It doesn't matter if he stops. Force is squared. If he slows down by half he reduces the force to a 1/4. High speed + stopping on a dime = painful.
Those are Aspen and Spruce. Aspen won't have 'impalers' that low. Spruce is cushy. I've jumped out onto spruce bows 50+ feet up(cuz it's easier than climbimg down) it doesn't hurt. The saplings at the roadside are supple and flexible. They would have slowed him down considerably without breaking off. Way better than hitting the broadside of an SUV at high speed.