Noble biomass: Restore, recycle, profit using cork oak (Quercus suber L.)

Abstract

Land use changes over recent decades have led to serious decline in natural ecosystems, in particular the Mediterranean forests. This is due mainly to uncontrolled urbanisation causing agricultural land to be abandoned or to become partially polluted. In such areas, forest restoration appears the most appropriate remedy, in particular, by using native species with high ecological and economic values, such as cork oak. This species can be used for noble biomass production, that is biomass not addressed for energy production but mainly for industrial purposes. This work describes a case study located in central Italy, which is characterised by the integration of forest restoration with water-saving management for irrigation purposes, based on the use of effluents from a phytodepuration plant. By joining thematic maps with a map of topographic wetness index (TWI) a suitable site was selected in the municipality of Tuscania for a cork oak plantation. An irrigation scheme, useful for maximising the growth rate of cork oak and consequently for maximising the economic profits retrievable from the plantation, was determined based on the estimated potential evapotranspiration using Thornthwaite's equation, the soil type and the available wastewater. An economic analysis showed that the total cost of the works might be amortised within the first stripping of gentle cork or even before, for example, if cork oak was cultivated in conjunction with an economically relevant non-food species. In this case study, the advantages of dyeing species were analysed. Results show that an integrated forest restoration and wastewater management system could be implemented to provide an economic income that ensures both cost recovery and a significant profit over time.