The effects of fire and stand age on seedling establishment ofPulsatilla patensin a pine-dominated boreal forest

Abstract

Successful management of disturbance-related endangered plant species requires thorough knowledge concerning their recruitment ecology. Pulsatilla patens (L.) Mill. is found in northern European forests that in the past have been subjected to a periodic wildfire regime and, thus, is supposedly adapted to corresponding changes in forest light conditions and thickness of the moss and litter layers. We tested whether this is true in a field experiment where seeds of P. patens were sown in experimentally burned and control boreal Scots pine forest sites of different successional age (clear-cut, 30 years old, 45 years old). The germination and early establishment of P. patens was enhanced in the experimentally burned conditions and was more successful in younger successional stages. On the other hand, in sites with a tree layer, the germination of P. patens was better in relatively darker areas, suggesting that the negative effect of successional age is probably not a result of changing light conditions, but rather a result of thicker moss and litter layers in the later successional stages.Key words: boreal forest, germination, forest fire, litter layer, Pulsatilla patens, seed sowing.