Birch sap is a clear, slightly sweet liquid collected from birch trees in early spring. It flows from the tree as it begins to thaw after winter, typically between late March and early April. The sap is rich in nutrients, including vitamins and minerals, making it a popular natural beverage. Harvesting birch sap involves tapping the tree by drilling a small hole and inserting a spout. The sap can be consumed fresh, fermented, or processed into syrup. It has been used traditionally in various cultures for its health benefits and refreshing taste.