The effect of thinning on the growth in coppice chestnut forests: Five-year results

Anatolian chestnut (Castanea sativa Mill) is an important species that contributes to forest ecology, has a wide area of use, stands out with its visuality, is operated as high forest and coppice in Türkiye, and establishes pure or mixed stands. Due to its variety of use and contribution to forest ecology, silvicultural studies are needed to make these areas productive. Thinning is a forest maintenance performed to reduce stand density and, accordingly, competition between trees. The aim of this study is to evaluate the five-year results of the effects of thinning made at different intensities [18% (medium), 34% (heavy), 49% (very heavy) of basal area were removed and control] on mortality, diameter at breast height, stand volume, basal area and aboveground biomass (AB) in chestnut coppices. According to the research results, the highest five-year diameter increases on a stand basis was found in the very heavy thinned area. The diameter increment of moderately and heavy thinned areas was similar and lower than that of very heavy thinned area. As the initial diameter class thickened and the thinning intensity increased, the diameter increases accelerated. The basal area increment was highest in very heavily thinned areas, while the volume and AB increments were similar in all areas. The relative basal area, volume, and AB increment increased with an increase in thinning intensity. The five-year total stem separation was determined as 17.4%, 14.5%, 5.4%, and 0.5% in the control, moderate, severe, and very severe thinned areas, respectively. According to the five-year results, since the positive effect of thinning continued in very heavily thinned areas, but the positive effect of thinning decreased in moderate and severe thinned areas, it is recommended to proceed to second thinning in these areas.