Pyrenean oak acorns: a non-wood forest product in northern Portugal

Acorn availability in Pyrenean oak forests of Montesinho Natural Park, Portugal, varies significantly between 2022 and 2023, with higher mature acorn yields and greater individual weight in 2023 despite lower overall availability. Data from 59 plots show 109.4 kg/ha of dry acorn weight (including shells) in 2022 versus 84.9 kg/ha in 2023. Fully mature acorns (category h) accounted for 17.78% of total in 2022 and only 2.46% in 2023, though individual h acorns were heavier in 2023 (4.35 g vs. 1.17 g). Domes contributed 26.3 kg/ha in 2022 and 13.2 kg/ha in 2023. These findings support the development of sustainable acorn-based value chains, particularly for gluten-free food products, in underutilised forest areas facing land abandonment and depopulation.