Land vith young stands of Norway spruce

Doctoral project: Transition of forest carbon balance in young stands of Norway spruce II

Measurements of the greenhouse gases, carbon dioxide, methane, and nitrous oxide from the forest floor in unfertilized and fertilized young stands of spruce and birch were compared to see if the positive effects on growth at the same increase the levels of these greenhouse gases in the atmosphere. The project also examined how the growth of the birches is influenced by fertilization.

This project was concluded in 2023.

Project information

Name
Transition of forest carbon balance in young stands of Norway spruce stand by using Eddy-covariance, measurements of GHG-emissions and allometric measurements
Doctoral student
Charlotta Håkansson
Supervisor
Johan Bergh
Assistant supervisors
Anna Monrad Jensen, Linnaeus University; Per-Ola Hedwall, Monica Strömgren and Tomas Lundmark, SLU
Timetable
1 Nov 2015–
Financier
Södra (land owner)
Subject
Forestry industry production systems (Department of Forestry and Wood Technology, Faculty of Technology)

More about the project

My PhD-studies, which is carried out part-time, examines how the carbon balance, i.e. the amount of carbon dioxide and carbon, changes in a fairly common young Swedish forest from the time when spruce seedlings are planted and the birch self-seeds and about fifteen years onwards.

Today, there are many different actors in the forest market who are interested in wood to use in both traditional products such as houses, floors, and furniture, but also more recent products such as vehicle fuel and textiles, while more and more new areas of use are emerging. The forest and its wood material are requested to be enough for many.

Young trees grow quickly, and in their growth, they use a lot of nutrients. The more the trees grow, the more carbon they bind from atmospheric carbon dioxide and thereby contribute to counteract climate change. Fertilizing forest land with nitrogen and sometimes also other nutrients can therefore be an alternative to quickly increase the rate of growth and get large trees felled earlier in time.

When fertilizing agricultural land, we know today that there will be increased levels of greenhouse gases that flow from the ground. My research examine how mineral forest soils reacts to fertilization. If the fertilization causes the forest floor fluxes of carbon dioxide, methane, and nitrous oxide to increase so much that the beneficial effects on the growth of the trees are countered or completely eaten up by increased outflows of greenhouse gases, then from that perspective, fertilization is a bad option for counteracting climate change. If, on the other hand, the flows of greenhouse gases increase marginally, not at all, or only for a shorter period, fertilizing young stands with spruce and birch can help counteract climate change. At least on Swedish mineral forest land.

The measurements me and my research colleagues have carried out, within the framework of the project, are of two kinds. Both above the tree crowns by so-called eddy-flux towers, that continuously measure the net flows of gases from the stand and, on the ground via airtight chambers that measure single and recurring days at fixed points.

The project is part of the research in the Forestry and Wood research group.

Publications