There are several trees around the horses.
There are several redwoods around the horses
Because there are several tress around that doesn't automatically mean they're redwoods.
exists p1 x1 x3.(n_horse(x3) & exists s1 x2.((x1 = x2) & around(x2,x3) & n_tree(x2) & a_several(s1) & Theme(s1,x2)))
exists p1 x1 x3.(n_horse(x3) & exists s1 x2.((x1 = x2) & around(x2,x3) & n_redwood(x2) & a_several(s1) & Theme(s1,x2)))