diff --git a/src/pocketmine/block/Leaves.php b/src/pocketmine/block/Leaves.php
index 25cf33c45..aa0bd4e91 100644
--- a/src/pocketmine/block/Leaves.php
+++ b/src/pocketmine/block/Leaves.php
@@ -69,7 +69,7 @@ class Leaves extends Transparent{
 	}
 
 
-	protected function findLog(Block $pos, array $visited, int $distance, ?int $fromSide = null) : bool{
+	protected function findLog(Block $pos, array &$visited, int $distance, ?int $fromSide = null) : bool{
 		$index = $pos->x . "." . $pos->y . "." . $pos->z;
 		if(isset($visited[$index])){
 			return false;