Selective Thinning Research Articles

High resolution retinal scanning reveals regional structural differences between MS and NMOSD optic neuritis regardless of antibody status

BackgroundThere is a need for biomarkers that can classify optic neuritis (ON) attacks as belonging to either neuromyelitis optica spectrum disorder with optic neuritis (NMOSD-ON) or relapsing remitting multiple sclerosis with optic neuritis (MS-ON). This study uses spectral domain optical coherence tomography (SD-OCT) data to perform a preliminary contrast between NMOSD-ON and MS-ON by analyzing peripapillary retinal nerve fiber layer and intra-macular layer patterns of injury. MethodsIn this cross-sectional study, we used SD-OCT to obtain peripapillary retinal nerve fiber layer and intra-macular layer data for 26 NMOSD-ON, 25 MS-ON, and 26 healthy control (HC) age-matched eyes. Additionally, sub-comparisons compared 11 NMOSD-ON eyes that were seronegative for IgG antibodies against aquaporin 4 (NMOSD-ON (−)) and 16 NMOSD-ON eyes that were seropositive (NMOSD-ON (+)) to age-matched MS-ON eyes. Layer thicknesses were assessed using an automated algorithm and were then statistically compared using generalized estimating equations to account for inter-eye correlations. ResultsSelective thinning was found in the pRNFL, mRNFL, and GCL in NMOSD-ON compared to MS-ON. Thinning in the pRNFL nasal sector was found to persist in both NMOSD-ON (−) (P=0.017) and NMOSD-ON (+) (P=0.021) compared to MS-ON. Thinning in the mRNFL temporal sector was found to persist in NMOSD-ON (+) compared to MS-ON. Diffuse thinning was found in the pRNFL, mRNFL, GCL and IPL in NMOSD-ON compared to HC, and while diffuse thinning was also found in the GCL and IPL in MS-ON compared to HC, selective thinning was found in the pRNFL and mRNFL. ConclusionThe nasal region of the pRNFL may be capable of distinguishing between NMOSD-ON and MS-ON regardless of antibody status. Additionally, NMOSD-ON may cause more profound nasal axonal and inferior arcuate neuronal degeneration compared to MS-ON.

Exploring visitors' perceptions of silvicultural treatments to increase the destination attractiveness of peri-urban forests: A case study in Tuscany Region (Italy)

Peri-urban forests are characterized by multiple-use and various kinds of recreation activities. Public forest services have to take into account ecological, economic and social issues to provide a sustainable management of peri-urban forests, able to improve their attractiveness. Understanding visitors' demands and perceptions on peri-urban forests is a key element to support decision-makers and ensure proper management of these forests. This study is aimed at investigating visitors' perceptions and preferences regarding the characteristics of the peri-urban forests and the role of silvicultural treatments. The investigation was implemented in the Monte Morello peri-urban forest located near the metropolitan area of Florence (Italy). The forest is a dominant black pine and Calabrian pine plantation, established in the sixties for protection purpose but largely abandoned. Recently, silvicultural treatments have been applied to restore the ecological stability and enhance the resistance and resilience of forest. An innovative selective thinning was applied to compare its effects (economical, ecological and social) with the traditional thinning and with unmanaged areas. Visitors' perceptions and preferences were collected through the administration of a face-to-face interview to 201 respondents. The survey investigated three aspects: recreational use of peri-urban forests; benefits of peri-urban forest vegetation; preferences towards the characteristics of the peri-urban forest. The visitors assessed from the aesthetic point of view three images of the Monte Morello forest after different silvicultural treatments (traditional thinning, selective thinning and unmanaged forest). The results show that the preferred type of peri-urban forest is a mixed forest of coniferous and deciduous with a random arrangement of trees in space. The tourist facilities (i.e. waste baskets, picnicking and sport areas) are perceived in a positive way by visitors. With regard to the forest management alternatives, the results show that the visitors prefer the managed forest through a selective thinning.

