Fire crews were working to free the woman earlier today after she became trapped in her car by the tree in West Melton in Canterbury's Selwyn District.
Three fire engines were sent to Weedons Rd to free one person, the southern fire communications shift manager said.
The call came in just before 7.40am and the person was still trapped 30 minutes later.
St John spokesman Gerard Campbell said the woman was on the way to hospital about 9am.