diff --git a/src/ol/structs/rbush.js b/src/ol/structs/rbush.js
index baa0e3a1f1..4de21cbc1f 100644
--- a/src/ol/structs/rbush.js
+++ b/src/ol/structs/rbush.js
@@ -74,7 +74,7 @@ ol.structs.RBush.prototype.load = function(extents, values) {
   }
   goog.asserts.assert(extents.length === values.length);
 
-  var items = [];
+  var items = new Array(values.length);
   for (var i = 0, l = values.length; i < l; i++) {
     var extent = extents[i];
     var value = values[i];
@@ -86,7 +86,7 @@ ol.structs.RBush.prototype.load = function(extents, values) {
       extent[3],
       value
     ];
-    items.push(item);
+    items[i] = item;
     goog.object.add(this.items_, goog.getUid(value).toString(), item);
   }
   this.rbush_.load(items);