Plant Sociology, Vol. 54, Suppl. 1, June 2017, pp. 19-27 DOI 10.7338/pls2017541S1/03 Root adaptive management for improving plant quality and ield performance under drought: experiences with native tree species from a South American Mediterranean-type ecosystem J.F. Ovalle 1 , R. Ginocchio 1,2 , E.C. Arellano 1,2 , P. Valenzuela 2 1 Pontiicia Universidad Católica de Chile, Center of Applied Ecology & Sustainability (CAPES-UC), Avenida Liber- tador Bernardo O’Higgins 340, Santiago, Chile. 2 Pontiicia Universidad Católica de Chile, Facultad de Agronomía e Ingeniería Forestal, Departamento de Ecosiste- mas y Medio Ambiente, Avenida Vicuña Mackenna 4860, Santiago, Chile. Abstract Plant quality attributes have been widely studied for numerous tree species inhabiting the Mediterranean Basin, resulting in a positive impact on restoration success in degraded forest ecosystems. However, there has been less research on root morphological attributes, especially of native tree species in South American Mediterranean-type ecosystems, which are currently subject to unprecedented drought events and degradation. We summarize experiments examining the use of root adaptive management during the nursery and ield stages for improving plant quality and seedling performance under water-limited conditions in central Chile. The irst experiment (E-1) evaluated the effect of controlled-drought regimens on root development and seedling performance of two tree species (Quillaja saponaria and Cryptocarya alba) with contrasting root growth strategies. The E-1 results conirmed the importance of considering the root growth strategy as a criterion in the selection of species and watering decisions. The second experiment (E-2) assessed the effect of increasing fertilization doses in the nursery on Q. saponaria root morphology 1 year after planting seedlings in the ield. The results showed that, as a result of nutrient deprivation, small plants with a greater stem diameter and lower shoot:root ratio contributed to improving water-stress resistance early during a drought period. The third experiment (E-3) determined the effect of different locations of fertilizer placement into the soil proile on rhizosphere salinity and root development of Q. saponaria seedlings. The E-3 results showed that fertilization practices in dryland areas require watering because this acts to control the increase in salinity in the rhizosphere and, consequently, avoids negatively impacting the root volume growth. Our indings could be useful for identifying the major gaps present in the production and esta- blishment stages of native tress in Chile, and could address the latter through root adaptive management. Key words: central Chile, dryland forest, nursery fertilization, seedling quality, root architecture. Introduction Mediterranean-type forest ecosystems around the world have a long history of land-use change and de- gradation (Fuentes et al., 1989; Vallejo et al., 2012; Cianfaglione et al., 2014; Vadell et al., 2016). In South America, the Mediterranean-type forest located in cen- tral Chile (30°–36°S) is the ecosystem with the highest native forest coverage loss in the region (including the Amazonian forest) following Spanish colonization in 1536, with 83% of the original cover lost (Salazar et al., 2016). Today, the remnants of the Chilean Mediter- ranean forest (sclerophyllous trees and shrubs species) cover an area of 473437 ha, representing only 3% of the total area of native forest in Chile (CONAF, 2011). In addition, the persistence of the current mega-drou- ght has resulted in the deterioration of natural vege- tation throughout central Chile (Garreaud, 2015), and represents a strong limitation to the seedling recruit- ment of most native tree and shrub species (Van de Wouw et al., 2011). In this context, active restoration in Chile has become a priority because of the magnitu- de of forest coverage loss and its impact on ecosystem services (Lara et al., 2009; Newton et al., 2012; Smith- Ramírez et al., 2015). The increase in restoration and reforestation activi- ties has generated an increase in the demand for native species, as well as for more information on nursery management and plantation practices (Santelices et al., 2011; Bannister et al., 2013). The most common native species used for the restoration of Chilean Mediterra- nean forest are Acacia caven, Cryptocarya alba, Li- thraea caustica, Maytenus boaria, and Quillaja sapo- naria (Newton & Tejedor, 2011; Becerra et al., 2013). However, there is a lack of standardized management criteria and plant production protocols for use by local growers that would enable them to offer a product of certiied quality. Currently, in Chile, the only rule in force (NCh Nº2957/2006) is voluntary, and establishes standards of genetic, physiological, and morphologi- cal quality only for major exotic tree species for in- dustrial use (i.e., Pinus radiata, Eucalyptus globulus, and Pseudotsuga menziesii) (INN, 2006). Therefore, the poor technological development and scientiic re- search around the quality of native plant species result in the provision of low-quality seedlings, with highly Corresponding author: Juan F. Ovalle. Pontiicia Universidad Católica de Chile, Center of Applied Ecology & Sustai- nability (CAPES-UC), Avenida Libertador Bernardo O’Higgins 340, Santiago, Chile; e-mail: jrovalle@uc.cl