Morphophysiological responses of forest tree species conducted under different levels of shading in the enrichment of degraded ecosystem

Abstract

The luminous intensity is one of the limiting factors for the plant’s development, however, the existing information is based on observations on natural succession dynamics of tropical species, which are rarely studied as to their performance after planting. Thus, the present study aimed to answer: a) what is the performance of arboreal forest species (Inga vera, Schinus terebinthifolius, Handroanthus heptaphyllus, Parapiptadenia rigida, and Casearia sylvestris) after five years of planting, and what is the level of shading provided by these species in the subsoil? b) what is the behavior regarding survival, initial growth, and morphophysiological attributes of the species (Allophylus edulis, Cordia americana, Eugenia involucrata, and Psidium cattleianum) used in the enrichment of the underwood?, and c) indicate the best planting condition for the species studied, in degraded areas in the south of the Atlantic Forest Biome. We found that species described by their heliophilous behavior may be unsuitable for planting in full sun in degraded areas, as is the case with C. sylvestris. On the other hand, I. vera and S. terebinthifolius, have the potential for rapid growth in full sun, intermediate for H. heptaphyllus and P. rigida. Consequently, these species provided different shading after five years. Some species (A. edulis, C. americana, and E. involucrata) demonstrated that the morphophysiological performance was favored under shading of 76 and 80% (S. terebinthifolius and Inga vera, respectively). A. edulis and P. cattleianum were the species with the greatest assimilation of CO2, in the range of photosynthetically active radiation of 1500 mmol m-2s−1. Species with behavior similar to I. vera, S. terebinthifolius, A. edulis, P. cattleianum are appropriate to make up the group of framework species or fillers together, and to a lesser extent those similar to P. rigida and H. heptaphyllus. So, this will reduce the action of ecological filters, factors that act by selecting the species that will be a part of the ecosystem and determining the pace of restoration of ecological processes (biotic and abiotic),favoring the establishment of other species less tolerant of high soil and air temperatures. C. sylvestris, C. americana, and E. involucrata are typical species to compose the diversity group in restoration projects, as they are restricted to growth in full sun, but are important in enrichment. We found that the pattern of behavior of tree forest species, in the initial phase of growth in the field, must be known to accelerate the soil cover of the degraded area, easing ecological filters for recovery.