Silvicultura de espécies florestais arbóreas nativas em plantio puro e sob diferentes níveis de sombreamento

Abstract

The luminosity is one of the limiting factors for the development of the plants, however, the existing information is based on observations of the natural occurrence of the species, as they are rarely studied regarding their post-planting performance. Thus, the present study aimed to evaluate: a) the performance of native forest species after five years of planting (Inga vera, Schinus terebinthifolius, Handroanthus heptaphyllus, Parapiptadenia rigida and Casearia sylvestris), which provided different levels of shading in the sub-grove; b) survival and initial growth of Allophylus edulis, Cordia americana, Eugenia involucrata and Psidium cattleianum seedlings planted in the understory. The treatments were S1-80%, S2-76%, S3-36% and S4-11% shading. In addition to survival, the growth of existing planting species was assessed using the height (H) and stem diameter (DC) attributes. It was found that I. vera and S. terebinthifolius have the potential for rapid colonization in full sun, followed by H. heptaphyllus and P. rigida, but C. sylvestris is not suitable in this condition. The survival of seedlings planted in the understory was evaluated one year after planting, using the morphophysiological attributes height (H), stem diameter (DC), average stoma density, chlorophyll fluorescence a and chlorophyll content a and b. In general, the species planted in the understory showed better responses in environments with greater shading (76 to 80%). Environmental variables, such as photosynthetically active radiation, influenced air temperature, relative humidity and soil temperature and, consequently, in the species planted in the understory, P. cattleianum has a wide tolerance to environmental variables associated with different levels of solar irradiance, while the other species showed variable behavior. A. edulis and C. americana showed greater survival in an environment with 36% shading, while E. involucrata with 80%, however, in general, A. edulis, C. americana and E. involucrata demonstrated that the morphological and physiological performance was favored under shading of 76 and 80%. A. edulis and P. cattleianum were the species with maximum carbon assimilation, in the range of 1500 mol m-2 s-1 photosynthetically active radiation. I. vera, S. terebinthifolius, A. edulis, P. cattleianum can make up the group of framework species or filler species together, in a lower density, P. rigida and H. heptaphyllus, which will reduce the action of ecological filters, such as temperature soil and air, favoring the establishment of other less tolerant species. C. sylvestris, C. americana and E. involucrata are typical species to compose the diversity group in restoration projects, not showing adequate performance in full sun.