The Secret of the Fire Trees
This is not a fleshed out adventure, just taken from my notes but some may find it adaptable to their own uses.
The far western portion of the Republic of Thanmyr consists of the Wythera Islands, Great Wythera and Little Wythera island.
The principle exports from the two islands are the Red and Golden Fire trees. Both trees are in great demand; every potion of them can be used. The timber is a durable hardwood which when polished up makes highly prized furniture. The real demand however comes from spell casters. Every portion of the tree can be used to make fire and heat based magical items. The sap for potions, the wood for staves, wands, etc.
Unfortunately demand has outstripped supply and the islands are becoming denuded of both varieties of Fire Tree. There are no new saplings being produced. The fruit of the trees, also in great demand, appears to be infertile. Why is this so?
An alchemist visiting the island has discovered that the Fire trees are not grown, they are created. If the islanders still know this they have kept it to themselves.
The alchemist has discovered how to create Fire trees. First he needs the fruit of the trees, either variety will do but the Golden is the more potent.
The secret is;
The fruit is fed to a person after a ritual dedicated to the lord of Fire is performed on both the fruit and the person.
The person is then strapped to a wooded stake or frame, any wood will do, which is then ignited.
The fire is then tended for three days. At the end of this period a new Fire tree sapling emerges from the ashes.
To produce the more potent Golden Fire tree the sacrifice must be willing, coercion is acceptable.
PCs could get entangled in this in any number of ways;
1. A PC or PCs are to be the sacrifice. Multiple saplings could be made.
2. They could have been hired to retrieve the fruit for the alchemist.
3. They could have been hired to retrieve a victim before the sacrifice. Etc.
Then if any of the islanders do know how these trees are created where do they stand, especially as these trees are also the islanders main income source.