A developer has unveiled plans to build two 39-story residential towers in Crown Heights, confirming fears of the Brooklyn Botanic Garden and its advocates who have warned the city that tall developments in the increasingly gentrifying neighborhood will cast damaging shadows across a beloved green space.

Earlier this month, Continuum Company and Lincoln Equities filed applications with the city Department of Planning for zoning amendments that would allow them to build a 1.4 million square feet development containing 1,578 units of housing, half of which would be affordable, at 960 Franklin Avenue. One tower would rise to 421 feet, while the other would top off at 424 feet.

In 2017, the developers paid around $75 million for the three-acre site, which is currently home to a warehouse. Continuum is helmed by Bruce Eichner, the builder behind the 777-feet-tall luxury condo tower Madison Square Park in the Flatiron district.

The deal immediately raised concerns in the community, which has over the decades fought to protect the area around the Brooklyn Botanic Garden from overdevelopment. Community activists have frequently cited a 1991 city rezoning, which limits buildings around the Botanic Garden to 13 stories.

"The zoning in that area must remain unchanged," said Elizabeth Reina-Longoria, the director of communications at the Brooklyn Botanic Garden. "The position of that building is very close to our greenhouses and conservatory."

The Garden and community activists have long been expecting the developers to roll out a mega-project. As early as 2017, Eichner had talked about building a complex of four buildings between 20 and 30 stories on the site.

Buildings on that particular block are currently not permitted to be greater than 80 feet, or seven stories in height, according to Reina-Longoria.

Alicia Boyd, one of the founders of Movement to Protect the People, a grassroots organization which has fought the spread of large developments in the neighborhood, called the project a "monster."

"This is a neighborhood where we have an average of four-stories," she said. "This is an unprecedented leap that this developer is taking."

In June, Boyd’s group commissioned a shadow analysis that showed that a 441-foot building, slightly taller than what the developers have planned, would cast shadows on portions of the Botanic Garden for significant durations of time in the morning and afternoon.

As the city's skyline grows taller, more attention is being paid to how much light is being lost to mammoth-sized buildings. In 2016, the New York Times' Upshot blog mapped the shadows of thousands of buildings in New York City. Around Central Park, buildings like the Plaza, Ritz-Carlton and Hampshire House, can produce shadows several blocks long that can last the whole day.

Continuum did not immediately respond to a request for comment.

Should the 960 Franklin Avenue plan be approved, it would be one of the largest residential complexes in Crown Heights, a neighborhood that has faced increasing development pressures. Amenity-laden rental buildings have been popping up in recent years, with brokers attributing the growth to developers trying to lure the Williamsburg crowd in advance of the now-canceled L-train shutdown. The monthly median asking rent in January was $2,400, up 4.3 percent over last year, according to Streeteasy.

Continuum would not be the sole developer to capitalize on a development site near the Garden. In December, the City Council approved a rezoning that will allow developers Cornell Realty Management and Carmel Partners to erect two 16-story rental towers near Franklin Avenue at 40 Crown Street and 931 Carroll Street. The project, which will sit across the street from the proposed 960 Franklin Avenue plan, will be comprised of 518 rentals, 140 of which would be below-market-rate. As part of a last-minute deal with Crown Heights’ City Councilmember Laurie Cumbo, the developers agreed to give a roughly 1,000-square-foot parcel of land to an affordable housing developer, who will build 118 units on the site.

In a move that raised eyebrows among some Garden members, officials at Brooklyn Botanic Garden elected to not take a position on the Cornell project, saying that it was farther away and would have less impact on its green space.

The public will get to weigh in on the project next month. As part of the city’s effort to assess the environmental impact of the rezoning, a public scoping hearing has been scheduled for March 12 at the Department of City Planning’s office at 120 Broadway. Community stakeholders are invited to testify about a range of environmental concerns about the proposed plan, ranging from displacement to impacts on parks and open space.

Boyd as well as the Garden administration are expected to speak at the hearing, as are many advocates of the Garden.

"Our members are very protective of the Garden," she said. "The Brooklyn Botanic Garden has been here over 100 years and is a really vital part of the community and Brooklyn as whole."