scholarly journals The Impact of a CO2 Laser on the Adhesion and Mold Resistance of a Synthetic Polymer Layer on a Wood Surface

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 242
Author(s):  
Ladislav Reinprecht ◽  
Zuzana Vidholdová
Keyword(s):  
Co2 Laser ◽  
Phase Interface ◽  
European Beech ◽  
Solid Wood ◽  
Synthetic Polymer ◽  
Polymer Layer ◽  
Fagus Sylvatica L ◽  
Mold Resistance ◽  
The Impact ◽  
Wood Surfaces

In the wood industry, laser technologies are commonly applied for the sawing, engraving, or perforation of solid wood and wood composites, but less knowledge exists about their effect on the joining and painting of wood materials with synthetic polymer adhesives and coatings. In this work, a CO2 laser with irradiation doses from 2.1 to 18.8 J·cm−2 was used for the modification of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies /L./ Karst) wood surfaces—either in the native state or after covering them with a layer of polyvinyl acetate (PVAc) or polyurethane (PUR) polymer. The adhesion strength of the phase interface “synthetic polymer—wood”, evaluated by the standard EN ISO 4624, decreased significantly and proportionately in all the laser modification modes, with higher irradiation doses leading to a more apparent degradation and carbonization of the wood adherent or the synthetic polymer layer. The mold resistance of the polymers, evaluated by the standard EN 15457, increased significantly for the less mold-resistant PVAc polymer after its irradiation on the wood adherent. However, the more mold-resistant PUR polymer was able to better resist the microscopic fungi Aspergillus niger Tiegh. and Penicillium purpurogenum Stoll. when irradiation doses of higher intensity acted firstly on the wood adherent.

scholarly journals How Does Radial Growth of Water-Stressed Populations of European Beech (Fagus sylvatica L.) Trees Vary under Multiple Drought Events?

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 129
Author(s):  
Tamalika Chakraborty ◽  
Albert Reif ◽  
Andreas Matzarakis ◽  
Somidh Saha
Keyword(s):  
Soil Water ◽  
Fagus Sylvatica ◽  
Tree Growth ◽  
Radial Growth ◽  
Basal Area ◽  
European Beech ◽  
Canopy Openness ◽  
Fagus Sylvatica L ◽  
The Impact ◽  
Neighborhood Competition

European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availability in the forest. Besides, we quantified the influence of competition and canopy openness on the mean basal area growth of beech trees. We carried out this study in five near-natural temperate forests in three localities of Germany and Switzerland. We quantified available soil water storage capacity (AWC) in plots laid in the transition zone from oak to beech dominated forests. The plots were classified as ‘dry’ (AWC < 60 mL) and ‘less-dry’ (AWC > 60 mL). We performed dendroecological analyses starting from 1951 in continuous and discontinuous series to study the influence of climatic drought (i.e., precipitation-potential evapotranspiration) on the radial growth of beech trees in dry and less-dry plots. We used observed values for this analysis and did not use interpolated values from interpolated historical records in this study. We selected six drought events to study the resistance, recovery, and resilience of beech trees to drought at a discontinuous level. The radial growth was significantly higher in less-dry plots than dry plots. The increase in drought had reduced tree growth. Frequent climatic drought events resulted in more significant correlations, hence, increased the dependency of tree growth on AWC. We showed that the recovery and resilience to climatic drought were higher in trees in less-dry plots than dry plots, but it was the opposite for resistance. The resistance, recovery, and resilience of the trees were heterogeneous between the events of drought. Mean growth of beech trees (basal area increment) were negatively impacted by neighborhood competition and positively influenced by canopy openness. We emphasized that beech trees growing on soil with low AWC are at higher risk of growth decline. We concluded that changes in soil water conditions even at the microsite level could influence beech trees’ growth in their drought limit under the changing climate. Along with drought, neighborhood competition and lack of light can also reduce beech trees’ growth. This study will enrich the state of knowledge about the ongoing debate on the vulnerability of beech trees to drought in Europe.

Fe-Sem Characterisation Of Pinus Radiata Solid Wood And Plywood Surfaces Following Machining

IAWA Journal ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 69-84
Author(s):  
Adya P. Singh ◽  
Bernard S.W. Dawson
Keyword(s):  
Cell Wall ◽  
Pinus Radiata ◽  
Morphological Characteristics ◽  
Solid Wood ◽  
Outer Face ◽  
Subsurface Layers ◽  
Cell Layers ◽  
Wooden Surface ◽  
The Impact ◽  
Wood Surfaces

