Dendroflora of Złakowo Park comprises 36 taxons. The total of 1465 trees was inventoried. The dominant tree species in the park are those associated with the communities of fertile broad-leaved forests. Trees of Carpinus betulus are the most numerous, whereas common species include: Fagus sylvatica, Fraxinus excelsior and Quercus robur. The total of 203 trees was classified as valuable of which 77 trees were included in the group with monumental circumferences, 35 trees – were classified as trees with circumferences close to monumental and 91 trees – as splendid. Trees which frequently attained considerable circumferences comprised: Carpinus betulus, Quercus robur, Fagus sylvatica, Alnus glutinosa, Fraxinus excelsior and Acer platanoides.

The aim of this study was to analyse genetic diversity of H. annosum s. s. population in selected Scots pine stands with planted beech as a second floor or understorey, in Bolewice and Tuczno Forest Districts. In these stands the 14 genets of H. annosum s. s. were recognised. The biggest genet occupied 84 m² and the smallest one colonized only one beech. The beech was attacked by pathogen similarly like Scots pine. The genetic diversity of H. annosum s. s. populations was high and the basidiospores played a major role in pathogen‟s spreading process in studied stands.

The paper presents research results into quantities of branches and tree tops forming logging residues as well as the calorific value, moisture and ash contents of chips burned in a fluidal boiler. The results showed that logging residues make up 17% of the above ground tree biomass, which gives about 52.8 t/ha. The calorific value of the wood chips was 7.8 MJ/kg for fresh material, 12.9 MJ/kg for chips after 4 month storage time and 16.2 MJ/kg after storing the chips for 8 months. The ash from chips burned in a boiler with a fluidised bed contained 62% of silicon dioxide, resulting from the filling role of sand in the fluidal bed. The share of CaO was 6%, MgO – 2.8% and N 2 O – 0.4%.

The study is an attempt to determine variation in the proportions of sapwood and heartwood in the radial and axial sections in stems of common oak (Quercus robur L.), representing the main tree stand (according to Kraft biosocial classification), age classes V (81-100 years) and VI (101-120 years), growing in the fresh mixed forest and fresh forest sites. Sample trees were selected according to Urich I method from four plots (of 1 ha each). For each model tree its crown projection area was determined. After felling all necessary biometric traits of tree stem and live crown were measured. Stems were divided into 2-metre sections, from which centres discs were cut in order to determine selected wood macrostructure parameters and volumes of sapwood rings and heartwood cylinders. Additional discs were cut from breast height and kerf planes of trees. When analyzing results for individual discs and trees arithmetic means of widths (or volumes) of studied wood zones were used. During the study the irregularities were determined of sapwood and heartwood zones in stems. Strong and plus interrelations were found between crown volume and crown projection area (as area of cylinder external surface) and sapwood area at the cross stem section, although some of the correlation coefficients were not significant. Large variation was observed in the proportions of volumes of sapwood and heartwood in individual Kraft‟s biosocial classes. Differences were also found in sapwood and heartwood radial share between age classes, and rather small differences between forest site types.

The paper contains research results into the time consumption and costs of fuel woody biomass production, in the form of bundles and chips from logging residues. The tests were conducted in adult pine stands and machine technologies for wood harvesting and extraction were used. The share of logging residues in the total tree biomass was assessed based on measurements carried out on three experimental plots in adult pine stands. The costs calculations contained fixed and variable cost categories. The share of the woody biomass which forms logging residues in the total above-ground tree biomass was 15%. The time consumptions of the energy wood harvesting, using machine technologies, were 0.447 h/m³ for wood chips and 0.481 h/m³ for residue bundles, and the costs amounted to 53 PLN/m³ and 70 PLN/m³, respectively.

The aim of the performed experiments was to assess energy expenditure and static loads of the operator of a chain sawing machine harvesting timber in a pine stand intermediate cutting. The investigations included two technological variants. In variant I, all technological operations were carried out by one worker – operator of the chain saw, while in treatment II the operations were carried out by a team of three persons – two operators of chain sawing machines and a helper. The energy expenditure was determined on the basis of measurements of the ventilation of lungs, whereas the static load – using the OWAS method. The determined net unit energy expenditures of the chain saw operators in the experimental variants exceeded 20 kJ·min^-1 and differed statistically significantly between one another. With regard to static loads, a greater proportion of positions negatively affecting the muscle-skeletal system of the operator were found in variant II.