Wood Discs Research Articles

Identification, Enzymatic Activity, and Decay Ability of Basidiomycetous Fungi Isolated from the Decayed Bark of Mongolian Oak (Quercus mongolica Fisch. ex Ledeb.)

Decay fungi can decompose plant debris to recycle carbon in the ecosystem. Still, they can also be fungal pathogens, which can damage living trees and/or wood material and cause a large amount of timber loss. We isolated and identified basidiomycetous fungi from the decayed bark of Mongolian oak wrapped with sticky roll traps. The degrading enzyme activities were then tested for all fungal isolates. The decay ability of selected isolates was assessed based on the weight loss of wood discs after inoculating with culture suspension of decay fungi under the different humidity levels. A total of 46 basidiomycetous fungal isolates belonged to 12 species, and 10 genera were obtained from Jong Myo (16 isolates), Chang Kyung palace (7 isolates), Cheong Gye (10 isolates), and Gun Po (13 isolates). Gymnopus luxurians was the most dominant fungus in the present study, and this species distributed in all survey sites with 9 isolates in Jong Myo, followed by 3 isolates in Chang Kyung palace, while Cheong Gye and Gun Po had only 1 isolate each. Among 46 isolates, 44 isolates secreted at least one enzyme, while 25 isolates produced both cellulase and phenol oxidase enzymes, and 2 isolates produced neither. The assessment of decay ability by artificial inoculation indicated that the weight loss of wood discs was significantly influenced by humidity conditions when inoculated with bark decay fungi. The percent weight losses by G. luxurians inoculation in RH of 90-100% and RH of 65-75% were 4.61% and 2.45%, respectively. The weight loss caused by Abortiporus biennis were 6.67% and 0.46% in RH of 90-100% and RH of 45-55%, respectively. The humidity reduction approach should be applied for further studies to control the growth and spread of bark decay fungi on the trunks wrapped with sticky roll traps.

ОЦЕНКА БЕЗОПАСНОСТИ ПРИМЕНЕНИЯ ПОЛИМЕРНОГО МАТЕРИАЛА «ПЕНОПЛЕКС» В ЖИВОТНОВОДСТВЕ

The article presents data on veterinary and sanitary and hygienic assessment of the polymer material «Penoplex». The above material is made of Styrofoam and used in many areas of production, including to reduce heat loss of livestock facilities. Cattle and pig manure was used as a contact medium with the material under study. The duration of contact with the material (exposure) was 30 days. To study the resistance of the material to disinfectants, we used: 10 % sodium hydroxide solution (80 °C); 5 % solution of soda ash (70 °C); clarified solution of bleach containing 3 % active chlorine; 40 % solution of formaldehyde; 2 % solution of hydrogen peroxide. Studies of samples of the polymer material «Penoplex» for resistance to animal secretions and disinfectants have shown that the polymer material is resistant to them. During the experiment and after its completion, the «Penoplex» material had no visually visible changes on the outer layer. The used disinfectants and the model environment did not violate the structure of the polymer material «Penoplex». A slight change in the color of the «Penoplex» was found on the 20th day of exposure to 10 % solution of sodium hydroxide with temperature of 70 °C. For sanitary and bacteriological evaluation of «Penoplex», the disk method was used. Discs with a diameter of 10 mm were prepared from the material under study; wood discs were used as a control. Studies have found that Penoplex has no effect on sanitary-indicative microorganisms and is neutral in relation to their growth, which indicates the absence of release of substances from it into the environment that can delay or stimulate the growth of test cultures. The veterinary and sanitary and hygienic assessment of the polymer material «Penoplex» is the basis to recommend it for use in the construction of livestock buildings and inclusion as an addition to the current «List of polymer materials and structures permitted for use in the construction and technological equipment of livestock facilities» in the prescribed manner.

