Effect of soil bulk density on forest tree seedlings

The paper presents the results of an analysis of the influence of soil bulk density in a forest nursery plot on the growth and quality parameters of Scots pine and European beech seedlings. Particular density variants were obtained using a tractor device exerting controlled pressure on the soil, while field examinations were performed on an area of ‘Kłaj’ forest nursery in Niepołomice Forest District. Three series of plots were prepared for each species, applying a unit pressure of the values of 50, 100, 150, 200, 250 kPa, corresponding to the dry bulk density in the range of 1.03-1.19 g cm-3, and control plots without the pressure. Seeds of the examined species were sown on the prepared plots, and after 6 months of growth the seedlings were subjected to biometric analysis determining differentiation in root neck diameter, length of the above-ground part and root system, as well as dry mass of particular parts of the plant. The quality of the seedlings was also determined using the method of Schmidt-Vogt. The results obtained show that the change in dry bulk densitysoil significantly affected most of the growth parameters of theexamined seedlings. Especially high negative correlations were obtained for the length and dry mass of the root system. A significant influence of dry bulk density variant on all growth parameters of Scots pine seedlings, and on some parameters of European beech was demonstrated. An increase in soil bulk density clearly caused also a deterioration of European beech seedlings quality.