Oscar-winning Dame Judi Dench (Shakespeare In Love, As Time Goes By) is one of Britain's best-loved actresses, but few people know that she holds another great passion, a deep love for trees. JUDI DENCH: MY PASSION FOR TREES is a magical study of the changing seasons and their effect on Surrey, the most-wooded county in Britain. Ever since she was a child, Dench has been fascinated with trees. She shared that passion with her late husband, actor Michael Williams, and together they nurtured a collection of trees at the bottom of their garden. For the past seven years, she has continued to care for this woodland with her close companion, wildlife enthusiast David Mills, planting trees for dear friends and family who have passed away. This documentary follows Judi's experience through the four seasons, and brings to light her mission to understand the past and future vital role of trees. Top scientists and historians help unlock the remarkable secret lives of trees and the stories that they cannot tell. With the latest scientific techniques and equipment at her disposal, we can truly understand how trees work, and gain an insight into their secrets. Dench meets a designer with a special microphone that allows her to hear water rushing up the trunks to newly unfurled leaves in springtime. And, a scientist with 3D scanning technology reveals her favorite oak in a new light, uncovering an astonishing 260,000 leaves and a vast network of branches measuring over 12km. Through the cycle of the seasons, Judi discovers how trees "feel," learns how they communicate and how they fight off invading armies and extreme weather. NASA satellite imagery shows how effective trees are as carbon-capture machines that are fighting to protect our planet. A fungi expert reveals the incredible action going on beneath the ground -- an astonishing fungal network that looks up to the tips of tree roots, connecting many trees in a forest together, creating an incredible system known as the "wood wide web." It's confirmation for Judi that trees aren't just trees, they are a real community that help each other, humans and the planet.