Towards optimizing acorn use as animal feed in Tunisia: evaluation and impact on natural regeneration

In Mediterranean forests, besides the conflict between forest managers and local populations who are often poor and dependent on livestock for survival, the cost of raw materials used in animal feed is increasingly a burden for farmers. There is growing recognition that wise use of acorns can reduce feed costs and enhance sustainable participatory governance of these woodlands. This paper aimed to carry out a quantitative, qualitative and economic evaluation of acorn potential in a cork oak forest in north-western Tunisia and to investigate the impact of their post-dispersal on natural regeneration. Quantities were estimated in November and February, respectively for acorns collected directly from trees and from the ground. Time-dependent monitoring of acorn quality and numbers of new seedlings was also conducted from autumn 2014 to spring 2015. The results show a significant decrease in acorn quantity from 5.28 ± 4.61 t/ha in November to 0.684 ± 0.1 t/ha in February. However, this loss did not put the early stages of natural cork oak regeneration at risk since the percentage of acorns not able to germinate was estimated at only 37% in late February. Furthermore, the average number of new seedlings was estimated in April at 40,000 seedlings/ha. A model was fitted to predict tree acorn production and to establish the best agroforestry system to optimize acorn use. Based on acorn quantity and quality data, earlier acorns should be directed to nursery and livestock production and the later acorns to wildlife and natural regeneration.