The other options involve chemicals, so this is an automatic giveaway. The density of something can alter the way the shape of it is by either splitting it or adding to it. However, it STILL has mass and occupies space because for instance, we do not cremate it.
I think the best way is to try providing helpful things that will help the humans or have people try to plant the plants somewhere that reminds them of their old climate I REALLY HOPE THAT HELPS I tried
