The objective of this study was to determine the factors causing the deterioration of the stand structures of chestnut forests in Kütahya-Simav  and to reveal the relation between these factors and chestnut diseases. Chestnut forests in Kütahya Simav were chosen as research area in this study. The damages given to forests in the result of the combating against chestnut blight, Cryphonectria parasitica, and harvest of chestnut fruit were investigated in terms of silvicultural treatments. Three different sample plots were chosen from the research area. In each sample plot, the diameters, diseases and grafting status (exist or not) of the trees were determined. Stand structures of these forests were also investigated. As a result of the study, the disease state of the chestnut individuals in the sample areas was determined. It was found that on average 11% were completely dry, 6% were partially dry, and 46% were cancerous but capable of survival. Also, effectiveness in the combating against chestnut blight of silvicultural treatments was investigated. In the result of unconscious interventions made by the local people (grafting, harvesting, etc.) have observed that stand structure of chestnut forests are corrupted and disease increase.