"Taken for granted' Expert's mission to save ancient trees

Ted Green is a rebel. He calls sheep "land maggots". A horseriding centre is "a dogfood complex". And the new book from the expert on ancient trees includes a photo of him sticking up two fingers at a portrait of Margaret Thatcher.

- Patrick Barkham

But the influential, iconoclastic Green, 89, who has lived his whole life around Windsor Great Park and still works as a conservation adviser for the crown estate, is also a staunch advocate for King Charles's protection of Britain's unique range of ancient trees.

Taking the Guardian on a grand tour of Windsor Great Park, which contains one of the greatest concentrations of old oaks in the world, Green says the king is not only conserving these uniquely biodiverse living monuments but also their genetics in the next generation of trees.

We pass through private gates where he once trespassed, and Green points to King Offa's oak, a spectacularly stout and sprawling oak that may be 1,300 years old.

"The tree you are looking at is a 1,000-year-old gene bank with more than 1,000-year-old genebank soil," he says. "Conserving the genes of these ancient trees is absolutely priceless."