Outside one of the biggest greenhouses you have ever seen, a coach pulls up and a stream of seven and eight-year-olds spills out. It's the third class this week from Peterborough's Bishop Creighton school to visit the Spalding Tropical Forest, and their excitement is palpable. Regaled by their friends with tales of poisonous trees and waterfalls, they can hardly wait to see it for themselves.
The Tropical Forest is the largest of its kind in the country. Established just four years ago, it consists of half an acre of lush, frondy greenery, interlaced with paths, bridges, viewing platforms, waterfalls and pools teeming with fish. Less conspicuous are the Chinese quail, frogs, geckos and spiders that dart among the foliage.
More than 3,000 plants have been arranged into four landscaped zones to create oriental, temperate, tropical and arid environments. The forest is managed organically, and careful monitoring of temperature, light and humidity ensures that correct conditions for each of the zones is maintained.
The children's guide for the day is plantsman Alan Collier who, much to their delight, turns out to be something of a stand-up comic as well. As the tour gets underway, a particularly vigorous climbing plant suddenly appears to grab him by the throat and drag him into the undergrowth. The children gasp, then laugh with relief as he emerges unscathed seconds later.
"To really capture a child's imagination," he says "a tour of the forest has got to be entertaining. I could walk round here and rattle off botanical terms for hours on end, but that wouldn't engage their attention, so I try to make it funny as well."
A standard tour lasts around an hour and can be adapted to suit the needs of visiting schools. Today, the focus of attention is on roots, stems, light and leaves, requested by class teacher Barbara Green to complement their science work on living things.
Undoubtedly the highlight of the day is to walk behind the waterfall that leads to the deadly angel's trumpet tree, whose deceptively pretty yellow flowers contain lethal doses of mercury. Spellbound, the children listen as Alan's cautionary tale warns them never to fall asleep under one of these trees, should they ever happen across one.
After a short break for lunch (and a chance to let off steam in the adventure playground), they are back with clipboards and a mission to record leaf shapes and patterns. At this stage, they are supervised by their own teachers but Alan is also on hand to answer any questions that might arise.
Barbara Green is in no doubt as to the educational value of a visit to the forest. "It's good to have a guide who knows so much about the plants and can make it all so interesting. Here, the children get a true hands-on experience. It's all very well having a few plants at school but, here, there's such a wonderful collection and it just brings the rainforest to life."
Not every group starts out as enthusiastically as Bishop Creighton school, but the forest wins them over in the end. "Sometimes you get a group who come in with the attitude that plants are boring," says Alan. "But I quite like that because, inevitably, when they leave they're completely converted. Just last Friday, I had seven children come up to me at the end of the day and say, 'I didn't know that plants could be so interesting'."
* The forest is linked in to the Botanical Gardens Education Network, and provides education packs to cover key stages 1-4. All age groups are welcome, from reception to FE colleges and beyond.
* Before booking a day at the forest, teachers are encouraged to make a free preliminary visit, during which Alan Collier will show them round and give them the appropriate key stage pack.
* Facilities include an adventure playground, a shop selling plants, books, micro lenses and a variety of pocket-money toys from frog superballs to rubber spiders and snakes.
* Schools pay Pounds 1.56 per child for a day at the forest with a guided tour; there is no charge for adults.
* The Tropical Forest is open seven days a week throughout the year (except Christmas Day). Summer 10am-6pm, winter 10am-dusk. For private visits, charges are adults Pounds 2.25; senior citizens Pounds 1.95; children Pounds 1. 25. Details: Spalding Tropical Forest, Glenside North, Pinchbeck, Spalding, Lincs. Tel 01775 710882.