Leaf area – sapwood area relationship in Scots pine (Pinus sylvestris L.) under mistletoe (Viscum album ssp. austriacum) infection

Leaf area is linearly correlated with sapwood area in trees. The linearity of this relationship can be affected by some biotic and abiotic factors. Mistletoes are hemi parasitic plants that take up water and mineral nutrients from their hosts and affect host physiological responses. There is no conclusive evidence to show the effect of pine mistletoe (Viscum album ssp. austriacum) on leaf area and sapwood area relationship in Scots pine trees (Pinus sylvestris L.) at tree level. The aim of this study is to determine and quantify the effect of pine mistletoe on the structural variation of leaf area and sapwood area relationship at tree level in Scots pine. A total of 18 mistletoe infected and 12 uninfected Scots pine trees were destructively sampled. All needles and mistletoes were completely removed from sampled trees to determine needle and mistletoe characteristics, biomass and leaf area. Sapwood areas at breast height (BH) and at crown base height (CBH) were determined from wood discs taken from BH (1.3m) and CBH. Sapwood area was delineated by benzidine staining method. Pearson correlation, t-test and regression analyses were conducted to determine the relationship between sapwood area and needle-mistletoe leaf area relationships. The results indicated that both the relationships between sapwood area and leaf area in uninfected, and sapwood area and total leaf area (needle plus mistletoe leaf only) in infected trees were linear. However, the slope of regression equation for mistletoe infected trees was considerably lower when compared to the uninfected trees. As for the variation of the sapwood area along the stem below live crown, there was a slight difference between sapwood area at BH and CBH. The study showed also that mistletoe infection led to a significant reduction in needle size (length, width, area and weight) in Scots pine trees. Significant relationships were found between the sapwood area and leaf area in this study. The results of this study may help fill the gap in the knowledge concerning the impacts of pine mistletoe on the dynamics of Scots pine trees.

Modelling dendro-anthracological parameters with dendrochronological reference datasets: Interrogating the applicability of anthraco-typology to assess Aleppo pine (Pinus halepensis Miller) wood management from archaeological charcoal fragments

Aleppo pine (Pinus halepensis Miller) is present in the palaeoenvironmental records of Mallorca (Balearic Islands, Western Mediterranean) since the Early Holocene. It is also documented in the archaeological charcoal analysis (aka anthracology) of early prehistoric sites, but it was especially exploited at certain sites during the Late Iron Age. However, different woodland exploitation strategies cannot be deciphered purely through the taxonomical identification of charcoal fragments, so it is difficult to assess if the presence of Aleppo pine in archaeological assemblages is due to specific social management strategies (branches and/or trunks exploitation). Anthraco-typological methods, based on the measurement of charcoal-pith distance (allowing original wood diameters to be inferred) and ring width, have already been proposed for temperate species (Quercus petraea/robur) as a methodology to define the woodland exploitation of past societies and human impact on forest formations. However, such an approach yet to be set up for conifers growing in Mediterranean environments. In this study we have adapted the anthraco-typological methodology to conifer wood anatomy and evaluated its applicability on the archaeological charcoal assemblages of Aleppo pine, through complete dendrological analysis of the referential material. Our research is based on the systematic measurement of two different dendro-anthracological parameters on archaeological charcoal fragments: charcoal-pith distance and ring width. The results have been compared with the information on ring width and the growing conditions of modern trees in three different forest formations in Mallorca, representing the entire environmental variability of the Aleppo pine forests on the island. Trunk cores and wood discs of different diameter were measured in order to establish criteria to distinguish between both tree organs from the archaeological charcoal fragments. Analysis of this dataset has proved that anthraco-typological methods are applicable to Mediterranean conifers and to further interrogate pinewood exploitation in prehistoric Mallorca. Additionally, we have been able to question the formation of archaeological charcoal assemblages, identify various woodland management strategies and the human impact on woodlands during prehistory.

English

Cassava processing requires peeling, which is mainly done manually and not effective for large scale processing, hence, the need to mechanise the peeling process. A motorized cassava peeler with four drum and disc linings (concrete, metal, rubber and wood) was designed. The prototype was tested at three disc speeds; (250, 350 and 500 rpm) to determine peeling capacity, peel removal efficiency, and flesh loss. The capacity for the concrete, metal, rubber and wooden discs increased with increased speed from 180-360, 360-1440, 120-540 and 80-144 kg/h, for speeds 250-500 rpm, respectively. Metal and concrete discs recorded the highest peel removal efficiencies of 75.97 and 78.33%, respectively at 350 rpm. The average flesh loss for concrete, metal and rubber discs increased with increasing speeds from 19.66-26.57, 20.94-34.83% and 7.98-31.06%, respectively for 250-500 rpm speeds. The wooden disc on the other hand had no regular pattern with highest value of flesh loss of 12.95% at 500 rpm. Regarding optimum performance, rubber and concrete discs were better, comparing peel removal efficiency and percent flesh loss for all speeds. The study shows the rotating disc linings had more effect on peeling than the drum linings. Key words: Cassava, lining material, disc material, evaluation, peeling quality index.