Wafer Level Integration of 3-D Heat Sinks in Power ICs

In this paper, an innovative process flow developed to improve the thermal resistance of power ICs was presented. In this field, one of the major device failure mechanisms is related to the high temperatures reached during the working cycles due to the extremely critical electrical current densities. Therefore, heat transfer and dissipation are crucial aspects that need continuous improvements. Usual approaches to face this issue deal with package heat sinks design, solder selection, and wafer thinning. In this paper, a novel technological approach was settled, in which heat sinks microstructures were successfully integrated at wafer level stage on standard p-i-n diodes. To this aim, the bulk Si on the backside was partially replaced with Cu, a material characterized by a higher thermal conductivity material. Moreover, the well microstructures filled by Cu provide the advantage of wafer self-support, without requiring dedicated and more expensive thinning and handling technologies. An extensive characterization of the final devices was also carried out to evaluate the process and the thermal and electrical improvements. Finally, a failure analysis on selected devices was performed to identify any critical issue with the standard packaging process.

Selective and traditional forest management options for black pine forests in Central Italy: effects on ecosystem services

Sustainable Forest Management (SFM) should be able to produce an optimal level of bundle of Ecosystem Services (ES), thus ensuring more resilient forest ecosystems also creating benefits for local population and human well-being. Yet, choosing between alternative forest management practices is not straightforward as it necessarily involves ES trade-offs. Forest management decisions have to reconcile the socio-economic and ecological contributions of forest ecosystems by fostering a synergistic relation between multiple ES while lowering ES trade-offs. The aim of the study is to analyze different forest management practices (selective and traditional thinning) in black pine peri-urban forest in Central Italy, by investigating their contribution in terms of provisioning (wood production), cultural (recreational benefits), regulating (climate change mitigation) ES. For each management option was performed: (1) the biophysical assessment of selected ES by using primary data and calculating indicators for wood production with special regard to biomass for energy use (living trees and deadwood volume harvested), recreational benefits (tourists’ preferences for each forest management practice), climate change mitigation (carbon sequestration in above-ground and below-ground biomass), and (2) the economic valuation of wood production, recreational benefits and climate change mitigation ES using direct and indirect methods (environmental evaluation techniques). The results show that the effects of the selective thinning on ES is higher that the effects of the traditional thinning. The economic value of the three ES provided by traditional and selective thinning are respectively: bioenergy production 154.2 € ha -1 yr -1 and 223.3 € ha -1 yr -1 ; recreational benefits 193.2 € ha -1 yr -1 and 231.9 € ha -1 yr -1 ; carbon sequestration 29.0 € ha -1 yr -1 and 36.2 € ha -1 yr -1 . The integrated (biophysical and economic) assessment of ES in addition to the trade-off analysis can provide multi-perspective insights for forest policy makers and can be included as a part of the local forest management plans.

Development of Sessile Oak and European Hornbeam Sprouts after Thinning

We observed the growth of juvenile sprouts at stool level in an oak-hornbeam selective coppice after selective thinning. We tested the relations of sprouting probability, number and height of new sprouts, and stool biometric characteristics with thinning intensity and light conditions. We compared the results between the two species. The sprouting probability, number of new sprouts, and height of new sprouts were modelled using different types of regression (logistic, generalized linear, and multiple linear regression) evaluated from 84 sessile oak (Quercus petraea Matt. Liebl.) and 139 European hornbeam (Carpinus betulus L.) stools with the same site conditions. There were no significant relations between sprouting probability and the tested parameters because nearly all stools re-sprouted. The growth (number and height) of new sprouts depended on the stool basal area before thinning and on thinning intensity. Light conditions (indirect site factor) only influenced the number of new European hornbeam sprouts in 2016 and the height of new sessile oak sprouts. The number of new sprouts in European hornbeam was higher than in sessile oak.

