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Scots pine (Pinus sylvestris L.) represents one of the most important commercial coniferous tree species, providing valuable timber. Due to climate change, it is experiencing serious problems in some areas, therefore, finding a suitable substitute for its wood is currently a challenge. In this study, we compared the wood quality of three different non-native pine species and Scots pine growing at the same site to ensure identical growing conditions. Black pine (Pinus nigra J. F. Arnold), a pine species native to Southern Europe, lodgepole pine (Pinus contorta Douglas ex Loudon), and ponderosa pine (Pinus ponderosa Douglas ex C. Lawson) native to North America were compared to Scots pine for selected quantitative (productivity) and qualitative (physical and mechanical) properties. Significant differences between pine species were found in all quantitative dendrometric parameters, except average diameter at breast height. The stand volume ranged from 157 m3 ha−1 for lodgepole pine to 356 m3 ha−1 for Scots pine. For qualitative characteristics, wood density, shrinkage, and compressive strength were used to find differences among species in choosing the best alternative. The highest wood density was obtained for Scots pine (458 kg m−3), followed by black pine with 441 kg m−3. The density of the remaining pine species was significantly lower. Scots pine also exceeded the tested species in compressive strength (44.2 MPa). Lodgepole pine achieved the second highest value (39.3 MPa) but was statistically similar to black pine (36.5 MPa). The tested pine species exhibited similar values in shrinkage, which were statistically insignificant, ranging from 14.3% for lodgepole pine to 15.1% for Scots pine. Based on applications and preferred characteristics, black pine or lodgepole pine could serve as the Scots pine substitute in some areas. And vice versa, ponderosa pine did not attain the Scots pine wood quality.

Oak is one of the most economically important hardwood tree species in Europe, and its prevalence will increase due to progressing global climate change, according to predictive models. With the increasing demand for timber and with the need for a balance between carbon emissions and sequestration, it is essential to address the afforestation of agricultural land. Therefore, this research aimed to investigate the physico-mechanical properties and anatomical structure of pendulate oak (Quercus robur L.) wood—specifically focusing on the trunk’s cross-section—in post-agricultural areas compared with the forest land in the western part of Poland. Wood density, bending strength, modulus of elasticity, and other parameters were analyzed from 1626 wood samples. The analysis of physico-mechanical properties reveals that, historically, agricultural land use has an almost negligible impact on wood quality. Despite significant differences in small vessel diameter and fiber length favoring trees from post-agricultural land, the physico-mechanical properties remain consistent. Large vessel measurements show comparable diameter and length in both land types. These findings suggest that post-agricultural land can serve as an effective alternative for high-quality pendulate oak wood production for industrial purposes. However, wood from post-agricultural land may exhibit a decrease in modulus of rupture by over 30% and potentially lower density above the trunk’s halfway point. This observation hints at the fact that oak trees in post-agricultural areas could be cultivated in shorter rotation periods compared to forest land.

The Coastal Cliffs Morphology Analysis (CCMORPH) Toolbox is a collection of PYTHON scripts and a JavaScript tool to produce georectified information specifically tailored for the generation and quantitative analysis of coastal cliffs’ morphology. Although experts have employed numerous methods to extract coastal indicators from digital elevation models, most do not enable software code to repeat the proposed processes. Here, we provide an easily accessible software solution that demonstrates how to automatically extract line indicators from digital elevation models using different scientific methodologies and generate comparable datasets representing coastal cliff dynamics.

Objectives This study examined the physiological strain experienced by workers employed in motor-manual timber harvesting performed in winter and summer, and the applicability of heart rate indices for estimating energy expenditure. Material and Methods The heart rates (HR) of 2 teams consisting of 2 persons working simultaneously during felling and forwarding, in both winter and summer, were measured. Heart rate at work (HR work ), resting heart rate (HR rest ), relative heart rate (%HRR), ratio of working heart rate to resting heart rate, and 50% level were used to estimate the physiological workload in particular jobs. The HR index (HR work /HR rest ) equation was used to estimate the energy expenditure (EE). Results For all jobs, significantly higher physiological workload and energy expenditure were recorded during winter. Conclusions The season significantly affects the physiological workload during logging operations. If there is no possibility of harvesting wood in summer, in order to limit the workload of workers during winter activity, attention should be paid to the proper organization of work and selection of workers. Int J Occup Med Environ Health. 2022;35(4):437–47

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.