Efficiency of radiofrequency-vacuum (RF/V) technology for mixed-species drying of wood disks with inherent defects

Freshly cut 30-mm-thick wood disks of Scots pine, Caucasian elm, narrow-leafed ash, wild cherry, black walnut, and European alder with various natural grade defects were dried together in a radiofrequency-vacuum (RF/V) dryer. A mild four-step drying schedule at the maximum temperature of 45 °C and power density in the range of 1-2 kWm−3 with an “on-off” control of RF radiation at the final step was used. The moisture content of the disks at the end of drying ranged from 10.6% to 13.4%. An almost uniform radial moisture gradient developed in the dried disks. The six wood species, however, exhibited variations in checking. The RF/V drying schedule used here was able to completely inhibit near-bark radial checking in all disks but pine and elm, whereas it failed to efficiently prevent V-cracking in pine and ash with a high mean tangential to radial shrinkage anisotropy (ST/SR). A strong positive correlation was also found between ST/SR and the proportion of V-cracked disks. The occurrence of ring failure within the reaction wood-containing disks of walnut, pine, and elm was almost completely prevented by the drying schedule, but a significant correlation was observed between the pith eccentricity and V-crack length in the compression wood-containing disks of pine. All other natural defects, i.e., scar in cherry, bark pocket, double or triple pithing in walnut and elm, sound knots in pine, and roundness deviation, exhibited no statistically significant effect (p > 0.05) on check formation.

On the sensitivity of an air pycnometer

An air pycnometer is constructed based on the concept of energy conservation for the investigation of its sensitivity. The apparatus assumes that the ideal gas law holds and energy transfer between the system and its surroundings is negligible. It comprises two connected chambers—reference and sample. The addition of a ball valve helps isolate them. The volume ratios between them, i.e., 0.52 and 1.00, are explored experimentally for their sensitivity. The predictions for the ratio of 0.20 and 0.33 are also given. Acrylic disks of known volumes are used for testing filling fractions under the volume-ratio conditions. The data are fitted to the model, derived from energy conservation, for the atmospheric pressure and the initial pressure of the reference chamber. The derivative of the model gives rise to sensitivity curves in terms of filling fractions for given volume ratios. Four volume ratios, 0.20, 0.33, 0.52, and 1.00, are explored for their sensitivities and characteristics. The results show that the sensitivity of the pycnometer relates to both the volume ratio between chambers and the filling fraction. When graphed for different volume ratios, the sensitivity monotonically increases as the filling fraction rises for all ratios. The system is more sensitive for a greater ratio only when the filling fraction is more than 75%. For lesser filling fraction, the sensitivity becomes subtle and is unlike that of the nearly-filled chamber. Here, we reveal and discuss this phenomenon. Besides, the results also indicate that sensitivity customization can be achieved. To clarify this statement, we apply the apparatus to determine the void volume, for four filling fractions, of divided solids—full and broken grains of rice and sugar beads—and a fibrous sample—a palm wood disk. The results agree with those of the water saturation approach. Our apparatus gives reliable results, and its sensitivity dependence is elucidated. Locations of the sensitivity degeneracy are identified. The correlation between the filling fraction and volume ratio of the system cavities is described.

Investigating the Anatomical and Physical-Mechanical Properties of the 8-Year-Old Superior Teakwood Planted in Muna Island, Indonesia

Muna teakwood, especially from old stands, has been popular as raw material for timber industries in Indonesia for the past ten decades. Due to the scarcity of this wood, superior-grown seedlings of Muna teakwood have been developed and widely planted. Since there is no information on its characteristics, therefore, the aim of this research was to investigate wood characteristics of the 8-year-old superior-grown teak from Muna Island to ensure their proper utilization as raw material for wooden furniture. Wood discs and boards from basal area of three different trees were used as the samples. Macroscopic and microscopic anatomical characteristics were observed following the IAWA

How Vikings crossed the North Atlantic? The reinterpretation of ‘sun compasses’ — Narsarsuaq, Wolin, Truso

The discovery of the Narsarsuaq disc (Uunartoq, Greenland) in 1948 sparked a long discussion on the identification of wooden discs as solar compasses used by the Vikings during sea voyages across t...

