Pruning on Gmelina Arborea

Dear Friends,

in our farm(Thanjavur, Tamil Nadu) we have planted around 400 Gmelina Arborea saplings around 6 months ago. now all the trees are about 6 feet height. is these growth average? or for six months it should be more than? around 100 trees are not growing straight, at 5 feet height, the branches are separating in to two sides like ‘V’ shapes. we have not done any pruning yet. kindly advise?

Regards,
Thaya