 Gum @-@ digging was the major source of income for settlers in Northland , and farmers often worked the gumfields in the winter months to subsidise the poor income from their unbroken land . By the 1890s , 20 @,@ 000 people were engaged in gum @-@ digging , of which 7000 worked full @-@ time . Gum @-@ digging was not restricted to settlers or workers in the rural areas ; Auckland families would cross the Waitemata Harbour by ferry at weekends to dig in the fields around Birkenhead , causing damage to public roads and private farms , and leading to local council management of the problem . 
