One of the Earth's richest zones, the tropical forest canopy, is the target of a new scientific initiative.
By Alex Kirby
BBC News Online environment correspondent
The organisers plan a network of treetop observatories to provide unrivalled insight into life high above the forest floor.
They say this will hugely increase their knowledge of forest life and climate change.
But they fear the canopy is being destroyed faster than any other habitat.
The Global Canopy Programme (GCP) is launching its campaign, A 20:20 Vision For Canopy Science, on 11 July at the Royal Botanic Gardens, Kew, UK.
It aims to combine research, conservation, education and fundraising, and to work to improve the lives of people dependent on the forests.
The GCP hopes to obtain several million pounds a year over the next 10 years to build and operate a network of observatories using cranes, balloons and walkways.
CREATURES OF THE CANOPY
Perhaps 40% of the world's living species reside in the tropical forest canopy
Tropical alarm system
The "20:20" in the campaign title refers to the plan to have 20 observatories at work for two decades.
There are 10 already, in temperate forests: the plan is to build another 10 in "biodiversity hotspots", areas rich in species in places like Brazil, Ecuador, West Africa and India.
The easy way to explore (Image: Laurent Pyot)
The observatories would serve as an early warning system to monitor global change, besides investigating the species living in the treetops.
The GCP describes the forest canopy as "the richest, most threatened and least-known habitat" on the Earth's surface.
It says there is evidence that 40% of all living species may be found in the canopy, many of them specialists adapted to life high above ground.
Helping the poor
It is seeking funding from industry, foundations, and the United Nations.
Dr Klaus Toepfer is executive director of the UN Environment Programme (Unep).
He said: "If we are to significantly reduce biodiversity loss by 2010, in line with commitments made at the World Summit on Sustainable Development, then we will need innovative investigations like the GCP.
Towering over the Sarawak forest (Image: Tohru Nakashizuka)
"We need not only to tackle the science but also to understand better how biodiversity can provide benefits to local communities and help poverty alleviation."
The director of the GCP is Andrew Mitchell, a British zoologist. He told BBC News Online: "What we're planning wouldn't have been possible a few years ago.
"We can do it thanks to technology - the new tool is canopy cranes.
"They're static, and we'll combine them with mobile balloons for maximum flexibility.
"In the old days all you could do was fire ropes up into the trees and build platforms or shaky walkways.
"The only way to find what lived there was to fog the trees with pesticide and see what came down. Often up to 80% of what fell to Earth was new to science.
"The canopy's a terribly important source of activity - it's the real engine-room of the forest.
Parsons chameleon, from Madagascar (Image: Katherine Secoy)
"Apart from the species it harbours, and all the pollination that goes on there, it produces a huge amount of oxygen and takes up vast quantities of carbon.
"Yet it's really being damaged by development, and climate change is a growing threat.
"In an experiment in Switzerland researchers pumped carbon dioxide into the treetops through 12 miles of thin tubing, raising the concentration to about 550 parts per million.
Cheap at the price
"That's the sort of level we may expect globally by around 2050, on present trends.
"It caused changes to the composition of insect communities, which could alter disease patterns. It also affected hydrology and wood quality.
TROPICAL FOREST CANOPIES
Tropical rainforest trees rise to over 65 metres and Pacific redwoods to as
much as 90 metres
of forest canopies on climate change is thought to be significant
The Kyoto Protocol focused attention on the role of forest canopies in
absorbing carbon from the atmosphere
"This campaign will revolutionise our knowledge of life on Earth.
"It'll cost about five times less than building a go-kart for Mars - and it'll be a lot more use, at least in the short term."
The Global Canopy Programme's work is described in the journal Science.
Image of balloonist and net by Laurent Pyot