Complex sentence: It currently has a population of around 50 but was much larger during the mid- 19th century due to the gold rush and another population boom during the Depression when many returned to distil eucalyptus oil and search again for gold.
Split into simpler sentences: It currently has a population of around 50 but was much larger during the mid- 19th century due to the gold rush. Another population boom followed during the Depression when many returned to distil eucalyptus oil and search again for gold.