Forest area Prašnik is 250-300 years old stands of oak. The rest of the Slavonian rainforest. Already in 1929. was excluded from regular forest management because of its value, and the special status of forest reserves gets 1965th The decision of the Institute for Nature Protection, Zagreb. The typical woods Slavonian plains are located at 96 m above sea level and has an area of 58 hectares. To sustain this ecosystem is very important annual flood period caused by the spilling of the river basin. In recent years, oak forests are threatened by lowering the groundwater level and land reclamation. According to data from 1979.1 Prašnik has 1487 trees and 48 oak trees, hornbeam and beech. Age of oak trees is 150-300 years. Their height reaches up to 40 m and dbh of 200 cm. The largest among these giants are felled more than 50 m3. The area was mined.