cut—forest margins. We observed disproportionate growth of different body parts and allometric growth of wings in both sexes in areas with different logging-induced disturbance. Gynes had larger heads in clear-cut areas and males had narrowest thoraxes in forest clear-cut edges. With an increasing thorax width, the wing length decreases steeper in clear-cuts than in other habitats in gynes and increases steeper in clear-cuts than other habitats in males. It seems that in a strongly disturbed clear-cut environment, the gynes invest the growth of head width. There seems to be a trade-off between the growth of the thorax and wings in gynes but not in males. The altered body shape may be adaptation to clearings caused by storm events of wild fires, but not forest management practices of modern era. Large-headed gynes may be better in a colony take-over, needed for the establishment of new colonies in early succession stage habitats in this temporally social parasitic species. Long-winged males may have better long-range flight ability, and they may thus have better fitness and change to disperse their genes onto new habitats.

Femtosecond laser–assisted descemetorhexis for Descemet membrane endothelial keratoplasty: cell-based and tissue-based ex vivo analysis of precision and safety

To analyze precision and safety of femtosecond laser-assisted descemetorhexis and postoperative corneal wound healing in human ex vivo specimens. Department of Ophthalmology, University Hospital, LMU Munich, Munich, Germany. Experimental ex vivo study. 4 donor corneas underwent femtosecond laser-assisted descemetorhexis. The descemetorhexis was performed using the LDV Z8 femtosecond laser, followed by live/dead staining, phase contrast microscopy, and scanning electron microscopy. The descemetorhexis parameters were set using a modified optical coherence tomography image capturing of 8 segments within a focus of 100 μm at the posterior corneal stroma (reversed capsulotomy program). Live/dead sample staining analysis demonstrated that the femtosecond laser had minimal impact on the vitality of surrounding endothelial cells. Phase contrast microscopy and scanning electron microscopy evaluation showed that the laser produced precise, clear-cut edges, leaving no stromal tissue bridges. Femtosecond laser-assisted descemetorhexis could serve as a safe and precise technique with only minimal endothelial cell damage. To minimize stromal damage, further laser energy profile adjustments are necessary to optimize corneal treatment within different stages of corneal tissue swelling.

Effects of permanent and temporary edges onPinus clausa(sand pine) architecture and stand conditions

Effects of permanent (i.e., maintained) and temporary edges with north- and south-facing exposures were studied in sand pine (Pinus clausa var. clausa (Chapm. ex Engelm.) Vasey ex Sarg.) scrub, an open-canopied forest type in Ocala National Forest, Florida. On edges and interiors of four stands of each type, we measured canopy tree architecture in 5 m × 100 m plots and stand density and basal area in 5 m × 200 m plots. Edge effects were modest but often stronger on south- than north-facing edges and along permanent forest roads than temporary edges of clearcuts that were allowed to regrow. Compared with interior trees, those on edges were typically shorter, retained branches lower on their boles, oriented their first branches more towards the edge, and produced more asymmetrical crowns with the long axis extending into the opening; these trends were greater on south- than north-facing edges and along permanent than temporary edges. Contrary to expectations, there were no edge effects on total basal area, dead tree densities, proportions of sand pine trees with leaning trunks, directions of lean, or angles of lean. Instead of an edge effect, most trees leaned towards the southwest, which seems related to the northeastern origin of prevailing winds and wind gusts.

Dispersed Variable-Retention Harvesting Mitigates N Losses on Harvested Sites in Conjunction With Changes in Soil Microbial Community Structure

