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The influence of some morphological characteristics of pine logs on the results of calculating their volume by different methods
Comparison of the Foraging Activity of Bats in Coniferous, Mixed, and Deciduous Managed Forests
The aim of this study was to compare the foraging activity of bats in coniferous, deciduous, and mixed forests and to test whether this activity was subject to seasonal variation. Sample points were selected in stands of similar spatial structure in coniferous (Pinus sylvestris L.), in mixed (Pinus sylvestris and Quercus petraea (Matt.) Liebl.), and in deciduous (Quercus petraea) managed forests in western Poland. Bat calls were recorded using automated ultrasound recording devices (Batcorder 3.0, ecoObs, Nürnberg, Germany) during five consecutive nights from May to September in each of the six stands. A total of 4250 bat passes were recorded. Overall, 63.1% of bat passes were identified to species, 31.6% were identified to genus or sonotype group, and 5.3% remained unidentified. In total, eight species of bats and seven sonotype groups were recorded. The dominant species in all types of forests were Pipistrellus pygmaeus (44.5% of recorded bat passes), followed by Nyctalus noctula (10.3%) and Pipistrellus nathusii (5.7%). There were no significant differences in the total activity of bats between the three types of forests; however, high seasonal fluctuations in bat foraging activity were found. This study demonstrates that when coniferous, deciduous, and mixed stands with similar spatial structure are compared, forest type does not affect the foraging activity of bats.
How the Spruce Ageing Process Affects Wood
Climate change and the gradual phaseout of the spruce from Central Europe inspired us to study the effects of the ageing process of trees on wood properties. This study was conducted in old tree stands with significant involvement of the spruce (Picea abies (L.) H. Karst) in the ages between 122 and 177 years. The study material (samples) was collected from the selected trees to study wood properties such as density, resilience to compressive strength, resilience to bending strength, and modulus of elasticity. The results and findings of this study indicate that the spruce currently reaches the optimal technical quality of wood tissue at approximately 60 years of age. It is approximately 20 years earlier than the planned cutting age for the species. This could be due to water stress which led to adaptive changes in the wood tissue and earlier technical maturation of the wood in the studied trees. Significant radiant variabilities of wood properties of the Norway spruce were observed. It was determined that wood density does not fully reflect its mechanical properties, and it can be considered an indicator of the technical quality of wood tissue, but only within a limited scope. The results obtained may not only be applied in optimising the use of wood from spruce stands. They can also indicate the need to change the approach to managing spruce stands and their conversion towards broadleaf species.
Influence of cutting attachment on work efficiency, fuel consumption and environmental pollution from plastic wire during tending of young forests with brush cutters
Abstract Petrol brush cutters are among the most widely used devices for tending young forests. During this work, environmental pollution is generated by the combustion of fuel and by the discarding of pieces of the plastic cutting line. The aim of this study was to compare operating parameters and the degree of plastic pollution from the cutting line, and to determine fuel consumption during tending of young forest with the use of a petrol brush cutter equipped with different cutting attachments: a plastic wire head, and 2-, 3-, and 24-tooth cutting blades. Measurements were made in the course of work on 2–3-year-old oak plantations containing two vegetation types (herbaceous and mixed). It was found that the most efficient cutting attachment was the wire head, but its use was associated with significant wire and fuel consumption. In the mixed vegetation case, wire consumption was 575.89 g*ha−1, which is comparable to eighteen polyethylene terephthalate (PET) bottles. Similar performance and significantly lower fuel consumption were obtained with the 2-tooth blade. In addition, when using cutting blades, there was no wire consumption and thus no plastic pollution of the environment. It was concluded that, in order to eliminate plastic pollution and reduce fuel consumption while achieving satisfactory working efficiency, the use of wire heads should be abandoned in favor of metal cutting blades.