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Abstract

In Boreal forests, wildfires are common disturbance agents, important for sustaining forest regeneration and ecosystem processes. However, climate warming has intensified fire activity and severity in recent years, and warmer conditions following fire can alter environmental factors affecting tree seedling survival and growth. Management interventions can potentially counterbalance the effects of fire severity and warming. Using a field experiment, we investigated the main and interactive effects of fire severity, experimental warming, understory shrub presence and salvage logging on the growth of different conifer (Picea abies and Pinus sylvestris) provenances, to provide insight about how tree seedlings of various species respond to multiple environmental drivers following fire. Our study shows that low fire severity without salvage logging resulted in poorer seedling above-ground growth, whereas experimental warming and ericaceous shrubs removal increased seedling biomass regardless of fire severity or logging treatment. Our results suggest that enhanced light availability and reduced resource competition from the understory supports the growth of conifer seedlings following fire. Post-fire warming further stimulated the growth of conifer seedlings (particularly in high-severity burn areas) potentially due to increased early colonization by fast-growing deciduous trees. Moreover, in warmer conditions, northern provenances of P. sylvestris planted in southern locations also showed greater height growth compared to local populations, highlighting the potential for assisted migration under climate change. Synthesis and applications. This study demonstrates that artificial regeneration through planting can support forest recovery following wildfire, especially under high fire severity in sites where natural regeneration is poor. Salvage logging can enhance the growth of P. sylvestris seedlings and indirectly benefit P. abies on low-severity sites by facilitation by deciduous species that create favourable microhabitats. However, the broader ecological impacts of salvage logging (such as on biodiversity loss and soil and habitat structure) must be considered in management planning. Post-fire vegetation management, including control of competitive ericaceous shrubs, may further improve seedling establishment. Selecting climate-adapted seedling provenances can boost reforestation success under future warming. These findings support an adaptive management framework that integrates fire severity, logging intensity, understory control and assisted migration to foster resilient forest landscapes in a changing climate.I boreala skogar & auml;r skogsbr & auml;nder viktiga f & ouml;r att uppr & auml;tth & aring;lla skogens f & ouml;rnyelse och ekosystemfunktioner. Klimatf & ouml;r & auml;ndringar har under senare & aring;r lett till oftare f & ouml;rekommande br & auml;nder och br & auml;nder som resulterar i h & ouml;gre brandh & aring;rdhet vilket kan p & aring;verka skogarnas & aring;terh & auml;mtning och f & ouml;ryngring. Skogssk & ouml;tsel & aring;tg & auml;rder kan potentiellt motverka negativa effekter av b & aring;de h & ouml;gre brandh & aring;rdhet och ett varmare klimat. Ett f & auml;ltexperiment genomf & ouml;rdes f & ouml;r att unders & ouml;ka hur brandh & aring;rdhet, experimentell uppv & auml;rmning, n & auml;rvaro av undervegetation samt avverkning av brandskadad skog p & aring;verkar tillv & auml;xten hos tr & auml;dplantor av Picea abies (gran) och Pinus sylvestris (tall) fr & aring;n olika provenienser. Syftet var att & ouml;ka f & ouml;rst & aring;elsen f & ouml;r hur tr & auml;dplantor av olika ursprung svarar p & aring; flera samverkande milj & ouml;faktorer efter brand. Resultaten visade att l & aring;g brandh & aring;rdhet i fr & aring;nvaro av avverkning hade en negativ effekt p & aring; tr & auml;dplantornas tillv & auml;xt. Samtidigt bidrog b & aring;de experimentell uppv & auml;rmning och borttagning av risartade v & auml;xter till & ouml;kad biomassa hos tr & auml;dplantorna, oberoende av brandh & aring;rdhet och avverkning. Vi fann att & ouml;kad ljustillg & aring;ng och minskad resurskonkurrens fr & aring;n undervegetationen gynnade barrtr & auml;dens tillv & auml;xt efter brand. Uppv & auml;rmning efter brand stimulerade tillv & auml;xten ytterligare, s & auml;rskilt i omr & aring;den med h & ouml;g brandh & aring;rdhet. Detta berodde sannolikt p & aring; att snabbv & auml;xande l & ouml;vtr & auml;d etablerade sig snabbt och skapade gynsamma f & ouml;rh & aring;llanden f & ouml;r barrtr & auml;dsplantorna. Nordliga provenienser av P. sylvestris, uppvisade h & ouml;gre tillv & auml;xt & auml;n lokala populationer n & auml;r de planterades i sydligare och experimentellt varmare f & ouml;rs & ouml;ksytor. Detta tyder p & aring; en potential f & ouml;r klimatanpassad migration av genetiskt material. Till & auml;mpning och syntes. Denna studie visar att f & ouml;ryngring genom plantering kan fr & auml;mja skogens & aring;terh & auml;mtning efter en skogsbrand, s & auml;rskilt i omr & aring;den med h & ouml;g brandh & aring;rdhet d & auml;r den naturliga f & ouml;ryngringen & auml;r begr & auml;nsad. Avverkning av brandskadad skog kan f & ouml;rb & auml;ttra tillv & auml;xten hos P. sylvestris och indirekt gynna P. abies i omr & aring;den med l & aring;g brandh & aring;rdhet genom att fr & auml;mja l & ouml;vtr & auml;d som i sin tur skapar gynnsamma mikrohabitat f & ouml;r barrtr & auml;dsplantor. De bredare ekologiska konsekvenserna av avverkning efter brand, s & aring;som f & ouml;rlust av biologisk m & aring;ngfald och d & ouml;d ved samt f & ouml;r & auml;ndringar i markstruktur, b & ouml;r dock beaktas i planeringen av skogssk & ouml;tsel & aring;tg & auml;rder efter brand. Att kontrollera konkurrerande risv & auml;xter, kan ocks & aring; hj & auml;lpa plantorna att etablera sig b & auml;ttre. Att v & auml;lja klimatanpassade provenienser kan & ouml;ka framg & aring;ngen f & ouml;r & aring;terbeskogning under

Keywords

assisted migration; boreal forest; climate warming; conifer reforestation; fire severity; open-top chamber; provenances; salvage logging

Published in

Journal of Applied Ecology
2025
Publisher: WILEY

SLU Authors

UKÄ Subject classification

Forest Science

Publication identifier

  • DOI: https://doi.org/10.1111/1365-2664.70162

Permanent link to this page (URI)

https://res.slu.se/id/publ/143729