As an alternative to clear-cutting, variable-retention harvesting is now standard forest management practice on the coast of British Columbia and in temperate forests globally, due to the benefits associated with maintaining mature forest species and forest structural diversity. Although there is some evidence that variable-retention harvesting, particularly single-tree (dispersed) retention will mitigate the impacts of clear-cutting on soil microbial communities and nutrient cycling, findings have been inconsistent. We examined microbial community structure (phospholipid-fatty acid), and nutrient availability (PRSTM probes) in a large (aggregated) retention patch and over three harvesting treatments: dispersed retention, clear-cut and clear-cut edge 2 years after harvest. Unlike previous studies, we did not observe elevated nitrate in the harvested areas, instead ammonium was elevated. Availability of N and other nutrients were surprisingly similar between the dispersed-retention treatment and the retention patch. The microbial community, however, was different in the clear-cut and dispersed-retention treatments, mostly due to significantly lower abundance of fungi combined with an increase in bacteria, specifically Gram-negative bacteria. This was accompanied by lower δ13CPDB value of the Gram-negative PLFA's in these treatments, suggesting the decline in mycorrhizal fungal abundance may have allowed the dominant Gram-negative bacteria to access more of the recently photosynthesized C. This shift in the microbial community composition in the dispersed-retention treatment did not appear to have a major impact on microbial functioning and nutrient availability, indicating that this harvesting practice is more effective at maintaining generic microbial functions/processes. However, as Mn levels were twice as high in the retention patch compared to the harvested treatments, indicating the other “narrow” processes (i.e., those performed by a small number of specialized microorganisms), such as lignin degradation, catalyzed by Mn peroxidase, which concomitantly removes Mn from solution, may be more sensitive to harvesting regimes. The effect of harvesting on such narrow nutrient cycling processes requires further investigation.

Melanoma Inhibitory Activity (MIA) Is Able to Induce Vitiligo-Like Depigmentation in an in vivo Mouse Model by Direct Injection in the Tail.

In the complex pathogenesis of vitiligo, the exact mechanism of the dermatosis is still to be clarified. We previously demonstrated that a protein called melanoma inhibitory activity (MIA) is present in non-segmental vitiligo skin and seems to cause the detachment of melanocytes, consequently creating the depigmented macules. In this study, we present an animal model of vitiligo on the basis of the ability of the MIA protein to induce vitiligo-like lesions. Twenty pigmented mice were chosen for the experiments and received injections in the tail with saline (control group) or with saline + MIA protein (treated group). The control group did not show any sign of depigmentation. The treated group showed, instead, clear zones of complete depigmentation in the injected areas in each mouse, with the appearance of white patches with whitening of the hair and a clear-cut edge. Histological examination of the tail in the treated zone showed the absence of melanocytes, without the presence of any inflammatory cell or any sign of skin inflammation patterns, confirming the detachment of the melanocyte operated by the MIA protein. These data seem to confirm a possible role played by the MIA protein in the pathogenesis of vitiligo and may support the development of treatments able to inhibit its action as an alternative therapeutic strategy for this disorder.

Interference rings induced by ultrafast laser pulse in GaAs crystal

Gallium arsenide (GaAs) is an important semiconductor material with direct bandgap and clear-cut absorption edge. High-quality crystal is available, which has excellent performances in the field of high power transmission and luminescence because of high laser damage threshold and high thermal conductivity. Nonlinear optics is of great significance for developing the laser technology, spectroscopy, and optoelectronic devices. The Z-scan technology is a nonlinear measurement method based on the analysis of single beam transmittance. Previous studies mainly focused on the measurement of the nonlinear absorption coefficient of the sample by open-aperture configuration of Z-scan and the nonlinear refractive index of the sample by shut-aperture configuration of Z-scan. We build a dual-channel Z-scan system with variable optical path difference, equipped together with a high speed camera, to observe the spatial distribution of transmitted light. Besides, we find the interference rings induced by nonlinear absorption in semiconductor GaAs crystals. Using three kinds of lasers (continuous-wave laser, 80 MHz femtosecond pulsed laser, 1 kHz femtosecond pulsed laser) to illuminate the GaAs crystal separately, multi-level interference rings come out only when a GaAs crystal wafer is illuminated by a femtosecond pulsed laser. In the single-channel Z-scan experiment, we observe that the interference rings contract or expand regularly when changing pulsed laser intensity incident on the surface of GaAs crystal. The higher the intensity of pulse, the more interference rings appear, and the maximum exiting angle becomes larger. Nonlinear effect of high intensity femtosecond pulsed laser locally changes the refractive index of GaAs crystals, resulting in optical path difference (Kerr lens effect). However, the Kerr lens generated by ultrafast light pulse in GaAs crystal cannot focus a beam as done by an ideal thin lens, leading the transmitted light to form interference rings instead. By analyzing the variation of the interference rings, the nonlinear absorption coefficient and refractive index of GaAs crystal can be obtained. In the dual-channel Z-scan experiment, different interference rings are induced in the GaAs crystal as the path difference between the two pulses changes, as done by the nonlinear transmission power. Thus we obtain the formation time of the interference rings and ascribe it to the ultrafast relaxation process of GaAs carriers.

