Hello student it's not relevant to pursue BSc in forestry after BSc, you can pursue Msc in forestry after completing your BSc if you fulfill the eligibility criteria - Bachelor degree in science with at least one of the subject from botany, geology, Chemistry, Mathematics, physics, zoology or Bachelor degree in Agriculture or forestry.

For more details refer to the link mentioned below - https://www.careers360.com/courses/forestry-course

Feel free to comment if you've any you've any doubt

Good luck