Natural regeneration of European Larch outside natural area with minimum of seed trees

The study of dissemination and success of natural regeneration of European larch outside its growing area, with a minimum supply of seed plants, is presented. It was analyzed that the success of natural regeneration of larch is affected by the absence of air sacs in pollen grains, this limits their dispersion at close distances and reduces the quality of seeds of the species, due to unsatisfactory pollination, more than fifty percent are dissimilar. It was found that the distance of maximum dissemination of European larch reaches 112–114 m. The undergrowth and self-seeding of European larch was represented by different height gradations. Half (49 %) of the recorded plants represent a gradation from 2 m and more, 36,5 % up to 1 meter in height, which indicates that the process of formation of the young generation of European larch can last up to 10 years, subject to the necessary conditions (good mineralized soil). Biometric measurements show that the leading position in height is occupied by birch, and the leader among conifers in height in height is Scotch pine. The dynamics of the annual growth of European larch until 2017 has a positive trend, after which it gradually decreases, from 38,6 cm to 24,7 cm in 2020, which is caused by the lack of silvicultural care, as well as the process of the emergence of new individuals of self-seeding, which is 23,5 % of accounted plants. In general, the natural regeneration of European larch and Scots pine under conditions of simple fresh subores (B2) has a higher growth energy than that of forest crops and undergrowth of European spruce.

Laws Governing Free and Actual Drying Shrinkage of 50 mm Thick Mongolian Scotch Pine Timber

The relationships between free shrinkage and actual shrinkage of different layers in Mongolian Scotch pine (Pinus sylvestris var. mongolica Litv.) were explored to provide basic data for the further study of drying shrinkage properties. The free shrinkage coefficients at different temperatures and the actual shrinkage strain of each layer were examined under conventional drying. The results showed high precision of free drying shrinkage of corresponding layers of thin small test strips in each layer of sawn timber. The free shrinkage increased linearly as moisture content declined. At the same temperature, the free shrinkage coefficient reached the largest values for the first layer (above 0.267), while the smallest values were recorded for the ninth layer (below 0.249). Except for the ninth layer, the free shrinkage coefficients in width directions of other representative layers decreased as temperature increased. At constant temperature, the difference in free shrinkage coefficient of test materials in the length direction of sawn timber was small for the first layer, but slightly larger and changed irregularly in the fifth and ninth layer direction. At the end of conventional drying, the plastic deformation of each layer in the early stage of drying showed a reducing trend or even reversal due to the effects of reverse stress and later damp heat. In sum, these findings look promising for future optimization of wood drying process.

The results of the use of gridless technology for the selection and sowing in a forest nursery of 1000 pieces equalized by weight and size (thickness) of Scotch pine seed fractions

The aim of our research is to analyze the quantitative composition of standard and non-standard Scots pine seedlings grown with all sowing options: calibrated small and large seeds, as well as uncalibrated seeds. As the material for the study, we used a batch of Scots pine seeds, which were divided by weight into two equal parts. Subsequently, one part was calibrated on a sieve-free separator in thickness into small and large fractions, and the second was not calibrated. The size gap in the calibrated fractions was determined experimentally based on the minimum and maximum size of the seed thickness. All the seeds obtained were sown separately from each other in the nursery areas. At the end of the second growing season, using the field method of accounting for the grown planting material, a sample of standard and non-standard seedlings was carried out. As a result, it was found that in crops with calibrated seeds of non-standard seedlings is 25 … 30% less than in crops with non-calibrated seeds. Thus, sowing with Scots pine seeds calibrated in thickness makes it possible to significantly increase the productivity of forest nursery areas in comparison with sowing with uncalibrated seeds.

Moisture swelling and shrinkage of pine wood versus susceptibility to robotic assembly of furniture elements

