State and local officials gathered this morning in downtown Raleigh to place a ceremonial tree on top of the Nature Research Center, the N.C. Museum of National Sciences’ new 80,000-square-foot wing.

The tree, an eastern red ceder, was lifted up by a crane and placed on the building’s highest point. The center, currently under construction, is expected to open in early 2012.

The Nature Research Center is a $54 million public-private project. The state contributed $10 million for it; the rest is being paid for with private donations.

The center is part of the Green Square Project, a complex of eco-friendly buildings now under construction on two blocks between Jones and Edenton streets.