Fruit tree and Melon tree

Fruit tree noun - Tree bearing edible fruit.

Melon tree and fruit tree are semantically related. In some cases you can replace phrase "Melon tree" with "Fruit tree", this phrases are similar.

Melon tree noun - Tropical American shrub or small tree having huge deeply palmately cleft leaves and large oblong yellow fruit.

Fruit tree and melon tree are semantically related. You can use "Fruit tree" instead a noun phrase "Melon tree".