Lise Dalsgaard
Forsker
Lenker
My profile at ResearchGateBiografi
Arbeidsoppgavene mine er for det meste knyttet til estimater av endringer i mengden karbon i skogsjord som følge av arealbruksendringer.
For tiden er jeg involvert i følgende prosjekter:
- INVENT ("Improving National forest inventory-based carbon stock change estimates for greenhouse gas inVENTories), finansiert av Forskningsrådet. INVENT er en del av FACCE ERA-GAS.
- Karbonbalansen i drenerte avskogede myrer ("Long term carbon balance in drained afforested mires". Dette er et norsk tilleggsprosjekt til SNS-prosjektet "Menneskeskapte klimagassutslipp fra organisk skogjord: Resultatet av bedre taksering og betydningen for en bærekraftig skogforvaltning“. Prosjektet er finansiert av Miljødirektoratet.
Forfattere
Carl-Fredrik Johannesson H. Ilvesniemi O. Janne Kjønaas K.S. Larsen A. Lehtonen Jenni Nordén D. Paré Hanna Marika Silvennoinen J. Stendahl I. Stupak L. Vesterdal Lise DalsgaardSammendrag
Nordic and Canadian forests store substantial amounts of carbon (C) and are largely managed in a silvicultural system with clear-cut harvest. Previous meta-analyses of harvesting effects on soil C have shown short- to long-term declines after harvest, but effects of clear-cutting on boreal and northern temperate forest soil C stocks remain unresolved. We harmonized National Forest Soil Inventory (NFSI) data from Sweden, Denmark, Finland, Norway and Canada to examine soil C stocks up to 53 years following clear-cut harvest using a space-for-time approach. We analyzed forest floor and mineral soil C stocks in coniferous and deciduous/mixed forests. Coniferous forest floor C stocks decreased for ∼30 years after clear-cutting: when at its lowest stock level, Picea and Pinus forest floor C stocks had decreased by 23 % and 14 % relative to initial stock levels, respectively. Picea forest floor C stocks then remained close to its lowest levels until 53 years after clear-cutting, while for Pinus-dominated forests they increased again and recovered to the pre-harvest level 48 years after clear-cutting. No C stock changes were detected in the 0–10 cm or 10–20 cm mineral soil layers, while a small increase in 55–65 cm mineral soil was detected in Podzol soils. Data was too limited to detect statistical signals of clear-cutting for deciduous/mixed forests. Our results shows that clear-cut harvest has substantial and long-lasting effects on northern temperate and boreal forest soil C storage, and that combining data from several NFSIs can help elucidate forest management effects on soil C storage. Soil organic carbonForest harvestClear-cuttingBorealTemperateNational forest inventoryNational forest soil inventory
Sammendrag
ire has the immediate effect that roughly half of carbon and nitrogen is emitted and lost from forest floors, that the remaining ashes fertilize the ground and pools of dead organic matter and stable black carbon is produced. Depending on the intensity of the fire it will potentially have long lasting physical, chemical and biological effects. Fire as a disturbance agent to the forest floor has acted on the forest landscapes in Scandinavia since the last glaciation as a natural phenomenon and as a result of human activities. Fires have likely occurred in all forests in Norway even though sampling and dating of charcoal in selected landscapes indicate a lower frequency along the west coast than in the southeastern forest region and in neighboring Sweden. Where the availability of synthetic fertilizers in agriculture (ca. 1900) and the significance of timber value and -trade (ca. 1700) mark important shifts in fire occurrence and avoidance, forest fires have been successfully suppressed with documented effects since the 1970’s likely leading to an accumulation of forest floor organic matter. Using a one-time survey of >8000 registrations of the thickness of the forest floor, its sub-layers, humus form and the occurrence of charcoal in upland forests of the Norwegian National Forest Inventory, we investigate the regional distribution of charcoal occurrence in upland forests indicating earlier fire activity and look for legacies on carbon stocks or forest floor characteristics using available national soil survey data. Forest floors in boreal and cold temperate forests hold 30-60% of total forest soil carbon stocks equivalent in magnitude to that held by the living biomass of trees. Thus, we further estimate the areas and forest floor carbon stocks most likely to gain increased vulnerability to fire under future climate conditions.
Forfattere
Marte Ragnhild Owren Ingvild Byskov Britta Marian Hoem Julien Jabot Hans H. Kolhus Elise Grieg Jakob Sandven Kathrine Loe Bjønness Trude Melby Bothner Mona Irene Andersen Engedal Eirik Knutsen Lene Skyrudsmoen Berit Storbråten Kristina Vikesund Evan Hart Ana Aza Gry Alfredsen Johannes Breidenbach Lise Dalsgaard Rune Eriksen Katharina Hobrak Christian Wilhelm Mohr Christophe Moni Gunnhild SøgaardRedaktører
Ingeborg RønningSammendrag
Norwegian greenhouse gas emission 1990-2023, report to the UN