The research on Paulownia cultivation and wood properties is up to date in many countries. However, there are no data on the properties of this wood defined on a microscale, on microtome samples. The main aim of this study was to find the best valorization path for the wood of Paulownia Shang Tong Hybrid F1 from an extensively cultivated plantation established in April 2017 in Poland by determining the tensile strength, the wood density, the strength-to-density ratio, and the modulus of elasticity on a cross-section of the trunk. The wood was collected from extensive plantation, where production is based on the natural resources of the habitat and ambient weather conditions, which is the opposite to the intensive cultivation model, which is the recommended model of Paulownia cultivation. The results of this study show that the mean density of the analyzed samples was approximately 210 kg/m3 when the mean value of the modulus of elasticity (MOE) was approximately 2400 MPa. The mean result for the tensile strength ratio to density was 11.25 km. In the case of anatomical structure, the increasing trend with age was noticed both in fiber and vessel characteristics. The study results provide unique data worldwide about Paulownia wood’s properties based on a cross-section of the trunk, from plantations cultivated in conditions which are not recommended by seedlings producers. The obtained data indicate that the Paulownia wood (examined) from the cultivation in this study has a technical quality similar to that of model-intensive agricultural plantations.

This experiment was conducted in the pine woods of central Europe at a research area established in 1951. The experimental area of 1.35 ha was set up in a 14-year-old pine tree stand, which was divided into lots, and the pruning procedure took place in different variants. Some lots constituted control lots without pruned trees. The trees were pruned in four variants, reducing the living tree crown by 1/4, 1/3, 1/2, and 2/3 of its length. The study’s main aim was to determine the influence of pruning forest trees on the tree tissue. Moreover, the study attempted to answer whether pruning was a significant procedure for wood valorisation, and if yes, then which variant was the optimal one for Scots pine growing on the European plain. The results indicated a significant impact of pruning young pine tree stands on the properties of wood tissue, which differed regarding the adopted pruning variant. Significant differences in the width of annual rings, the size of the particular areas of the annual rings (latewood or earlywood), and the wood density depending on the pruning variant were observed. Furthermore, the results indicated that pruning induced numerous processes, which optimised the physiological and mechanical functions of the tree trunks. The outcome of this optimisation was, among others, the diversification of the vascular and strengthening area of the annual ring as well as the wood density, which was a reaction to reducing a part of the assimilation apparatus. From the technical wood value viewpoint, the optimal pruning variant for pine was between 1/3 to 1/2 of the living crown.

Expanding the base of raw materials for use in the production of wood-based materials, researchers and panel manufacturers around the world are increasingly trying to produce panel prototypes from raw materials available in a given area and climate, or by managing waste from wood industry processing. The aim of the study was therefore to test the hypothesis that forest residues de-rived from Scots pine roundwood harvesting have the same suitability for the production of three-layer particleboard as the wood of the most valuable part of the Scots pine stem, by comparing selected properties of raw wood material and final product—particleboard. Characterization of both the raw material and the physical-mechanical and hygienic properties of the produced panels was carried out. For these panels from the tree trunk, MOR was 14.6 N/mm2, MOE 1960 N/mm2 and IB 0.46 N/mm2. The MOR and IB values turned out to be higher for the panel from the branch and are 16.5 and 0.72 N/mm2, respectively. Excessive swelling of the panels resulted in all manufactured particleboards meeting the standardized performance requirements of EN 312 for interior furnishing panels (including furniture) for use in dry conditions (type P2).

The aim of the study was to analyse the changes in the infection rate development inside the beech stem as a result of browsing by deer (Cervus elaphus). The research materials were collected from three research plots located in the Polanów Forest Inspectorate from March to April 2020. For the study, 80 beech trees were selected, for which the size of the fallow tree, the percentage of the section taken from its centre infected with rot, and the number of years passed since the tree was wounded were determined. The study shows that the infection affects only the rings formed before the tree was injured. The average size of stem rot was 7.75% of its area, and it spread at the rate of 2.52% of the cross-sectional area per year. The analysis of the obtained results proved that both the size of the wound (splits) and the time elapsed since the tree was damaged are significantly correlated with each other. It is also possible to build a model for estimating the size of decay in stunted beech trees based on easy-to-determine predictors, such as maximum wound width and elapsed time since tree damage.

