Naturrestaurering, restaureringsøkologi, effekter av ferdsel og tekniske naturinngrep, forebygging av naturinngrep, naturovervåking, planlegging, forvaltningsmetodikk, planteøkologi. 

planteøkologi, overvåking av biologisk mangfold, naturtyper, truet natur, rekreasjonsøkologi

Community ecology, ecosystem ecology, spatial ecology, fungal ecology, dispersal ecology, population dynamics, conservation biology, trait ecology, functional ecology, forest ecology, soil ecology, evolutionary biology, decomposer fungi, environmental DNA, climate change, land use change, forest management.

I am a forest ecologist and conservation scientist with a special interest in temperate deciduous forest and its biodiversity. I engage in two main lines of research:

1) As a trained mycologist, I study aspects of biodiversity and conservation of fungi (incl. lichenized) in forests. At the most fundamental level, we cannot conclude on the best way to conserve the biodiversity or monitor changes without knowing the species. Knowledge on species identification and taxonomy of hyper-diverse taxa are essential, but highly threatened and decreasing skills worldwide. My own taxonomic expertise is within pyrenomycetoid ascomycetes, especially those associated with living trees and dead wood, and i have described several species new to science from Norway. There is a strong tendency of taxonomic bias within conservation, meaning that nearly all interest is focused on a few taxa such as large animals and vascular plants, while hyper-diverse taxa such as fungi and insects are often neglected. I therefore engage in both both basic exploration of biodiversity within hyper-diverse taxa, and study the effects of habitat loss, management et c on this biodiversity. This interest started already in my thesis (presented in 2000), where I studied the poorly known dispersal ecology of wood-living fungi in relation to conservation. I also use my expert knowledge to perform red list assessments of disfavoured ascomycete species, and black list assessments for species brought to Norway by man.

2) My second main research area is the restoration of temperate deciduous forest, the worlds' most degraged biome. Since 2000, I have been co-leader of the Swedish Oak project, a long-term experimental research project aiming to improve our understanding of how oak-rich mixed forests function and can be managed for (primarily) conservation purposes and biological diversity. Many oak-rich mixed forests, and almost all our "noble" (hardwood) broadleaved forests developed from an older, more open, traditional agricultural landscape, where several special species thrived but are now declining. Active management measures to create more open forests are hence motivated, but need to be evaluated for many taxa, and we study the effects of partial (restoration) cutting in forest with relatively old oaks on biodiversity. In another one of my projects, TransForest, we experimentally evaluate the biodiversity effects of restoration cutting of spruce in more recent mixed forests and focus on insects, plants and fungi. 
         Starting in 2023, I lead a new large trans-sectorial research project, SynForest, which aims to develop new sustainable uses of forests and wood. Climate risks and their associated costs in spruce-dominated forestry motivate an increased focus on temperate broad-leaf (TBL) trees, and higher demand for high-quality timber from, and planting of, these trees can assist their dispersal and climate tracking. At the same time, a higher share of TBL trees has important co-benefits for biodiversity. By involving important private and public stakeholders in a dedicated collaborative effort we focus on four key areas to enable the described transition: 1) creating new products and value chains based on Norwegian oak, 2) overcoming the practical challenges of converting (storm-damaged) spruce forest to oak forest considering the unsustainably high browsing pressures, 3) developing the potential for sustainable high-quality oak timber production by management of recent mixed forests with spruce, and 4) analysing the opportunities for a transition to TBL production ensuing from national and international policy and regulations. The project is a collaboration between forestry partners and small enterprises from southern Norway, and researchers in the fields of wood technology, forestry, ecology, environmental economics, and social sciences.