Sea buckthorn (Hippophaë rhamnoides L.) is a pioneer species, well adapted to colonize soil-less substrata. It features rapid growth, due to symbiosis with nitrogen-fixing actinomycete Frankia. This species is recommended for reclamation of degraded lands, especially soil-less areas endangered by erosion. This work investigates the influence of substratum acidity (pH(KCl)) on growth of sea buckthorn on the external spoil bank of the Bełchatów Brown Coal Mine in central Poland. First year survival and subsequent growth of planted specimens was strongly dependent on substratum acidity. The range of pH variability tolerated by sea buckthorn on spoil bank was comparable with the range observed in natural conditions. The best growth (and potentially the best ability to stabilize substratum) was observed on neutral substrata pH(KCl) 6.61-7.2. while the worst on very acid substrata (pH(KCl) 3.51-4.5). The pH level of substratum could be very useful diagnostic feature to assess suitability of sea buckthorn for substratum stabilization.

The paper presents the structure analysis of breast height diameters, heights and of the biosocial structure of the 39-year old pedunculate oak introduced artificially and growing until 1991 in different conditions created by three different cuttings carried out in the hornbeam-oak old-forest growing on the fresh mixed broad-leaved forest site. Following the removal of the old-forest in winter 1986/87 (group clear cutting) and in winter 1991/92 (shelterwood cutting), in all three variants the oak is growing in open space. The inventory carried out in 2007 showed that in each case the best experimental results were recorded in the stand with clear cutting (1-Rz). Stands from the 2-Rcz and 3-Rg achieved worse, albeit statistically non-significantly different, results. However, formally, from the point of view of mean breast height diameter and height, a slightly better situation was recorded on the 3-Rg plot, while from the point of view of the mean biosocial class – on the 2-Rcz plot.

Stands dominated by wild cherry [Cerasus avium (L.) Moench] are characterised and site conditions under which such stands may come into being are described. It was found that in foothills of the Bieszczady Mts. wild cherry can form self-sown stands on brown soils rich in nutrients and humus compounds formed of clay shale. Adequate terrain configuration, which gives protection against spring frosts and provides proper soil moisture, creates optimal conditions for growth of wild cherry stands. Rich forest floor vegetation, composed of species typical for eutrophic beech forests, sub-mountain sycamore maple forests, and riparian forests, was observed under canopy of wild cherry stands.

The total content of mineral substances (ash) and heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Pb) in the wood of healthy and dying beech trees from different regions of Poland was subject to analysis. The material for the analysis came from the nine Forest Districts in which Poland’s main sources of beech wood are located. Two healthy and dying sample trees of the same age were collected from each stand bearing symptoms of weakened vitality and decline of trees. Wood samples cut out of the central zone between cambium and pith, of the cross section of the trunk at the butt-end of beech trees aged 80-145 were used for analysis. The content of mineral substances in the wood of healthy and dying trees was within a similar value range. No statistically significant difference in the content of each of the analysed elements was found in healthy and dying trees. A relationship was found between the content of heavy metals in wood and geographic origin of trees.

The article presents results of one-year long observations concerning the main causes of failures of power chainsaws of various manufacturers. The observations were conducted at two authorised service repair shops. It was found that new chainsaws subject to free guarantee surveys constituted the highest number of serviced devices. On the other hand, the principle causes of defects included: the feeding system and the body as well as the piston-crankshaft system (total of 50% of defects). The smallest number of defects was recorded in the case of the exhaust system followed by the starter system and elements of the work safety. The majority of defects resulted from the application of improper use of operational materials, incorrect usage and inadequate knowledge of users as well as discrepancies between the intended application of the analysed equipment and real operational conditions.

The total content of mineral substances (ash) and heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Pb) in the wood of healthy and dying oak trees from different regions of Poland was subject to analysis. The material for analysis came from the 12 Forest Districts in which the main source of oak wood in our country is located. Two trees healthy and dying of the same age were cut in each stand showing symptoms of a decline trees in the past and at present. Wood samples cut out of the outer heartwood at the butt-end of the trunk of oak trees aged 60-155 were used for analysis. The content of mineral substances in the wood of healthy and dying trees was at a similar level. No statistically significant difference in the content of each of the analysed elements was found in the wood of healthy and dying trees.

Red ring rot caused by the fungus Phellinus pini is a serious problem from the point of view of forest economy in Poland, as well as in other countries. The rot attacks the hard part of trunk, it develops unnoticed for several decades of years, frequently, it is not detected before the felling of the tree and it causes enormous economic losses. One can suppose that about 8% of gained pine felling product consists of rotten wood. The main objective of the presented studies was the determination of the occurrence of Scots pine stands threatened by red ring rot on the basis of the presence of fruit bodies of Ph. pini and of red ring rot developed in result of a hollow in the trunk which was settled by Ph. pini mycelium. During observation of disease symptoms on the ten separated areas (2490 trees), sings were detected on 61 trees. A great number of fruit bodies and their locality exert a high influence on the development of rot foci and thereby they cause great economic losses.

Phellinus pini is the most frequent cause of the development of red ring rot creating great economic losses in the felling product. Phellinus pini remains a constant threat and it causes significant losses in timber raw material. It affects the functioning of the forest ecosystem and its stability from the economic point of view. The main purpose of the presented work was to make an inventory of Phellinus pini fruit bodies in stands in the age of over 100 years on the area of forest division of North Poland. For the estimation of red ring rot fruit bodies, 30 forest division were selected with pine being the dominating species in the age of 100-170 years. In results of the presented estimations, one can state that only one of the observed stands did not show any red ring rot fruit bodies.

In comparison with other natural objects situated within the administrative boundaries of the city of Poznań, the “Strzeszyn” ecological site distinguishes itself by significant floristic values. The flora of this object includes 531 vascular plants deriving from 91 families and 296 genera, of which 20 species can be found on all-country and regional lists of disappearing and threatened plants. The most valuable floristic elements include Dactylorchiza incarnata, Dianthus superbus, Epipactis palustris and Polypodium vulgare. In addition, 12 trees of monumental or near monumental circumference were found to grow here as well as several dozen splendid trees.