Communities of Fungi in Black Cherry Stumps and Effects of Herbicide.

So far, there have been no studies on fungal communities in Prunus serotina (black cherry) wood. Our objectives were to characterize fungal communities from P. serotina wood and to evaluate effects of glyphosate (Glifocyd 360 SL) used on P. serotina stumps on abundance, species richness and diversity of those communities. In August 2016, in the Podanin Forest District, stumps of black cherry trees left after felling were treated with the herbicide. Control stumps were treated with water. Wood discs were cut from the surface of the stumps in May and July–August 2017. Eight treatment combinations (2 herbicide treatments × 2 disc sizes × 2 sample times) were tested. Sub-samples were pooled and ground in an acryogenic mill. Environmental DNA was extracted with a Plant Genomic DNA Purification Kit. The ITS1, 5.8S rDNA region was used to identify fungal species, using primers ITS1FI2 5′-GAACCWGCGGARGGATCA-3′ and 5.8S 5′-CGCTGCGTT CTTCATCG-3′. The amplicons were sequenced using the Illumina system. The results were subjected to bioinformatic analysis. Sequences were compared with reference sequences from the NCBI database using the BLASTn 2.8.0 algorithm. Abundance of fungi was defined as the number of Operational Taxonomic Units (OTUs), and diversity as the number of species in a sample. Differences between the number of OTUs and taxa were analyzed using the chi-squared test (χ2). Diversity in microbial communities was compared using diversity indices. A total of 54,644 OTUs were obtained. Culturable fungi produced 49,808 OTUs (91.15%), fungi not known from culture had 2571 OTUs (4.70%), non-fungal organisms had 1333 (2.44%) and organisms with no reference sequence in NCBI, 934 OTUs (1.71%). The total number of taxa ranged from 120 to 319. Fungi in stump wood were significantly more abundant in July–August than in May, in stumps >5 cm diameter than in stumps <5 cm diameter, in glyphosate-treated than in untreated stumps when sampled in May, and in untreated than in glyphosate-treated stumps when sampled in July–August. Species richness was significantly greater in July–August than in May, and in stumps >5 cm diameter than in stumps <5 cm diameter, either treated or untreated, depending on size. Herbicides can therefore affect the abundance and diversity of fungal communities in deciduous tree wood. The greater frequency of Ascomycota in herbicide-treated than in untreated stumps indicates their greater tolerance of glyphosate.

Experimental Parameters Influence the Observed Antimicrobial Response of Oak Wood (Quercus petraea).

The present investigation aimed to utilize a direct wood disc diffusion method to study the influence of plane of cutting, cutting method, sterilization method, and origin of tree on the antimicrobial activity of wood material. Six oak wood trees (Quercus petraea) were collected from 3 different locations in France. They were cut into 4 mm thick slices with either transverse (RT), tangential (LT) or radial (LR) faces. Round discs (diameter 9.95 ± 0.1 mm) were cut from the slices via a laser machine or a manual punch machine, and were sterilized with gamma irradiation (25 kGy) or autoclaving (121 °C). The antimicrobial activity of wood was tested using a direct diffusion method against Staphylococcus aureus and Acinetobacter baumannii isolates. The zone of inhibition around the wooden disc was recorded following the recommendations used for antibiotics tests. The results showed that S. aureus was more susceptible than A. baumannii, to the chemicals that diffused from the wood. The transverse face discs exhibited higher antimicrobial activity. Samples that had been sterilized by autoclaving showed significantly (p < 0.05) lower antimicrobial activity, whereas the cutting method and origin of tree did not influence the antimicrobial activity of wood material. Therefore, the choice of sterilization method and cutting planes must be taken into account while studying and interpreting the antibacterial properties of wood material.

