Post fire ground vegetation development over 25 years

Fire has been a part of natural disturbance regime in boreal and to some extent also hemiboreal forests, affecting soil and light conditions, seedbanks, trees and ground vegetation. The most significant factors affecting occurrence, severity and size of forest fires are anthropogenic, weather and the environment, all of which are changing due to human-caused climate change. This paper discusses medium term (25 years) vegetation development in five different biotopes after fire disturbance. Sample plots were established in Slitere Reserve (now National park) in north-western Latvia on areas affected by large fire in 1992. Data were collected in 1993, 2002 and 2017. The aim of the study was to characterize the regeneration and succession of ground vegetation after the fire. In 1993, species such as bog-rosemary (Andromeda polifolia), heather (Calluna vulgaris) and cloudberry (Rubus chamaemorus) were observed in the ground vegetation a year after the fire. In 2002 liverworts appeared, indicating that the bog has acquired more stable and wetter conditions, but in 2017, liverwort mosses were no longer present and the percentage cover of Rubus chamaemorus decreased significantly and Calluna vulgaris, sphagnum sp., and Betula pendula were present in large quantities in the bog. Comparing these studied years, it can be concluded that all these years the biotopes and species have continuously developed and are regenerating.