A Scots pine tree plantation has been established in the area of the Experimental Forest Station of the Warsaw Agricultural University. The plantation consisted of seedlings colonised by different species and numbers of mycorrhizal fungi. Formerly, the experimental forest area was used as a tree nursery for over almost 40 years. Before planting, the seedlings were grown on non-sterile peat-perlite medium. One half of the medium was supplied with mycorrhizal inoculum containing fungus Hebeloma crustuliniforme. In the nursery, the seedlings were treated with six fungicides, with untreated ones left as a reference. In spite of statistically significant differences in degree of mycorrhizal colonisation among different treatments, the seedlings had similar heights. After the first year, the degree of mycorrhizal colonisation of the seedlings grown in plantation became similar and exceeded 80%. The seedlings inoculated at the start of the experiment had significantly smaller height increments when compared with non-inoculated ones. Regardless of the treatment, survival rates of seedlings were high and averaged 97%.

The character of this work is faunistic and its main aim is to present the largest spectrum of mite species. As a result of acarologic examination on territory of the “Bory Tucholskie” National Park, 42 samples were collected, from which 77 mite species of Mesostigmata order were separated. The greatest numbers of species were represented by the families Ascidae (16 species), Laelapidae (13) and Parasitidae (10). The most plentiful species that occurred in the collected material were Trichouropoda rafalskii, T. ovalis, Veigaia nemorensis, Trachytes aegrota and Zercon triangularis, while in the greatest number of samples T. ovalis, V. nemorensis, Z. triangularis and T. aegrota were recorded.

This study constitutes an attempt to analyse the filling of forest space in two-generation felling stands growing on an upland forest site. The purpose of the performed investigations was to determine the area and space of a single tree in the layer of the young generation and the influence of the old forest on these tree parameters. The experimental material was collected in 2001 from the area of the Krasiczyn Forest Division (RDLP Krosno). The analysis was performed in 28 test sites in which the proportion of the common beech in the old forest composition was at least 70%. The coefficients calculated in this study were characterised by a fairly high variability, especially in the field of the tree unit area. As a rule, this variability was higher in the beech young crop than in the fir one. It is to be presumed that this was a natural outcome of diversified structural traits resulting from a conscious, albeit subjectively realised, process of forest utilisation and forest self-regeneration. The performed analysis failed to reveal a significant influence of old trees on the size of the area and space in the layer of the young generation developing under their canopy. Therefore, there is a need to continue this kind of investigations, also in stands characterised by a different structure, with the aim to verify the usefulness of the applied indices in spatial analyses concerning structural traits of the Carpathian beech forest. The identification of the filling parameters of the forest space may help foresters in planning their economical recommendations and the achievement of appropriate silvicultural tasks.

The larch stem profile was analysed on the basis of 40 stems of Polish larch in the strictly protected J. Kostyrka reserve situated on the Chełmowa Mt in the Świętokrzyski National Park. An attempt was made to describe this profile in such a way that it would be possible to determine the volume of wood size classes on standing trees. For this reason the taper model worked out by Bi [2000] was used. On the basis of the material collected the taper model parameters were worked out. The model explains over 97.5% of the stem profile variation. The method of the stem form determination used is characterized by a high accuracy in determining the stem profile and stem volume. The formula worked out in this study, describing the stem form of Polish larch from the Chełmowa Mt, is of a local importance. Its practical application on a wider scale would require an estimation of formula parameters on the basis of a larger study material.

Studies were carried out to work out a protocol for in vitro propagation of the Krotoszyn oak tree using fragments of 3-month old seedlings. The focus of the study was to select the best medium and the concentration of growth hormones for oak multiplication. The highest average multiplication rates were observed on A2, WPM and Pin media supplemented with 2.0-3.0 mg·dm^-3 BA + 0.01 mg·dm^-3 NAA.

Comparative investigation carried out with both modified fiber cloth – KYS-type FINESS and standard fiber cloth with homogeneous structure on the whole thickness – KYS-type PROGRSS showed essential differences in the performance of both types of material used for filtration of air containing very small dust particles. It was concluded that separation properties of that material are very good in relation to the number of particles in the air. The amount of dust particles in the air which flew through filtration bag made of fiber cloth covered with microfibers (KYS-type FINESS) is from two and a half up to three times smaller than in case of standard cloth. It is very advantageous as it guarantees compliance with strictest air cleanness requirements in the production halls. Very high air cleaning efficiency of clothes covered with microfibers allows for total freedom in designing and exploitation of closed air systems used in furniture factories.

Changes in crystallinity of wood cellulose in situ under gamma radiation were investigated with infrared (FTIR) spectroscopy and X-ray diffraction technique. The correlation between degree of crystallinity determined by X-ray diffraction and crystallinity index calculated with normal and second-derivative IR spectra were studied. Good correlation obtained only for ratio A₁₃₇₃/A₂₈₈₅. It has been shown that absorbance/valley ratio: A_{1373 cm-1}/A_{1350 cm-1} or A_{1160 cm-1}/A_{1148 cm-1} with FTIR spectra can be used for estimation crystallinity of wood cellulose in situ.

The theory of axially compressed cylindrical shaped plywood stability is presented in the paper. The differential equation of the elastic line, its slope, the critical stress and the shell stresses and strains of very slender plywood tube in elastic states are considered in the paper under conditions of flat cross-sections and little slope of the elastic line. The received theoretical results of critical stresses are related to slenderness ratio and to product of the radius and the wall thickness of the cylindrical shaped plywood made of birch. The received theoretical results of stresses and strains are presented as an example of the cylindrical shaped plywood.