Comparison of remote sensing based RFID and standard tree marking for timber harvesting

Forest inventory is the basis for creating forest management plan. In Europe, forest inventory data is usually collected manually by standard survey methods based on sampling procedures. The information from forest management plan to execute silvicultural and harvesting treatments is transferred to the field by standard tree marking methods e.g. marking spray, marking tape, chalk, bark blazer and plastic shim. A new computer-aided approach based on UAV (Unmanned Aerial Vehicle) and TLS (Terrestrial Laser Scanner) technology was developed to generate a 3D forest model, which replaces standard survey procedures and is the basis for tree marking with RFID (Radio Frequency IDentification)-tags. The goal of the developed survey and tree marking method was to increase timber harvesting efficiency in mountain forests by implementing a higher degree of mechanization, automation and intelligent technologies. The objective of this study was to analyse the practical applicability and the advantages and disadvantages of standard and innovative procedures as well as performing a comparison based on requirements, efforts and costs. For this purpose, tree marking was executed for a negative selective thinning in a forest stand in Austria. The costs for marking the trees with RFID tags amounted to 1.55 € per tree. In comparison to that standard tree marking of the same trees with spray by experienced forester amounted to 0.36 € per tree. The results had shown that the new tools were already applicable from a technological point of view, but efforts and costs are still high, especially survey costs. Therefore, further improvement has to be made to transform the innovative method into a marketable and competitive tool.

Natural Regeneration in Harvested and Unharvested Forest Plantations - Case Study in Chittagong University Forest, Bangladesh

This study was aimed to identify the dominant species establishing during regeneration, their species diversity and whether selection thinning could enhance the regeneration of secondary forest species. Chittagong University Forest was selected for the study and harvested and unharvested sites of forest plantations were demarcated and set 30 quadratic plots (3m × 3m) for each site. Ten per cent selection thinning was done in harvested site although a little anthropogenic disturbance was noticed in both the plantations. Regenerations were identified into species level and their numbers were counted. Shannon-Weiner diversity index for unharvested plantation was 2.21 and it was 1.45 for harvested plantation. Species evenness index was recorded as 0.81 and 0.74 for unharvested and harvested plantations respectively. Both the plantations did not show a significant difference in diversity of species. According to the Important Value Index (IVI) the dominant species in the harvested site were Acacia auriculiformis followed by Acacia mangium and Albizia lebbeck. In the unharvested site, IVI was the highest for Acacia auriculiformis followed by Aphanamixis polystachya and Lagerstroemia speciosa. In both the sites, Acacia auriculiformis had a significantly (p<0.05) higher number of regeneration in harvested plantations than those of unharvested plantations. Therefore, thinning has a positive impact on natural regeneration and Acacia auriculiformis is the best for natural regeneration in plantations.

Beech coppice conversion to high forest: results from a 31-year experiment in Eastern Pre-Alps

Selective thinning is a more viable method for beech coppice conversion to high forest when compared with thinning from below as it enhances tree growth, reduces mortality of the remaining trees, and allows to obtain stands with a higher mechanical stability and larger crowns. Beech forests in North-East Italy have been largely managed as coppice. Due to socio-economic changes, a large conversion to high forests program started in the second half of the past century. A long-term experiment testing the effects on tree growth and stability of two different conversion methods (thinning from below—method A; selective thinning—method B) was implemented. Both silvicultural treatments started in 1979 with a first thinning followed by a second one in 1997. All trees were periodically measured in order to assess mortality, stability, and growth during the period 1979–2010. In 2010, an assessment of stem quality and crown size was also performed. Both methods were economically viable, but method B acted with a higher intensity both in 1979 and in 1997, thus making the harvest more profitable for the owners. Moreover, method B enhanced tree growth, especially in the period after the first thinning, reduced mortality, and allowed to obtain stands with a higher mechanical stability and with larger crowns. It would be possible to adopt some of the criteria prescribed with method B in future thinnings over the large areas actually managed with method A, as prescribed by the law.

Forest Edge Regrowth Typologies in Southern Sweden\u2014Relationship to Environmental Characteristics and Implications for Management

After two major storms, the Swedish Transport Administration was granted permission in 2008 to expand the railroad corridor from 10 to 20 m from the rail banks, and to clear the forest edges in the expanded area. In order to evaluate the possibilities for managers to promote and control the species composition of the woody regrowth so that a forest edge with a graded profile develops over time, this study mapped the woody regrowth and environmental variables at 78 random sites along the 610-km railroad between Stockholm and Malmö four growing seasons after the clearing was implemented. Through different clustering approaches, dominant tree species to be controlled and future building block species for management were identified. Using multivariate regression trees, the most decisive environmental variables were identified and used to develop a regrowth typology and to calculate species indicator values. Five regrowth types and ten indicator species were identified along the environmental gradients of soil moisture, soil fertility, and altitude. Six tree species dominated the regrowth across the regrowth types, but clustering showed that if these were controlled by selective thinning, lower tree and shrub species were generally present so they could form the “building blocks” for development of a graded edge. We concluded that selective thinning targeted at controlling a few dominant tree species, here named Functional Species Control, is a simple and easily implemented management concept to promote a wide range of suitable species, because it does not require field staff with specialist taxonomic knowledge.

