Survival, growth and regeneration of forest species in mining areas in the Eastern Amazonia

Abstract

Planting forest saplings is the most usual method for restoring areas degraded by mining. Therefore, the objective of this study was to evaluate the survival growth of planted forest species and spontaneous regeneration in post-bauxite mining areas. For this purpose, we sampled plots in recovery areas with ages ranging from five to nine years, in which the establishment, recruitment, mean annual increase in diameter and total height of the species were evaluated. The species were further classified for conservation status and origin. Of the 156 species found, 18 presented less than 25% of survival and were therefore not recommended for use in the areas, while another 22 planted species showed more than 55% survival, indicating that they can be used. Five species were registered with some threat level, another nine species were registered as exotic to Brazil and four to the Amazon. In general, 35 species were classified as suitable for planting, with an acceptable mortality rate and satisfactory growth. Thus, it was possible to select those most suitable for planting the post mining area through an evaluation of the survival rate and growth of the species.

Restoration through trenches does not demand organic fertilization and sawdust coverage on plant establishment

“…4). These species belong to the ecological group of pioneers and/or initial secondary forest, with rapid growth, and C. matourensis was identi ed as one of the most representative in the natural regeneration of bauxite mining areas close to this study site (Martins et al 2020a). The high mean annual increment in crown area of C. fairchildiana, is a favorable characteristic for the restoration of intensely degraded ecosystems since the soil is quickly covered by the treetops.…”

“…Regarding kaolin mining, in which the return of soil conditions can exceed 150 years (Lane et al 2020), trenches can be an e cient alternative to minimize impacts caused by intense soil compaction during mining operations (Ribeiro et al 2021). Besides this, seedling planting has been the most recommended active restoration method that ensures high initial plant density and diversity, especially in sites with low resilience (Ribeiro et al 2019; Brancalion and Holl 2020; Martins et al 2020a). Normally, mortality rate are high in initial plantings with many tree species (Löf et al 2019; Erickson and Halford 2020; Martins et al 2020a).…”

“…Besides this, seedling planting has been the most recommended active restoration method that ensures high initial plant density and diversity, especially in sites with low resilience (Ribeiro et al 2019; Brancalion and Holl 2020; Martins et al 2020a). Normally, mortality rate are high in initial plantings with many tree species (Löf et al 2019; Erickson and Halford 2020; Martins et al 2020a). For this reason, species adapted to the local soil and climate conditions, with rapid growth, and attractive to the wild fauna are recommended (Brancalion and Holl 2020).…”

“…Planted individuals commonly show higher growth than those from the natural regeneration in the Brazilian Amazonia(Salomão et al 2014;Martins et al 2020a), with mean increment higher than 1.40 m yr − 1 and 2.39 cm yr − 1 in height and diameter at soil height, respectively. The reestablishment of proper soil conditions comes through the insertion of pioneer species that accelerate forest succession and the structural characteristics of the forest over the years.…”

Eficiência do uso de bioestimulantes para a produção de mudas de Ipê-roxo (Handroanthus impetiginosus Mart.)

“…ex DC.) Mattos, popularmente conhecido como ipê-roxo, apresentam elevado potencial de restauração, sendo recomendada como estratégia de enriquecimento (Martins et al 2020b). A espécie apresenta sementes do tipo ortodoxa, as quais resistem à dessecação de até 5% do teor de água sem reduzir a qualidade fisiológica (Martins et al 2011).…”