Forest fires are one of the impacts of the increasing level of pressure on forest resources. Impacts related to forest or land fires are environmental damage and pollution, such as damage to flora and fauna, soil and water. Forest fires impact on the environment and biological ecosystems. The aim of becoming a reference for forest managers in their efforts to prevent forest fires at PT Toba Pulp Lestari. The analysis tested in this study is an analysis of a descriptive quantitative. The interview data contained in the questionnaire will be analyzed to determine the level of forest fires. The results obtained from this study are the age of plants that burn the most are 2-3 years old plants as much as 96 times. And the age of the plant that rarely burns is the plant that is 1-2 years old as much as 16 times. The most common factor causing forest fires from 2014 to 2021 was due to being burned by unknown people 187 times, followed by community farming activities for 31 times. The number of incidents and the area of forest fires occurred 221 times and an area of 163.23 ha. The highest period of fires occurred in February and June while the lowest occurred in December and January.

Biodiversity is a term used for the degree of diversity of living natural resources, including the number and abundance of genes, species, and ecosystems in an area. Consists of various forms of life, their ecological role, and the diversity of germplasm contained therein. The purpose of this study was to examine the effect of changes in forest area designation on the diversity of understorey species. Data analysis used the method of placing plots in the lane using the plotted path method, with a plot area of 2 m x 2 m, by recording all understorey plants from sprouts to a seedling height of no more than 1.5 m. And also using the analysis of the important value index (INP) and species diversity. The results obtained from this study can be concluded that the species diversity in plantation forests is 3.470, in protected areas is 3.525 and in natural forests is 3.093. This shows that there is no serious effect on plant species diversity because the species diversity obtained shows results that are not much different between plantation forests, protected areas, and natural forests.