Nutrient status and field performance of tree seedlings planted in Mediterranean degraded areas

Abstract

In degraded Mediterranean woodlands, nutrients, in addition to water, may be the major factors controlling reforestation success. But information on nutritional status of planted seedlings is scarce. We aimed to evaluate the nutritional status and field performance of Pinus halepensis and Quercus ilex seedlings planted on two characteristic Mediterranean forest soils developed from marl and limestone. We used root growth response to localized N and P enrichment, and foliar analysis as indicators of nutrient limitation. Vermiculite cores enriched with P showed higher root density than N-enriched and control cores, particularly on soils derived from marl. Three years after planting, seedlings showed low foliar P and K as compared to other species and adult trees. Principal Component Analysis conducted on foliar macronutrient concentration clearly separated species and soil type. Foliar K and Mg depended on soil type (higher on limestone and marl, respectively), whereas N, P and Ca concentration in leaves and needles differed between species (higher N and P in pine, higher Ca in oak). Survival and growth depended on species and site, but we found no effect of soil type on these variables, suggesting that seedling performance may not be strongly affected by nutrient status within the range of soils evaluated. © INRA, EDP Sciences, 2006.