Selective inflorescence thinning as a tool to improve yield quality of everbearing strawberry

Selective inflorescence thinning as a tool to improve yield quality of everbearing strawberry

Structural drivers of biomass dynamics in two temperate forests in China

AbstractThis study evaluated the effects of forest attributes on the dynamics of aboveground coarse woody biomass (AWB) and belowground coarse root biomass (BRB) based on two large stem‐mapped field plots: a secondary conifer and broadleaved mixed forest (near‐mature forest) and an old‐growth Korean pine and broadleaved mixed forest. In 2015, the kernel densities of both AWB and BRB had a lower mass in the left tail and a greater mass in the right tail than those in 2010. Both AWB and BRB changed especially at the right end of the biomass distribution and less at the left end. The counterfactual decomposition approach, used to identify the sources of kernel density changes in the biomass distributions from 2010 to 2015, revealed that forest attributes contributed jointly to the observed biomass dynamics. The change in species richness (SR), accounting for less than 10% of overall changes in biomass at all estimated quantiles, has only a minor effect on the AWB and BRB dynamics in two studied forests. But the decrease in tree density (TD) and the increase in stand density (SD) from 2010 to 2015 contributed positively toward the observed density changes in AWB and BRB. Therefore, the changes in TD (measured in terms of the number of trees per ha) and SD (measured in terms of the basal area per ha) were identified as important drivers of biomass dynamics in the two studied forests. Overall, diameter skewness and diameter inequality exert greater influence at the highest quantiles of biomass distribution than at the lowest. It indicates that the changes in diameter structures will further increase biomass dispersion. The results support the assumption that specific methods of selective thinning may be effective to improve the biomass production in the natural forests. Further studies are needed to explore relevant details.

Solid-state nanopore localization by controlled breakdown of selectively thinned membranes

We demonstrate precise positioning of nanopores fabricated by controlled breakdown (CBD) on solid-state membranes by spatially varying the electric field strength with localized membrane thinning. We show 100 × 100 nm2 precision in standard SiNx membranes (30–100 nm thick) after selective thinning by as little as 25% with a helium ion beam. Control over nanopore position is achieved through the strong dependence of the electric field-driven CBD mechanism on membrane thickness. Confinement of pore formation to the thinned region of the membrane is confirmed by TEM imaging and by analysis of DNA translocations. These results enhance the functionality of CBD as a fabrication approach and enable the production of advanced nanopore devices for single-molecule sensing applications.

Microsteganography on WS2 Monolayers Tailored by Direct Laser Painting.

We present scanning focused laser beam as a multipurpose tool to engineer the physical and chemical properties of WS2 microflakes. For monolayers, the laser modification integrates oxygen into the WS2 microflake, resulting in ∼9 times enhancement in the intensity of the fluorescence emission. This modification does not cause any morphology change, allowing "micro-encryption" of information that is only observable as fluorescence under excitation. The same focused laser also facilitates on demand thinning down of WS2 multilayers into monolayers, turning them into fluorescence active components. With a scanning focused laser beam, micropatterns are readily created on WS2 multilayers through selective thinning of specific regions on the flake.

Effects of selective thinning and residue removal on ground layer structure and diversity in a mixed pine–oak stand of the Qinling Mountains, China

Plant species in the forest ground layer are the main food resources for animals and other organisms in the Qinling Mountains, China. To optimise forest thinning programs, we examined how different selective thinning and thinning residue removal regimes influence ground layer diversity and cover. We explored these factors for 2 years in a mixed pine–oak stand. Results indicate the treatments resulted in an increase in the numbers of species, genus and family by 10, 10 and six, respectively, after 1 year thinning and by 14, 10 and four, respectively, after 2 years thinning, compared with the starting point. The highest richness index was achieved at a selective thinning intensity of 17% and a residue removal rate of 57% concurrently. The highest evenness index was achieved at a selective thinning intensity and residue removal rate of 25 and 43% concurrently. The highest ground cover layer was achieved at a selective thinning intensity and residue removal rate of 25 and 69% concurrently. Our results suggest medium thinning intensity and thinning residual removal rate may benefit ground layer richness, whereas a high thinning intensity and medium thinning residual removal rate may maximise evenness and ground layer cover in current forest.

