Abstract This study aimed at quantifying the accumulation of litter in formative compartments (bark, branches, leaves, and miscellaneous) above the soil in a 23-year-old Eucalyptus grandis plantation, located on the campus of the Universidade Federal de Santa Maria, Rio Grande do Sul. We installed four parallel plots on the settlement lines, measuring 3.0 m × 6.0 m. In order for litter collection, we utilized a 25 cm × 25 cm iron frame and randomly collected 15 samples of each plot, totaling 60 samples. The burlap consisted predominantly of branches (39%) and miscellaneous (29%) fraction, followed by leaves (23%) and bark (6%). Such accumulation may be associated with the age of the Eucalyptus grandis, the density of the forest, and the stability achieved by the plantation.

ABSTRACT This study aims at determining and differentiating the floristic groups of a Deciduous Seasonal Forest’s arboreal component, located on the ridge of the Southern Plateau, in Southern Brazil. Individuals with diameter at breast height ