One reason for Tauranga becoming a main city was the strong growth of its port after the Kaimai rail tunnel opened in 1978. This connected the city to the export forests of the central North Island. By 2008 its port was second only to Auckland in the value of its trade. Wellington, once the country’s largest port, had been reduced to a minor player. In the South Island, Christchurch had the busiest seaport and airport, although Dunedin’s Port Chalmers dominated the export trade.