I'm developing a tree that has a peculiar fruit. Instead of having water in said fruit, there is nothing but sugar. The tree pumps sugar into a hollow orb which slowly "bakes," caramelizing into an amber shell of stained-glass sugar. This caramel shell fruit contains tiny seeds. What's more, to protect this fruit from dissolving or getting soft or tacky, the tree coats it with a super thin layer of waterproof, edible, tasteless wax. Sometimes, though, when the fruit falls and isn't eaten/smashed, it explodes violently, throwing shards of sugar-glass through the air, as it impacts with the ground (or after lying there for a while.
The reason for the explosion is because the same heat that the tree generates for caramelizing the sugar into a single shell is sometimes expelled in waves through the tree roots because the tree needs to cool down. The now cool "fruit" suddenly gets a blast of intense, fiery heat, causing it to explode (hence, "sugar-bomb").
How would the tree
- catalyze the heat and expel it (Edit: to clarify, expel it through its roots)
- the tree generate that level of heat? (I already made the tree have black leaves for maximum heat/sun absorption: anything else the tree could do?)
In accordance with this meta post, please do not use magic as an answer. Try not to use "it's handwavium/impossible/magic" answers. I've set my premise (caramelized sugar fruit, ignoring water/uselessness).
Thank you to all in the Sandbox who helped me develop this question.