A wind-pummeled tree fell and crashed onto a Q train Thursday morning as it was stopped at the Cortelyou station in Brooklyn, causing major commute backups, officials said.

The tree, which was in a private yard, fell just as a southbound Q train was stopped at the station at 8:45 am. It destroyed the fence surrounding the station, damaged the train, and sprawled across all four tracks, said MTA spokeswoman Amanda Kwan. No one was injured, she said.

Crews were still working to clean up the tree, and the train was still stuck at the station as of about 11:15 a.m., said Kwan.

Meanwhile, there was no B train service south of Second Avenue and Q trains were being rerouted on the N line.

High winds caused other problems around the subway system. D trains had to travel over the N line in Brooklyn as the MTA cleaned up low-hanging branches at Ninth Avenue, and hanging wires at Kingsbridge Road in the Bronx were causing delays on the 4 train.