Solution-based flexible indium oxide thin-film transistors with high mobility and stability by selective surface modification

Improved performances of solution-based flexible indium oxide (In2O3) thin-film transistors (TFTs) was achieved by introducing clear-cut edges of the active areas on substrate surfaces. Patterned areas for the In2O3 active regions were converted to hydrophilic by oxygen plasma treatment whereas the remaining areas between the active region patterns were converted to hydrophobic by transferring oligomer molecules from a partially cured polydimethylsiloxane (PDMS) mask. This way, In2O3 precursor could be settled only on the intended patterns for the active regions and therefore the active regions were formed with distinct edges and regular shapes. A model TFT prepared via this method exhibited significantly improved performances over a reference device prepared without the selective surface treatment in terms of threshold voltage (Vth), subthreshold swing (SS), saturation mobility (μsat), off-state current (Ioff), and bias-stress stability. Furthermore, the TFT exhibited good electrical stability under a bias stress and sustainable mechanical stability even at 10,000 cycles of bending tests at a radius of curvature of 5 mm. Such improvements were attributed to decreased trap state density at the channel/dielectric interface due to clear distinction of the active region edges and good interface properties, which also helped improving the mechanical stability under prolonged cyclic bending.

Local habitat association does not inform landscape management of threatened birds

Species that use open patches in forested landscapes often select clearcuts. However, it is unknown whether local associations with clearcuts translate to an effect of clearcut amount in the surrounding landscape on occupancy or abundance at local sites. This question is important because forest management decisions are made at landscape scales. We examined whether the amount of clearcut in the surrounding landscape influenced site occupancy of two threatened aerial insectivores, Common Nighthawk and Eastern Whip-poor-will. Both species nest in/near clearcuts at a local-scale. We used acoustic recorders placed on edges of recent clearcuts (≤ 15 years old, n = 49 sites) to measure presence-absence. We estimated occupancy in relation to the proportion of clearcut and open wetland within the surrounding landscapes at spatial extents between 0.5 and 5.0 km. Occupancy of Eastern Whip-poor-will was not related to clearcut amount in the surrounding landscape at any scale. Common Nighthawk occupancy was lower in sites surrounded by landscapes with higher proportion of older (11–15 years old) clearcuts. Both species’ occupancy was higher in sites where the surrounding landscapes had higher proportions of open wetland. Two possible mechanisms for our results include multi-scale selection of breeding sites or demographic responses to higher productivity in wetlands than clearcuts; both need further study. Our results show how the association of species with clearcut habitats at a local scale does not necessarily translate to a higher occurrence of those species at the landscape scale at which management decisions are made.

Spectral-divergence based pigment discrimination and mapping: A case study on The Scream (1893) by Edvard Munch

ABSTRACT An important application of imaging spectroscopy or hyperspectral imaging is the classification or discrimination of pigments based on the obtained spectral reflectance information. As opposed to being a point-analysis tool, this non-invasive method captures the entire surface of interest. This means that its potential is not only in the discrimination of pigments but also in their mapping. However, the challenge lies in the fact that in a real painting, there is no clear-cut edge between regions with certain pure pigments or of the exact same mixture. Pigments and other paint materials mix seamlessly and continuously in the physical domain. In this article, we introduce a divergence-based approach to pigment discrimination and mapping. The methodology is then applied to Munch’s masterpiece The Scream (1893), whose pigments and materials have been identified for several points in the painting in a previous study. Through the introduced methodology, we have been able to extend the point analyzes of pigments and materials to the entire surface of the painting, recto and verso.

