The study analyzes the causes of premature failure in wooden power line poles in Slovenia, where multiple cases of rapid fungal decay have occurred despite a projected service life of 30 to 50 years. The poles were made from Scots pine and impregnated with a copper-ethanolamine biocidal product. The objective of the research was to assess the condition of standing poles and investigate the primary causes of premature degradation, using two fallen poles as case studies. The methods employed included resistograph measurements to determine the extent of wood decay across cross-sections, core sampling to determine preservative penetration and retention, and microscopic and hyperspectral analyses of wood samples to precisely characterize the decay. The results revealed that wood impregnation was generally insufficient, leading to extensive decay, particularly in areas with insufficient biocidal retention or where the entire sapwood of the pine poles was not fully impregnated. The accelerated degradation of the poles was attributed to brown rot fungi. The study underscores the need for improved impregnation techniques and regular monitoring to ensure the longevity of the poles and the reliability of the electricity supply.
This article presents the key results and scientific findings from two national postdoctoral research projects supported by the Ministry of Education, Science and Sport of the Republic of Slovenia (MIZŠ) and the Slovenian Research and Innovation Agency (ARIS). We analyzed the biorefinery potential of low-value Scots pine (Pinus sylvestris L.) and black locust (Robinia pseudoacacia L.) wood for the extraction of natural bioactive compounds. Knotwood and heartwood were used as biomass for extracting polyphenolic compounds, which were subsequently applied in bio-based wood preservatives. The results showed that hydrophilic extractives from Scots pine knotwood and black locust heartwood inhibit fungal decay and demonstrate strong potential as biocidal components and antioxidants in natural wood protection formulations. Further research on the antioxidant and antifungal properties of wood and bark extractives is ongoing.
Residential wood fence posts may be dug directly into the ground, secured to a metal spike that goes into the ground, or secured to a concrete footing with a metal boot. It was hypothesized that, by keeping wood posts out of the ground, both spikes and boot attachments would increase protection against decay and termites and extend the service life of the posts. After 9 years of exposure in Kincardine, Ontario, Canada, at a site with decay and subterranean termites, we found that elevated fence post footings were associated with less biodegradation than posts dug directly into the soil. The spike and boot installations were particularly effective in reducing the incidence of termite attack under the conditions of this study. Spike and boot footings may offer a way to remediate posts by reusing the top portion of posts that were initially dug into the ground following a groundline failure.
Total wood demand is projected by the FAO to increase by 49% between 2020 and 2050, despite deteriorating supply conditions such as deforestation and degradation due to fire and biological damage to forests. Service life extension and reuse of wood can help to mitigate this projected gap between supply and demand. Common construction timber species with moderately durable heartwood include Scots pine, Douglas fir and Japanese cedar. However, this durability varies widely among clones, growing sites and within tree trunks. The selection and utilization of highly durable clones or individuals within these timber species could contribute to extending the service life of building and civil engineering structures that are at greater risk of biodegradation, such as building facades and landscape engineering applications. The authors would like to advance the discussion on measures to utilize this selected timber with higher durability, including maintenance strategies and the complementary use of treated timber within the circular economy.
This article presents the key results and scientific findings from two national postdoctoral research projects supported by the Ministry of Education, Science and Sport of the Republic of Slovenia (MI8) and the Slovenian Research and Innovation Agency (ARIS). We analyzed the biorefinery potential of low-value Scots pine (Pinussylvestris L.) and black locust (Robinia pseudoacacia L.) wood for the extraction of natural bioactive compounds. Knotwood and heartwood were used as biomass for extracting polyphenolic compounds, which were subsequently applied in bio-based wood preservatives. The results showed that hydrophilic extractives from Scots pine knotwood and black locust heartwood inhibit fungal decay and demonstrate strong potential as biocidal components and antioxidants in natural wood protection formulations. Further research on the antioxidant and antifungal properties of wood and bark extractives is ongoing.
