Objectives of this dissertation thesis are evaluation of the effect of application of commercial products (hydrogel Stockosorb, microbial additives Mycorrhizaroots, Ectovit) and fertilizer Silvamix Forte on survival, damage and growth of Norway spruce (Picea abies [L.] Karst.), Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) after several growing seasons after planting. Also estimation of the effect of planting time (autumn, spring) and seedling type (bare-root and container-grown) on survival, damage and growth of selected tree species. The work contributes to knowledge about effect of above mentioned soil additives, planting time and seedlings type on nutrient content in photosynthetic apparatus and soil, ectomycorrhizal colonization of roots and on parameter of chlorophyll a fluorescence of outplanted seedlings. The experiments were established on three planting sites in Kremnické vrchy Mts., Strážovské vrchy Mts. and Javorie Mts. (Slovakia) and in complete randomized block design with three repetition. Experimental unit was plot with 50 seedlings of each combination of the main effect. Despite the results of experiments presented in this study are valid just for the used planting stock of specific quality in a given environmental conditions (location, soil, course of weather) and cannot be generalized, but several outputs can be emphasized and any also indicate possibilities of their practical use. The results confirm the importance of the use of planting stock of high physiological and morphological quality. Comparison of the results on the sites where spruce, pine and beech were outplanted shows that after a complex estimation of survival, damage and growth a bit better results achieved spruce. The use of pine and beech seedlings of less growth parameters (1+0) caused excessive plantation mortality. Damage of plantations was most frequently caused by game browsing and dry leading shoot of seedlings. Effect of applied additives on survival, drying of leading shoots, growth, eventually content of basic nutrients in photosynthetic apparatus and ECM colonization of roots were considerably variable – mostly insignificant, but in several cases also easily to significantly stimulated.