The Wilds exist to help players increase their resource production. Conquering wilds provides bonuses to your resources depending on which wild you take control of. Grasslands and Lakes provide Food, Mountains provide Ore, Hills provide Stone, and Woods provide Wood.
Wilds award a certain percentage of resource production increase dependent upon the Wild’s level. For each level wild, expect to receive 5% (Level 1 Wild) bonus up to a maximum of 50% increase (Level 10 Wild).
The idea is to have all Level 10 wilds to maximize your production but in the beginning this will be nearly impossible due to the strength of troops that are stationed at higher levels. It is best to focus on conquering Level 1-3 wilds to begin with and slowing replacing them with higher levels as you grow and train more and better troops. Keep in mind that you can only conquer as many wilds as the level of your Keep up to a maximum of 9 (Limit increases to 10 if you have upgraded the Keep to Level 10 using a Hobbit Building Crew).