Wood is a highly sustainable material and there is significant interest in its use in the construction industry in terms of modern building construction. However, safety rules and regulations, including fireproof requirements, have become increasingly demanding. In this regard, more effective and eco-friendly approaches for wooden materials treatment related to this topic are subject to research interest in laboratories around the world. The rapid development of nanotechnology offers new materials with unique properties, which will be able to partly substitute or even replace regular chemicals, often toxic to the environment, in the future. This paper overviews traditional fire retarding methods and fire retardants that are applied for the modification of wooden materials. In addition, the potential use of nanomaterials for wood and wooden applications were discussed by extensively literature review.

Keywords: wood-based materials; flame retardancy; reaction-to-fire testing; nanomaterials; nano additives

   The study is focused on the rate of vibrations and level of noise in the chainsaw model Stihl MS 362 which belongs in the group of the best-selling professional chainsaws in the world with a highly efficient anti-vibration system. Testing cuts to determine the rate of vibrations were made on the stems of two tree species: sessile oak (Quercus petraea (Matt.) Liebl.) and Norway spruce (Picea abies (L.) H. Karst.). The purpose of noise level measurement was to compare the influence of chainsaw noise on its operator and on the person occurring behind the zone of protection (5 and 10 metres) from the source of noise. Then a distance from the chainsaw was measured where the level of noise reached 80 dB. The measurements were performed according to ČSN EN ISO 22868:2021. At measuring the chainsaw vibrations, the rate of vibrations acting on both operator’s hands (front and rear grip) was examined. Vibrations were measured according to ČSN EN ISO 22867 (2012).

   It was found out that the rate of vibrations on the rear handle was in both cases of measurements higher than the rate of vibrations on the front handle. At the same time, a higher rate of vibrations was recorded in sessile oak. As to the level of noise, results of measurements indicated that at working with the chainsaw, hearing protectors have to be used at all three measured distances (close proximity, 5 m from the operator, 10 m from the operator) in order to reduce high noise level as the average noise level was higher than permissible in all measurements. The highest possible tolerable level of acoustic noise (80 dB) at which permanent damage of hearing does not happen was measured at a distance of 21 m from the working place of chainsaw operator.

Keywords: chainsaw; Stihl MS 362; vibrations; noise; occupational hygiene; forestry

   The Alnus glutinosa swamps are the most species-rich forest communities in the Fennoscandian hemiboreal zone. Considering the species abundance in different layers and their indicator values, in Estonia these stands can be classified into ten community types: 1) Calliergonella cuspidata–Carex acutiformis–Thelypteris palustris–Alnus glutinosa; 2) Brachythecium rutabulum–Scutellaria galericulata–Rubus caesius–Alnus glutinosa; 3) Brachythecium rutabulum–Urtica dioica–Aegopodium podagraria–Alnus glutinosa; 4) Plagiomnium elatum–Galeobdolon luteum–Oxalis acetosella–Alnus glutinosa; 5) Sphagnum fallax–Filipendula ulmaria–Phragmites australis–Alnus glutinosa; 6) Sphagnum riparium–Vaccinium myrtillus–Impatiens noli-tangere–Alnus glutinosa; 7) Calliergon cordifolium–Lysimachia thyrsiflora–Carex elongata–Alnus glutinosa; 8) Calliergonella cuspidata–Deschampsia cespitosa–Filipendula ulmaria–Alnus glutinosa; 9) Climacium dendroides– Calamagrostis canescens–Athyrium filix-femina–Alnus glutinosa; 10) Calypogeia integristipula–Filipendula ulmaria–Ulmus laevis–Alnus glutinosa. The species composition of the communities is determined mainly by the soil reaction and nitrogen content in the soil of their habitats.

Keywords: community types; indicator species; Ellenberg’s indicator values; habitats’ reaction gradient; nitrogen content gradient

   Global population growth and increasing urban population density together are responsible for many disruptions such as environmental pollution, especially air one. Trace metals are of specific prominence as air pollutants because they are conservative pollutants. They tend to accumulate biologically; some have poisonous or carcinogenic effects, even at small concentrations. Among toxic trace metals, lead (Pb) and zinc (Zn) can be harmful to human health in certain quantities. These trace metals were included in primary pollutant lists of the Agency for Toxic Substances and Disease Registry. Therefore, determining these trace metal concentrations in the air and monitoring the differences is very important for determining the risky districts and the level of risk. Biomonitors are the most important indicators of differences in trace metal concentrations in the atmosphere. The plants chosen as biomonitors intake several of the trace metals from the soil and/or the air into their bodies and determining the level of this accumulation might provide insight into the trace metal pollution of the atmosphere and soil. The present study aims to determine the variations of Pb and Zn concentrations in various landscaping plants growing in different districts of Kastamonu (Türkiye) depending on tree species, organs and traffic density. It was found that unwashed leaves of Acer negundo L. can be suggested as a good biomonitor for the presence of both analysed trace metals.

Keywords: biomonitor; air pollution; trace metal; lead; zinc; traffic