Debrecen "Big Forest" Nature Conservation Area, Nature conservation area in Debrecen, Hungary

The Debrecen "Big Forest" Nature Conservation Area is a 1,092-hectare protected woodland in the northern part of Debrecen, near the university district. It preserves a sand-steppe oak forest whose main native tree is the pedunculate oak, with white poplar, small-leaved lime, field maple and wild pear as mixed species. About 700–800 plant species are recorded here, and trees older than 100 years are individually protected.

The forest was declared a park in the 18th century and entered the national register of protected natural areas in 1939 under number 1, the first such entry in Hungary. The protection aims to keep the old oak woodland and its surrounding forest communities for future generations. The area is now part of the Natura 2000 network.

The forest's name comes from its old oaks, many 100 to 120 years old. In 1939 it was entered as number 1 in Hungary's register of protected natural areas, the first old oak woodland so listed. Today the Medgyessy Promenade, lined with statues of writers and poets, is a favourite walking route.

The forest has several entry points around its perimeter, and parking is available near the main access spots. Sturdy footwear is a good idea since the trails can be muddy after rain, especially in spring and autumn.

The forest was entered as number 1 in Hungary's register of protected natural areas in 1939, making it the country's first protected old oak woodland. Its sessile oaks, some over 100 years old, are the reason the area was listed, and the aim was to keep this stand and the surrounding woodland communities for future generations.