Java Tree Implementation

I wrote a simple tree data type in Java consisting of nodes which are themselves trees, and where each tree has its own list of children (not a binary tree). I plan on eventually using it in a minimax algorithm where I keep track of future game states in a board game by holding different board states in nodes and holding moves that lead to each state as edges in the tree. Here's my code so far — any suggestions (whether it be conceptual or performance related, or other features I should add) are appreciated:

public class Tree<V, E> {
   private V data;
   //here the edgeVal is the edge leading from the node's parent to the node itself,
   //not from the node to any of its children
   private E edgeVal;
   private Tree<V, E> parent;
   private ArrayList<Tree<V, E>> children;
   public Tree(V data, Tree<V, E> parent, E edgeVal) {
      this.data = data;
      this.edgeVal = edgeVal;
      this.parent = parent;
      this.children = new ArrayList<Tree<V, E>>();
   }
   public void addChild(V childData, E edgeVal) {
      Tree<V, E> child = new Tree<V, E>(childData, this, edgeVal);
      this.children.add(child);
   }
   public Tree<V, E> getParent() {
      return this.parent;
   }
   public ArrayList<Tree<V, E>> getChildren() {
      return this.children;
   }
   public V getData() {
      return this.data;
   }
   public E getEdgeVal() {
      return this.edgeVal;
   }
   public boolean isRoot() {
      return this.parent == null;
   }
   public boolean isLeaf() {
      return this.children.size() == 0;
   }
   public String toString() {
      //assuming type of data has a nicely defined toString() method
      return this.data.toString();
   }
}