My Tablegroup wants to build a wall to protect a village from future invasions. They intend to cut down the trees around the village and use those as the primary material.

How long would it take a group of 5 people to build a wall of 1600 feet (rough measure from my map)? There will probably be more people helping in the construction, but I'd like to have a starting point to calculate.

We're playing 5e, if that matters.