Soil charcoal addition affected biochemistry but not growth in European beech and Norway spruce seedlings

• Main Author: Kolstad, Anders Lorentzen
• Format: Dissertation
• Language: English
• Subjects: Black carbon; Condensed tannins; Fagus sylvatica; HPLC; Picea abies; Pyrogenic carbon

Climate change is projected to result in European beech (Fagus sylvatica) expanding northwards into Norway spruce (Picea abies) forests where, in addition to climate, numerous local factors will determine the relative success of these two species. Among these are soil related factors, including charcoal from previous forest fires, which is present in soils in considerable amounts and exerts largely unknown and species-specific effects on plant growth and metabolism. Here I show that glasshouse grown beech and spruce seedlings responded differently to laboratory-produced charcoal addition and that the effect was dependent on plant organ, charcoal origin (beech- or spruce wood), and soil type (beech- or spruce forest). Charcoal addition had no effect on plant biomass, but caused several compound specific changes to the concentrations of low molecular weight phenolics assumed important in plant defences. Shoot:root ratios, specific leaf area, condensed tannin concentrations, and C:N ratios were also affected, but in such a way that the overall positive versus negative effect of charcoal addition could not easily be determined. This was largely due to the organ specific responses that complicates interpretations of the whole-plant response. Overall, the effects of charcoal addition fades in comparison to the effect imposed by soil origin. Results further indicate an uncoupling between growth and phenolic synthesis, contrary to predictions from the protein competition model. The common consensus that soil charcoal has unequivocally beneficial effects on plant growth is challenged. Sammendrag Klimaendringene er sagt å føre til at bøk (Fagus sylvatica) sprer seg nordover inn i områder med granskog, hvor i tillegg til klima, flere lokale faktorer vil påvirke dominansforholdet mellom gran (Picea abies) og bøk. Blant disse er flere jord-aspekter, bl.a. effekten av trekull fra tidligere skogbranner. Trekull finnes i jorda, ofte i betydelige mengder, hvor det har en stort sett ukjent og artsspesifikk effekt på plantevekst og -metabolisme. Her viser jeg hvordan drivhusdyrkede småplanter av gran og bøk reagerte ulikt på tilsetning av laboratorieprodusert trekull til vekstjorda og at effekten av kullbehandlingen var avhengig av opphavet til jorda (bøk- eller granskog) og trekullet (bøk- eller granved), i tillegg til at den ofte var ulik for forskjellige plantedeler. Trekull hadde ingen påvirkning på vekst (biomasse), men induserte flere endringer i konsentrasjonene av ul