It’s nearly Christmas in the foggy Nahuelbuta Range of south-central Chile and berries the size and color of ping-pong balls are ripening in small gardens that tumble down steep forested slopes. The dwindling number of aging farmers who still cultivate these frutillas blancas have just five weeks to comb these gardens and harvest their goods. Five weeks to make a year’s worth of profit. In that brief time, these white strawberries—which turn a pale pink when ripe—will have two local festivals in their honor. There will be white strawberry cooking…