Effects of heavy thinnings on the increment and selection of trees for tending in Norway spruce monoculture in natural hazard conditions

The paper studies the effects of two heavy selection thinnings on the increment of Norway spruce trees exposed to ice and snow breaks in eastern Serbia. In a thinning that was carried out at 32 years of age, 556 candidates per hectare were selected for tending, and at the age of 40, of the initial candidates, 311 trees per hectare (55.9%) were selected as future trees. In all trees at 41-50 age period, diameter increment was higher by 31%, basal area increment by 64% and volume increment by 67% compared to 32-40 age period. The collective of indifferent trees is significantly falling behind compared to future trees in terms of increment values in both observed periods. However, the value of diameter, basal area and volume increments, of the collective of "comparable" indifferent trees are lower in comparison to the values of increments of future trees by 10-15% in the 32-40 age period, and by 15-21% in the 41-50 age period and there are no significant differences. The results show that heavy selective thinnings, initially directed at a larger number of candidates for tending at stand age that does not differ much from the period of carrying out first "commercial" thinnings, improve the growth potential of future and indifferent trees, where it is rational to do the tree replacement for the final crop in "susceptible" growth stage to snow and ice breaks.

Establishment of woody species across 26 years of revegetation on a Queensland coal mine

SummaryThe establishment success of woody plant species at 56 revegetation sites, four to 26 years old, across the Meandu open‐cut coal mine in south‐east Queensland was assessed. The revegetation process involved returning stockpiled topsoil, deep ripping and mechanical sowing of a mix of native seeds. Blakes Wattle (Acacia blakei) and less often Black Wattle (A. leiocalyx), both primarily derived from respread topsoil seed, dominate the vegetation canopy at 59% and 20% of revegetation sites, respectively. The additional sowing of seeds of many tree and shrub species within the sites has had limited success with most failing to persist or grow well. Revegetation management, for example selective thinning of acacias (Acacia spp.) saplings within the first 5 years is recommended to release the competition pressure on the poorly performing tree species. This will also allow opportunities for other less well represented shrub and herb species to persist. This study has shown that a range of tree and shrub species, including Eucalyptus spp., are performing poorly under the current revegetation regime, suggesting adjustments to revegetation species selection and/or methodologies are needed. The natural colonization of woody native species within the sites from nearby remnant vegetation is shown to be limited to only four species, and therefore is unlikely to significantly supplement the species diversity of the revegetation.

Optimization Forest Thinning Measures for Carbon Budget in a Mixed Pine-Oak Stand of the Qingling Mountains, China: A Case Study

Forest thinning is a silviculture treatment for sustainable forest management. It may promote growth of the remaining individuals by decreasing stand density, reducing competition, and increasing light and nutrient availability to increase carbon sequestration in the forest ecosystem. However, the action also increases carbon loss simultaneously by reducing carbon and other nutrient inputs as well as exacerbating soil CO2 efflux. To achieve a maximum forest carbon budget, the central composite design with two independent variables (thinning intensity and thinning residual removal rate) was explored in a natural pine-oak mixed stand in the Qinling Mountains, China. The net primary productivity of living trees was estimated and soil CO2 efflux was stimulated by the Yasso07 model. Based on two years observation, the preliminary results indicated the following. Evidently chemical compounds of the litter of the tree species affected soil CO2 efflux stimulation. The thinning residual removal rate had a larger effect than thinning intensity on the net ecosystem productivity. When the selective thinning intensity and residual removal rate was 12.59% and 66.62% concurrently, the net ecosystem productivity reached its maximum 53.93 t·ha−1·year−1. The lower thinning intensity and higher thinning residual removal rated benefited the net ecosystem productivity.

