Hasbruch, Nature reserve in Ganderkesee and Hude, Germany.

Hasbruch is a 627-hectare oak-hornbeam forest in the municipalities of Hude and Ganderkesee, Lower Saxony. Two-thirds of its trees are oaks and a fifth beeches; some hornbeams were pollarded at about two metres for leaf hay. The Brookbäke flows south to north through the forest, and a small wooden viewing tower stands by its renaturalised meanders.

Hasbruch was first mentioned in a 1258 contract in which Hude Monastery, as owner, agreed on rural use rights with surrounding farming communities. Until the 18th century, plaggen cutting and illegal clearances shrank the forest, and farmers sold their grazing rights piecemeal, the last in 1882. In 1889, 16.8 hectares were protected and excluded from forestry; this area grew to 29 hectares in 1938, and since 1997 the entire 627 hectares have been protected, with about 40 hectares left as unmanaged natural forest.

Many of the old oaks carry names given by Duke Peter Friedrich Ludwig of Oldenburg in the early 19th century, while others were named by local people; the Friederike Oak honours Friederike Elisabeth Amalie, the Amalie Oak her sister. Court painters of the Grand Duchy recorded these trees on canvas in the first half of the 19th century, and the travel writer Johann Georg Kohl described a visit in 1864, when around 100 oaks with trunks about three metres across still stood.

The forest is accessible year-round for walking visits, with trails suited for different fitness levels. Wear sturdy footwear and allow time to explore at a slow pace, especially if you plan to watch birds or spot wildlife.

The Amalien Oak, about 1,250 years old, was considered the oldest and most imposing oak in Hasbruch until it fell on 10 February 1982; its remains can still be visited. The oldest living oak here is the Friederike Oak, roughly 1,200 years old, with a trunk circumference of 7.81 m measured in 2016.