Caracterização do crescimento de mudas de três espécies florestais sob diferentes níveis de sombreamento

Abstract

The production of seedlings of forest essences, with economical or conservationist purposes, depends on the knowledge of plant growth and development. The study of the growth and development of a plant, in different environmental conditions, allows to define and to improve more appropriate forms of cultivation. The objective of this study was to assess the development of seedlings of Schinus terebenthifolius (aroeira), Dalbergia nigra (jacarandá caviúna) and Chorisia speciosa (paineira) grown in green house under 0%, 22%, 50%, 70%, 84% and 91% of shading. The parameters used for growth evaluation were height, diameter of the base of the stem, leaf area and total drought mass in relation to the shade level. Were analyzed 24 seedlings by species, which were analyzed up to 90 days after the emergency under different shade levels. The samplings were carried out periodically, every other day in the first month, every four days in the second and every eight days in the last month. S. terebenthifolius and C. speciosa had their growth favored under 22 and 50% of shading. The seedlings of D. nigra were favored by intermediate levels of shadow (50, 70 and 84%). According with the results S. terebenthifolius and C. speciosa can be benefitted with the presence of gaps in their natural ambient, acting as secondary species. In this way these species can be used in plantations at open sky or in the enrichment of secondary forests. On the other hand, the seedlings of D. nigra seem to be more favored in closed canopies, acting as a late secondary species. The planting of this species, therefore, could be more appropriate for the enrichment of forests. An increasing order of shade demand could be established as follows: S. terebenthifolius = Chorisia speciosa < D. nigra.