It's unclear what caused the woman to hit the tree.
Raleigh police have ruled out foul play.
Raleigh police said they got dispatched to check in with Wake County EMS at 7:40 pm Saturday night.
Bicyclists who use the trail said it's hilly and curvy.
If you are a regular cyclist or hiker, Wake County EMS Assistant Chief Jeffrey Hammerstein has these suggestions:
"It's important for people to always be aware of what their access point was and which way they traveled from that access point," Hammerstein said. "And then if they call, having even a vague idea of how far they may have traveled from that access point can help us figure out the best access point for us to take and kind of zero in on where somebody is."