Pietrzykowski Marcin, PhD.

Forest regeneration by means of seedlings grown in container nurseries is usually performed manually with the use of the standard dibble bar or the tube dibble. Manual placement of a large number of seedlings in the soil requires a lot of work. Manual removal of the soil cover and digging the soil in spots with a diameter of 0.4 m requires, under average conditions, about 38 man-hours/ha, while planting with a dibble bar requires about 34 man-hours/ha. Additional work time is needed to carry seedlings over an area that is being afforested. At present, forestry does not have automatic planters that would enable the establishment of forest cultures. The aim of the paper is to present the concept of an autonomous robot and an innovative technology of performing forest regeneration and afforestation of former agricultural and reclaimed areas. The paper also presents the design solutions of the key working unit, which is a universal, openable dibble, cooperating with a three-toothed shaft to prepare a planting spot. The solution proposed enables continuous operation of the machine, i.e. without the need to stop the base vehicle.

Understanding the impact of reclamation measures on the quality of timber produced in post-mining areas is crucial for the proper establishment of future forest cultures on such sites. We studied European larch trees (Larix decidua Mill.) grown since 1981 on the external dump of a brown coal mine in Bełchatów (Central Poland). In particular, the effects of stand admixture and the intensity of mineral fertilization, applied in the initial phase of tree growth, on the increments and quality of larch wood were evaluated. Total tree height and stem diameter of 4-meter sections were measured. Qualitative timber classification took into account the share of wood defects, which excluded the timber from a higher quality-dimensional class. Larch trees grown in a monoculture had a better quality of wood compared to larch grown mixed with other species. Fertilization, applied in the initial afforestation period, had only a limited effect on the growth of larch trees. Curvature and knots determined timber quality most significantly. While knots had a decisive importance in larch growing in the monoculture stands, curvature determined wood quality in the admixed larch stands.