Braving a windy Wednesday in Tel Aviv, environmentalists rappelled from the roof of city hall to hang a 200-square-meter banner encouraging Tel Aviv Mayor Ron Huldai to stop using controversial timber in Tel Aviv building projects.

The massive banner read “Huldai, climb down off your tree” in Hebrew, which is an idiom meaning “change your ways”; and in English, “STOP Amazon Crime!” The activists were protesting the city’s use of rare ipê trees from the Amazon rain forest in the construction of city projects, such as the Tel Aviv port, and further plans to use the timber as decking on the Lahat Promenade, according to environmental organization Greenpeace.

Seven activists were arrested for disturbing the peace and refusing to leave the premises, police said.

The organization also said that it plans to file a complaint against the contractor, Shamayim Yerukim (Green Sky), for importing ipê through the company KM Comercio in the Amazon, which, Greenpeace said, had been fined in 2014 by the Brazilian authorities “over $400,000 for trading illegal timber.”

Huldai’s office denied the allegations, but said the municipality would look into switching the type of wood it used for city projects.

“The Tel Aviv municipality insists that its woodwork be done with wood that comes from a licensed source only and not trees cut from their natural environment,” the municipality said in a statement. “The municipality will ensure that guidelines are clarified and updated to use recycled wood or wood-like substitutes for future projects as part of [the municipality's] commitment to protecting the rain forests.”

According to Greenpeace, Israel is the second highest per-capita user of ipê wood in the world, importing around 5,000 tons in 2013. The organization is calling on all Israeli municipalities to cease using the timber.