2019-04-222019-04-222008HIRAI, Eliana Harumi. Avaliação da exploração florestal de impacto reduzido em atributos físicos e químicos do solo e na regeneração natural em Paragominas, PA. Orientador: Cláudio José Reis de Carvalho. 2008. 141 f. Dissertação (Mestrado em Ciências Ambientais) – Instituto de Geociências, Universidade Federal do Pará, Museu Paraense Emílio Goeldi, Empresa Brasileira de Pesquisa Agropecuária, Belém, 2008. Disponível em: http://repositorio.ufpa.br/jspui/handle/2011/10991. Acesso em: .https://repositorio.ufpa.br/handle/2011/10991This work was carried out at Fazenda Rio Capim, property of the Cikel Brasil Verde Madeiras Ltda., in the municipality of Paragominas, State of Pará, Brazil. The main objective was to study the effect of logging on the physical and chemical properties of the soil and on natural regeneration in three Working Units logged in 2000, 2003 and 2006., The treatments were gap center, primary and secondary skid trails, logging landing and one control plot. The diameter of each individual was measured at approximately 1,30 m of the ground; all species were identified and calculated the species richness, abundance, diversity Index, evenness and floristic similarity. Samples of litterfall were collected in same the locations of soil plots. For physical analysis (granulometry, texture, soil bulk density, resistance to the penetration, porosity and volumetric humidity) soil samples were collected at 0-5, 5-10, 10-20, 20-30 cm depth, and for the chemical analysis (pH, carbon stock and nitrogen, C/N) the samples were at 0-10 cm depth. In the primary skid trails it was considered its beginning, middle and end of the extension, and both for primary and secondary skid trails, the marks of the wheels of the machinery (RM), the place between the wheels (ER), and the edges of the trail (BT). Felling gaps were randomly measured and classified with areas <600m2 and> 600m2. The soil of the study areas is Yellow Latosol with very clay texture. The soil bulk density and porosity varied significantly among years and between treatments (p <0,001); no significant differences were found at 20-30 cm depth. Main and secondary skid trails and logging landings were the most affected treatments. Gaps had no influence on bulk density. It was verified that ER and BT did not differ statistically. The comparison among beginning, middle and end of the skid trails showed ere no significant differences for any of the comparisons. Results for to resistance to penetration were very similar to the bulk density and porosity. Volumetric humidity varied according to the combination year x treatment (p <0,001). Average pH values varied between 4,72 to 5,92. Litterfall decreased as time elapsed since logging. Average contents of C varied between 25,94 to 42,59 g.kg-1 and the contents of N between 2,23 to 3,35 g.kg-1, both considered as high values. For carbon stock of (Mg.ha-1) it was not found significant difference for any of the interactions (year, season and treatment). The relationship C/N for logged forest showed values between 10,37 and 15,42, indicating mineralization of the soil inorganic nitrogen. The three studied WUs presented high diversity and evenness. WUs logged in 2000 and 2003 showed the highest similarity (35,93%), followed by the WUs logged in in 2003 and 2006 (33,46%), and WUs logged in 2000 and 2006 (26,93%). It has been concluded that it is necessary a long observation period for evaluation of the effects of soil compaction on the growth of the regeneration. Indicators for good forest management practices should consider soil attributes (physical, chemical and biological) for a better understanding of the system and choice of other indicators that can give answers on the equilibrium of the forest ecosystem. The studied parameters can be used as indicators of environmental quality.Acesso AbertoSolosReprodução natural de florestasParagominas - PADissertaçãoCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIASECOSSISTEMAS AMAZÔNICOS E DINÂMICAS SOCIOAMBIENTAISCLIMA E DINÂMICA SOCIOAMBIENTAL NA AMAZÔNIA