Search

Agia Bay is located on the southeastern coast of Lemnos Island. The coastal area today is characterized by aeolian sandy deposits (dunes). The systematic investigation of a 15.5-m long sediment core from the coastal plain of Agia Bay aimed to shed light to the paleoenvironmental evolution of the area that prehistoric groups occupied. The exhaustive study of the faunal and floral remains of the deposits including benthic foraminifera, ostracods, mollusks, pollen, and dinoflagellate cysts as well as plant remains was further supported by sedimentological, micromorphological, and elemental analyses, magnetic susceptibility measurements, ERT, and absolute dating. Four main evolutionary stages have been identified since the Late Glacial. At the base of the sequence, the fluvial activity dominated the sedimentation in the area forming a small shallow wetland, while after 12,500 cal BP, a marine signal was observed at the wetland. At 7500 cal BP, the wetland increased in size and depth, whereas at 6000 up to 4000 cal BP, a connection of the wetland to the sea was established, and an inner lagoon formed. After 4000 cal BP, a nearshore environment developed due to the sea-level rise. Pollen assemblages record the occurrence of a mixed deciduous oak forest in the island interior around 6000 cal BP, while after 5000 cal BP, an expansion of Mediterranean vegetation, shaped by human activity, is inferred. [ABSTRACT FROM AUTHOR]

The occupational exposure to softwood and hardwood wood dust was determined during forestry work in timber stands. In the determination of inhalable wood dust, three tree species (Fagus sylvatica, Quercus sp. and Pinus brutia) and three chainsaw operating parameters were taken into account (in total six assessment indicators). The first operating parameter was the chainsaw operating under normal conditions (regular chain sharpening). The second and third operating parameters were improper chainsaw maintenance (irregular chain sharpening) and low throttling pressing (operating the chainsaw at low engine speeds), respectively. The determination of inhalable wood dust concentrations from the ambient air was performed using the Inhalable Organic Matter (IOM) sampler, manufactured by SKC Button Sampler (Dorset, United Kingdom). Out of a total of 108 concentration cases of inhalable wood dust, 44 (40.74%) showed concentrations greater than 3.00 mg·m−3, while in 10 (9.26%) cases, the dust concentration exceeded 5 mg·m−3. The eight-hour time-weighted average exposure to wood dust ranged from 0.99 mg·m−3 to 12.52 mg·m−3, with an average of 4.22 mg·m−3. The results indicated that the increase in wood dust concentration was dependent on improper chainsaw maintenance, while low throttling pressing reduces dust concentration levels. Additionally, an increase in wood dust concentration was observed in species with thick bark (Pinus brutia and Quercus petraea). [ABSTRACT FROM AUTHOR]

This study examines the impact of chainsaw chain type and tree species on the concentration of inhalable wood dust generated during motor-manual harvesting in forested areas. The effects of conducting real-world measurements of inhalable dust within the operator's breathing zone during forestry work are investigated. Two different chain types were evaluated: the commonly used 3/8" pitch chain (conventional chain) and the 0.325" pitch chain. Additionally, measurements were taken for three tree species: beech, oak, and pine (including both live and standing dead trees after a fire). Results showed that, overall, using the conventional 3/8" chain type yielded the highest concentration of wood dust for all three tree species. Notably, the highest wood dust concentration was observed in the burned Pinus brutia cluster, also with the 3/8" chain pitch. These findings emphasize the importance of understanding how chain type and tree species contribute to wood dust levels. [ABSTRACT FROM AUTHOR]

Due to climate change, windstorms are becoming increasingly common resulting in the destruction not only of extensive forest areas but, quite often, of small-sized and scattered forest lands, thereby adversely affecting both the productivity and the safety of workers employed in the harvest of windblown trees. In the present study, an attempt is made to identify and record areas in the northeastern forests of Greece covered by mixed stands of conifers and broadleaves that experienced massive windthrow following local storms. Our results reveal that where Pinus sylvestris was mixed either with Quercus sp. or with Fagus sylvatica, it had been substantially protected, while in plots where it stood on its own it had been extensively uprooted. On the other hand, Picea abies, even if it was mixed with Fagus sylvatica and Pinus sylvestris, had been blown down to a large extent. Based on tree-level data, local topographic features, forest characteristics, and the mechanical properties of green wood, a reliable model, to be used for the prediction of similar disturbances in the future, has been selected after a thorough comparative study of the most well-known intelligent Machine Learning (ML) algorithms. Specifically, Random Forest Classifier, k-Neighbors Classifier, Decision Tree Classifier, Light Gradient Boosting Machine, Gradient Boosting Classifier, Ada Boost Classifier, Ridge Classifier, Linear Discriminant Analysis, Logistic Regression, Naive Bayes, SVM – Linear Kernel, and Quadratic Discriminant Analysis were evaluated and compared using six performance measures (confusion matrix, accuracy, precision, recall, F1-score, and ROC). [ABSTRACT FROM AUTHOR]

The aim of the present paper is to investigate the influence of biotic factors (fungi and insects) on the mechanical properties of wood through the effect of blue-stain, taking into account the time of harvesting and the time of stay of wood in the forest. Specifically, the resistance to axial compression and to bending (modulus of rupture (MOR)) was studied using infected specimens of Scots Pine (Pinus sylvestris) and Norway Spruce (Picea abies) (the usual types of wood used in woodwork). The specimens were obtained from logs of Scots Pine and Norway Spruce that were harvested in three different seasons of year, namely in July 2012, November 2012 and June 2013, respectively, in the forest of Elatia-Greece, and the attack pace by biotic factors with respect to the time of logging was studied. The placement of the experimental surfaces of each type of tree was made on skid road and in the stand. Totally, 120 laboratory measurements in axial compression and 120 measurements in bending (MOR) took place. The results proved that blue-stain hardly affect the mechanical properties of both wooden species and particularly the specimens that were derived during the winter logging. [ABSTRACT FROM PUBLISHER]