Because Canterbury had little native forest, the government planted exotic forests in North Canterbury from the early 1900s. These proved vulnerable to fire and other hazards. On 1 August 1975 extremely strong north-westerly winds created havoc in the four major state forests of Eyrewell, Ashley, Balmoral and Hanmer. Most trees in the Eyrewell forest, on the north bank of the Waimakariri River, were blown over at the roots.