-This paper aims at characterizing the tree species natural regeneration and evaluating the relation of this stratum to both the adult component and the environmental variables in a fragment of a cloud forest in Santa Catarina, Brazil. In each of 25 20 × 20 m plots, where the adult component and environmental variables have previously been evaluated, subplots of different sizes varying according to plants' height were then allocated as follows: Class 1 -plants with a height varying from 0.15 cm up to 1 m, being evaluated within 5 m 2 ; Class 2 -plants with a height varying from 1 up to 3 m, being evaluated within 10 m 2 ; Class 3 -plants with a height greater than 3 m and DBH smaller than 5 cm, being evaluated within 20 m 2 . Data have been analyzed with regard to the determination of diversity (Shannon index), evenness (Pielou), Natural Regeneration Index (NRI), similarity with the adult component (Jaccard and Bray-Curtis), floristic-structural organization (Nonmetric Multidimensional Scaling -NMDS) and their relation to environmental variables. A total of 518 individuals distributed in 28 species were sampled. The low values of Shannon index (2.51 nat/ind) and evenness (0.75) suggest low diversity and elevated ecological dominance. The highest NRI has been found in the species Symphyopappus itatiayensis (Hieron.) R.M. King & H.Rob (19.36%). The similarity with the adult component were of 0.45 (Jaccard) and 0.24 (BrayCurtis), demonstrating a low overall similarity (<0.50). The soil compaction was the only variable that has shown a relation with regeneration, which can be related to cattle's presence in the fragment.Keywords: Phytosociology; Araucaria Forest; Forest management.
REGENERAÇÃO NATURAL DE ESPÉCIES ARBÓREAS EM UMA FLORESTA NEBULAR EM SANTA CATARINA, BRASILRESUMO -Os objetivos do presente estudo foram caracterizar a regeneração natural arbórea e relacionar esse estrato com o componente adulto e com variáveis ambientais em um fragmento de floresta nebular em Santa Catarina. Em cada uma das 25 parcelas de 20 × 20 m, onde previamente foi realizado um estudo com caracterização do componente adulto e de variáveis ambientais, foram estabelecidas subparcelas, com tamanhos diferenciados de acordo com o tamanho das plantas, para a avaliação dos regenerantes: Classe 1, plantas com altura de 0,15 cm até 1 m, avaliadas em 5 m²; Classe 2, plantas com altura entre 1 e 3 m, avaliadas em 10 m², e; Classe 3, plantas com altura maior que 3 m e DAP menor que 5 cm, avaliadas em 20 m². Foram determinadas: diversidade (índice de Shannon), equabilidade (Pielou), Índice de Regeneração Natural (IRN),
1074Revista Árvore, Viçosa-MG, v.40, n.6, p.1073-1082, 2016 DALLA ROSA, A. et al.