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The impact of resin harvest history on properties of Scots pine wood tissue
This study was conducted in Central Europe (Poland) in pine forests that were subjected to the process of resin harvesting in the 1970s. Forty trees were designated for the study, which had one or two resin blazes. The objectives of the experiment were to determine the effect of resin tapping on the changes in annual growth, wood density, and mechanical strength of wood in the damaged trees. Resin tapping affected the development dynamics, especially in trees with a single resin blaze. In addition, bark cutting affected wood density over the cross-section. However, no significant variation was found in terms of the mechanical properties of wood, which may support the theory of adaptive tree growth and optimization of tree’s structure to its functions.
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.
Results of a 57-Year-Long Research on Variability of Wood Density of the Scots Pine (Pinus sylvestris L.) from Different Provenances in Poland
This research was conducted in the forests of Poland between 2019 and 2022. The aim was to study Scots pine provenances and compare the wood density variability among the various provenances growing on one experimental plot (in situ). The experiment was established in 1962 in the Zielonka Forest Division, Potasze Forest District. In 2019, five model trees from each provenance, which grew on the experimental plot, were chosen. In total, 40 trees were cut down, from which samples were collected in order to determine their wood density variability. The results indicate significant differences among the Scots pine provenances. It is not necessary to repeat it in situ. It appears that genetic factors highly impact the process of forming the wood density of the Scots pine. The research revealed that the best-quality wood, as far as wood density is concerned, comes from the Zielonka provenance, whereas the lowest relative density comes from the Gleboki Brod provenance. Both the provenance experiments and the analyses allowed for the selection of the research material that indicated the best genetic properties. Moreover, the research provides analytical tools that will allow for the prediction of the Scots pine provenance with the best quality together with high resistance to exogenous factors, such as habitat conditions, which can be vital to improving wood quality.
How the scots pine and beech aging process affects wood
This study investigates the effects of aging trees on wood properties, which are caused by climate change, the withdrawal of coniferous species from Central Europe, and the increased crown sweep in old beech stands. The research was carried out in old tree stands with a high proportion of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.) species. The collected material was from five tree pine stands aged between 151 and 182 and three beech stands between the ages of 165 and 184. The samples were subjected to an analysis of wood properties such as density and modulus of elasticity. The results and findings of this study indicate that the Scots pine currently reaches the optimal wood tissue quality at around 80 years of age, which is approximately 20 years earlier than the species’ anticipated cutting age. However, the beech, which reaches maturity at about 120–140 years, reaches the maximal quality of wood tissue already at the age of 80–90 years. Above the age of 110, the quality of beech wood (density and modulus of elasticity) decreases. Moreover, it is necessary to emphasize that the radial trend of wood density does not coincide with the trend of the modulus of elasticity. Additionally, it is found that wood density is not a perfect representation of its mechanical qualities; it can, however, be regarded as a measure of the technical quality of wood tissue. The results indicate that the pine and the beech that grow on the European Plain mature faster and reach technical quality earlier than just a couple of decades before.
Scolytus spp. associated with elms with symptoms of Dutch elm disease in Poland and the reproductive potential of Scolytus multistriatus (Marsham, 1802) (Coleoptera, Curculionidae, Scolytinae)
Moisture content of fresh Scots pine wood in areas near damage caused by harvester head feed rollers
By damaging bark, mechanized harvesting deprives wood of its natural mechanical barrier. This study concerns the effect of this damage on the changes in moisture content that occur near the damaged areas of Scots pine (Pinus sylvestris L.). This study was carried out using 45 randomly selected 11 m long logged pine stems. Additionally, the effect of bark thickness on the depth of damage was measured. To determine the influence of the location of the damage and bark thickness on the wood moisture near the damaged region, wood samples were collected from two sections. The first was located one meter above the log’s base, while the second was located one meter from the end of the log. Two increment cores were taken by a Pressler borer in each section: one from the damaged wood zone and the second from the undamaged wood zone. The average bark thickness one meter from the base of the log was 11.2 mm, which decreased to 1.8 mm in the samples taken one meter from the top of the log. The average depths of the damage caused by feed roller spikes in the two sections were 3.9 and 3.8 mm, respectively, indicating that there was no significant effect of bark thickness on the depth of the damage. The wood samples collected near the damaged wood zone (DW) had about 13 percent lower moisture content than those taken from the undamaged zone (UDW). This difference was statistically significant. We observed greater mean moisture content closer to the top of the log for both the samples taken near the damaged zone and the samples taken from the undamaged zone. One meter from the base of the log, the moisture content difference between the DW and UDW was 9.8 percentage points, which was statistically insignificant. By contrast, significantly lower moisture content (−16%) was observed in the DW one meter from the top of the log.
Wood quality of silver birch Betula pendula Roth stands growing on former agricultural lands in Poland
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.