View Gardens; REACH FOR THE SKIES: Visitors Will Climb a 60ft Tower to Explore the Hidden World of Insects, Bats and Fungi in the Canopies of Chestnuts, Oaks and Limes HIGH ASPIRATIONS: Curator Nigel Taylor, Inset, Hopes the 650ft Long Bridge, Which Offers Stunning Views of Kew, Will Inspire Visitors to Plant as Many Trees as Possible in Their Gardens. 'Trees Have Never Been More Important,' He Says

Article excerpt

Byline: Duncan Farmer

If you have ever wondered what life is like high in the branches of thechestnut tree at the bottom of your garden, a new attraction at Kew Gardenswill give you a bird's eye view of that unseen, green world.

The 60ft high, 650ft circular Treetop Walkway, which opened yesterday, takesvisitors into the very heart of the canopy allowing them to walk among thehighest branches of American oaks, Corsican pines, beech and sweet chestnutsand see at first hand the birds, bats, lichens, insects and fungi that callthem home.

While it will undoubtedly be a popular attraction for sightseers - the walkwayalso gives panoramic views across London - the new feature has a serious aim:to increase our knowledge and appreciation of the crucial role trees play inour lives.

'Trees have never been more important,' says Nigel Taylor, Kew's curator ofgardens. 'They absorb atmospheric carbon, provide fuel, building materials,food and medicine, but deforestation accounts for more carbon additions thanthe transport systems of the entire world.' The Royal Botanic Gardens has named2008 as the year of the tree and, together with a second interactiveattraction, an underground Rhizotron (from the Greek rhiza, or root), visitorscan learn about trees from top to bottom.

'High up in the canopy you can see how healthy the trees are,' says Taylor.'When trees are unhealthy they start to shed leaves and small branches from thetop - parts of the tree that you can't easily see from the ground - but theproblems are usually happening below ground in the root system.' Spottingtrouble in large trees in your own garden may not be easy when they are in fullleaf, but Taylor says that spring, when new shoots and leaves should begrowing, is the best time to check from ground level.

The Rhizotron includes an interactive display about the benefits of fungi andworms as well as fascinating facts about subterranean life - such as that twomillion worms inhabit a football pitch. Visitors can also listen to a treedrink. It sounds like a series of pops.

Taylor is keen to see as many new trees planted this year as possible.

For small gardens, he suggests flowering cherry, Japanese maples and smallerspecies of rowan. However, there are two golden rules to give new trees thebest possible start.

'Always dig a square hole,' says Taylor. 'Pot-grown trees have a round rootsystem that will just go round in circles if planted in a round hole. But in asquare hole they will seek out corners and spread out from there.' Trees shouldalso be planted in the ground at the same level that they grew in the nurseryor in a pot. Any lower and they simply won't grow - although they could takeyears to die.

Compacted soil is another problem that inhibits good root growth. To loosen thesoil under trees at Kew, the gardeners pump in nitrogen in sharp bursts at highpressure to cause small underground explosions.

For amateur gardeners, worms do an equally effective, if slightly slower, job.'Put an inch or two of mulch - composted bark is good - around the base of yourtree and you will attract more worms,' says Taylor. Water is key, too. At Kew,they wrap large plastic bags filled with water around the base of new treeswith small holes at the bottom to drip-feed the roots.

The new walkway, which cost [pounds sterling]3million and took nine months to build, has shownTaylor and his team that Kew's trees are in perfect health.

'We have suffered a lot of drought here in the past but last year's wet summerand winter, as well as the warm spring, have really helped. …