For the last seven years, British actress Judi Dench has been nurturing a forest dedicated to those close to her who have passed. The touching living memorial, tucked within her 6-acre property in Surrey, England, contains native species honoring deceased fellow actors, as well as family members and close friends.

Dench, 83, says she started the tradition with her late husband, actor Michael Williams.

"Every time a relative or friend died we would plant a tree," she told the Telegraph. “There is one for Stephen Hanley, who performed in A Little Night Music at the National. It's very like him, he was very tall and pale. We have Ian Richardson and Natasha Richardson. It is about remembering and for me it's something that's living and goes on. The memory goes on and gets more wonderful."

Dench's fascination with trees, a life-long interest she says started when she just a little girl, is the subject of a new BBC documentary, "Judi Dench: My Passion for Trees." The one hour special, filmed over the course of a year, follows Dench as she learns more about the secrets of forests with the assistance of tree scientists and historians. As she explains, the experience has made her even more engaged with the wondrous and sophisticated ecosystem growing ever-higher around her.

"I will never think of trees as individuals again," she said. "A forest is a very social place. Everyone is sharing and passing on things to everyone else. When I planted trees in memory of my friends I always hoped they would be part of a community, that they would be communicating with each other. And now it’s so reassuring to find out it’s true."

Unlocking the secrets of the forest

As part of the groundbreaking science exposing the secrets of trees, researchers Dr. Mathias Disney and Phil Wilkes conducted 3-D laser measurements of a 200-year-old oak in Dench's garden. Using a technology called lidar, they were able to capture a 3-D digital representation that showed the tree weighs 25 tons, has an estimated 260,000 leaves, and almost 7.5 miles of branches.

Dench joked to the The Times that she could one day see herself giving up acting to lecture on the wonders of trees.

"My life now is just trees," she added. "Trees and champagne."

You can see Dench express her love for forests in the 2012 clip below as part of a tree-planting campaign for the Queen's Diamond Jubilee. The BBC holiday special "Judi Dench: My Passion for Trees" premieres Dec. 20.

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.