diff --git a/OpenRa.FileFormats/Map.cs b/OpenRa.FileFormats/Map.cs
index 6c957274dc..4776132f25 100644
--- a/OpenRa.FileFormats/Map.cs
+++ b/OpenRa.FileFormats/Map.cs
@@ -120,6 +120,9 @@ namespace OpenRa.FileFormats
 		void ReadTrees( IniFile file )
 		{
 			IniSection terrain = file.GetSection( "TERRAIN" );
+			if( terrain == null )
+				return;
+
 			foreach( KeyValuePair<string, string> kv in terrain )
 				Trees.Add( new TreeReference( int.Parse( kv.Key ), kv.Value ) );
 		}