Comparison of Norway spruce artificial regeneration techniques tested in the area destroyed by spruce bark beetle in Kysuce Region (Slovakia)

Ongoing coniferous monocultures decline in Beskydy Mts. Slovakia, emerged into establishment of Demonstration object of reconstruction of spruce forests (DORS) Husárik, focused on various technological processes of regeneration of economically important tree species. For Norway spruce (Picea abies [L.] Karst.) assessment of less frequently used artificial regeneration technologies, including planting of containerized transplants (CRT) or direct seeding procedures (direct seeding DS, seeding into vegetation cell VCS) and commonly used planting of bareroot transplants (BRT) was carried out. Seven years after experimental plot establishment, the lowest survival rate was recorded for DS treatment with 42% survived seedlings, the highest for CRT treatment with 79% survived transplants. For germinated seedlings, average seeding spot occupation rate recorded for DS (72%) was significantly lower than for VCS (98%) one year after seeding and remained significantly lower also over further consecutive years. Average survival recorded for planted transplants over monitored period did not differ markedly and gradually decreased to 76% for BRT and 79% for CRT. Reflecting different ontogenetic stage of individuals assigned to selected treatment average height 134.6 cm for DS, 134.1 cm for VCS and 182.0 cm for CRT, 215.0 cm for BRT was recorded seven years after establishment. The results suggest that for spruce, less frequently used artificial regeneration technologies (VCS, CRT), that markedly curtail time period required for target tree species installation on planting sites, with survival and growth rate of plants recorded in this study, could provide reasonable alternative to commonly used planting of BRT.