Mitigating the Stress of Drought on Soil Respiration by Selective Thinning: Contrasting Effects of Drought on Soil Respiration of Two Oak Species in a Mediterranean Forest

Drought has been shown to reduce soil respiration (SR) in previous studies. Meanwhile, studies of the effect of forest management on SR yielded contrasting results. However, little is known about the combined effect of drought and forest management on SR. To investigate if the drought stress on SR can be mitigated by thinning, we implemented plots of selective thinning and 15% reduced rainfall in a mixed forest consisting of the evergreen Quercus ilex and deciduous Quercus cerrioides; we measured SR seasonally from 2004 to 2007. Our results showed a clear soil moisture threshold of 9%; above this value, SR was strongly dependent on soil temperature, with Q10 of 3.0–3.8. Below this threshold, the relationship between SR and soil temperature weakened. We observed contrasting responses of SR of target oak species to drought and thinning. Reduced rainfall had a strong negative impact on SR of Q. cerrioides, whereas the effect on SR for Q. ilex was marginal or even positive. Meanwhile, selective thinning increased SR of Q. cerrioides, but reduced that of Q. ilex. Overall, our results showed that the negative effect of drought on SR can be offset through selective thinning, but the effect is attenuated with time.

Short‐term selective thinning effects on hydraulic functionality of a temperate pine forest in eastern Canada

AbstractForest plantations are commonly used to restore the ecological and hydrological functionality of landscapes. In this study, we investigated the hydrological response of a 74‐year‐old pine plantation forest in southern Ontario, Canada to a selective thinning, wherein 30% of trees were harvested in winter of 2012. Tree‐level and ecosystem‐level water fluxes were monitored from 2011 to 2013 using sapflow and eddy‐covariance techniques, and were compared with an adjacent 39‐year‐old pine plantation forest that was not thinned. In the 74‐year‐old forest, transpiration declined after thinning in the 2012 growing season, while tree‐level water transport increased despite a severe drought. Time lag between sapflow and ecosystem evapotranspiration showed that the older stand had a significantly shorter time lag when compared to the younger stand, particularly in the thinning year. Linear regression modeling indicated that this was likely due to higher soil moisture status in the older stand versus the younger forest. Hydraulic redistribution of soil water was apparent during drought periods in both forests and did not appear to be negatively affected by the thinning treatment in the older forest. We conclude that selective low density thinning did not negatively impact the forest's response to seasonal drought, and that the availability of more soil moisture as a result of thinning may improve the resilience of the forest to future climatic extreme events such as drought.

Accelerating tropical forest restoration through the selective removal of pioneer species

Demand for tropical forest restoration has grown rapidly as the potential role of recovering secondary forests in sequestering carbon and enhancing biodiversity has been recognised. Active forest management is often prescribed to accelerate natural regeneration, but evidence for the efficacy of interventions is scarce for tropical forests. In this study we examine the hypothesis that the selective removal of abundant pioneers in the understory of recovering selectively logged forests can improve the composition of forest stands and accelerate succession. Four selective thinning treatments of increasing intensity were implemented in 8.75hacompartments and replicated six times. Within each compartment, three monitoring plots were established and measured immediately after thinning and one year later to assess implementation of thinning treatments, growth and survival of stems, and changes in stand composition. Canopy openness was measured using hemispherical photography. Thinning treatments substantially reduced the abundance of pioneers, but there was only a slight increase in canopy openness (3.7–4.3%) relative to the control (1.8%) 8monthsafter implementation. Canopy openness increased dramatically across all treatments in the follow year due to the 2015–16 El Niño event and increased more in thinning treatments. Large (>10cmdbh) and small (2–10cmdbh) late-successional stems showed enhanced growth only in the low intensity thinning treatment, whereas the growth of small pioneer stems increased across the thinning intensity gradient. The cost of implementing thinning treatments was $US80 per ha or approximately 10% of the cost of planting treatments in the same forest. Our findings suggest that selective thinning of understory pioneer stems is a practical option for manipulating stand composition and potentially accelerating natural regeneration. Continued monitoring of the experiment should reveal the long-term impact and cost-effectiveness of treatments.