Distributions of 137Cs and 90Sr activity concentrations in trunk of Scots pine (Pinus sylvestris L.) in the Chernobyl zone

Possibility of the economical utilization of forests in the radioactive contaminated areas depends on compliance of the radionuclide activity concentrations in wood with the hygiene norms or national standards that are established by the governments or regulators. Since such regulations consider wood as a whole, development of the sampling methods for assessment of compliance of wood to the norms or standards requires the adequate addressing the issues related to heterogeneity of the radionuclide distributions within the tree trunks.In this paper we present spatial distributions of the 90Sr and 137Cs activity concentrations in the trunk wood of mature Scots pine (Pinus sylvestris L.) trees in the Chernobyl exclusion zone in the late stage (30 years) after the deposition. Four 52–53 year old model trees were sampled in the forest stand located in approximately 5 km from the accidental nuclear reactor. The radionuclide concentrations were measured in 156 wood samples collected from the wood disks cut off the tree trunks at the set of heights. To address variability of the tree sizes and radionuclide concentrations between the individual trees, we applied the corresponding relative indices enabling identification of the general patterns of the spatial distributions of 90Sr and 137Cs. We demonstrated significant differences in bioavailability and distribution trends between the studied radionuclides. 137Cs is translocated to the younger parts of the tree trunk, while the 90Sr concentrations are higher in heartwood and in senescing tissues, which is explained by the different chemical properties of Cs and Sr and by different physiological roles played in plant development by their chemical analogs and major plant nutrition elements, Ca and K respectively. In this reason, the principal distribution patterns of the studied radionuclides in the trunk wood do not significantly change with time, and the results of our study generally are in good agreement with those obtained in the earlier stage after the deposition. The above trends are clearly expressed in both radial and longitudinal directions and result in systematic deviation of the concentrations estimated based on core sampling from the average concentrations in the whole tree trunk.

Tracing radioactive cesium in stem wood of three Japanese conifer species 3\xa0years after the Fukushima Dai-ichi Nuclear Power Plant accident

To understand the dynamics of accident-derived radioactive cesium (137Cs) in stem wood that had a substantial amount of heartwood at the time of the Fukushima Dai-ichi Nuclear Power Plant accident, the radial and vertical distributions of 137Cs activity concentration in stem wood of Japanese cedar (Cryptomeria japonica), cypress (Chamaecyparis obtusa), and larch (Larix kaempferi) were investigated. In addition, the natural distribution of stable cesium (133Cs), rubidium (85Rb), and potassium (39K) concentrations was analyzed to determine the characteristics of 137Cs distribution. Wood disks were collected from the tree stems of six cedars, three cypresses, and two larches at multiple heights in 2014, and the concentrations were measured every 2 cm in the radial direction. 137Cs distribution in stem wood differed among tree species, sampling site, and vertical position of the stem within a tree. Statistical analyses suggested that the radial distribution of 137Cs within the heartwood can be explained by the heartwood moisture content and the distance from the treetop, regardless of species, while the distribution between sapwood and heartwood was dependent on the heartwood cross-sectional area and was additionally different between larch and other species. Similarly, the heartwood/sapwood concentration ratios of stable alkali metals differed between larch and the other species. In the larch, the ratio was ca. 0.5 for all elements, but the ratio was over 1.0 and differed among elements in the other species. Consequently, the species-specific difference in the distribution of 137Cs between sapwood and heartwood was considered to be due to different activity levels of radial transport toward the heartwood. The radial variation pattern of the 137Cs/133Cs concentration ratio showed that less 137Cs was transferred to the inner heartwood compared with the 133Cs distribution pattern in many trees; however, there was also a tree in which 137Cs was excessively transferred to the inner heartwood compared with the 133Cs distribution pattern. Such patterns may result from a combination of significant foliar uptake of 137Cs and poor root uptake after the accident, in addition to the high moisture content of the heartwood.

