Epsilon Archive for Student Projects

Abstract

Norway spruce is one of the most important species for Swedish forestry. Spruce is sensitive to drought, and it is hypothesized that the tree species will experience frequent drought-induced growth declines under the future climate. This study investigated the impact of drought on the stem growth of Norway spruce, using stem analysis and breast height data collected from two sites in the county of Halland, Southern Sweden. I hypothesized that using breast height data would produce biased estimates compared to the stem analysis data. I found that the stem growth has experienced a reduction under the moderate drought threshold of the SPEI value below -1.31 in May, considering relative growth responses and the SPEI value of -1.23, considering absolute growth responses, based on data combined from the two sites. The results showed that trees have undergone varied recovery years across years following drought years, ranging from one to more than ten years. Further future research is necessary to include more and older trees in the analysis.