Quantitative charachteristics of regeneration in natural and tree fall canopy gaps in the mixed beech stands, Northern Iran (Case Study: Namkhaneh district, Kheyrud Forest)

Canopy gaps have an important role in constitution of the forest stand composition and natural regeneration establishment in the forest ecosystems. In the single selection method، forest manager try to improve the forest regeneration by the creation of gaps in the crown canopy layer. This study was carried out in the Kheyrud forest to investigate the characteristics of established seedlings within natural and artificial gaps. The study was done in sixty canopy gaps. Gap properties including gap size and shape were precisely measured. The main objective of research was to discover the relationship between abundances and height of seedling with gap properties. Results showed that in the natural canopy gaps، total abundance of seedlings correlated with gap size، moreover beech seedlings density correlated negatively with size of gaps. Meanwhile there is no relationship among density and height of maple، hornbeam and minor species seedlings. Canopy gap shape in natural and artificial gaps correlates significantly with total density of seedlings. Also oriental beech constitutes more than 90 percent of definitive gap fillers. The comparison of total number of seedlings and sapling in different size classes in the natural and artificial canopy gaps revealed significant relationship between size of gap and seedling density. According to our findings، we strongly recommend that forest manager to consider the size and shape of canopy gaps in single tree selection method.