Moisture swelling and shrinkage of pine wood and susceptibility to robotic assembly of furniture elements. Background and Objectives. Processing technology, storage conditions and wood properties affect the actual dimensions of wooden elements. It was decided to experimentally check how the dimensions of samples, made of the selected wood species, will change under the influence of different storage conditions, typical for industrial environments. And especially how these changes will affect the susceptibility to assembly of upholstery frame rails that form a box joint. Materials and Methods. The tests were performed on three series of rails made of Scotch pine wood. Each tested series consisted of 12 elements. First, the five dimensions forming the box joint were measured. Then, each series was exposed to different conditions: in the industrial hall (air of RH = 29-48% and t = 16-24°C), in the compressor room (RH = 24-51%, t = 13-27°C) and outside in a covered shed (RH = 20-50%, t = 3-23°C). After 35 days the dimensions were measured again. Results. It was found that the average moisture content decreased and the dimensional deviations increased in the samples stored in the production hall and in the compressor room. In samples stored outside, the mean moisture content did not change, but the dimensional deviations increased significantly. Discussion. The storage of wooden elements increases the deviations from assigned dimensions. Exposure to repeated changes in moisture content and ambient temperature, even without changing the final moisture content of the elements, results in greater dimensional changes than storage under more stabilized conditions that reduce wood moisture content. Conclusions. The shrinkage and swelling of wood due to changes in its moisture content are not fully reversible, therefore, apart from maintaining the appropriate temperature and air humidity during storage, it is important to keep these conditions unchanged.

Study of effect of waste tire rubber which is a recycling material in production of laminated veneer lumber (LVL) boards

The amount of waste produced by people increases with the increasing population in the world. Especially non-recyclable wastes have become a major environmental problem. Waste tires that emerge as car demands of people increase are one of the non-recyclable wastes. In this study, the usage possibilities of powder rubbers obtained from waste car tires were examined in the production of laminated veneer lumber (LVL) boards, which are preferred as furniture and decoration material in the forest products industry. For this, three different tree species (Scotch Pine— Pinus silvestris L., Oriental Beech— Fagus orientalis L., Stinking Juniper— Juniperus foetidissima Wild.) and two different types of glue (UF and PVAc glues) were used. Waste tire rubbers (WTR) were mixed into the glue in different proportions (0%, 10%, 20%, 30%). Physical (full dry and equilibrium moisture density, contraction in the transversal and longitudinal direction) and mechanical tests (MoR, MoE, bonding resistance) were performed on the LVL samples prepared. According to the results obtained, it has been seen that the mixtures of 10% and 20% WTR increase the LVL resistance. An eco-friendly building material has been obtained by using WTR produced from waste car tires in production of LVL.

Evaluation of Creep Characteristics of Single- Staple Furniture Joints Made of Different Wood Species

In this study, creep characteristics of single stapled furniture joints made of Scotch pine, alder and beech wood under three different load levels were considered. Load levels were determined as 30 %, 40 % and 50 % of the maximum load obtained as a result of static shear test before creep load and applied to wood joints. Laboratory test results showed that the highest creep deformation was observed in the joints made of Scotch pine with the lowest density, while the lowest creep deformation was observed in the joints made of beech with the highest density. In addition, the joints were exposed to lowest creep deformation at the 30 % load level, then the creep deformation of the joints increased at 40 % load level and it reached the highest value at 50 % load level. As a result of creep test, deformation in single stapled joints made of Scotch pine, alder and beech were determined as 2.74 %, 3.71 % and 4.37 % of the deformation that occurred as a result of static shear test performed before creep test, respectively. Ultimately, the overall average creep deformation value of a single staple wood joint under creep loading was determined as 3.61 %.

Territorial distribution alleles of SSR-loci of chloroplast DNA of scots pine (Pinus sylvestris L.) in Belarus

Scotch pine (Pinus sylvestris L.) is one of the main forest forming species in Belarus, which cover 49.2 % of the country’s forested area. The aim of the study was to investigate spatial distribution of microsatellite (SSR) alleles (chloroplast DNA) and identify the features of the genetic structure and genogeographic differentiation of P. sylvestris populations in Belarus. Molecular genetic analysis of six SSR loci of Scotch pine cpDNA in samples form 73 naturally originated stands was carried out. 35 allelic variants of loci PCP1289, PCP4507, PCP83314, PCP71987, PCP26106, PCP30277 were identified. The analysis of the geographic distribution of the dominant allelic variants showed that the population structure of the pine forest is rather homogeneous. Certain regional differences in a number of cases were found for less common, but also widespread variants. One group of alleles is characterized by an increase or decrease in the frequency of occurrence in the direction from the southwest to the northeast. Another group includes allelic variants which share is maximal in the zone covering the Grodno region, the southwestern part of the Minsk region and the Gomel region, while to southwest and to northeast from this zone their frequency of occurrence decreases or is absent. A number of alleles were found only in one of the analyzed stands or in a limited area, which may indicate their local origin as a result of spontaneous mutations. The obtained results are important both from a general biological point of view in studying the evolution and formation of the genetic structure of P. sylvestris in Belarus, and from a practical point of view, since they allow to improve the forest seed zoning of the species.