From the NY Times:
As long as there have been immigrants from Greece and Italy in Astoria, there have been fig trees — they dot virtually every block from Ditmars Boulevard to 36th Avenue, between the East River and Steinway Street, in the neighborhood’s southern European quadrangle. The trees are native to the Mediterranean region, where winters are decidedly milder than in New York, but the fig trees of Astoria, like true New Yorkers, have proved resilient.
The immigrants planted fig tree roots they had smuggled from the places they left behind, and then cared for the trees as if they were part of the family, carefully wrapping them in the winter to protect them from the cold.
From November until maybe April, the trees look like hastily made packages of plastic and duct tape, and while they were once a common sight, they are a rare find these days: people have grown too old, too busy or too tired to carry on the tradition.
From a scientific perspective, covering a fig tree in the winter has more to do with protecting it from changes in temperature, which can be more harmful than the cold itself, said Todd Forrest, vice president for horticulture and living collections at the New York Botanical Garden. Rainwater can seep into a tree’s roots and cells, and if the water freezes, it can rupture the tree’s vascular connections and potentially kill it, he said.
There are two ways to protect a fig tree from winter weather. One is to bury the tree branches, a strenuous days-long process that requires slowly bending the trunk. The other is to wrap it and perhaps place a garbage can on top of the tree for extra protection. It is the more popular and easier method, but can still be time-consuming.