Silvicultura de Araucaria angustifolia no Rio Grande do Sul: certificação de plantios, perfil das propriedades e crescimento das árvores

Abstract

Conventional agriculture and silviculture strongly impact biodiversity on worldwide scale. Brazil is one of the main representants of these sectors, which must look for more sustainable models. Forest plantations with native species are alternatives to develop socioeconomic production with biodiversity conservation. However, such "bottom-up" approaches to conservation, incorporating the interests of the local population, are little encouraged in the country. Araucaria angustifolia is a native conifer with high timber and non-timber values. Its was intensively harvested until the 1970s, which influenced its classification as endangered to extinction. Although cutting A. angustifolia is prohibited, the timber trade still occurs and is sustained by illegal means, or by licensed private plantations. Thus, because of its high-quality timber and its importance for native biodiversity, silvicultural plantings with this species can be a strategy for conservation use. The aim of this dissertation was to characterize the silvicultural plantations of A. angustifolia in Rio Grande do Sul (RS), in order to support the sustainable development of the sector. The Secretary of Environment of Rio Grande do Sul allows the silvicultural planting of this species, by issuing the Certificate of Identification of Forest Planted with Native Species. Thus, information from all open CIFPEN processes from January 2017 to May 2021 was used as the basis of this research. In total, 640 processes were studied. The properties with A. angustifolia plantations in RS are concentrated in two centers in RS. Landowners showed little interest in new planting of native species. Properties with plantations of A. angustifolia are different in terms of land tenure and environmental aspects compared to properties with silviculture of native species and without silviculture. In summary, these characteristics indicate that the silviculture of A. angustifolia is associated with improved conditions of native ecosystems, besides promoting the conservation of the species itself. The average annual diametric increment is influenced mainly by the age factor, with higher rates occurring up to 40 years of planting, approximately. Above this age range, the best increment results are found in regions with humid autumn, in deep soils with high organic matter content, and also with summers below 142mm of precipitation, characteristics concentrated in a large region in the north of the state of RS and in spots to the west. Still, it is important to consider that other variables not analyzed in this study may have an influence on the growth of the species, such as genetic factors and management. We conclude that to extend the CIFPEN, it is 10 essential that it be better translated and disseminated to the population, especially in relation to legal aspects. Furthermore, this research reflections aimed at expanding the silviculture of A. angustifolia in RS, from the analysis of data from the public environmental agency.