Cost–benefit analysis of different container capacities and fertilization regimes in Pinus stock-type production for forest restoration in dry Mediterranean areas

Abstract

Seedling quality and nursery practices have been studied extensively for Mediterranean pine species in recent years. However, the cost–benefit relationship of producing different planting stock-types has not been addressed. We cultured eleven different stock-types of Pinus halepensis Mill. and Pinus pinea L. by combining different container capacities and nursery fertilization regimes; all stock-types were then outplanted under varying ecological conditions. Container capacity mainly determined pre-planting morphology, production costs and post-planting growth of the different stock-types. Survival was generally lower in the seedlings raised in the smallest container, but no differences were detected among the others in spite of a large morphological range. Additional late season fertilization enhanced post-planting performance on all the sites and for both species. In general, the optimum stock-type for both species was that resulting from propagation in medium size containers (300cm3) with additional late season fertilization, because this minimized cost per living seedling and per stem volume after three years in the field. These results reveal the importance of late season fertilization as an inexpensive tool to improve field performance and establish an operational limit to increasing stock-type size in Mediterranean pine species.