Over 700 firefighters battled a wildfire on Sunday in a national park west of Lisbon that forced Portuguese authorities to evacuate about 350 people.The fire that broke out overnight has already injured 17 firefighters and one civilian, Andre Fernandes of Portugal's civil protection agency said on Sunday, adding that 300 people were evacuated from a campsite while another 47 were removed from their homes in the wooded area as a precaution.Firefighters on the ground are being supported by 225 vehicles and six aerial fire-fighting units as they try to put out the blaze. Public broadcaster RTP showed planes dumping water on plumes of smoke rising from densely wooded hills 40km west of the capital.Fernandes said firefighters were combating the fire on two fronts, and their efforts were being helped by a decrease in the winds that had fanned the flames during the night."The first hours of the fire were very, very difficult," Fernandes said.Wildfires routinely blacken large areas of forest every year in Portugal. Last year they killed 106 people in what was by far the country's deadliest summer fire season on record.That was a wake-up call for authorities, who were slow to react to social trends and a changing climate. This year the Portuguese government enacted a raft of preventive measures to reduce fire deaths, like employing goats to munch flammable undergrowth along key roads.