Here's a slightly embarrassing secret - I always take an umbrella when I go to the rainforest. Some people take waterproofs, but even in the breathable ones you can sweat like anything. Some people believe in just getting wet, but this can be uncomfortable and surprisingly chilly. So I take a brolly. I look silly but I feel dry.

I put the damn thing up a little before six last Sunday morning and set off into the forest. I was at San Rafael, a chunk of Atlantic rainforest in Paraguay. The determined, soaking downpour explained how such forests get their name. Atlantic rainforest bears the distinction of being the most damaged habitat on Earth. There's about 5 per cent of it left.

I was travelling with a conservation organisation called Guyra Paraguay, and for me the glass was 5 per cent full.

The forest was silent, no voices, just the sound of the rain pattering on umbrella and the wide leaves of the understorey. Pretty much the same sound. The pattering silences were broken occasionally by a liquid whistle, or a shrill piping. These laconic, piercing calls have been adapted for the thick, soupy acoustic of the rainforest. It was a quiet time of year, so really it was just me and the forest.

The place is both inhospitable and enchanting. It sucks you in, it involves you. You raise your eyes and see plants on plants on plants.

Everything is soft, damp growth. If you are still enough, you can hear the trees growing. It is not a good place for human beings; it lacks the clear logic of the African savannahs from where we sprang.

This is a sad place, a lonely place, a broken forest crying out for healing. A fragile and fractured environment, it has been patched and patchworked. That it survives at all is miracle enough. Some might think that the surviving 5 per cent is hardly worth bothering with, but you don't think that when you are in the guts of the place.

From the air, bouncing in by light aircraft, I could see chunks here, chunks there. This part has been bought up by Guyra Paraguay with the support of the World Land Trust in this country. There are holes at the edge of the forest and here, gloriously, the broken forest is being healed.

Ximena Silva is a forest engineer, and when we talked in Asunción, she looked like a pretty, effective and ambitious career woman. When we walked in San Rafael, she had turned in a wood sprite, wearing leather chaps and carrying a machete half as tall as herself, utterly involved with the life and growth of her forest. She has been restoring this place, planting trees of extravagant diversity and attempting to put the toothpaste back into the tube.

It's a wonderfully encouraging thing - what Paraguay needs and what the world needs. A sudden explosive call came from deep in the forest. It was, I'm pretty sure, a rusty-margined guan. I made my rainswept way back through the rainforest, bashing my brolly on vines and epiphytes.

A flavour of saffron

Sometimes when the forest stops, it is not because the bastards have felled it. Sometimes it is because there is a dramatic change in the substrate and the vegetation becomes open grassland. Here, in these sudden, dramatic spots, you can find the saffron-cowled blackbird, officially listed as “vulnerable”. For once, I was the one to find it.

There it was, sitting on a post: a fine thing, and for a change, the name has it pretty well right. It's a striking little bird. Then we were given a treat - a flock of eight of them came together and fed in plain view before giving us a black-and-saffron flypast. After the difficulties of birding in deep forest, these were gratifyingly co-operative creatures. The light was failing. It was time to head back to camp for a couple of beers. Beer and brollies: rainforest essentials.

Nameless joy

The forest opened out, and on the river-bank was a constellation of butterflies: lemon yellow, orange yellow, crimson, and the best, egg custard and black with wings shut, electric blue when open. I didn't know their names: but joy doesn't always need a name.

Extraordinary vision

Paraguay is fabulous. I was deeply taken with the place, the scenery, birds, people, frogs, toads and wood sprites. San Rafael and the Atlantic rainforest made a nice bonus at the end of an unforgettable trip. But the main purpose of my visit was elsewhere.

I had travelled to Paraguay to visit a conservation project of startling vision and grandeur in one of the most extraordinary places I have set foot in. Its immediate future will be settled next week, and - well, I hate to be a tease, but I'll tell you all about it in times2 next week.

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