Assessing reforestation after a fire using UAVs

Abstract

In 2022, an aerial photograph of a 16-year-old burnt area was carried out along the northwestern border of the Botanical Garden of Petrozavodsk State University (Republic of Karelia, Russia). In addition to this, a field survey of the survey sites was carried out. The work was carried out to assess the state of natural forest regeneration after the fire. The results of combined studies showed that after the fire, viable young growth of mixed composition was formed with a predominance of Pinus sylvestris (71% of the total number of tree species), Betula pendula (22%), Populus tremula and Alnus incana (3.5% each). When comparing plant heights on three-dimensional point clouds with field measurements, it was only possible to reliably determine plant heights for a large generally accepted category (> 1.5 m), while the dependence of determining tree heights obtained by different methods turned out to be very significant (R2 = 0.95). The maximum height of P. sylvestris trees in the study area was 6.2 m, the average values varied from 3.5 m to 4.5 m, which indicates the success of reforestation after a fire on rocky outcrops.