Summary The response of nursery seedlings and wildings of oriental beech ( Fagus orientalis Lipsky) to canopy gap size was studied in a climax beech forest in northern Iran with respect to seedling survival, shoot growth and vitality. These parameters were followed for 2 years after planting in gaps of 50, 200 and 600 m 2 , as well as in the open fi eld. Foliage coloration was used as a criterion for vitality. The survival rate of nursery seedlings and wildings dropped rapidly with increasing gap size from 84 per cent in 50-m 2 canopy openings to �∼� 55 per cent in the 600-m 2 gaps and the open fi eld 2 years after planting. Shoot growth of wildings and nursery seedlings differed in response to gap size variation. Shoot growth of wildings was higher in small gaps than in larger openings, whereas for nursery seedlings the inverse was observed. Most beech seedlings were not discoloured or slightly discoloured under gaps of 50, 200 and 600 m 2 and were slightly to moderately discoloured in the open. There was a general tendency for higher discoloration in larger openings. It is concluded that small non-regenerated canopy gaps (�≤� 200 m 2 ) of beech forests in northern Iran can be restored by planting beech wildings as well as nursery seedlings in small openings, whereas nursery seedlings are preferred in larger gaps (�≥� 600 m 2 ).