Menkis, A., Lygis, V., Burokienė, D. and Vasaitis, R. 2012. Establishment of Ectomycorrhiza-inoculated Pinus sylvestris Seedlings on Coastal Dunes following a Forest Fire. Baltic Forestry 18(1): 33-40.

Replanting of coastal dunes following forest fires often result in low seedling survival, as the site is characterized by loose sand, low water and nutrient availability, lack of ectomycorrhizal (ECM) inoculum and increased susceptibility to insects and diseases. The aim of the present work was to check whether certain treatments of root systems have any impact on Pinus sylvestris seedling establishment as compared with standard planting procedures. Treatments included: i) inoculation with vegetative mycelium of Cenococcum geophilum (CGV); ii) inoculation with vegetative mycelium of Suillus luteus (SLV); moreover, in each of those two treatments damp sphagnum peat / sand mixture was added to roots upon planting; iii) inoculation with basidiospores of S. luteus applied during preceding growing season in the nursery (SLB), and iv) standard planting, no treatment (control). A two hectare experimental plantation of P. sylvestris was established in the spring of 2007 on coastal dunes of the Curonian Spit in western Lithuania on a site of approx.100 year-old Pinus mugo plantation that one year previously was devastated by a forest fire and clear cut. The three treatments and control, comprising 2,500 seedlings each, were planted in rows as 16 replicates (5000 seedlings /ha). Results showed that after the first growing season seedling survival was poor in all treatments (5.1 – 30.0%), but seedlings in CGV, SLV and SLB showed respectively 591%, 533% and 196% better survival than no-treatment controls. Thus, inoculations with vegetative mycelia and addition of peat/sand mixture were by far the best, although the most labour-consuming. After two growing seasons, the proportion of ECM-colonised roots in treatments was 27.3- 39.8%, while 22.5% in the controls, and observed ECM types resembled those from forest nurseries. In conclusion, investigated treatments had a considerable positive impact on seedling establishment under high-risk site conditions.

Key words: ectomycorrhiza, reforestation, forest fire, Scots pine, seedling pathogens, fungal communities