From the not always reliable The Golden Bough:
In Münsterland these Easter fires are always kindled upon certain definite hills, which are hence known as Easter or Paschal Mountains. The whole community assembles about the fire. The young men and maidens, singing Easter hymns, march round and round the fire, till the blaze dies down. Then the girls jump over the fire in a line, one after the other, each supported by two young men who hold her hands and run beside her. In the twilight boys with blazing bundles of straw run over the fields to make them fruitful. At Delmenhorst, in Oldenburg, it used to be the custom to cut down two trees, plant them in the ground side by side, and pile twelve tar-barrels against each. Brush-wood was then heaped about the trees, and on the evening of Easter Saturday the boys, after rushing about with blazing bean-poles in their hands, set fire to the whole. At the end of the ceremony the urchins tried to blacken each other and the clothes of grown-up people. In the Altmark it is believed that as far as the blaze of the Easter bonfire is visible, the corn will grow well throughout the year, and no conflagration will break out. At Braunröde, in the Harz Mountains, it was the custom to burn squirrels in the Easter bonfire. In the Altmark, bones were burned in it.