We leave our presence in the pavement. We're walking over it, sitting on steps.

I take the opportunity each day offers.

The photography is not the aim of the work; the articulation of the work through photography is another way of understanding what's going on and what's happening outside.

I can't edit the materials I work with. My remit is to work with nature as a whole. I find nature as a whole disturbing. Nature can be harsh – difficult and brutal, as well as beautiful. You couldn't walk five minutes from here without coming across something that is dead or decaying.

I have worked with this red all over the world - in Japan, California, France, Britain, Australia - a vein running round the earth. It has taught me about the flow, energy and life that connects one place with another.

When I do the permanent projects or the big projects, when a work is finished, that's the beginning of its life.

The first snowball I froze was put in my mother's deep freeze when I was in my early 20s.