Around 3,000 volunteers on Sunday began an ambitious reforestation project in Portugal's oldest forest, ravaged by last year's devastating wild fires.

Some 67,500 pine trees were planted in the Leiria forest, in central Portugal, which was almost entirely burned to ashes during a series of fires in October.

"We lost 80 percent of the Leiria pine forest in the fires, a great task is waiting for us: the reforestation will require the planting of about 22 million trees," said Cidalia Ferreira, the mayor of Marinha Grande where part of the 800-year-old wood is located.

Volunteers were supported by military, police and fire personnel in the government-led initiative.

"We will rebuild this pine forest, so that it becomes pretty and so that our children will have clear air to breathe in the future. That is what motivates me," volunteer Jose Dyonisio told AFP.

The forest dates back to the 13th century and its pine was used by Portuguese explorers to build sailing ships between the 15th and 17th centuries.

The wave of fires which ripped through swathes of land in central Portugal killed 49 people in October last year.

The latest victim of the blazes died of her wounds on Saturday in hospital.

Those fires came after 64 people died in June in the central Pedrogao Grande region, in what were the deadliest wildfires in the country's history.