Do resources reset every Reign in Dragonfire?

Yes. That's THE economic rule to internalize. With every new Reign (8 weeks), these go back to zero:

• The 4 base resources: Wood, Stone, Iron, Food/Grain
• Meat
• Resolve
• All buildings and research in Infrastructure / War Tactics / Dragon Care
• Your Stronghold tier and tile ownership

What never resets: Gold, your dragons, their Star Rank, their Habits, Relics, Breedmarks, Cores, and the keys (Dragonbone / Dragonglass / Dragonfire).

The moral: don't hoard base resources, spend them within the Reign. Save and accumulate everything permanent instead (gold, Relics, keys).