Fault Detection in Fiber Optic Communication Cable by Coherent Anti-Stokes Raman Scattering using Superconducting Nanowire Single-Photon Detectork

Objective: In this paper, the author has used the coherent anti-stokes Raman scattering and the time correlated single photon count technique to locate the fault position and fault in fiber optic communication cable. Method/Statistical Analysis: The coherent anti-stokes Raman scattering where used to measure the single photon count and the counts are correlated with time to measure the position of the fault in fiber optical cable. The proposed method is experimented on a 4 meter length fiber optic cable which is under test. The experiment is performed by considering prefixed faults at different length of the fiber optic cable under test. The author has done one of its kinds of experimentation to measure the faults and fault position in the fiber optical cables, lay underneath the ground. Findings: The experimented results have shown a clear cut edge with the technique that the photon count rate is decreased at the fault position of the optical fiber cable under test. The sharp increase of counts after the fault position and sharp decrease of counts before the fault position strongly supports the proposed method for fault finding in fiber optic cable. Application/Improvement: The proposed method is much more accurate in finding faults which is not possible by the pervious technology or devices. The proposed method can be applied to lengthy fiber optic cables by selecting high range pump lasers and advanced filters.

Dynamic anthropogenic edge effects on the distribution and diversity of fungi in fragmented old-growth forests.

Diversity patterns and dynamics at forest edges are not well understood. We disentangle the relative importance of edge-effect variables on spatio-temporal patterns in species richness and occupancy of deadwood-dwelling fungi in fragmented old-growth forests. We related richness and log occupancy by 10 old-growth forest indicator fungi and by two common fungi to log conditions in natural and anthropogenic edge habitats of 31 old-growth Picea abies forest stands in central Sweden. We compared edge-to-interior gradients (100m) to the forest interior (beyond 100m), and we analyzed stand-level changes after 10yr. Both richness and occupancy of logs by indicator species was negatively related to adjacent young clear-cut edges, but this effect decreased with increasing clear-cut age. The occupancy of logs by indicator species also increased with increasing distance to the natural edges. In contrast, the occupancy of logs by common species was positively related or unrelated to distance to clear-cut edges regardless of the edge age, and this was partly explained by fungal specificity to substrate quality. Stand-level mean richness and mean occupancy of logs did not change for indicator or common species over a decade. By illustrating the importance of spatial and temporal dimensions of edge effects, we extend the general understanding of the distribution and diversity of substrate-confined fungi in fragmented old-growth forests. Our results highlight the importance of longer forest rotation times adjacent to small protected areas and forest set-asides, where it may take more than 50yr for indicator species richness levels to recover to occupancy levels observed in the forest interior. Also, non-simultaneous clear-cutting of surrounding productive forests in a way that reduces the edge effect over time (i.e., dynamic buffers) may increase the effective core area of small forest set-asides and improve their performance on protecting species of special concern for conservation.

Dynamics in forest patterns during times of forest policy changes in Latvia

In the context of forest management intensification, European countries are attempting to promote the sustainable management of forest landscapes. The aim of this study was to determine the structural dynamics of managed state forest landscapes in the context of changing forest policy. Four landscapes in the North Vidzeme Biosphere Reserve of northern Latvia were studied for the period between 1988 and 2011. The spatial patterns of clearcuts, regenerating stands and uncut stands were analysed using landscape metrics at the class level. For more comprehensive structural analysis, we additionally analysed the stand age structures and spatial pattern characteristics of over-mature stands and woodland key habitats (small voluntarily set-aside forest stands with high biodiversity values in Nordic and Baltic countries) that existed in 2011. The results indicated a substantial increase in the overall landscape structure complexity (measured by the number of patches, edge density and patch isolation at the class level) in three of the four analysed landscapes. At the class level, clearcut harvesting intensity increased after 2000, with the establishment of a new forest policy and management system in state forests combined with an abundance of timber available for felling. Significant increase in clearcut edge density and aggregation, with a corresponding decline of matrix connectivity, coincided with an increase in allowed felling volume by 4 million m3 for the period between 2009 and 2010 (increase in felling by about 60 % in state forests). Management reform and the introduction of a concentrated felling strategy in state forests also contributed to management intensification. Relatively higher WKH isolation, compared to that of over-mature stands, in all landscapes suggested that setting aside part of these stands could be a means of improving connectivity in the future. We suggest that the integration of landscape ecological principles, such as inclusion of ecological networks or retaining clusters of older stands, into Latvia’s forest management plans is needed and would contribute to more sustainable forest management.