Preliminary Study on Coppice Thinning Trial of Bawzagaing ( Leucaena Leucocephala ) After First Rotation by U Khin Maung Oo, Deputy Director, Kayin State, U Mya Win, Range Officer, U Maung Maung Khin, Range Officer, and U Chit Hlaing Win, Range Officer, Forest Research Institute August, 1997