Gap characteristics under oriental beech forest development stages in Kelardasht forests, northern Iran

Abstract

This study was carried out to evaluate gap characteristics and gapmakers for different development stages of an oriental beech forest in northern Iran. Development stages of 1 ha square-shaped mosaic patches were identified using 100 × 100 m sampling grid and all gaps within these mosaics were recorded. Gap areas were calculated and classified into four classes and gapmakers were counted and classified into 4 decay and 4 diameter classes as well. Results showed that gaps comprised 13.7, 9.1 and 17.6% of the study area in initial, optimal and decay stages, respectively. There was a significant difference between development stages with respect to gap size and the highest amount was observed in decay stage. Medium-sized gaps were the most frequent in all three stages. Frequency distribution of gapmakers varied among development stages. Our findings revealed that 200–500 m<sup>2</sup> is the most preferable gap size for close-to-nature silvicultural approaches in Hyrcanian beech forests. To achieve this gap size 1–2 trees should be marked for harvesting operations.