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Tree plantations can facilitate the establishment of native trees, thus providing opportunities for the ecological restoration or rehabilitation of degraded forest lands. Stand variables can influence the establishment of native tree species, but few studies have been carried out to determine how sapling growth response to stand variables varies among functionally different species. We evaluated the effect of stand age, stand basal area, tree density, and time since last logging on stem diameter growth rates, as well as the dependence of such effect on whole plant, stem, and leaf functional traits. We measured the stem diameter increment on 280 individuals of 22 species in permanent plots for a period of 2 years in araucaria (Araucaria angustifolia (Bertol.) Kuntze) plantations in the Atlantic Forest, NE Argentina. Increasing all-species basal area and plantation age negatively affected the growth rates, and such effect tended to be higher in species with low wood density. Two functional axes independently explained growth rate differences between species in growth rate. Growth rates increase with decreasing wood density, increasing leaf phosphorus and potassium content, and decreasing specific leaf area. Among species that are similar in the traits associated with the first functional axis, plant growth increases with increasing leaf nitrogen content. [ABSTRACT FROM AUTHOR]

Novel ecosystems occur when new combinations of species appear within a particular biome. They typically result from direct human activity, environmental change, or the impacts of introduced species. In this paper, we argue that considering commercial tree plantations as novel ecosystems has the potential to help policy makers, resource managers, and conservation biologists better deal with the challenges and opportunities associated with managing plantations for multiple purposes at both the stand and landscape scales. We outline five inter-related issues associated with managing tree plantations, which are arguably the largest form of terrestrial novel ecosystem worldwide. This is to ensure that these areas contribute significantly to critical ecosystem services, including biodiversity conservation, in addition to their wood production role. We suggest that viewing tree plantations as novel socioecological systems may free managers from a narrow stand-based perspective and having to compare them with natural forest stands. This can help promote the development of management principles that better integrate plantations into the larger landscape so that their benefits are maximized and their potential negative ecological effects are minimized. [ABSTRACT FROM AUTHOR]