jiti is a huge tree, since 'huge' implies larger than usual. In Swahili there's what we call ukubwa, kawaida and udogo, which is roughly supersize, normal size and small size. For tree it's:
Ukubwa: jiti (huge tree)
Kawaida: mti (tree)
Udogo: kijiti (stick)
Ukubwa will always have the prefix 'ji-', while udogo has the prefix 'ki-'