Locally or sustainably produced? : Comparison between carbon dioxide emissions from two wood source alternatives for bridge construction over Skellefteälven

Emissions of greenhouse gasses, such as carbon dioxide, have been shown to be strongly connected global warming. In 2020 the European Union adopted the goal of reducing emissions of greenhouse gasses to a net of zero before year 2050. This is essential for keeping the average global temperature rise below 1.5 degrees. A large source of carbon dioxide emissions in Sweden is the forestry sector. The carbon balance in ecosystems is usually disturbed due to clear-cutting, which is the main silvicultural system used in Sweden. Introducing more sustainable silvicultural systems, such as continuous cover forestry, is a measure that authorities advocate. This study aimed to examine emissions of carbon dioxide from two timber sources that may be used for a bridge construction in Skellefteå. The timber would either come from a local clear-cut, transported by truck, or from continuous cover forestry in Lithuania, transported to Sweden by ship. The result is based on literature and calculations on data from previous studies. The results showed effects on carbon balance due to different silvicultural systems are complex, though the alternative with continuous cover forestry seemed to contribute to less emissions, despite the timber not being locally produced. The main factor between the systems, and therefore the different levels of emissions, seems to be highly dependent on how much of the harvested trees that is suitable for timber. However, emissions will also depend on local conditions such as timber storage. Therefore, it is important to take this into account when comparing silvicultural systems.