my guest is isabella tree, the co—owner of this knepp estate.ow, does her passion for rewilding represent an indulgence or a pathway to a healthier planet? isabella tree, welcome to hardtalk and thank you so much for inviting us to your estate here in sussex. pleasure. absolute pleasure to have you. i'm sorry it's not better weather. ah, well, it's actually still, for me, very exciting to be here. but i'm trying to understand what has happened to this land of yours, because when you arrived here, this was an intensively farmed land, wasn't it? it was. my husband, charlie, inherited it from his grandparents when he was in his early 20s, and this was back in the 1980s. and every inch of the land was ploughed, it was producing arable crops and dairy. and we fully expected to be farmers for the rest of our lives. mm. 17 years on, we were £1.5 million in debt, tearing our hair out and realised that, you know, this is very marginal land. we're walking on 320 metres of clay, over a bedrock of limestone, and it's an absolute pig to farm. so you were lit

my guest is isabella tree, the co—owner of this knepp estate.r a pathway to a healthier planet? isabella tree, welcome to hardtalk and thank you so much for inviting us to your estate here in sussex. pleasure. absolute pleasure to have you. i'm sorry it's not better weather. ah, well, it's actually still, for me, very exciting to be here.

for 17 years, he and his wife, isabella tree, tried everything to compete with modern industrial farmse coming on. >> reporter: but the wet, heavy clay in the soil made efficient farming impossible. >> we were 1.5 million pounds in debt by then. so it was really looking desperate. >> reporter: and then in 2000, they learned about a new idea in land management called rewilding. that's where you give away your land to nature. you stop plowing, irrigating, mowing, applying chemicals, and you let wilderness return. >> what has been absolutely astonishing is how quickly nature has bounced back. so from being one of the most depleted pieces of land you can imagine to being one of the most important biodiversity hot spots in the uk. >> reporter: after 20 years, nep now teams with an incredible variety of plants, animals, birds, and insects, some of them endangered. >> the rarest species in britain, turtle doves, nightingales, purple butterflies. we have peregrine falcons nesting in a tree, which is almost unheard of. >> what i wanted to see what's the first breeding stocks to be back in brita