Shading levels on growth of sideroxylon obtusifolium (roem. & schult.) t.d.penn. seedlings

The species Sideroxylon obtusifolium (Roem. & Schult.) T.D.Penn. has environmental, economic, ecological and social importance, but despite that, the native populations are difficult to be located. The objective of this study was to evaluate the production of Sideroxylon obtusifolium seedlings at different levels of shading. The experiment was carried out in the forest nursery of the Universidade Federal da Paraíba, in Areia - PB. The seedlings were produced at the following levels of shading: full sun (0), 30, 50 and 70%, in black polyethylene bags with dimensions 15 x 28 cm (width x height), containing substrate formulated with subsoil soil (55%) + washed sand (20%) + kaolin waste (20%) + bovine manure (5%). The plants were measured every 30 days for the following variables: plant height, stem diameter and plant height/stem diameter ratio. In the last evaluation, in addition to the previous mentioned variables, the following variables were determined: number of branches, root length, roots dry matter, leaves, stems, shoots, and total dry matter, shoot dry matter/root dry matter ratio, Dickson quality index, percentage of leaves and roots. The initial development of Sideroxylon obtusifolium in the nursery was consistent with the expected patterns for the occurrence species in the Caatinga, with a stabilization of growth of its morphological characteristics in the lower levels of shading, investing in the formation of roots and in the height/stem diameter ratio. For the production of seedlings is recommended environment of full sun light or with up to 15% of shading.