Way to slow and full up. the plane was really to far away. I was at a field that I was not familiar with and the runway was very narrow. So on my downwind leg I flew over the trees. I cut the power just as I started to turn base. I think with the wind behind the plane it just didn't have enough airspeed. However, the ground speed looked OK. But, they don't fly by ground speed, do they? It was really one of those dumb moments.