Epsilon Archive for Student Projects

Abstract

Boreal forests store about 32% of the global forest carbon stocks, second only to tropical forests that store around 55% of the global forest carbon stocks. However, with the changing climates, it is unsure whether managed or unmanaged forest store more carbon, especially after disturbances such as forest fires. Therefore, carbon stock analyses are important to help prevent climate change. This thesis aimed to compare the carbon stocks of living and dead trees in the boreal zone between two chronosequences: one of managed forest stands and one of previously burnt forest stands. The two chronosequences were created in Västerbotten and Norrbotten counties in northern Sweden and were based off similar site characteristics. Each stand in each chronosequence was inventoried and living and dead tree data was collected. The wood density was calculated for the living trees in each stand. Then the carbon stocks were calculated for all living and standing dead trees above 5 cm in diameter at breast height and for all lying dead wood above 1 cm at the smallest end. Finally, regression analyses were performed to compare the average carbon stocks over time for both chronosequences. The results showed that burnt forests had on average larger carbon stocks over 100-year time periods, but that the managed chronosequence had a larger and more linear carbon stock increase over time. This study did not include carbon stocks for trees smaller than 5 cm dbh, shrubs or the soil and did not account for the impact of soil nutrient availability on total carbon stocks. The study also did not include any calculation of the substitution effect of carbon stocks extracted from the managed stands. Overall, the study showed that 100 years after a forest fire or final harvest, burnt forests store more carbon than managed forest, but this topic could be expanded further.