  For a vertex $u$ of a tree $T$, the leaf (internal, respectively) status of
$u$ is the sum of the distances from $u$ to all leaves (internal vertices,
respectively) of $T$. The minimum (maximum, respectively) leaf status of a tree
$T$ is the minimum (maximum, respectively) leaf statuses of all vertices of
$T$. The minimum (maximum, respectively) internal status of a tree $T$ is the
minimum (maximum, respectively) internal statuses of all vertices of $T$. We
give the smallest and largest values for the minimum leaf status, maximum leaf
status, minimum internal status, and maximum internal status of a tree and
characterize the extremal cases. We also discuss these parameters of a tree
with given diameter or maximum degree.
