Changes of ground vegetation after shelter wood cuttings in pine forests, the hemiboreal zone, Lithuania

Sustainable forestry plays an important role in applying forest management measures. In many forests, management is oriented towards closer natural forest processes. Silvicultural systems that retain some part of the trees in the stand, such as shelter wood cuttings have been introduced. The aim of the study was to evaluate the early changes of ground vegetation after shelter wood cuttings in sites of different soil fertility gradient in pine dominated stands on sandy soils in the European hemiboreal zone. The Scots pine stands in which first step of shelter wood cuttings was applied were investigated. The stands were selected in fresh (normal humidity) sites according to soil fertility gradient: very poor, poor and medium fertility soils. All mosses, lichens, herbaceous vegetation and dwarf shrubs were recorded, and projection cover was estimated in June - August. Ellenberg’s indicator figures were used to evaluate site conditions. In shelter wood cuttings (5-6-year-old) the number of species was higher in medium fertile sites than in very poor sites. After shelter wood cuttings the abundance of herbaceous species increased in all sites, while the abundance of mosses and lichens decreased. Within the first year after shelter wood cuttings, the abundance of Ericaceae species decreased, and abundance of Rosaceae and Poaceae species increased. Average Ellenberg’s indicator values showed that site conditions changed after shelter wood cuttings. The changes were more intensive in medium fertile sites than in poor sites. After shelter wood cuttings the richness and abundance of ground vegetation changed. The intensity of change differed in sites of certain soil fertility and was caused by alteration of site conditions, which were more homogenous in sites of the certain fertility in uncut stands than in cuttings. Key words: herbs, mosses, non-clear cuttings, vegetation