Exploration of the rain forest canopy using airships and other methods
At present there are perhaps 100-1000 biologists worldwide actively involved in rainforest canopy exploration. Given that the canopy is so important in terms of its biodiversity, at first this number seems suprisingly low. However, it is important to realise that scientific research has been historically hindered by the problem of access. It is difficult to get safely and routinely to the canopy, especially the uppermost region - the "bright zone" that might be as high as 70 metres above the ground.
In order to improve access, fixed-structures have be built, such as walkways, platforms and cable-systems, but these structures are obviously restricted to predetermined locations. In recent years cranes (with rotating jibs) have been used to achieve greater canopy mobility, but they are also each limited to an survey radius of less than 50 metres. How is it is possible to access larger areas of canopy? Lots of biologists, architects and biologists have tried to tackle this problem over the past 50 years or so, with varying degrees of success.
Otis Barton - the engineer who designed the first deen ocean bathysphere for William Beebe - could be described as one the world's first "dendronauts". In the 1950's he developed a rope-lifting system to photograph canopy wildlife, however he found the system clumsy and ineffective, see below:
"With some local air pilots I discussed the idea of using a helicopter for photographing the tree-tops. They said that the noise as well as the appearance of the strange contraption would drive all the animals down to lower levels, and that I would see nothing but quivering tree-tops. There is, however, another possibility. During long periods of time there is no wind in the forest. A balloon might work - with a thousand feet of cable attached (five hundred to remain on the ground, the rest to act as ballast). With a hand winch I could raise or lower the balloon; with long poles I could hook it from limb to limb. And it would be silent. Perhaps I will try it when I return to Africa on another tree-climbing expedition."
O. Barton, "Adventure on land and under the sea", Longmans, London, 1954.
Towards the end of his life, Barton recognised the possibility of an airship that he called a "spacecraft of the jungle" to film canopy wildlife. Indeed, when he was 79 he actually flight-tested a prototype airship (or dirigible/blimp) in the USA and planned to use it above the rain forest of Guatamala.
Barton's "Jungle Spaceship" (1978)
Barton's vision was actually later realised by a French team led by Professor Frances Halle in "Operation Canopy" (1989-present). This team used a Thunder and Colt thermal airship (with a propane burner and piston engine) to carry and deposit a large inflated raft on top of large tropical forest trees, as well as to carry a "luge" to fly just above the canopy. See http://www.radeau-des-cimes.org
Today there are a large number of canopy access methods - each offering various advantages - as well as having major limitations for scientific exploration:
1) Use of climbing equipment such as ropes or climbing grips. One of the oldest climbing tools is the pecohna used by Amazonian Indians. This requires considerable stamina and is limited to mid-canopy strata. The upper canopy is difficult to reach with simple rope climbing techniques. See, e.g., http://www.canopyaccess.co.uk/index.html
2) Use of permanent structures such as ladders and walkways. Although ecotourism has benefitted from such structures, they are obviously limited by the very fact that they are fixed to one site, and they can cause changes to the local ecology. See, e.g., http://www.canopyaccess.com/ http://www.integratedconservationresearch.org/
3) Tram systems have been developed for ecotourism, but again these are obviously limited to their predetermined locations. See, e.g., http://www.exploringcostarica.com/aerialtram/rainforest.html
4) Use of civil construction cranes. Several canopy research groups have set up cranes in different rain forest locations. This is perhaps the best technique to survey a circular area of forest with a radius less than about 50 metres, although it is relatively expensive method. See, e.g., http://www.globalcanopy.org/canopycam/
5) Use of thermal airships. The pilot of Halle's team, Dany Cleyet-Marel, has also successfuly made use of a motorised hot-air balloon and a tethered helium balloon - usefully expanding the range of canopy access methods still further, but they are both limited to operation in calm (no wind) conditions and hot-air propane burners are relatively noisy. For more information see: http://www.chez.com/cinebulle/cine_eng/photo/frame.html http://web.uvic.ca/~canopy/ibisca.htm http://www.cleyet-marrel.com/