As winter yields to spring, the land and water surrounding the Culinary Vegetable Institute are teeming with activity. It is a precise, seasonal point in time when nature offers precious and plentiful gifts to seize and savor before the special moment is gone.The natural rhythm of freezing nights and warmer days releases the flow of sap running through the black walnut trees lining the CVI property. That means the time is ripe for tapping the trees and collecting their crystal clear liquid for transformation into syrup.