diff --git a/src/rct2.h b/src/rct2.h
index 59dd74dcf3..4d0b3a97ce 100644
--- a/src/rct2.h
+++ b/src/rct2.h
@@ -122,6 +122,7 @@ enum {
 
 enum {
 	GAME_FLAGS_PARK_OPEN = (1 << 0),
+    GAME_FLAGS_BELOW_TREE_HEIGHT_ONLY = (1 << 5),
 	GAME_FLAGS_NO_MONEY = (1 << 11),
 	GAME_FLAGS_PARK_FREE_ENTRY = (1 << 13)
 };