Experimental establishment of big-leaf mahogany (Swietenia macrophylla King) seedlings on two soil types in native forest of Pará, Brazil

Research into the mechanisms underlying edaphic associations reported for many tropical forest tree species, including those in the Meliaceae, has paid little attention to the earliest post-dispersal life stages. We conducted a reciprocal sowing experiment to examine germination and establishment rates of big-leaf mahogany (Swietenia macrophylla King) during the first seedling growing season in two local edaphic habitats in southeastern Amazonia. In this region, adult populations are restricted primarily to low-ground soils associated with seasonal streams, but rarely are found on high-ground soils. Soil analyses revealed that low-ground soils at the study site were silty loams whereas high-ground soils were clays. High-ground soils were less acidic and more fertile than low-ground soils, especially with respect to total nitrogen, Mg, and sum of basic cations.