SELEKSI TIPE HABITAT ORANGUTAN SUMATERA (Pongo abelii Lesson 1827) DI CAGAR ALAM SIPIROK, SUMATERA UTARA (Selection of habitat types by Sumatran Orangutan (Pongo abelii Lesson 1827) in Sipirok Nature Reserve, North Sumatra)* - Kuswanda, Wanda (Pusat Penelitian dan Pengembangan Hutan, 2012)