South Korean firefighters were able to fully contain the wildfires that have ravaged the southeastern part of the country and left 30 dead, officials said, while authorities began a joint investigation into the cause.

A South Korean man tending a family grave is suspected of sparking one of the record wildfires that ravaged the southeastern part of the country last week, the National Police Agency said on Monday.

Soil erosion remains severe for up to two years after a wildfire, stabilising within three to five years. However, full ecosystem recovery varies. Fish take three years to rebound, marine invertebrates nine and eusocial insects such as ants and bees 14.