To determine the appropriate final use of wood from a particular tree species, it is first necessary to know its properties. Methods that use wood samples taken directly from the trunk of a growing or felled tree are very time-consuming and require a great deal of manual work. Non-destructive methods may be more effective and much faster, thanks to the use of advanced technologies. The resistance drilling can be used to determine the variation in wood density along the radius of the stem. The main aim of the present study was to determine the basic density of the wood on a cross-section of the trunk of oak trees and to investigate the correlation of the results with those obtained by drilling the same trees with the IML RESI-PD 400. The results of Spearman’s correlation test showed strong positive correlations between all examined properties. We observed a trend whereby the density of the wood and Resi amplitude increased in direct proportion to the width of the annual rings. The results of linear regression show a strong relationship between examined properties. This study provide evidence that the Resi is an appropriate tool for non-destructive determination of wood density.

An important problem associated with the aerial mapping of the seabed is the precise classification of point clouds characterizing the water surface, bottom, and bottom objects. This study aimed to improve the accuracy of classification by addressing the asymmetric amount of data representing these three groups. A total of 53 Synthetic Minority Oversampling Technique (SMOTE) algorithms were adjusted and evaluated to balance the amount of data. The prepared data set was used to train the Multi-Layer Perceptron (MLP) neural network used for classifying the point cloud. Data balancing contributed to significantly increasing the accuracy of classification. The best overall classification accuracy achieved varied from 95.8% to 97.0%, depending on the oversampling algorithm used, and was significantly better than the classification accuracy obtained for unbalanced data and data with downsampling (89.6% and 93.5%, respectively). Some of the algorithms allow for 10% increased detection of points on the objects compared to unbalanced data or data with simple downsampling. The results suggest that the use of selected oversampling algorithms can aid in improving the point cloud classification and making the airborne laser bathymetry technique more appropriate for seabed mapping.

This study evaluated within-stem differences in the moisture content of stored summer-harvested oak wood with respect to drying method. The felled oaks were naturally dried for eight weeks, from 4 July to 29 August 2017. We analyzed two methods of preparation and storage: a transpiration drying method (W), and an air-drying method for stem-wood (L). Transpiration drying is a better method for oak stems than air-drying. Statistically significant differences between drying methods were found after six weeks of storage. This coincided with complete wilting of the leaves. However, signs of wilting and leaf color change appeared earlier, between the second and fourth weeks of storage. In parallel, in scenario W, a statistically significant difference in MC of sapwood was observed between the second and fourth weeks of storage. Such a phenomenon was not observed in scenario L. The MC of heartwood also gradually decreased, especially in scenario W. Explanation of this phenomenon lay outside the scope of this study; however, it indicates how the structure and properties of wood, in addition to storage conditions and methods, influence the efficiency of biomass drying in the harvesting area.

This paper presents the challenges encountered in the dimensional control of ships, platforms, and offshore units. This novel approach utilizes machine learning (MLP—Multilayer Perceptron Neural Network) for three-dimensional (3D) spatial coordinate transformations when only three common points are known. The proposed method was verified based on laboratory and field data. The main issue was to provide a sufficient number of valid training points. The oversampling method was used to meet this criterion. The achieved results indicate equal or better accuracy when the points were located inside the adjustment points array. In the case where the points lay outside this array, no improvement in the accuracy of the transformation was observed. The neural approach restores the transformation symmetry, and in some cases, such as the study of deformation of engineering objects, breaks the symmetry rather than restoring it.

A prerequisite for solving issues associated with surf zone variability, which affect human activity in coastal zones, is an accurate estimation of the effects of coastal protection methods. Therefore, performing frequent monitoring activities, especially when applying new nature-friendly coastal defense methods, is a major challenge. In this manuscript, we propose a pipeline for performing low-cost monitoring using RGB images, accessed by an unmanned aerial vehicle (UAV) and a four-level analysis architecture of an underwater object detection methodology. First, several color-based pre-processing activities were applied. Second, contrast-limited adaptive histogram equalization and the Hough transform methodology were used to automatically detect the underwater, circle-shaped elements of a hybrid coastal defense construction. An alternative pipeline was used to detect holes in the circle-shaped elements with an adaptive thresholding method; this pipeline was subsequently applied to the normalized images. Finally, the concatenation of the results from both the methods and the validation processes were performed. The results indicate that our automated monitoring tool works for RGB images captured by a low-cost consumer UAV. The experimental results showed that our pipeline achieved an average error of four pixels in the test set.

