The pilot and passenger departed from a hayfield in the powered-parachute. The pilot reported that just after takeoff, when the powered parachute was 20 to 25 feet in the air, the powered-parachute lost lift and descended. The pilot added that he was unable to climb or turn the powered-parachute. A witness reported that when the powered-parachute was about the same height as the trees, it looked like the powered-parachute got caught in a downdraft and the canopy partly collapsed. The witness added the canopy re-inflated just before the powered-parachute impacted trees. During the forced landing and collision with trees, the powered-parachute received substantial damage to its airframe. The pilot added that there were no preaccident mechanical malfunctions or failures that would have precluded normal operations.