The Tree-glider is the result of an 18 years experience of the tropical forest. An alternative to the Canopy Raft missions, it furthers our possibility of intervention and exploration. It is easy to use, which means missions can be more specific, lighter and more frequent.


For the last 18 years, Canopy Raft missions have been an ideal context for developing means of access to the canopy, and more generally to refine exploration strategies in a forest environment.

Those missions have thus given birth to a number of devices (Airship, Raft, Sledge, Bubbles, Ikos), resulting from in situ observations and experiments, debates and discussions with their main users, scientists.
Researchers were most enthusiastic about the sledge, a platform moved around by airship. That device and its purpose, the intensive collection of samples, were the inspiration for the Tree-Glider.

This new device is a welcome addition to our range of tools and furthers our capacities of intervention and exploration. The Canopy Raft missions remain fundamental events for canopy research, but they are few, being costly and complicated to organize on a practical level.

The Tree-Glider provides an alternative to such missions that require long preparations and imply complex implementation. It is easy to use and enables us to offer targeted missions, with lighter set-ups, on a more frequent basis.


The Tree-Glider is a motored aerostat of the Rozière type. Lift comes from hot air and helium. Unlike typical Rozières, the helium is not located in a sphere above a cone of hot air, but in a tore, underneath.
Hot air is the main thing. The influence of helium is limited so as to retain the precise piloting granted by rapid changes of lift due to temperature changes in the hot air envelope. Helium is not responsible for the whole lift. It is there to increase flight autonomy. Its elevatory force being much greater than that of hot air, an equal load can be borne with less volume, thus increasing air penetration.
Thanks to a little balloon inflated by small ventilators, the helium tore pressure is kept constant, which makes the hot air envelope rigid, enabling greater speed without it being distorted and giving the whole device greater stability.
The gondola has two levels. At the lower one is the “sledge” which can accommodate two scientists and their equipment and has enough room for botanical or entomological samples collected during flight. The top one is for the pilot, the instrument panel and the rest of the instrumentation.
It is powered with a Rotax engine equipped with a variable pitch propeller, located at the back of the gondola, at the upper level.


The main characteristic of tropical forests, by comparison with temperate regions, is the great variety of the fauna and flora encountered on sites close to each other, say about a hundred metres away from each other.
In this context, the Tree-Glider is an ideal device to make the most of such variability. All it needs to set off is a small clearing, the edge of a track, the deck of a boat: a new site can be explored each day. All sample collecting activities are considerably stimulated, be they plant or animal (especially insects) samples, aimed at biochemistry or genetics research… Not only is collection itself made easier, but enhanced mobility also means more representative samples.

The Tree-Glider can come back to the same site after only a few hours, a few days or a few weeks. Experiments implying monitoring over a period of time are thus possible: herbivory dynamics, trappings, ecophysiology, micrometeorology.

This new machine can have numerous applications in regard to species and ecosystems conservation and it opens up new perspectives for international scientific collaborations. It can be used in many current biodiversity research programs around the world, serve as a link between various research sites and strengthen partnerships between major Conservation NGOs and scientific institutions.
Beyond its own capacities, the Tree-Glider is a powerful communication medium and a catalyst for biodiversity research and protection.

Dany Cleyet-Marrel