Wildfires as natural disturbances have had important impacts on terrestrial ecosystems, including forests. We studied patterns of short-term vegetation recovery after surface fire in protected hemiboreal Pinus sylvestris L.-dominated forest. Our study was carried out near Stikli village in Western Latvia. Seven forest stands – middle-age and over-mature were sampled on nutrient-poor and mesic soils. Forest fire occurred in the summer of 2018 and covered 1440 ha of forested area. In each stand we established 16 sample plots (1 m × 1 m) in a radial pattern from the center. Every summer from 2019 till 2022 we surveyed these sample plots – recorded projective cover (%) and identified Ellenberg indicator values and species traits – plant strategy groups (C-S-R after Grime), Raunkiær life history forms and habitat types. Additionally, the occurrence of specialized fire-adapted plants was recorded. In total we identified 15 species in the ground layer, 47 species in the herbaceous layer, and 9 regenerating tree species. The colonization at the ground layer was the most rapid (projective cover increased overall by 67% in middle-aged stands and by 82% in over-mature stands). Species diversity was the highest at the herb layer during the third (middle-aged stands) and fourth (over-mature stands) after fire disturbance but showed overall declining trends. Betula spp. and Populus tremula L.-dominated regenerating tree species. The dominance of fire-adapted species declined rapidly after the fire except for moss Polytrichum spp. Overall, hemiboreal over-mature stands demonstrated higher vegetation cover and more rapid rate of initial colonization compared to middle-aged stands.
Passive rewildening of forest ecosystems is commonly used for rehabilitating degraded habitats closer to their natural origin in addition to costly active restoration measures. However, it is not clear if passive processes are effective and how long the recovery of main ecosystem properties takes. We investigate the recovery of forest soil and tree stand characteristics a century after cessation of slash-and-burn cultivation, a major historical intensive disturbance regime that was applied widely in boreal zone of Finland until late 1800s. We systematically sampled soil and tree stand parameters within former slash-and-burn and nearby control areas. Humus layer thickness and soil organic matter (SOM) stocks were still lower in the historical slash-and-burn than in control areas. Slash-and-burn areas also had a larger volume of live birch trees and a higher standing dead wood volume than control areas. Accordingly, organic matter (humus layer thickness and SOM stocks) correlated negatively with birch standing live tree volume. Combined OM stock in humus and uppermost 10 cm mineral soil layer was positively correlated with lying dead wood volume. Overall, we observed clear recovery of several natural properties but we also found that a century after cessation of frequent anthropogenic burnings, clear legacies of disturbance in the above- and below-ground parts of boreal ecosystem were evident. Our results indicate that if only passive rewildening is applied as a restoration measure, the full recovery of boreal forest is slow and the effects of historical land-use may persist for over hundred years in soil and tree properties.