‘DALI’ GREEN GIANT

Surreal eco-tower pitch on Roosevelt I.

An air-scrubbing high-rise behemoth that looks straight out of a sci-fi flick has been proposed for the middle of Roosevelt Island.

The tree-studded, 2,400-foottall building is designed to loosely resemble a mandrake plant — with a base like a cruise ship morphing into a gleaming, twisty tower à la surrealist Salvador Dali — and would take over much of the East River isle off Manhattan.

The residential proposal, by French architecture firm Rescubika, was posted on the Web site designboom as part of a “city of tomorrow’’ feature.

The pie-in-the-sky project is all about going green, with its architects telling The Post on Monday, “This project is able to absorb a large amount of carbon and is therefore less polluting for the ecosystem.”

Calling the building “the world’s largest carbon-sink tower,’’ the firm says the development — featuring 1,600 trees, more than 80,000 feet of plant walls and 8,300 shrubs — would “absorb carbon circulating in the biosphere.”

“This carbon is then trapped in living matter and subsequently more or less sustainably sequestered in organic matter,” the firm said.

The specially designed ecosite also would reduce carbon emissions through a network of buried pipes to capture and circulate hot and cold air from the development as needed, as well as by having residents work in a home office in every apartment instead of using transit.

There would be 160 floors to the structure — which would be at least partly fueled by energy from 36 wind turbines and nearly 3,000 feet of solar panels.

The Mediterranean mandrake plant was used as a design inspiration because “like [it], the project is an evocation of the human figure, of a bodily movement that is synonymous with life,’’ Rescubika said.

The building proposal is just theory at this point.

The Roosevelt Island Operating Corporation, which was created by New York state in 1984 to oversee the planning, development and operation of the unique land mass, did not respond to a request for comment from The Post on Monday.

The island is owned by the city and leased to the state.