Timber harvested from fresh-felled trees has high moisture content and relatively high mass. During storage, the timber dries out and its weight decreases with the loss of moisture. The main objective of this study was to determine how the method and conditions of short-storage in summer affect weight changes and moisture loss in beech timber (not used for fuel). The study was carried out in a stand located in the north-eastern part of the range of beech. The age of the studied stand was 47 years. A total of 60 model trees were selected and divided into two groups. In the first group, 30 whole trees (WT) were left in the stand after felling. In the second group, 30 trees (CT) were delimbed and crosscut, and trunk sections (logs) were obtained (2.5 m). The timber (CT) was stored in a pile, and the weight of each log was measured daily. After 14 days, the trees from the first group, which had been left in the stand (WT), were delimbed and the trunks were cut into 2.5 m sections and weighed. It was assumed that timber intended for mechanical processing is stored in the forest for a short period of time, unlike energy wood. Therefore, the period of storage was not longer than two weeks. A more effective method of drying is to leave whole trees after felling, called transpirational drying. The timber stored in a pile (CT) lost moisture more slowly than the timber from trees that had been left whole after felling (WT). Comparing the weights of the logs stored in a pile, on days after harvesting, a statistically significant difference was found only between the first and the last day. It can be concluded that two weeks is the minimum period of storage in a pile (CT) required to obtain a significant degree of weight change and moisture loss.

Introduction and Objectives Holding determined body postures during work is connected with muscles activity. The more forced the posture, the larger the number of muscles taking an active part in holding and stabilizing the work posture. During logging, the greatest share of awkward (forced) working postures occurs in tree felling by chainsaw. Material and Methods A group of 10 experienced fellers aged 47.5±7.3 (37 – 59-years-old) was studied. Heart rate (HR) was measured during simulation of felling activity in 4 working postures: back bent forward with straight legs (stoop), back bent forward with bent legs (flexed-stoop), squat and kneeling on one knee (half-kneel). Results The lowest value of HR was noticed for squatting – 114.1 bpm, then for kneeling on one knee – 116.3 bpm. HR during felling in a standing posture with straight legs amounted to 121.5 bpm and for standing with bent legs 125.3 bpm. For all studied postures the differences in average HR values were statistically significant at p

The development of modern measurement methods for ship systems has occurred due to economic changes and increasingly stringent environmental requirements [...]

Modern seagoing ships are often equipped with converters which utilize semiconductor power electronics devices like thyristors or power transistors. Most of them are used in driving applications such as powerful main propulsion plants, auxiliary podded drives and thrusters. When it comes to main propulsion drives the power gets seriously high, thus the need for use of medium voltage power electronics devices arises. As it turns out, power electronic parts are the most susceptible to faults or failures in the whole electric drive system. These devices require efficient cooling, so manufacturers design housings in a way that best dissipates heat from the inside of the chips to the metal housing. This results in susceptibility to damage due to the heterogeneity of combined materials and the difference in temperature expansion of elements inside the power device. Currently used methods of prediction of damage and wear of semiconductor elements are limited to measurements of electrical quantities generated by devices during operation and not quite effective in case of early-stage damage to semiconductor layers. The article presents an introduction and preliminary tests of a method utilizing an acoustic emission sensor which can be used in detecting early stage damages of the gate turn-off thyristor. Theoretical considerations and chosen experimental results of initial measurements of acoustic emission signals of the medium voltage gate turn-off thyristor are presented.

The purpose of this study was to establish the impact of season on productivity, labour consumption, and working time structure during timber harvesting from young alder stands (Alnus glutinosa Gaertn.). An early thinning process was performed in summer and winter in pure alder stands (38 and 40 years old) in the Płaska Forest Division (NE Poland). The felling and processing operations were performed by experienced loggers using the cut-to-length (CTL) system, and forwarding with manual loading and unloading involved the use of a Zetor 7045 (65 HP) farming tractor and trailer. In both summer and winter, the loggers spent most of their labour time on felling trees (approx. 23%) and bucking (approx. 36%). Assistant loggers spent most of their time stacking logs (49.2% in summer and 58% in winter). The most time-consuming activities in forwarding were loading, unloading, and transportation. The average time consumption of tree felling and processing amounted to 0.36 ± 0.11 h/m3; that of forwarding was lower, at 0.24 ± 0.07 h/m3. No statistically significant differences in the labour consumption of tree felling were identified between winter and summer (p = 0.863). For forwarding, labour consumption was significantly higher in winter (0.28 h/m3) than in summer (0.19 h/m3, p = 0.001). Average productivity was 3.02 ± 1.09 m3/h for tree felling and 4.76 ± 1.80 m3/h for forwarding. The productivity of felling was similar in winter (2.83 m3/h) and in summer (3.22 m3/h). For forwarding, productivity was significantly higher in summer (5.70 m3/h) than in winter (3.81 m3/h, p < 0.01).

