I was thinking different tree? if that wasn't enough with already good suggestion base that submitted, I know coconut does tend float to other islands but what if floats to your raft as your floating along I have no idea if your going allow trash coming in so you "find" new tree seeds as motive for survival to "plant" it as way prosper? Lemon trees means to prosper, lucky and they stop people who sea faring from getting sick. Coconut is one I was thinking, others Not sure you have really think what look cool or feel in your game?
To be honest, we did think of bringing coconut trees into game a few months ago. But in current version, it seems weird to float locally and plants several kinds of plants.
Consequently, we decide to make rafts of survivors to float away first!