This study presents a method for protecting wood against fungal decay by precipitating insoluble copper salts within the lumina of wood cells using a two-step impregnation process. The procedure involves treatment with soluble copper sulfate followed by fixation with sodium carbonate. Fixation with sodium carbonate proved to be an effective method for reducing copper leaching from treated specimens. The natural retention capacity of copper in pine sapwood was around 2000 ppm, as determined by the leaching test according to SIST EN 84. With fixation, we successfully retained on average more than 5000 ppm of copper in the samples and almost completely prevented copper leaching from specimens impregnated with a 0.5% copper sulfate solution (0.5% corresponding to the concentration of copper ions in the solution). Despite sufficient copper concentration, the precipitated form of basic copper carbonate in the wood did not act as an effective fungicide, most likely due to its very low solubility in water (< 0.005 g/L at room temperature). Mass loss results according to SIST EN 113-1 indicated poor protection against Coniophora puteana and satisfactory protection against Gloeophyllum trabeum.
A method for converting stem quality assessments into log grade structure was presented. For 123 trees of four species, a comparison was made between actual assortments after felling and virtual assortments based on pre-harvest quality estimates. A total of 869 actual assortments were measured, and the results were compared with virtual bucking and sorting into log grades. The results showed good agreement for spruce, while the accuracy for hardwoods was lower due to undetectable internal defects. The method proved useful for improving harvest planning and assessing forest stand quality. Further refinement of existing models (e.g., knot size) would increase the the accuracy and applicability of the approach under Slovenian conditions.
Modern educational approaches emphasize the holistic development of children, which can be supported through well-designed learning materials. Montessori pedagogy is based on the use of specially designed materials that encourage independence, responsibility, and the development of motor skills. This study presents the development of a wooden children's device that combines the functions of a Pikler triangle and a learning tower, promoting the development of gross motor skills in children during the first stage of development (0-6 years). The development process included conceptual design, 3D modelling, numerical analysis using the finite element method (FEM), prototype manufacturing, and mechanical testing on a universal testing machine. Analysis of test results showed good agreement between the numerical simulation and the experimental data, confirming the suitability of the structural design and selected materials.
Due to the increasing need to humanize work and the general shortage of labour, the share of mechanized felling and timber extraction is rising, even on steep terrain. We analysed the feasibility of various technological solutions for operations on steep slopes. The selection and evaluation of technological solutions followed the German study by Findeisen (2008). Based on a comparison of available technological models, we initially selected five models out of nineteen: (1) a harvester and an articulated forwarder, (2) a crawler harvester and a forwarder equipped with a traction winch, (3) a model combining a chainsaw, a crawler harvester, and a forwarder with a traction winch, (4) a model combining a cable yarder and a chainsaw, and (5) a specialised skidder with a processor head. A sixth model (chainsaw, harvester with traction winch, and a forwarder with traction winch) was added because it had previously been applied on the selected work site. The selected models were evaluated according to three criteria -ergonomic, environmental, and economic -based on the actual conditions of the work site. For the chosen models, we calculated labour costs, accounting for cost adjustments derived from the characteristics of the terrain. In the second phase of the study, model 6 proved to be the most suitable, as it enables the felling of large diameter trees on steep slopes and thus allows work to be carried out across the entire site. Although the comparison of technological solutions and the subsequent optimization of the model selection is preliminary, we consider it a useful tool for the planned and effective introduction of modern technologies into Slovenian forestry.
The study analyzes the causes of premature failure in wooden power line poles in Slovenia, where multiple cases of rapid fungal decay have occurred despite a projected service life of 30 to 50 years. The poles were made from Scots pine and impregnated with a copper-ethanolamine biocidal product. The objective of the research was to assess the condition of standing poles and investigate the primary causes of premature degradation, using two fallen poles as case studies. The methods employed included resistograph measurements to determine the extent of wood decay across cross-sections, core sampling to determine preservative penetration and retention, and microscopic and hyperspectral analyses of wood samples to precisely characterize the decay. The results revealed that wood impregnation was generally insufficient, leading to extensive decay, particularly in areas with insufficient biocidal retention or where the entire sapwood of the pine poles was not fully impregnated. The accelerated degradation of the poles was attributed to brown rot fungi. The study underscores the need for improved impregnation techniques and regular monitoring to ensure the longevity of the poles and the reliability of the electricity supply.
