Most of my neighbours don't bother growing their own food because the rainforest birds and mammals harvest it with an efficiency and enthusiasm that humans can't match. You can't keep the animals away. Chicken wire? Birds fly over it. Nets? Rats crawl under them. Electric fences with motion-activated spotlights? Pademelons carry pliers in their pouches. You can have temporary success by overwhelming them with volume, but you can never win.
Still, there are bucketloads of native fruits in the rainforest: quandongs, bollywood, Atherton oak. They all have their fans. But the best of them — from this human's point of view, anyway — is Davidson's plum (Davidsonia pruriens).
Plummish in appearance, but not a true plum, Davidsonia makes the tastiest jam. It's slightly tart and goes well with just about everything. I doubt that I'll ever beat the fauna and collect enough fruit to make my own jam, so I'm stuck with buying it. But I'll collect seed and try the 'overwhelm by volume' approach. Always worth a try.