Survival in variable conditions of wind exposure depends on the strategy of trees in adapting to environmental constraints. There are many studies investigating the effect of wind on the adaptation of trees, but little attention is paid to the properties of the wood, particularly within-stem variability. In the present work, an analysis was made of within-stem variability of the density and mechanical properties of Scots pine wood from parts of stands with different wind exposure (stand edge, forest interior). The research was carried out in north-western Poland, in seven selected pine stands (without other species in the canopy) aged from 82 to 87 years. In each stand, three trial plots were marked, each at a different distance from the edge of the stand. The first plot was immediately adjacent to the edge (0–20 m), the second was at a distance of 30–50 m, and the third was at a distance of 60–80 m. Generally, wind exposure, defined by the distance from the windward edge, did not significantly affect the tree morphology and wood properties. A statistically significant difference was found only for the modulus of elasticity (MOE), between stand edge and forest interior. Trees growing at a distance from the stand edge compensate for their greater stem slenderness with higher elasticity. A certain growth response to wind loads is also represented by the within-stem variability of wood. We found that within-stem variability of wood at the stand edge is higher than in the forest interior. At various points along the stem, the wood density and strength were generally higher on the eastern radius (on the leeward side of the stem). Different wind resistance requirements at the stand edge and in the interior lead to combinations of tree architecture and wood properties that enable the best resistance to wind loads.

This article presents possible applications of a dynamic gravity meter (MGS-6, Micro-g LaCoste) for determining the dynamic height along the Odra River, in northwest Poland. The gravity measurement campaign described in this article was conducted on a small, hybrid-powered survey vessel (overall length: 9.5 m). We discuss a method for processing the results of gravimetric measurements performed on a mobile platform affected by strong external disturbances. Because measurement noise in most cases consists of signals caused by non-ideal observation conditions, careful attempts were made to analyze and eliminate the noise. Two different data processing strategies were implemented, one for a 20 Hz gravity data stream and another for a 1 Hz data stream. A comparison of the achieved results is presented. A height reference level, consistent for the entire estuary, is critical for the construction of a safe waterway system, including 3D navigation with the dynamic estimation of under-keel clearance on the Odra and other Polish rivers. The campaign was conducted in an area where the accuracy of measurements (levelling and gravimetric) is of key importance for shipping safety. The shores in the presented area of interest are swampy, so watercraft-based measurements are preferred. The method described in the article can be successfully applied to measurements in all near-zero-depth areas.

Wood properties have an influence on the safety around the tree itself as well as on actual possibilities of using wood. The article focuses on the wood properties of the Norway spruce (Picea abies (L.) Karst.) in reference to the time since the tree has decayed. The study was conducted among mature tree stands of spruce in Białowieża Forest, where over the last 10 years there has been a weakening of spruce tree stands due to water deficiency which has contributed to the gradation of the European spruce bark beetle (Ips typographus). The study focused on spruce wood of living and healthy specimens as well as the wood of standing trees which has decayed between one and five years before the sample was collected. The findings indicate a gradual decrease in wood properties as time passed since the physiological decay of the tree. Significant differences in the decrease of mechanical wood properties have been observed in trees which had been decayed for 3 years and they should be considered life and health hazard for people and animals.

This study evaluated changes in mass and the moisture content of stored summer-harvested Scots pine small diameter roundwood subject to different types of preparation and storage (drying methods). Small diameter roundwood was naturally dried for three months, from 15 June to 15 September 2018. We analyzed three methods of preparation and storage. First, logs 1.2 m in length were stored and air-dried in piles (C). In the second case, a transpirational drying method was used (W). Thirdly and finally, we used air-drying for logs with lengths between 9.6 and 14.4 m (L) stored in the harvesting area. Within three months, the moisture content of the logs stored in piles decreased by 22.9 percentage points. With the transpirational drying method (W) the decrease in moisture content was 10.0 percentage points. In scenario L, at the end of the storage period the moisture content was lower by 15 percentage points. Within three months, the density of the roundwood stored in piles decreased to 700 kg/m3, which is about 140 kg/m3 more than in scenarios W and L. Cutting stemwood into short segments and storing it in a pile appears to have positive effects on drying performance. Overall, this study shows that, for Scots pine wood, air-drying is a better method than transpirational drying.

