The aim of this study was to determine the most important abiotic and biotic factors that contribute to the decline of sessile (Quercus robur), pedunculate (Q. petraea) and holm oak (Q. ilex) in Europe and in Slovenia and to determine their role in Manion's decline disease spiral by reviewing the scientific literature. To further determine the situation of sessile and pedunculate oak in Slovenia we analysed the data from Slovenian Forest Service regarding the felling of both oaks in the period from 1995 to 2022. After the literature review we concluded that the decline phenomena of sessile, pedunculate and holm oak is caused by a complex of biotic and abiotic factors. As the main predisposing and at the same time inciting factor in sessile and pedunculate oak decline the literature mentions drought that is being enchanced with the changing climate. From biotic factors different species of fungi, phytopthora and introduced invasive species are mentioned (as bark beetles). The sanitation felling of sessile oak in analysed period accounted for approximately 35 % (204.000 m3) of all felling of sessile oak and the sanitation felling of pedunculate oak accounted for approximately 27 % (1.109.000 m3) of all felling of pedunculate oak. In the decline of holm oak the biotic factors play the crucial role, especially some phytophthora and fungi species. Abiotic factors (especially drought) are mentioned more as a predisposing than inciting factors in holm oak decline. Holm oak status in Slovenia is more than by any other factor endangered simply because of its rarity.
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