Effect of firebrand size and geometry on heating from a smoldering pile under wind

Smoldering firebrands can be lofted over long distances, easily igniting spot fires. This poses a threat to structures in the wildland-urban interface (WUI), where wildland fires spread into and within communities. This study investigates the influence of firebrand size and makeup on heating from a pile to a recipient surface in a small-scale wind tunnel. Two sizes of fluted birch wooden pins and wooden discs, one size of cylindrical birch dowels, two lengths of eucalyptus sticks, and pine bark flakes were used to simulate firebrands; all with 4 g of smoldering brands deposited. The porosity of the different firebrand piles, the heat flux to an inert test surface, spatial measurements of surface temperature, and videos of the experiments were recorded and analyzed. It was found that the realistic fuels, i.e. pine bark and eucalyptus sticks, could achieve higher peak heat fluxes than artificial birch fuels at higher wind speeds, which exhibited little change with geometry. This change was not due to material makeup alone, but also the way in which the bulk density and height of the pile changed for different smoldering fuels.

Wood and Veneer Properties of Fast Growing Species from Batai, Eucalyptus and Kelampayan

Anatomical, physical, chemical and veneer properties of wood are important aspect that affect applicability of wood based product. This study is focused on three fast growing species of Batai (Paraserianthes falcataria), Eucalyptus (Eucalyptus pellita) and Kelampayan (Neolamarckia cadamba). All trees were cut into three height portion (bottom, middle and top) and wood disc samples are taken for anatomical, physical and chemical determination from each part of height. Meanwhile veneer properties were determined for veneer sheet after peeling and drying process. Eucalyptus shows the highest number of vessel for 16 mm2 area and near pith has higher frequency of vessel occurrence than near bark. The highest specific gravity for Batai, Eucalyptus and Kelampayan were found in bottom portion, followed by middle and top portion. Percentages of moisture content for this tree species is increased going from bottom to top portion. Cold and hot water, alcohol toluene, ash content and lignin content were found to have significant differences for top, middle and bottom of tree portion. The highest of percentage of veneer shrinkage was shown by Kelampayan veneer. Meanwhile, Batai veneer exhibited the lowest contact angle. As the conclusion, species and tree portions were found to be significantly affected for the anatomical, physical and chemical properties. For veneer analysis, species were found to affect veneer parameters. The results are of importance in order to optimize the production of plywood from fast growing species in Malaysia.

Fungal communities in decomposing wood along an energy wood harvest gradient

The current requirements to decrease the consumption and greenhouse gas emissions of fossil fuels have increased the demand of renewable energy sources. In forestry, this situation has intensified harvesting practices resulting in a decreased amount of woody debris left on the clear-cut areas. Impacts of energy wood harvest on wood-decomposing fungi were studied in a large-scale experiment in clear-cut stands in three geographical areas in Finland. A sequence of treatments was expected to form a forestry induced soil disturbance gradient: (1) logging residues left at site, no soil preparation; (2) logging residues left at site, patch mounding; (3) 70% logging residue removal, patch mounding; and (4) complete stump and logging residue removal, patch mounding. Pre-weighed wood discs were incubated on the intact soil cover for four years to estimate decomposition rate and fungal decomposer community. A soil sample was taken underneath each disc to evaluate the direct inoculation potential of the soil. The main results were as follows: (1) The differences between the treatments were not significant, while the geographical factors affected the decomposition rate and the fungal communities of the wood discs. (2) The fungal composition in the wood discs did not reflect the underlying soil fungal community, which indicates that a part of the fungal species inhabiting wood discs originated from airborne surrounding sources. (3) The increase in fungal species diversity was associated to the wood decay process, indicated by parallel increase in the wood decomposition rate and the number of white rot and mycorrhizal fungi. Thus our study indicates that in addition to local environment, landscape-level factors control the decomposer fungal community and its activity in wood.

The Screening of White-Rot Fungi as Biological Control Agents against Ganoderma philippii

Ganoderma philippii is the causal agent of root rot disease causing economic losses to Acacia plantations. In an effort to control the Ganoderma root-rot disease, we isolated and screened white-rot fungi as biological control agents. We collected 107 samples from forestry plantations in Riau Province. The fungi were isolated from rotten wood including trunks and twigs, and fruiting bodies. Out of the 107 samples, 28 from rotten woods and 51 from fruiting bodies were successfully isolated. Screening of the isolated fungi was done on wood block, wood disc, and wood-powder-containing agar. Eleven isolates showed fast growth on wood block and in subsequent second screening in dual culture on wood disc, three isolates showed fast growth and were capable of overgrowing G. philippii. The third screening was to examine quantitative growth rate of selected fungal isolates on malt extract agar wood powder (MEA-WP) two isolates were selected. These two isolates have shown potential as biological control agents of the root-rot pathogen, G. philippii.

