B

Mark Brown. 57. had been making films for 30 years, but he found himself feeling tired of it. "I thought, things can only go downhill." Brown knew he needed to do something else - but what? A few years earlier, he had bought his childhood house and moved in. While Brown wondered about a second care er in gardening, he heard a different internal voice. "That child who used to love drawing whispered to me down the years," he said. Some unacknowledged longing in him was brought out.

There was a great oak tree near his home. It had stood out to his young self as a "fantastical giant - a treasure home to birds, insects and animals. There was a cave inside. We used to squeeze in through this hole." He decided to lock himself away for two months to draw it in all its glorious detail.

"While I was drawing," he said, "there came moments when it was as though the tree was drawing itself. I had spent so much time playing in it. I could feel it. It was deep inside me." His finished oak held "a real power", he said. "As you walk towards it, it just grows." Brown became a tree portraitist.

Over the next few years, he travelled across Britain and spent days with the trees selected with the help of the Ancient Tree Forum, the Tree Council and the Woodland Trust. Brown has started work on a 20-drawing series of Britain's most important ash trees. "These beautiful old ash trees are going to be lost to us," he says. "They are 350 years old and they are dying because of a disease that we've spread."

Drawing is not only an act of care and a demand for preservation, but it "gives me that interface between my passion for the natural world and my creativity," Brown says. It has also given him a different perspective on the passage of time. "I'm an old man yet I'm only 71, and some of the trees I've drawn are 1,000 years old. When I'm with them and when I draw them, I think about the end of my life and the brief nature of human life that passes momentarily beneath them."