Epsilon Archive for Student Projects

Abstract

I studied how and if clear-cut forestry mimics the disturbance of wildfire by comparing the impacts of these disturbances on coarse woody debris (CWD) volumes, CWD characteristics, as well as species richness of wood inhabiting fungi (WIF) and red-listed species. I compared a wildfire chronosequence with a temporal range of 4-375 years since the last disturbance, and a managed chronosequence ranging between 1-109 years since clearcut. I found that young post-disturbance forests showed the highest CWD volumes. On average, burnt forests showed three times higher CWD volumes, albeit with high variability over time. Characteristics of CWD greatly differed, with fire-disturbed forests showing higher amounts of CWD in larger diameter classes and later decomposition stages. I found that CWD volume predicted species richness of WIF similarly in both chronosequences. Fire-disturbed forests generally reached higher values of WIF species richness; however, when comparing species richness per CWD volume, no significant differences were found between the chronosequences. Species composition differed between the chronosequences, attributed to higher occurrences of red-listed wood fungi in the wildfire chronosequence, particularly those associated with Norway spruce CWD. My study highlights the very different impacts of the fire and clear-cut disturbances on WIF in boreal pine-dominated forests and the need for prescribed burnings to generate charred CWD and thus, maintain natural pine-dominated forests and associated wood fungal species. Furthermore, my results demonstrate the importance of young and old growth post-fire stands as landscape-level habitats and species reservoirs, particularly for red-listed fungal species. Importantly, I found an increase in CWD volumes in the managed forest in the youngest managed stands of the chronosequence, likely due to recent CWD retention efforts over the last few decades due to higher environmental concern in forestry.