I suspect that if you remove the file that the logging will not happen (I have't tried this so am not certain).
You could also set the threshold to ERROR (or WARN), that way only error messages would show in the log.
You could also use a rolling file appender with a limit on the size, and a limit on the number of logs to keep. That is usually the best way to limit log sizes. Any turorial on Log4J should show you how.