If you go down to the woods today...

...you're sure for a sculptural surprise. On a walk through Grizedale Forest, in the Lake District, Mike Gerrard stumbled on a god of Thunder and a living room straight out of Habitat

"HABITAT'S my favourite," the little boy told us, with a fervour that would have brought a rosy glow to Sir Terence Conran's cheeks. "It's great, it's got a television and a sofa and everything." He consulted his clipboard. "It's number 42, down there on the left." We promised we wouldn't miss it, and returned to our cheese sandwiches.

We were gazing out at a small lake in the Grizedale Forest, between Windermere and Coniston Water. Out of the lake grew the bones of half a fish, several feet long. The reflections of the water cleverly completed the lower half of the wooden skeleton. Only One Fish Left it was called, one of dozens of magical natural sculptures in the Grizedale Forest Sculpture Project. We had thought it sounded fun, so had gone along, planning to spend an hour or two or however long it would take to complete the inevitable Sculpture Trail.

"How long will it take to get round?" we asked the woman in the Visitor Centre as we bought the guide map. "To see them all? I'd say about two days. There are about 70 shown on the map, and we're adding new ones regularly. And they're in several different places around the forest. So, two days at least." Two days? That`s not so much a trail, more a way of life.

The project began in 1977, when sculptors wanting to work in the natural environment of the forest were invited from around the world to come on residencies of up to six months. Working mainly in stone, wood, water and other natural materials, their projects are mostly hidden down tracks in the forest. Part of the fun is finding them in the first place. And fun they are, as the little boy with the clipboard and his family, trailing behind, confirmed. Small wooden carvings - of ants, wasps, bees, birds, deer, otters and other creatures - at the side of the main path indicate where you need to veer off and explore.

We headed for Habitat. Off to the right was something we had to see, one of several works by Andy Goldsworthy, the British genius at this kind of art form. His stunning works are in Australian deserts, Californian forests, Alaskan wildernesses, Japanese museums - and three are here in Grizedale. Off to our right was Taking a Wall for a Walk!, a long and sinuous piece of dry-stone walling which wiggles round trees as it disappears into the forest. "I enjoy the idea of walls travelling," Goldsworthy says in the guide, "old walls becoming new - changing shape in the process."

Nearby is The Passage hut by Keith Rand, out of the front of which a long, thin tree trunk projects, arched like a fishing rod. A family is just leaving, and seeing us apparently content to enjoy the creation from a distance, the mother tells us: "You've got to go up to it and go round the back. There's a little peep-hole. I won't say any more." Indeed, there is a little peep-hole, almost hidden, and as we leave we bump into a Dutch girl whose path keeps criss-crossing ours. "You've got to go round the back," we tell her.

Elsewhere, we meet up with the little boy and his family again. "Habitat's down that way," he tells us. We're going, we're going, honest! They have just been looking at God of Thunder 4 by Shigeo Toya. "Pain accompanies anger," says the artist's note, "The Thunder-god in pain makes a wry face. Pain is transmitted to a tree in a fusion with the Thunder-god." Hmmm... "You've got to thump it," says the little lad's dad. So we do, and an eerie reverberation fills the air.

And then we're at Habitat by Richard Caink, a living room complete with curtains and standard lamp, made from wood. It is big and bold and simple, a kind of wooden Fred Flintstone room. "The intention," according to the artist, "is to articulate notions of our relationship to the natural world," although I'm sure he'd be happy with the little boy's assessment: "It's great."

While some sculptures are fun, others are spooky, and the Wolves created by Sally Matthews are positively frightening. We knew they were there somewhere, and were talking under the outcrop on which they stand, when I happened to look up and nearly had a heart-attack. Looking down at me was a wolf, both realistic and a fairy-tale nightmare at the same time. And there was another one, and another. Elsewhere there are wild boars, elephants, waterwheels, fountains, owls and deer. On another trail, there are marimbas to play, extravagant seats to sit on, and a larch arch.

"Look," says my partner as we near the end, "through the trees." Has she spotted another sculpture? No, it's a bushy-tailed red squirrel, posing on a tree trunk. I get a sudden vision of it waiting till dark, when the last visitors leave, and heading for Habitat, sitting down with a packet of nuts and watching the telly.

For information, contact the Visitor Centre (tel: 01229 860010). Silverholme, in Graythwaite, a secluded Georgian house near the sculpture trail forest and on the shores of Lake Windermere offers b&b for pounds 23 per person per night, based on two sharing (tel: 015395 31332).