The biker carries his bike over the obstacle.
The biker is carrying his bike over a fallen tree.
You can not infer the obstacle is a fallen tree.
exists e1 x1 x2 x3.(n_obstacle(x3) & n_bike(x2) & of(x2,x1) & n_male(x1) & n_biker(x1) & Theme(e1,x2) & Actor(e1,x1) & v_carry(e1) & over(x2,x3))
exists e1 s1 x1 x2 x3.(n_bike(x2) & of(x2,x1) & n_male(x1) & n_biker(x1) & Theme(e1,x2) & Actor(e1,x1) & v_carry(e1) & over(x2,x3) & n_tree(x3) & a_fallen(s1) & Theme(s1,x3))