Deh- Kohneh forest is an enclosed area by 466 hectares, in the north of Fars province. This area has been protected as a wild pear species genetic storage since 1973 by the Fars Province Department of Natural Resources and Watershed Management. In order to study effects of protection in forest zone, a fifty hectare area from enclosed forest and a 50 hectare area from unclosed forest, which are same in topography and forest type, were compared. The results showed that the numbers of tree and shrub species in enclosed area were significantly more than unclosed area. Compare the abundance of trees and shrubs represents a decline of P.glabra and P.syriaca  and upgrades F.rotundifolia and D.mucronata identified in the unprotected area. The canopy cover in both areas was almost the same. The average of height for trees and shrubs in the protected area were smaller than unprotected area, because of regenerations. The current results showed that protection of Deh-kohneh forest for nearly half a century has been improved the quality and quantity of the forest structure. Therefore, it is suggested that with protection of such area, conservation of genetic resources in forests and creation a research area for other researchers can be provided in future.