There are trees with no leaves in the background.
It is winter.
Having no leaves doesn't make it winter, a dead tree has none either.
exists p1 x1 x4.(n_background(x4) & exists x2.(-exists x3.((x1 = x2) & with(x2,x3) & in(x3,x4) & n_leaf(x3)) & n_tree(x2)))
exists p1 x1.(n_thing(x1) & exists x2.((x1 = x2) & n_winter(x2)))