Associate Professor of Forest Ecology
Marit Halvorsen
I measure what happens to carbon underground when a boreal forest is cut, burned, drained or left alone - on plots that have been remeasured every autumn since 1994.
Marit Halvorsen1,2,* · PhD, Docent · Umeå, Sweden
- 1 Department of Forest Ecology, Nordvik University, Umeå
- 2 Storbäcken Research Forest, Västerbotten
- * Correspondence: [email protected]
Keywords soil carbon · deadwood decay · boreal forestry · long-term plots · peatland drainage · prescribed fire
In figures
The record in numbers
Everything below is counted rather than estimated, and every figure has a notebook behind it.
Fig. 1
31years
Of unbroken plot records
1994 to last October, no gaps
Fig. 2
42papers
Peer-reviewed, nine as first author
Eleven of them open access
Fig. 3
1,240plots
Remeasured across four networks
Every autumn, on foot
Fig. 4
11
Doctoral students supervised
Seven finished, four running
Counted from the plot notebooks and the publication list, August 2026. Nothing here is rounded up.
Profile
Abstract
The short version, for anyone reading twelve of these in an afternoon.
Abstract
I am a forest ecologist. I work on what happens to carbon in boreal soil after the forest above it is disturbed - and on the plots that are old enough to answer the question honestly.
My doctorate was on deadwood decay in old spruce stands. Since then the work has widened into soil: clear-felling, prescribed fire, peatland drainage and the slow recovery afterwards, measured on the same 1,240 plots every autumn since a colleague set them out in 1994. When he retired I took the notebooks and kept going.
Most of what I publish is unglamorous and long: the same sites, the same protocol, the same three weeks in September. That is the point. Short experiments give you a signal; thirty-one years give you a number a policy can be written against. I am finishing a synthesis of the whole network now, and I supervise four doctoral students working across it.
Keywords soil carbon · deadwood decay · long-term ecological research · peatland rewetting · boreal Fennoscandia
Corresponding author
- Position
- Associate Professor, Forest Ecology
- Institution
- Nordvik University, Umeå
- Since
- 2016 · Docent 2022
- Field site
- Storbäcken Research Forest
- Available from
- January 2027, for senior appointments
The work
Three lines of work
Each one started with a question somebody asked me while we were standing in the forest.
Soil carbon after felling
Where does the carbon actually go?
The standing crop is easy to count. What happens under it is not. We core the same plots the summer before a harvest and follow the loss for a decade afterwards, which is long enough to see the recovery begin and short enough that somebody will still fund it.
Deadwood and what eats it
How long does a fallen spruce take to disappear?
My doctorate, and still the thing I am asked about most. Logs marked in 1998 are on the ground and being weighed twenty-seven years later. The decay curve is far less tidy than the textbooks draw it, and the reason turns out to be fungal rather than climatic.
Drained peat, and undrained
Is rewetting worth what it costs?
Northern peatlands were ditched at scale for eighty years. Some of those ditches are now being blocked at public expense. We hold paired plots on both sides of that decision and report the flux, whichever way the number falls.
Projects
What is running now
Eight studies on the books, five of them shown here, with the site, the years and who pays for each.
The Storbäcken plot network
1,240 permanent plots in boreal spruce, remeasured every autumn since 1994. The series the rest of the work hangs off.
Rävmyran paired mires
Four drained mires and four rewetted ones, instrumented since 2019, reporting the flux whichever way the number falls.
The 1998 deadwood cohort
180 marked spruce logs, weighed at intervals for twenty-five years. The longest series of its kind we know of.
Klippen fire plots
Prescribed burning on nine hectares, with the pre-burn measurement that most burn studies never had.
Kvarnberget harvest transect
Sixty plots across a working clear-fell, cored the summer before the harvester arrived and every autumn since.
Publications
Selected publications
Five of forty-two. The full list, the datasets and the code are on the publications page.
Thirty-one years of soil carbon on the Storbäcken plots: the recovery is slower than the models allow
Journal of Boreal Ecology 41(2), 188-204 Open access
Ditch blocking raises the water table before it changes the flux: four paired mires in Västerbotten
Northern Soil Science 18, 41-59
What a long-term plot is for, and what it cannot tell you
Methods in Field Ecology 9(4), 512-518 Open access
Mass loss in Picea abies deadwood over twenty-five years is governed by the first fungal coloniser
Ecosystem Dynamics 31(1), 77-94
The Storbäcken plot network, 1994-2022: an open record of soil, litter and deadwood
Boreal Data Archive Version 4 Download
Ask me for a PDF of anything that is not open access and I will send it the same week.
Career
Appointments and degrees
Pulled straight from the CV, so this page and the PDF can never disagree.
Appointments
Nordvik University · Umeå, Sweden
Nordvik University · Umeå, Sweden
Nordic Institute for Water Research · Oslo, Norway
Bjørnfjord University · Bergen, Norway
Storbäcken Research Forest · Västerbotten, Sweden
Education
Bjørnfjord University · Bergen, Norway
Bjørnfjord University · Bergen, Norway
Bjørnfjord University · Bergen, Norway
References
People who will vouch for me
Write to any of the three. They have all agreed to be asked, and none of them owes me a favour.
Marit took over a plot network I had run for twenty years and did not lose a single autumn. She also found the error in my 2001 density figures, which took some nerve, and she was right.
Prof. Bengt Åkerlund
Professor Emeritus of Forest Ecology
Nordvik University
Doctoral supervisor, 2005-2010
We have co-authored four papers and argued about three of them. She writes the methods section first and will not let a number through that she has not seen measured. That is rarer than it should be.
Dr Priya Rehn
Senior Researcher, Peatland Hydrology
Nordic Institute for Water Research
Collaborator since 2019
I sat on the panel that gave Marit her first infrastructure grant and I have followed the work since. It is the kind of long, patient science that funding structures make almost impossible, and she has simply kept doing it.
Prof. Takeshi Mori
Chair, international evaluation panel
Nordic Research Council
Panel chair since 2021
Ask for anything on this page
The whole record is open
The CV, the plot data, a PDF of any paper, or the name of somebody who has worked with me. None of it sits behind a form you have to fill in twice.
PDF, four pages, updated August 2026
Answered within a week, outside the field season
Requests for raw plot data are answered in the order they arrive, usually within a fortnight.