diff --git a/src/saveload/oldloader_sl.cpp b/src/saveload/oldloader_sl.cpp
--- a/src/saveload/oldloader_sl.cpp
+++ b/src/saveload/oldloader_sl.cpp
@@ -1552,6 +1552,8 @@ static bool LoadTTDPatchExtraChunks(Load
 }
 
 extern TileIndex _cur_tileloop_tile;
+extern uint16 _disaster_delay;
+extern byte _trees_tick_ctr;
 static const OldChunks main_chunk[] = {
 	OCL_ASSERT( OC_TTD, 0 ),
 	OCL_ASSERT( OC_TTO, 0 ),