Vineyard

When the grapes in a vineyard were ripe, there was a danger that they would be picked by thieves or eaten by animals. For this reason, the vineyard was guarded during the grape harvest from a purpose-built watchtower.
This stone tower was built on a high location, giving a good view of the vineyard. It was a round or square tower, between two and five metres in height, with a staircase on the outside.
These kinds of towers were sometimes built to guard sheep and goats as well.

Not all vineyards had a stone tower. Sometimes the vineyard was guarded from a hut, as in Isaiah 1:8.