Epsilon Archive for Student Projects

Abstract

Boreal forests represent one of the largest terrestrial biomes on earth, shaped by natural disturbances such as wildfire. Climate warming across the globe is resulting in more frequent and severe wildfires yet, how the effects of fire severity shapes post-fire structure, regeneration, composition and diversity of boreal forests in Sweden is poorly understood. This study assessed post-fire structural and compositional recovery at a decadal scale within central Sweden. The study was conducted in the Västmanland burn area in the Sala region where a large fire occurred in 2014. The focus was on assessing how fire severity affected seedling and sapling diversity, composition, density, downed woody debris (DWD) and basal area. Additionally, the study investigated fire legacy effects on species growth and densities along with long-term structural recovery. Data were analysed using parametric and non-parametric tests, alongside multivariate ordination methods, to assess community composition, group differences and correlations with fire severity and structural components. Low fire severity promoted the highest seedling and sapling diversity, although a non-significant difference compared to high fire severity plots. Fire led to increased seedling and sapling density and compositional shifts towards pioneer species. Additionally, fire severity had a profound effect on DWD volume, basal area and their interactive effects on species growth patterns. Lastly, fire severity acted as a threshold for long-term structural and compositional recovery. These findings provide foundational information into how fire severity drives boreal forest trajectories in Sweden, with implications for management under a warming climate.