Estimation of acorn production by gall oak (Quercus infectoria Oliv.) in Baneh forests

Acorns provide important food sources for wildlife. In addition, they are traditionally used by forest dwellers and promote natural regeneration within forest ecosystems. However, a sufficient acorn mass is essential for a successful regeneration establishment. Here, we estimated acorn production of gall oak (Quercus infectoria Oliv.)trees in Kanybard in Baneh forests of Kurdistan province. Stand structure and general information were obtained from 20 square plots (20×20 m), which were scattered randomly in the study area. In a homogenous area of 80 ha, 80 sample trees were selected. To evaluate the effect of tree diameter and geographical aspect on acorn production, we selected two diameter classes (25 cm) nested in four main cardinal aspects (totally 8 levels). All acorns on each tree were collected at the end of 2013 growing season and were weighted in the field. In each level, 50 acorns were selected randomly, and their weight, length and width were measured. The results showed that geographical aspect does not affect acorn production. However, oak trees on northern and eastern aspects produce bigger and heavier acorns. In addition, tree diameter was found to positively affect acorn production, i.e. thicker trees produce more acorn. In average, each gall oak tree produces 1.907 kg acorn mass which varies between 0 to 19.87 kg in weight and 0 to 3088 acorns per tree. Our result indicated a weak acorn mast year for studied forest stands, which can help forest managers to evaluate and plan for acorn production in northern Zagros forests.