In this study, Resupinatus rouxii Consiglio & Setti was collected from Canakkale province, Tiirkiye, and identified using both morphological and molecular data. Macroscopically, the species is characterised by its small size, kidney-shaped pileus, light grey colour, and slightly hairy surface. Microscopic examination confirmed diagnostic features of the genus Resupinatus, and detailed evaluations were made of the basidia, basidiospores, and cystidia. The internal transcribed spacer (ITS) region of nuclear ribosomal DNA was sequenced and used in phylogenetic analyses. The resulting ITS sequence showed more than 99% similarity to the reference sequence of R. rouxii, supporting the morphological identification. This study represents the second scientific report of R. rouxii worldwide and provides the fourth known record of this species, extending its known distribution to Tiirkiye (Canakkale province) and contributing valuable data to its biogeography.
As part of the »ULTRA – University of Ljubljana for a Sustainable Society« project, a new test method was introduced into the curriculum to provide insight into key properties that affect wood durability. This study aimed to adapt and verify the “paste test”, which uses wood dust in nutrient media to assess the inhibitory effect of wood components on fungal growth. The method was adapted to match the available laboratory equipment and simplified for educational use by students at the Department of Wood Science and Technology (Biotechnical Faculty, University of Ljubljana, Slovenia). The study involved testing fungal growth on nutrient media supplemented with spruce wood dust, with the goal of evaluating different grinding methods, nutrient media, and data analysis. Potato dextrose agar nutrient media was confirmed as a suitable alternative to malt extract agar. The wood dust fraction size had no significant effect on fungal inhibition, enabling the use of coarser, less time-saving grinding methods. Image analysis and logistic growth modelling were conducted using freely available software (ImageJ and R-Commander), which proved to be effective alternatives to proprietary tools. Visualization of growth using logistic growth rates offered a clearer comparative analysis, despite some loss of dynamic growth information.
Natural disturbances represent one of the main management and scientific challenges faced by the forestry sector. Their role is increasing and changing with the growing impact of climate change. This review paper aims to provide a concise and up-to-date overview of scientific findings related to the role and functioning of natural disturbances in forest ecosystems, as well as their significance for forest ecosystem management and the sustainable provision of all forest functions. The article includes a review of recent research efforts and the evolving understanding of the function and role of natural disturbances. Additionally, it provides an overview of research results on various types of disturbances, with a particular focus on windthrows and barkbeetle outbreaks.
This paper discusses the basic ecology, potential invasiveness, regeneration, distribution, and characteristics of northern red oak (Quercus rubra L.) in Slovenia. In a pure northern red oak stand in Panovec, we analyzed tree composition and regeneration coverage using plot transects (three 4 x 4 m plots per transect) leading from the parent stand into neighboring, predominantly sessile oak stands. We found that northern red oak regenerates well within a 50 m range from the parent stand, with an average density of about 40,000 seedlings per hectare. Regeneration coverage of northern red oak at the edge of the parent stand was 79%, decreasing to 21% at a distance of 50 m, while sessile oak regeneration coverage increased from 4% at the edge to 39% at 50 m. The spread of northern red oak beyond parent stands is relatively limited and can be controlled by regular silvicultural measures. The goal in such areas is to establish mixed stands that include northern red oak, which grows rapidly, is resilient to climate change, and produces high-quality timber.
High-quality natural regeneration is the key to close-to-nature management, but forest inventories often fail to provide sufficient information. In 2023, we conducted additional sampling of regeneration in a network of permanent sampling plots on the Pahernik property. We found acceptable average densities for seedlings below 130 cm height, with 15,924 individuals hat, less satisfactory densities for saplings above 130 cm height and < 5 cm diameter, with 994 individuals hat, and low densities for saplings between 5 and 10 cm diameter, with 276 individuals ha(-1). On average, regeneration covered 24% of the forest floor, while ground vegetation covered 11%. There were no major differences in regeneration density and cover between elevations and spatially separated parts of the property. The regeneration was dominated by Norway spruce (38%), followed by silver fir (32%) and beech (26%). The high proportion of silver fir was due to its high densities in the height class up to 20 cm. In the higher classes, silver fir was less represented and increasingly browsed by ungulates. The average browsing rate of regeneration up to 1.3 m was 33%, and specifically for silver fir, 39%. This study indicates possibilities for improving the forest inventory.
