  For rooted trees, an ideal drawing is one that is planar, straight-line,
strictly-upward, and order-preserving. This paper considers ideal drawings of
rooted trees with the objective of keeping the width of such drawings small. It
is not known whether finding the minimum-possible width is NP-hard or
polynomial. This paper gives a 2-approximation for this problem, and a
$2\Delta$-approximation (for $\Delta$-ary trees) where additionally the height
is $O(n)$. For trees with $\Delta\leq 3$, the former algorithm finds ideal
drawings with minimum-possible width.
