Despite the universal availability of cultivated fruit species, wild fruits continue to play a significant role in many regions of Europe. For centuries, forests have been the primary source of valuable food and medicinal resources, and they continue to compete successfully with agricultural production. Bilberry fruit is one of the most important non−wood forest products harvested in northern, central, and eastern Europe. It is expected that harvest will remain at a consistently high level, as bilberry fruit is one of the resources that can only be picked in the forests. This is due to the fact that the plant from which it originates is not suitable for cultivation. The nutritional benefits of the bilberry fruit are related to both exceptional flavour and high content of anthocyanins. They are known as antioxidant substances useful in the dietary prevention of cancer, cardiovascular disease, neurodegenerative disorders and ageing. In Poland, bilberry fruit is not only picked for personal use, but also harvested in large quantities for both informal roadside trade and processing in the food industry. This study aimed to determine the optimal harvest period and identify the forest site type suitable for bilberry industrial−scale harvesting. Bilberry fruits were harvested from June 9th to August 18th, 2025, within the Leżajsk Forest District from two forest site types: fresh coniferous forest and fresh mixed coniferous forest. Along 150−meter transects, 150 g of randomly selected, ripe fruit were picked at three−day intervals. The following measurements of physical parameters were performed: colour (CIE L*a*b* colour scales), refractive index (expressed as Brix), and percentage of dry matter content. The study showed that both refractive index and dry matter content differed significantly depending on the forest site types; in both cases, higher values were observed for the fresh coniferous forest. On the other hand, L*a*b* measurement has identified a period when bilberry fruit is characterised by stable colour. Based on all the results obtained, the study identified the most favourable forest site type and the optimal period for harvesting raw materials of the highest quality and economic profitability in a food industry.
Bilek et al. (Wed,) studied this question.