Tree diversity and structure in shaded pineapple agroforestry system in Western México [estructura y diversidad arbórea en el sistema agroforestal de piña bajo sombra en el occidente de México]

Structure and perennial woody diversity in the cropping pineapple agroecosystem is described. It is developed like main component in understory of tropical subdeciduous and Quercus forest, in combinations with cultivated non-native species; revealing a characteristic agroforestry system, in western Mexico (Jalisco and Nayarit). This is an extensive cropping system of low external inputs and local technology, mainly growing on slopes from 25% to 45%, on irregular terrain and at altitudes from 67 to 610 m. We found 1 161 woody individuals from 69 species, 62 native and seven introduced species. The Fabaceae family had 11 species. The lowest and maximum richness was in Nayarit. Fisher's alfa diversity in the study area showed differences between sites and (F=7.12, ??0.001; F=7.09, ??0.0006, respectively). Shannon's index exhibited differences only in four sites of Jalisco with the lowest diversity sites in Nayarit. Beta diversity in Jalisco was different from Nayarit. Height and diameter in study area were heterogeneous, with the majority (92%) of individuals found in intermediate heights. Diameter sizes were concentrated in four structural types. Management of this diverse shaded agroecosystem contributes to tropical biodiversity conservation and also represents a pineapple sustainable management in America