Jenny Dahl

Forest ecosystems play an important role as carbon (C) sinks, sequestering C via photosynthesis. C dynamics and the forests capacity of being a sink varies depending on forest dynamics and management throughout rotation periods. Their ability to assimilate and store C makes forest and forest management highly important in climate change mitigation, especially in the light of the Paris Climate Agreement. Increasing expectations are also being placed on forests as a big part of the goal of Sweden as a society with zero net emissions of greenhouse gases by 2045. To fulfill the goal, one of the important strategies is to increase forest C sinks as well as producing wood products as substitution for fossil products. Woody biomass is an important part of this, but the majority of boreal forest C stock is in the soil. Soils in the productive forest in Sweden store on average 65 Mg C per hectare, and these C large stocks can be affected by management induced disturbances. In Sweden, forest disturbance have been relatively low until forest management intensified during the 20th century. However, some areas have yet remain undisturbed, mainly in the northwestern part of the country.

As demands on forests increase, an inevitable question is how we should manage forests in order to satisfy such needs; increase the area of managed forest or intensify forestry in already managed areas to maximize growth and yield. Management operations such as clear-cutting, fertilization and soil preparation can enhance production but also affects C storage both above and below ground. Although unmanaged forests often store a greater C accumulation in biomass and soils than managed with continuous rotations, this C stock can highly be vulnerable to natural disturbances such as fire or insect outbreaks with a building-up of fuel.

The areas in northwestern Sweden that still have unmanaged forests with a long tree continuity could possibly contribute to the demanded increase in wood products. Suitable management of these forests may benefit C sequestration and bio-economy, and thus help meet the increased societal demands. However, harvests in such forests may also cause a large C emission from soil and biomass decomposition and it can take a long time to rebuild such magnitudes of C stock. From a climate perspective, it could be better to intensify forestry in managed forests and keep old-growth forests in consideration also in regards of other values such as biodiversity and ecosystem services. Although it is urgently needed to optimize both ecosystem services and forest production, our understanding is limited.

The focus of my PhD project is the C balance of boreal forests in response to management regime and the role of old-growth boreal forests in a climate smart forestry. 

2018- Masterexamen i skogsvetenskap, Jägmästarprogramet, SLU Umeå.

2013- Kandidatexamen i biologi, SLU Uppsala.