Prognose para populações de angico vermelho (Parapiptadenia rigida (Benth.) Brenan) via exploração jardinada por produtoras de sementes

Abstract

The shelterwood system is a forest management system based on selective thinning of trees, with the aim of continuous production of natural regenerations by parental tree. All rural properties can develop this type of system in legal reserve areas. Therefore, the main objective of this thesis was to simulate a scenario that benefits the conduction of Parapiptadenia rigida population so that the spatial distribution of the propagules is directed to certain locations and consequently benefits the growth of natural regenerants. The analyzed populations are inserted in fragments of Secondary Deciduous Forest in the Atlantic Forest Biome/RS. This species (Parapiptadenia rigida) has anemochoric dispersion. The choice of this species is justified due to its potential for development and increment, with the possibility of extraction of noble and resistant wood. The questions that guided this project, taking into account the monitoring space and time, were: 1°) How do propagule shadows behave around the source? 2º) Which species interfere in the spatial distribution of propagules and natural regenerants? To obtain such responses, statistics were used: (i) classical (probability of events) and (ii) spatial (semivariograms, indicator kriging and marked point process). In AutoCAD Software (2020) orthogonal projections were made to visualize the events. The results with the used tools were able to identify the pattern of spatial dependence and to infer which species impair the seed fall in the soil and the development of natural regeneration. Therefore, species with perennial crowns and dense foliage below P. rigida propagule sources impair soil propagule drop, and this type of crown is a marker of spatial dependence and inefficiency at the time of dispersal. The main spatial dissociations with natural regenerants (P. rigida population) were with the species Cedrela fissilis, Nectandra megapotamica and Quillaja brasiliensis. We highlight the biological plausibility, including the inferences that for the spatial distribution of P. rigida species to be directed to an intentional place, it is necessary to occur occasional cuts of some species of N. megapotamica and Quillaja brasiliensis; and after cutting some of these individuals there will be clearings benefiting not only the P. rigida population, but species such as Alchornea triplinervia, Allophylus edulis, Enterolobium contortisiliquum, and Quillaja brasiliensis. These will become the main competitors due to ecological characteristics. Therefore, keeping the forest standing does not mean ignoring the resources it has to offer, but using them rationally; observing the current scenario to plan the production scenario following the one proposed in the forecast roadmap.