Influence of precommerial thinning on the growth of the chestnut coppice forests in Gölcük

Anatolian chestnut (Castanea sativa Mill.), one of most important deciduous forest trees, is established in large areas of Turkey as pure or mixed forests. Chestnut forests are important due to the diverse uses of the tree (wood, fruit, honey, etc.) and the quality of its visual appearance. Owing to various diseases and inappropriate silvicultural interventions, in many places the chestnut forests have been degraded and their transformation into coppice forests has become a silvicultural necessity. As with high forests, in order to compile an inventory of coppice forests, there is a need to develop models for the single-entry height, volume and aboveground biomass depending on the diameter at breast height (DBH) on a regional basis. The aim of this study was (1) to determine the short-term effect of thinning intensity on diameter, basal area, volume and biomass increment and (2) to obtain stem volume and biomass equation depending on diameter at breast height in chestnut coppice in Gölcük region. High accuracy volume (R2 = 0.99) and biomass equation (R2 = 0.97) were obtained. According to the obtained equations; while the increase in volume and biomass up to 17 cm in diameter is higher in chestnut coppices, the growth rate with increasing diameter turns in favor of grove even-aged chestnut high-forests. According to the results of one-year thinning; as the thinning intensity increases, the diameter increment increases, and as a result, the basal area, volume and biomass in the stand level increase as much as the control. The diameter increment in the very heavy thinned stand was twice the control. Depending on the intensity of the thinning, the diameter increase also increased as the initial diameter classes increased. Long-term results are needed to fully determine the influence of the thinning on growth. Keywords: biomass, coppice, low thinning, stand volume.