 Kauri gum was Auckland 's main export in the second half of the 19th century , sustaining much of the early growth of the city . Between 1850 and 1950 , 450 @,@ 000 tons of gum were exported . The peak in the gum market was 1899 , with 11 @,@ 116 tons exported that year , with a value of £ 600 @,@ 000 ( $ 989 @,@ 700 ) . The average annual export was over 5 @,@ 000 tons , with the average price gained £ 63 ( $ 103 @.@ 91 ) per ton . 
