  We show that List Colouring can be solved on $n$-vertex trees by a
deterministic Turing machine using $O(\log n)$ bits on the worktape. Given an
$n$-vertex graph $G=(V,E)$ and a list $L(v)\subseteq\{1,\dots,n\}$ of available
colours for each $v\in V$, a list colouring for $G$ is a proper colouring $c$
such that $c(v)\in L(v)$ for all $v$.
