Traversal: Iteration vs. Recursion

using System;
using System.Collections.Generic;
using System.Diagnostics;

static class Test
{
    private static void Main()
    {
        var root = new QuadNode();
        root.Split(10); // 1398074 nodes
        root.LinkNodes();

        var stopwatch = new Stopwatch();
        const int iterations = 100;

        stopwatch.Restart();
        for (int i = 0; i < iterations; i++)
        {
            root.TraverseRecursivly(a => { });
        }
        stopwatch.Stop();
        Console.WriteLine("TraverseRecursivly elapsed time: {0}ms", stopwatch.ElapsedMilliseconds);

        stopwatch.Restart();
        for (int i = 0; i < iterations; i++)
        {
            root.TraverseIteratively(a => { });
        }
        stopwatch.Stop();
        Console.WriteLine("TraverseIteratively elapsed time: {0}ms", stopwatch.ElapsedMilliseconds);

        Console.ReadKey();
    }
}

class QuadNode
{
    private QuadNode topLeft;
    private QuadNode topRight;
    private QuadNode bottomRight;
    private QuadNode bottomLeft;
    private QuadNode next;

    public void LinkNodes()
    {
        var queue = new Queue<QuadNode>();
        queue.Enqueue(this);
        QuadNode last = null;
        while (queue.Count > 0)
        {
            var node = queue.Dequeue();
            if (last != null)
                last.next = node;

            if (node.topLeft != null)
                queue.Enqueue(node.topLeft);
            if (node.topRight != null)
                queue.Enqueue(node.topRight);
            if (node.bottomRight != null)
                queue.Enqueue(node.bottomRight);
            if (node.bottomLeft != null)
                queue.Enqueue(node.bottomLeft);

            last = node;
        }
    }

    public void Split(int depth)
    {
        if (depth <= 0)
            return;

        topLeft = new QuadNode();
        topRight = new QuadNode();
        bottomRight = new QuadNode();
        bottomLeft = new QuadNode();

        depth--;
        topLeft.Split(depth);
        topRight.Split(depth);
        bottomRight.Split(depth);
        bottomLeft.Split(depth);
    }

    public void TraverseRecursivly(Action<QuadNode> action)
    {
        action(this);

        if (topLeft != null)
            topLeft.TraverseRecursivly(action);
        if (topRight != null)
            topRight.TraverseRecursivly(action);
        if (bottomRight != null)
            bottomRight.TraverseRecursivly(action);
        if (bottomLeft != null)
            bottomLeft.TraverseRecursivly(action);
    }

    public void TraverseIteratively(Action<QuadNode> action)
    {
        QuadNode node = this;
        while (node != null)
        {
            action(node);
            node = node.next;
        }
    }
}