Selection of coatings for good performance on textured wooden surfaces requires a sound knowledge of the wooden surface textures which result from machining treatments. In this work, Pinus radiata solid wood surfaces were planed, sanded and band-sawn while Pinus radiata plywood surfaces were peeled and rough-sawn. The impact of the various machining treatments was examined by field emission scanning electron microscopy. Particular emphasis was placed on micro-morphological characteristics of surface and sub-surface tissue layers. Planing and sanding resulted in even surface topographies. On planed surfaces, cell deformation and cell wall damage was confined to the outermost cell layers while on sanded surfaces they extended to one or two subsurface layers. Band-sawn solid wood surfaces and rough-sawn plywood surfaces were highly irregular, the result of distortion and loss of tissue masses along the outer face caused by forces generated during sawing. Cell wall level damage, such as delamination and cracking, were present in many cell layers below the surface. Compared to the band-sawn solid wood samples, tissue damage in rough-sawn plywood was more severe. These features are discussed in relation to how micromorphological damage embedded in the surface and subsurface tissue layers can create regions of a highly porous nature with increased surface area which are suited to coating entanglement.

scholarly journals The Impact of Adverse Weather and Climate on the Width of European Beech (Fagus sylvatica L.) Tree Rings in Southeastern Europe

Atmosphere ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 451 ◽  
Author(s):  
Stefan Stjepanović ◽  
Bratislav Matović ◽  
Dejan Stojanović ◽  
Branislava Lalić ◽  
Tom Levanič ◽  
...  
Keyword(s):  
Fagus Sylvatica ◽  
Tree Rings ◽  
Ring Width ◽  
European Beech ◽  
Growing Season ◽  
Deciduous Tree ◽  
Beech Forests ◽  
Adverse Weather ◽  
Fagus Sylvatica L ◽  
The Impact

European beech (Fagus sylvatica L.) is the most important deciduous tree species in Europe. According to different climate scenarios, there is a relatively high probability of a massive decline in and loss of beech forests in southern Europe and in the southern part of central Europe. Thus, the authors of this study explored the dynamics of tree diameter increments and the influence of extremely dry years on the width of tree rings. This study used dendroecological methods to analyze the growth and diameter increments of European beech trees at locations in Serbia and the Republic of Srpska. The sampling was conducted along the vertical distribution of beech forests, at five sites at the lower limit of the distribution, at five optimal sites of the distribution, and at five sites at the upper limit of the distribution. Long-term analyses indicate that dry conditions during a growing season can reduce tree-ring width, but a reduction in tree growth can be expected as a result of more than one season of unfavorable conditions. Low temperatures in autumn and winter and prolonged winters can strongly affect upcoming vegetation and reduce tree development even under normal thermal conditions during a growing season.

Effects of manganese addition on carbon release from forest floor horizons

2011 ◽  
Vol 41 (3) ◽  
pp. 643-648 ◽  
Author(s):  
Florence Trum ◽  
Hugues Titeux ◽  
Jean-Thomas Cornelis ◽  
Bruno Delvaux
Keyword(s):  
Forest Floor ◽  
European Beech ◽  
Organic C ◽  
Dissolved Organic C ◽  
Carbon Release ◽  
Fagus Sylvatica L ◽  
Forest Floors ◽  
Degrading System ◽  
The Impact ◽  
Clear Increase

Lignin concentration in organic residues largely controls their decomposition. Mn2+ may well play a key role in ligninolysis because it is a cofactor of manganese peroxidase, an enzyme of the lignin-degrading system. This study aims to investigate the effects of Mn2+ addition on forest floor horizon decomposition during laboratory incubation. Therefore, we sampled two distinct forest floors from European beech ( Fagus sylvatica L.) stands: a mor and a moder. Lignin and Mn concentrations in forest floor upper layer were significantly larger in moder than in mor. Three horizons from each forest floor were separately incubated with or without Mn2+ addition (250 mg Mn·kg dry matter–1) and the release of both CO2 and dissolved organic C was measured. The dissolved organic C release was not impacted by the Mn2+ addition, while a clear increase in CO2 release from specific horizons was observed. Our data suggest that the impact of the Mn2+ addition depends on (i) the forest floor type and on (ii) the organic matter decomposition stage.

scholarly journals Identification of stress biomarkers for drought and increased soil temperature in seedlings of European beech (Fagus sylvatica)

2017 ◽  
Vol 47 (11) ◽  
pp. 1517-1526
Author(s):  
Milica Popović ◽  
Marco Gregori ◽  
Dominik Vodnik ◽  
Mitja Ferlan ◽  
Tanja Mrak ◽  
...  
Keyword(s):  
Drought Stress ◽  
Soil Temperature ◽  
Fagus Sylvatica ◽  
Radical Scavenging ◽  
European Beech ◽  
Glutathione Peroxidases ◽  
Increased Risk ◽  
Fagus Sylvatica L ◽  
Rain Events ◽  
The Impact

