The total budget after studies is 52,4 million euros excluding taxes, one third of which is financed by Nantes Métropole.
Mentioned in 2005, this project was launched in 2016. Its cost was then estimated at 35 million euros and the opening to the public was expected around 2022.
"I really believe that the strength of this project is its ability to inspire people to dream", enthusiastically enthused the mayor of Nantes, Johanna Rolland (PS), referring to this planted structure 35 meters high, which will house several animals. mechanical.
"Our ambition now is to go from dream to reality", explained Fabrice Roussel, vice-president of Nantes Métropole in charge of tourism, indicating that the metropolitan council will vote at the end of 2021 to decide on the acquisition of the work.
The work will not start for a year, and will last five years on the site of the Miséry quarry opposite the island of Nantes, he said, specifying that the inflation and the technical nature of the project explain the increase in budget.
"It's an extremely complex project, unique in the world," said François Delarozière, co-author with Pierre Orefice of the work.
"It is almost impossible to define what the Heron Tree is. It is a unique work, it is at the same time a living work since it is in movement, animated, and it is also a challenge. technological, industrial and artistic, ”he said.
In the hangar housing the Grand Elephant, which took its first steps on the Ile de Nantes in 2007, visitors can already observe part of the bestiary of the future tree, and in particular a heron which will make its first flight tests this summer, on the ground.
Faced with criticism of the cost, the project leaders highlight the economic benefits that they amount to 30 million euros per year for the territory, counting on 500.000 annual entries.