Mugihe ibyuma bitagira umwanda bizwiho kurwanya ingese, ntabwo birinda rwose kwangirika.Hariho impamvu nyinshi zituma ibyuma bitagira umwanda bishobora gukomeza kubora.Ubwa mbere, kwanduza hejuru nkumwanda, umukungugu nu miti birashobora kwangiza urwego rwa oxyde ikingira kandi bigatera ibyuma kwangirika.Ni ngombwa guhora usukura ibyuma bitagira umwanda kugirango ukureho umwanda ushobora gutera ingese.Icya kabiri, niba ibyuma bidafite ingese bihuye nibindi byuma, cyane cyane niba bitose, bizakomeza kwangirika.