Scientific publications

The issues related to the restoration of forest communities destroyed by timber harvesting followed by burning are considered. The study object was 53-year-old pine crops seeded in
a burnt felling of the heather type with sandy soils. The work objective was to investigate the aftereffect of long-term annual application of phosphate fertilizers on the annual ring formation and timber quality in middle-aged pine crops. The experimental designwas as follows: control (no fertilization), P, PK, NP. Fertilizers were applied annually from the time the crops were 7 years old (1967) for 30 years (until 1996). From 1967 to 1972 urea and potassium chloride were applied in the dose of 60 kg/ha, superphosphate – in the dose of 120 kg/ha; and from 1973 to 1996 each of the fertilizers was applied in the 120 kg/ha dose.The composition of the fertilizers predetermined the growth of crops during treatments and influenced the duration and degree of their aftereffect. The greatest bole areaincrement was observed during application of NP fertilizers. P and PK fertilizers were more effective during their aftereffect. An average tree volume by the end of the observation period was 1.6; 2.0 and 2.5-fold greater than the control whenfertilization of P, PK and NP, respectively. The use of phosphate fertilizers increased the proportion of latewood in the annual layer by 13...25% in comparison with the control. The maximum value (30 %) this parameter reached at the application of superphosphate only. Wood density ranged from 406 to 446 kg/m3 depending on the type of the appliedfertilizer. Treatments with NP and PK fertilizers tended to reduce the basic density of pine wood, especially the nitrogen-containing fertilizers.