Regeneration and establishment of natural young generation in intact oriental beech stands of Hyrcanian forests

Process of natural regeneration in uneven-aged stands is one of basic issues for sustainability in close to nature silviculture approach. The present research started form 2009 in four intact oriental beech stands of the Hyrcanian forests. Twelve, one ha sample plots have been established in three development stages containing five micro sample plots of 4 m2. Three gap sizes (small, medium and large) with five micro sample plots of 4 m2 have been selected within the development stages and characteristics of saplings have been studied. Relative light intensity (RLI) and leaf area index (LAI) have been studied as well. Results showed that the stands in the initial and optimal stages were pure, while decay stage was mixed. The least RLI was observed in the optimal stage and small sized gap while the highest amount of RLI was in the decay stage and large gap. The lowest amount of LAI was calculated in the optimal stage and small gap size. The maximum mean height increment was measured in the initial stage and small gap, maximum length of uppermost internode and annual shoot in optimal stage and large gap and the widest crown width was calculated in the initial stage and small gap. The proportion of saplings with favored quality was highest in the optimal stage and medium gap size while the highest proportion of twig and broom shaped saplings was observed in the large gaps. Overall, small and large gaps can negatively affect the saplings, whereas medium sized gap creates better condition for saplings.