The objective of the study was to estimate biomass and selected morphological traits of fine roots (diameter ≤ 2 mm) in 26-year-old Scots pine stand originating from afforestation and growing as the first forest generation on formerly arable land. The stand is located about 30 km north-east from Poznań (western Poland) in the Murowana Goślina Experimental Forest Division, which belongs to Poznań University of Life Sciences. 20 sample trees were selected. Within a distance of 30 cm from each tree intact soil cores were sampled from 3 depths in the soil: 0–20, 21–40 and 41–60 cm. The total number of samples was 120. All roots were separated from the soil, scanned, dried to constant mass and weighed. Fine root biomass and morphological traits (such as: length, surface area, volume and number of root tips) decreased with soil depth. The only exception was diameter, which increased with soil depth.

The aim of the study was to investigate of moths species of the family Geometridae which live in and around the Słowiński National Park. Regular researches about the Geometridae were conducted in central and eastern part of the Słowiński National Park buffer zone on the section approx. 40 km in 2003–2008. To catches were used traps light. Data about species were supplemented also on the information gathered from the interval 1985–2015 based on irregular observations. In total it found 206 species of the Geometridae. Most species are frequently found in Poland (Buszko, 2000). This checklist is the first synthetic description about the Geometrid moths of the geographical zone the Pobrzeże Słowińskie after 1945.

The annual height increment of Scots pine exerts a direct influence on the determination accuracy of the tree and the stand volume increment. It is considered as a major dendrometric characteristic. However, the growth of trees depends on the meteorological conditions in the year that preceded increments, as well as in the given incremental year. In this study the relationship between annual increments, and temperature was examined. For this purpose correlation coefficients between monthly temperature and mean annual height increments were designated. Next, the forward stepwise regression procedure was used. For this purpose the SAS software package was applied. On the basis of the presented research it was found that the Scots pine increments are greater when summer months, both of the pervious year and of the given vegetation season, are cooler and when March is warmer.

Analyses were conducted in the Sulęcin Forest District. Measurement plots were established in two oak dominated saplings (Quercus robur L.), at the age of 17 years growing at different forest site types. The share of the so-called wolf trees was low (4%) and varied from 222 to 267 individuals per hectare. In this paper we presented the measurement of tree height (h), diameter of the breast height (d_1.3), slenderness (m/cm) for all living trees (D-w). These results were compared to the results obtained for the groups of trees (D-r, D-s and D-p). It was stated that wolf trees (D-r) dominate in size, independently of the forest site type. On average, they are 35% higher than the other trees. They are also thicker, almost twice, than the rest of trees. Silvicultural operations (tending treatments) in saplings should take into consideration the influence of the wolf trees (D-r) on the other trees, as well as on the stand structure.

The process of dying of trees in a forest stand is one of the most important developmental processes of forest ecosystems. The work presents the carried out study of the structure (composition and occurrence frequency) of subcortical insects community dwelling in Scots pine trees during the artificially initiated process of dying of trees. The analyses were conducted in the stands of the Durowo Forest District, in forest habitats of fresh and mixed forests (Bśw, BMśw, LMśw, Lśw). The trees were classified in into III, IV and V classes of age (from 41 to 100 years old). It was found that the community of subcortical insects in the initial stages of dying process were composed of cambiofagous species (for example Tomicus piniperda, Hylobius abietis). Among these species, Tomicus piniperda showed the largest frequency. In the advanced phase of tree dying, the community of subcortical insects was getting rich in species. It consisted of 9 cambiophagous and xylophagous species. There were two dominating species: Asemum striatum and Pissodes sp. The reproductive potential for Tomicus piniperda and Hylobius abietis (pine weevil) was defined too. It was also found that the accumulated pine wood (e.g. loose wood piles) can be supplemental nesting base for the weevil.

This study identified the most frequent causes of failure in gasoline-powered chain saws as well as total costs of their repairs (in terms of costs of replacement parts and costs of repair operations), performed by an authorised service agent of the leading manufacturer of these power tools, Husqvarna. Post-warranty and warranty repairs of chain saws were analysed including the specification of the most defective component systems.