Near Cölbe, not far from Marburg, 25 hectares of forest burned overnight and lasted until morning.
The area corresponds to about 35 soccer fields.
In the morning, about 150 firefighters and other helpers are still on duty.
At the top, more than 400 emergency services were on site to fight the flames, as a spokesman for the Marburg-Biedenkopf district said on request.
Eight firefighters were injured and taken to hospitals.
The helpers had come from the entire central Hessian district, and firefighters from the neighboring Gießen district had rushed to help, including 10,000 liters of water.
Nevertheless, in the morning there were still some embers in the ground, as it was further said.
Fire broke out in a field
In order to fight the fire from above, a helicopter took part in the extinguishing work from early in the morning.
To do this, the pilot lowered a sack hanging from the helicopter onto the surface of a nearby quarry pond.
The bag then filled itself after contact with the water. "It works like a cup that is pushed under water," explained the spokesman.
The pilot flew over the burning forest a total of 15 times, releasing around 2,000 liters each time.
The forest is mainly occupied by spruces and pines, with only a few deciduous trees.
According to previous knowledge, the fire broke out in a field.
According to the spokesman, it is unclear whether there were sparks flying during harvesting work, as is speculated.
The same applies to the amount of damage.