diff --git a/Quadtree/Quadtree.cs b/Quadtree/Quadtree.cs
index 89e1826..6228ab2 100644
--- a/Quadtree/Quadtree.cs
+++ b/Quadtree/Quadtree.cs
@@ -12,60 +12,48 @@ namespace SpatialCollections
     /// <typeparam name="T">Type of the managed entities.</typeparam>
     // TODO: Support for moving entites without having to remove and re-add them.
     // TODO: Add method to prune empty leaves. An empty leaf is not removed automatically when its last entity is removed.
-    public class Quadtree<T>
+    public class Quadtree<T>(int maxLeafSize, int maxTreeDepth, Func<T, Vector2> getPositionCallback)
     {
         // TODO: It should be possible to calculate whether average query time will be better with or without split, without resorting to max leaf size and max tree depth.
         /// <summary>
         /// Maximum number of items in a leaf vertex before it is split, unless the depth of the leaf is greater or
         /// equal to the maximum tree depth.
         /// </summary>
-        private readonly int _maxLeafSize;
+        private readonly int _maxLeafSize = maxLeafSize;
 
         /// <summary>
         /// Maximum depth of the quadtree, that is the maximum allowed length of the path from the root to a new leaf
         /// when determining whether a leaf vertex may be split.
         /// </summary>
-        private readonly int _maxTreeDepth;
+        private readonly int _maxTreeDepth = maxTreeDepth;
 
         /// <summary>
         /// Callback to determine the position of an entity.
         /// </summary>
-        private readonly Func<T, Vector2> _getPositionCallback;
+        private readonly Func<T, Vector2> _getPositionCallback = getPositionCallback;
 
         /// <summary>
         /// The list of quadtree vertices. The root vertex is always the first item. The four child vertices of a branch
         /// are always created together and stored contiguously.
         /// </summary>
-        private readonly List<QuadtreeVertex> _vertices;
+        private readonly List<QuadtreeVertex> _vertices = [new(-1, 0)];
 
         /// <summary>
         /// The list of all items stored in the quadtree.
         /// </summary>
-        private readonly List<QuadtreeItem<T>> _items;
+        private readonly List<QuadtreeItem<T>> _items = [];
 
-        private Rectangle _rootBoundingBox;
+        private Rectangle _rootBoundingBox = new(Vector2.Zero, Vector2.Zero);
 
         /// <summary>
         /// Stack of vertex indices with their bounding boxes. It is reused for each query.
         /// </summary>
-        private readonly Stack<QuadtreeQuery> _queryStack;
+        private readonly Stack<QuadtreeQuery> _queryStack = new();
 
         /// <summary>
         /// Stack of vertex indices. It is reused for each query.
         /// </summary>
-        private readonly Stack<int> _vertexStack;
-
-        public Quadtree(int maxLeafSize, int maxTreeDepth, Func<T, Vector2> getPositionCallback)
-        {
-            _maxLeafSize = maxLeafSize;
-            _maxTreeDepth = maxTreeDepth;
-            _getPositionCallback = getPositionCallback;
-            _vertices = [new(-1, 0)];
-            _items = [];
-            _rootBoundingBox = new Rectangle(Vector2.Zero, Vector2.Zero);
-            _queryStack = new Stack<QuadtreeQuery>();
-            _vertexStack = new Stack<int>();
-        }
+        private readonly Stack<int> _vertexStack = new();
 
         public int Count => _items.Count;