Drought is an environmental stress that impacts plant productivity. Projections show both an increase in intense rain events and a reduction in the number of rain days, conditions that leads to increased risk of drought. Consequently, the identification of molecular biomarkers suitable for evaluating the impact of water deprivation conditions on forest plant seedlings is of significant value for monitoring purposes and forest management. In this study, we evaluated a biochemical methodology for the assessment of drought stress coupled with variable soil temperature in European beech (Fagus sylvatica L.) seedlings by analyzing a set of metabolites and enzymes involved in free radical scavenging and cell wall synthesis. The results indicate that the specific activities and isoform profile of superoxide dismutases and glutathione peroxidases together with the variation of phenolic compounds enable discrimination between seedlings with different degrees of photosynthetic activity. This approach represents a promising platform for the assessment of drought stress in forest trees and could serve for enhancing selection and breeding practices, allowing for plants that are more tolerant of abiotic stress.

scholarly journals The impact of climate change on the growth of European beech at optimal altitudes in the Republic of Srpska

Topola ◽  
2021 ◽  
pp. 5-10
Author(s):  
Stefan Stjepanović ◽  
Boban Miletić ◽  
Branislav Drašković ◽  
Vesna Tunguz
Keyword(s):  
Negative Impact ◽  
Pearson Correlation ◽  
Aridity Index ◽  
European Beech ◽  
Climate Data ◽  
Temperature And Precipitation ◽  
Fagus Sylvatica L ◽  
The Republic ◽  
Ellenberg’S Climate Quotient ◽  
The Impact

Many studies have shown that small climate changes can strongly affect the forest trees growth rate, many times causing changes in species habitats. In general, drought is mentioned as the main problem, so it is necessary to carry out its identification and quantification to investigate its effects on forests in Republic of Srpska. This study aims to analyse the relationship between the growth of European beech (Fagus sylvatica L.) at optimal altitudes in the Republic of Srpska and its climate characteristics represented by the Forestry Aridity Index (FAI) and Ellenberg's climate quotient (EQ) for 1950-2015 timespan. FAI and EQ were calculated using climate data (temperature and precipitation) extracted from a gridded dataset (E-OBS). Sampling was carried out in two localities near Vlasenica and Mrkonjić Grad at 1050 and 1030 meters above sea level (m a.s.l.), sampling the cores from 15 dominant trees at each locality. Using the Pearson Correlation Analysis, a negative impact on tree rings width (TRW) with rising index values was identified. This is especially pronounced for the index values of the year prior to the ring formation. In general, stronger negative correlations between TRW and EQ are found for the locality near Mrkonjić Grad, while FAI index showed a greater negative impact on TRW for the locality near Vlasenica.

33 An Evidence Based Laser Therapy Algorithm for the Treatment of Burn Scars

2021 ◽  
Vol 42 (Supplement_1) ◽  
pp. S26-S27
Author(s):  
Rajiv Sood
Keyword(s):  
Laser Treatment ◽  
Laser Therapy ◽  
Co2 Laser ◽  
Statistical Significance ◽  
Evidence Based ◽  
Baseline Measurement ◽  
Burn Scar ◽  
Therapy Algorithm ◽  
Laser Treatments ◽  
The Impact

Abstract Introduction Hypertrophic scarring after burn injury can be extremely painful, cause profound itching, and affect the way patients view themselves and how the outside world perceives them. We have utilized laser therapy as a modality for scar modulation for our patients since 2013. In 2014, we initiated and completed a prospective IRB approved study to evaluate the outcome of scars treated with fractional CO2 laser therapy (FLT) utilizing objective and subjective tools. Recently, we have completed a prospective study evaluating the use of pulse dye laser (PDL) therapy and the impact on post-burn pruritis. In reviewing the outcomes from these two studies, we have developed an evidence-based laser therapy algorithm for burn scar management. Methods The FLT study entailed a series of three CO2 laser treatments minimally 4–6 weeks apart with scar measurements and POSAS form completion performed prior to each laser treatment and four weeks after the last FLT. Scar measurements that included color, pliability, and scar thickness; and completion of the POSAS form were obtained prior to each laser therapy session and four weeks after the third laser treatment. The measurements of color, pliability, and scar thickness were measured with the Colorimeter, Cutometer, and ultrasound. The PDL study utilized the 5-D Itch scale to evaluate post-burn pruritis. A baseline measurement was obtained prior to any laser treatments. Each patient underwent two PDL sessions and a 5-D itch scale was completed four to six weeks after the second PDL session. The baseline measurement was then compared to the final 5-D itch scale measurement. Results Data from the FLT study is in Table 1 and shows that there were statistically significant improvements in the Patient and Observer POSAS scores, patient rated Itch score, scar thickness, and measured skin density. Changes to patient rated scar pain, scar color, and pliability were noted but were not of statistical significance. Data from the PDL study is in Table 2 and shows a statistically significant decrease in the treated patients’ post-burn pruritis. Conclusions In reviewing the outcomes of these two studies, we have developed an algorithm based on our studies. All of our patients undergoing laser therapy receive two PDL sessions that are four to six weeks apart followed by 3 FLT sessions. The use of both PDL and FLT decreases post-burn pruritis, decreases scar thickness, decreases pain, and increases patient satisfaction as shown in our research.

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