Complex sentence: The boom of the logging industry from the 1950s to the middle of 1970s made Butuan the "Timber City of the South" and led to an influx of business and fortune seekers from other provinces.
Split into simpler sentences: The boom of the logging industry during the 1950s up the middle of 1970s has made Butuan the "Timber City of the South". The outcome of which was the influx of business and fortune seekers from other provinces.