This study is a part of the monitoring program of protective treatments in forest ecosystems of the Karkonosze National Park concerning mites from the order Gamasida. In character it is basically connected with the fauna and its objective was to determine mites in selected areas in the tree stands of the lower and upper subalpine forests. On the basis of the obtained results a preliminary comparative analysis was conducted concerning the size of the population and species composition of mites depending on the site and date of collection, as well as the altitude. The aim is to constitute in the future the basis for the analysis and determination of changes in the Karkonosze Mountains.

According to Poland’s international committments the proportion of energy from renewable sources must reach 7.5% by 2010 and 14% by 2020. As we know it today, biomas, but first of all wood is the dominant renewable source of energy in Poland. It is estimated that about 1 mln m³ wood from logging residue and 2.2-2.8 mln m³ from improvement cuttings can be harvested for energy purposes. In order to do that Swedish technologies should be used. Those technologies are based on big highly productive drum chippers mounted on forwarder chassis, equipped with hydraulic cranes with grapples and containers for wood chips. As the field tests show it is possible to produce 70 m³ of fuel wood chips in one work hour, an equivalent of 63 MWh.

The study analysed the significance of differences of the defoliation, scatter and variability of Scots pine tree crowns of various biosocial classes performed on the basis of observation results from 1996 and 1999 in pine stands of the Siemianice Experimental Forests Division. It was found that, irrespective of the impact of outside factors, the biosocial position of Scots pine (Pinus sylvestris L.) trees had a significant influence on the extent of mean defoliation of their crowns. The age was found to have influence on the increase of the mean defoliation of tree crowns of the main stand. High defoliation variability indicates the necessity of its analysis in the case of more extensive areas.

The paper presents the results of evaluation of the state of farmaland woodlots in 2000/2001 on the area of 5480 ha in the Swieta Katarzyna district (Lower Silesia Province). The woodlots are grouped as clumps, water-edge tree rows, avenues and shelterbelts. The woodlots are classified in a six-grade scale depending on degradation. The overall number of woodlots on the area studied was 238. Water-edge tree rows constituted the most numerous group (42%). The largest percentage, almost 50%, constituted woodlots that were degenerated and weakly developed. Avenues were the most degenerated group. Only 23% of the avenues did not show signs of degeneration. In the woodlots studied, together with manorial estate parks, 104 woody species were found. The share of floristically exotic elements was 44.2%.

The thesis characterized condition and dynamics of subboreal forest spruce association Querco-Piceetum in the Kozienice forest, in south area of occurrence of spruce in Poland. The results of research were compared with the data obtained by R. Zaręba research (1953-1965). Comparisons were made of: the composition and structure of association, the share of groups of species connected with class of associations and with indicator values of vascular plants. Suggestions of forest planning are presented in phytocenosis of Querco-Piceetum in the Kozienice Promotional Complex.

The objective of the study was to determine of fir (Abies alba Mill.) and beech (Fagus sylvatica L.) vitality in stands in the massif of Mt. Łysiec in the Świętokrzyski National Park. In 1994, the percentage of strongly weakened and dying fir and beech trees was 46 and 21%, respectively. There were distinct differences in spatial distribution of fir vitality. In the P₃ areas (487,5 m × 515,0 m) of a network of the SINUS System of Information on Natural Environment from 5 to 90% strongly weakened and dying fir trees were observed. The differences in spatial distribution of beech vitality were smaller. In the P₃ areas, from 5 to 45% strongly weakened and dying beech trees were observed.

The article presents the commune ownership structure of woodland in the Wielkopolska voivodeship in the years 1990-2001 and factors accounting for the spatial differences it displays. An analysis of changes that had occurred in the area of state- and privately-owned woodland over the study period was made. The reasons of the changes were described, too. The research showed that the dominant role in the Wielkopolska forestry was played by the State Forests, an organisation controlling nearly 90% of the voivodeship’s woodland area. It was also found that only slight changes in the woodland tenure system over the years 1990-2001 had taken place.

The objective of performed investigations was to determine the influence of the shape of the cutting link and the inclination angle value of the horizontal blade cutting edge on chain durability. The objects of the investigations were two types of chains with chisel and semi-chisel types of cutting links. The performed experiments showed that in conditions of cutting of soiled timber, chain saws with a chisel type of links were more durable than those with semi-chisel links, and for the two types of cutting chains tested, the variants with the angles suggested by the manufacturer.

The article presents the index of changes of forest site type, composition of species (species diversity, composition agreement), vertical and age structure, crown density and stand volume since 1969 to 1988. The index has been tested in the Jasień Forest (experimental forest of Warsaw Agricultural University in Rogów) covering 840,05 ha. Changes of site structure in 1989 influenced the result of the test of the stand composition and stand diversity. Share of pine stand reduced for the better of leaved stand, mainly with oak. Change growth of vertical structure, mean crown density of stand in the I-III age class and stand survival were found.

The pneumatic conveying of wood dust particles depends to a large degree on air stream properties. Relative humidity of air which carries off the dust particles has an influence on their basic aero dynamic property – entrainment velocity. The entrainment velocity varies with changes of relative humidity of air effecting on dust particles. These research works made possible the affirmation that between these parameters exists linear dependence. In an interval of relative humidity changes 35-95% the increment of the entrainment velocity is about 25%. This is the base for making the value of correcting the changes of entrainment velocity coefficient in dependence of relative humidity of air stream, in which the dust particles are conveyed.