Changes in species composition and cover of understory plants in stands disturbed by a hurricane in Piska Forest in 2002.
Comparison of understory of stands disturbed by hurricane and managed ones allowed to distinguish two phases that include degenerative and regenerative changes. In the first phase, which lasted about 6 years, following processes were observed: chaotic changes in species composition, invasion of exogenous species, increase in cover of Deschampsia flexuosa and Vaccinium vitis-idaea, decrease in moss cover and Vaccinium myrtillus as well. In the second phase changes had opposite direction. Structure of ground flora typical to Scots pine forest was slowly developing. Increasing shade of forest floor, caused by growing shrub layer and regeneration of tree species, was a key factor of the regeneration process.