The aim of this study was to examine certain properties of sessile oak wood (Quercus petraea (Matt.) Liebl.) with frost cracks, such as density (ρ), modulus of rupture (MOR), modulus of elasticity (MOE), and compressive strength in all anatomical directions and to compare it with control trees without frost cracks. Oak with frost cracks had a higher wood density (ρ = 765 kg × m−3) than the control (ρ = 650 kg × m−3). However, despite its lower density, the control oak was characterized by noticeably better mechanical parameters, with the exception of the compressive strength in radial and tangential directions. Differences in mechanical parameters reached up to 26%. The tests were performed on wood taken from trees with frost cracks that formed over 10 years to several decades ago. Frost cracks can render wood vulnerable to fungi growth, which leads to rotting and discoloration. Differences in strength were found on samples with no visible signs of decay, as they were cut at a distance from the crack. Nonetheless, the observed differences in strength allowed us to conclude that the shreds of fungi, as well as decay, may occur in the entire volume of the frost-damaged log. Such wood is, therefore, of a lower quality than that made of logs without any frost damage. Trees with frost cracks should be progressively be felled during the periodic intermediate cutting, as their wood quality may systematically deteriorate over the years.

The aim of this study was to investigate the effect of season of the year on the frequency and degree of damage to residual trees caused during winter and summer timber harvesting operations in young alder stands. Analyses were conducted in pure black alder (Alnus glutinosa Gaertn.) stands aged 38 and 40 years, located in north-eastern Poland. Chainsaw logging was performed in the cut-to-length (CTL) system, while timber was extracted using an agricultural tractor with a trailer with manual timber loading and unloading. Damage caused in the stand as a result of early thinning operations was evaluated in terms of: (1) damage location, (2) wound size, (3) wound depth, and (4) the distance of the damaged tree from the skid trail. Timber harvesting caused damage in 8.3% of trees remaining in the stand. Both the total number of damaged trees (p = 0.001) and the number of trees damaged during felling (p = 0.01) and extraction of timber (p < 0.001) were greater in summer than in winter. Irrespective of the season, two-thirds of all cases of damage were caused during timber extraction, with 67.7% of damage recorded on trunks or root collars and 32.3% on roots. Irrespective of the season and the technological operation, slightly over 50% of cases of damage were small wounds of max. 10 cm2. The proportions of medium-sized wounds (11−100 cm2) and large wounds (over 100 cm2) were comparable. The majority of damaged trees (85.1%) were found in the vicinity (p < 0.001).

The aim of the study was to determine whether there is a correlation between breast height diameter, tree height and stem total volume of Scots pines, on the one hand, and volume and proportion of juvenile wood, on the other. The investigations comprised pure pine stands of the IInd, IIIrd, IVth and Vth age classes developed in conditions of fresh mixed coniferous forest. A distinct curvilinear correlation was found between volume and proportion of juvenile wood in tree stems and breast height diameter, height and stem total volume. Because of high values of determination coefficients (R2), which characterised the above-mentioned correlations, it seems appropriate to use these regularities to assess the quality of the timber raw material regarding the proportions of its volume and juvenile wood in stems of Scots pine trees.

The study makes an attempt to analyse the width of annual rings, the width of the latewood zone and the proportion of the latewood within juvenile wood along trunks of Scots pine (Pinus sylvestris L.) trees and to verify the hypothesis about the heterogeneous properties of juvenile wood in a single trunk. It was found that the above-mentioned macrostructural elements of wood structure showed a curvilinear correlation with the height of measurement points along the tree trunk. As the distance from the base of trunk increased, the width of the annual ring and the width of the latewood zone decreased, while the proportion of the latewood increased. These types of changes can affect positively physical and mechanical properties of wood tissue. It can be assumed that there is a mechanism which modifies properties of juvenile wood causing axial diversification of the analysed type of wood tissue. It is probable that axial heterogeneity results in advantageous changes in the mechanics of the tree trunk.