Hiii

Yes, you can study forestry  (M.Sc forestry) after doing Bsc botany.

Eligibility for Msc. Forestry is

• Bachelor’s degree in science with at least one of the subjects namely Botany, Chemistry, Geology, Mathematics, Physics, Zoology or a Bachelor’s degree in Agriculture or Forestry.
• Even B.tech. or Bsc. Hon. In Biochemistry, Biophysics, Microbiology ,Agricultural Biotechnology can be considered.
  

I hope this will clarify your query. Feel free to revert back.

Thanks!!