Development of Low-Cost Portable Spectrometers for Detection of Wood Defects.

Portable spectroscopic instruments are an interesting alternative for in-field and on-line measurements. However, the practical implementation of visible-near infrared (VIS-NIR) portable sensors in the forest sector is challenging due to operation in harsh environmental conditions and natural variability of wood itself. The objective of this work was to use spectroscopic methods as an alternative to visual grading of wood quality. Three portable spectrometers covering visible and near infrared range were used for the detection of selected naturally occurring wood defects, such as knots, decay, resin pockets and reaction wood. Measurements were performed on wooden discs collected during the harvesting process, without any conditioning or sample preparation. Two prototype instruments were developed by integrating commercially available micro-electro-mechanical systems with for-purpose selected lenses and light source. The prototype modules of spectrometers were driven by an Arduino controller. Data were transferred to the PC by USB serial port. Performance of all tested instruments was confronted by two discriminant methods. The best performing was the microNIR instrument, even though the performance of custom prototypes was also satisfactory. This work was an essential part of practical implementation of VIS-NIR spectroscopy for automatic grading of logs directly in the forest. Prototype low-cost spectrometers described here formed the basis for development of a prototype hyperspectral imaging solution tested during harvesting of trees within the frame of a practical demonstration in mountain forests.

QUALITY OF Eucalyptus urograndis CHARCOAL PRODUCED IN THE SOUTHERN REGION OF TOCANTINS

The objective of this work was to determine the quality of the Eucalyptus urophilla x Eucalyptus grandis clone charcoal, defining the basic density and wood retractability, apparent density, breaking index, charcoal yield, condensable and non-condensable gas yield, AQI and calorific values, comparing the results of different trunk positions and in two different heating ramps, ramp 1 (R1) with a heating rate of 1.25 ºC/min, final temperature of 450ºC and total of 6 hours, and ramp 2 (R2) with a heating rate of 1.19 ºC/min, final temperature of 500ºC and total time of 7 hours. The six evaluated trees were from a six-year-old cloned tree plantation located in the municipality of Gurupi, in the south of Tocantins state. The specimens for the characterizations were made from wooden discs removed from three trunk positions (base, DBH, top). The Eucalyptus urograndis wood presented basic density considered average (0.47 g/cm³) and good dimensional stability. The charcoal presented an expected yield and high calorific value influenced by the final temperature of the heating ramps, high fixed carbon content, acceptable ash content, as well as a low breaking rate. The results were satisfactory and identified the species as a good energy source.

Kinetics of drying of certain lacquers and paints in isothermal conditions using a thermogravimetric analyser

The tools used for thermogravimetric analysis exhibit high measuring precision for three measurements: mass changes, temperature and temperature changes. This high measuring precision has contributed to the widespread use of thermogravimetric analysis in various scientific and technological fields: characterization and assessment of the thermal stability of various types of materials, composition analysis, kinetic studies, corrosion studies and industrial process simulation. The furnace of the Mettler Toledo TGA-SDTA851e equipment may be considered a mini-reactor capable of mimicking the conditions existing in an industrial reactor. Thus, 5-mm-diameter dry fir tree wooden discs were used, on which various lacquers and paints available on the market were applied. The experimental tests at constant temperature (25 °C) consisted of sample mass change analysis conducted for a period of 2 h. The findings enabled us to draw the drying curves (material moisture − drying time) and drying rate curves (drying rate − material moisture). The moisture ratio data obtained experimentally were fitted to different models, to determine the best-fit model. The drying rate curves revealed the existence of two drying periods: the constant-rate drying period (very short, lasting approximately 10 min) and the decreasing speed drying period. Thermogravimetric analysis in the air or nitrogen, in dynamic conditions, for the three types of fresh alkyd paint available on the market and the paint layer obtained after complete drying, i.e. natural ageing in laboratory conditions for 8 weeks, revealed a complex thermal decomposition mechanism including a sequence of three to six stages, with varying percentages of mass loss depending on their structure and on the working atmosphere.