String s = "";
		Stack<BSTNode<T>> pila = new ALStack<BSTNode<T>>();
		pila.push(null);
		BSTNode<T> act = nodo;
		while (act != null) {
			while (act != null) {
				pila.push(act);
				act = act.left;
			}
			act=pila.pop();
			boolean tieneder= false;
			while(act != null && tieneder == false){
				s+=act.nodeValue + "  ";
				if(act.right!=null){
					act=act.right;
					tieneder=true;
				}else{
					act=pila.pop();
				}
			}
		}
		return s;