The factors affecting tree establishment in boreal forests after fire will help determine the community composition of the regenerating forest. These may have large consequences on the community dynamics for years after the fire disturbance. Factors such as burn severity and soil moisture among others have been shown to play a key role in influencing several facets of establishment. However, tree establishment after megafire in boreal forest in Europe has not yet been fully understood. Here I capitalise on a megafire in Sweden in 2014 to investigate the relative impact of different abiotic factors and preconditions on tree establishment six years after the fire. This study used a systematic survey of tree saplings (height >30cm) at 625 locations inside the nature reserve set up within the burnt area. Tested factors were: The number of dead trees lying down, slope and slope aspect, elevation, soil wetness, pre-fire standing volume, distance to fire perimeter, forest stand age, stand productivity index, previous stand dominant tree species, humus thickness after fire and depth of burn. Generalized Linear Mixed Models (GLMMs) were used to estimate the effect of these factors on specific tree species abundance. Strong influences from previous wood volume, soil wetness, elevation, and dead wood lying down had an effective influence on sapling abundance but were typically species-specific. Only elevation and wood volume had a consistent effect on all species’ abundances. Habitat context was important on a landscape scale. These results support the pattern of increasing boreal deciduousness caused by high burn severity and shorter disturbance intervals, in turn, caused by hotter, drier weather, which will have implications on the composition of boreal forests of tomorrow.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-515960 |
| Date | January 2023 |
| Creators | Pim, Robert |
| Publisher | Uppsala universitet, Institutionen för biologisk grundutbildning |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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