ABSTRACT:The arbuscular mycorrhizal fungi (AMF) community presents a variable tolerance to changes in the medium, to which it responds modifying the number of propagules. For this reason, the study of the effect of different management practices on this community can help to understand the magnitude of the changes caused to the ecosystem. The objective of this study was to evaluate changes in the community of arbuscular mycorrhizal fungi in the soil in an area of arboreal Caatinga submitted to forest management. The study was conducted in Contendas do Sincorá (BA). Three types of forest management (clear-cutting, selective logging based on diameter, and selective logging based on species) and one control area were evaluated. Soil samples were collected at 0-10 cm depth in two periods (five and 10 months after management). AMF spores were present in low density (< 1 spore g -1 soil), dry and non-viable, and were generally more abundant in managed areas. Fewer species were observed in the control area. The AMF community showed to be related to the attributes of the soil and sensitive to management practices, demonstrating greater impact under clear cut management.Key words: AMF community; spore diversity; indicator of sustainability Fungos micorrízicos arbusculares em solo sob Caatinga arbórea submetida a manejo florestal RESUMO: A comunidade de fungos micorrízicos arbusculares (FMA) apresenta diferentes tolerâncias a alterações no meio, respondendo a estas mudanças com modificações no seu número de propágulos. Por essa razão, o estudo do efeito de diferentes práticas de manejo sobre esta comunidade pode auxiliar no entendimento da magnitude das alterações ocasionadas no ecossistema. O objetivo deste estudo foi avaliar mudanças na comunidade de fungos micorrízicos arbusculares do solo em área de Caatinga arbórea submetida a manejo florestal. O estudo foi realizado em Contendas do Sincorá (BA). Foram avaliados três tipos de manejo florestal (corte raso, corte seletivo por diâmetro e corte seletivo por espécie) e uma área testemunha. As amostras de solo foram coletadas na profundidade de 0-10 cm, em dois períodos (cinco e 10 meses após a execução do manejo). Os esporos de FMA apresentaram-se em baixa densidade (< 1 esporo g -1 de solo), secos e inviáveis e, geralmente, em maior quantidade nas áreas manejadas. Menor número de espécies foi observado na testemunha. A comunidade de FMA mostrou-se relacionada aos atributos do solo e sensível as práticas de manejo, demonstrando maior impacto do manejo corte raso.

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The magnitude of export of nutrients with forest harvest depends on the adopted waste management and, above all, on the distribution of biomass and nutrients in the trees, which is conditioned by the genetic potential and the species composition of forest stand.  The objective of this study was to quantify the biomass and nutrients of the trees and evaluate the effect of the management of harvest residues on the removal of nutrients from pure and mixed plantations of Pinus sp.. The study areas are located in the Southwest region of Bahia State, Brazil. Twenty trees per species were selected and felled under both planting conditions. The biomass quantification was performed by the destructive method. Samples of the tree components were analyzed for N, P, K, Ca and Mg contents. The total biomass was 75 Mg ha-1 for pure planting, and 81 Mg ha-1 for mixed planting, with wood and bark as the most representative compartments. Removal of the wood with bark led to too much nutrient removal, reaching a further 50% of the total contained in the biomass. Mixed planting has been shown more prone to export P, K and Mg. For both plantations, 64% of the N, P, K, Ca and Mg are in other components of the aerial part of the tree, and not in the wood. The elements that represent the highest risk for maintaining productivity are Ca and Mg.

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