Epsilon Archive for Student Projects

Abstract

This study examines the dynamic interplay between tree growth and drought stress in a second
rotation poplar plantation in southern Sweden. It evaluates the responses of trees, focusing on growth
metrics (volume, basal area increments) and recovery patterns after water stress, across various
thinning treatments and tree sizes by analysing tree ring width. Significant variations in growth
metrics were observed, particularly during the drought of 2018.
To analyse the resistance (ability to remain largely unchanged) of trees during the drought, deltaDiv
was calculated, where deltaDiv = (projected growth - observed growth) / observed growth. This
calculated result highlighted that smaller diameter trees (dbh 9-11 cm) showed higher resistance to
drought compared to larger diameter trees (dbh 25-35 cm).
The analysis of Volume Increment (VI) and Basal Area Increment (BAI) aimed to reveal the
resilience (capacity to recover) of trees across different tree sizes (dbh 9-11 cm, 15-18 cm, 20-22
cm, and 25-35 cm) and thinning treatments (control/unthinned, light thinning, medium thinning, and
heavy thinning). The study found that tree density influences drought resilience, with heavy thinning
treatment (550 trees/ha) demonstrating higher resilience compared to unthinned plots (6000
trees/ha) and light thinning (3000 trees/ha) treatments, which showed limited growth responses.