A character is moulded by experience. The slings and arrows and comings and goings of life force us to put up protective shells, and often what we are and what we're thinking and expressing is not in the dialogue - it lies beneath.
I love thinking about what lies beneath. With so much of our landscape, we as human beings have played God. We've moved mountains and filled lakes where rivers used to be, and we've cleared a lot of land.
I'm really interested in what was there before that, so I'll look at the trees - because there's always a clump left. You'll go around the Waikato and you'll see little remnants of the kahikatea forests, you'll go to the South Island and find pockets of beech that are gradually spreading again.
I once visited the Methuselah tree near Las Vegas, which is the oldest tree in the world. It's a 4000-year-old bristle cone pine. Tane Mahuta, if he's lucky, is 2000. Methuselah doesn't look very spectacular. It grows at altitude, and is stunted and gnarled, but I like the idea of a tree that can live that long and can connect us to so much of our personal history, but also to what has happened in nature during that time.
I'm curious, and that's what drives me as a naturalist, as an actor and as a human being.
I just turned 64, but I'm as curious as I've ever been. I believe that keeps you young. I can be in any street in any city and there's usually something of interest. I always carry a notebook, because you never know.
- as told to Bronwyn Sell
• Peter Hayden's new book, An Extraordinary Land: Discoveries and Mysteries from Wild New Zealand, with photographs by his former Natural History Unit colleague Rod Morris, is released this month by Harper Collins, RRP $49.99.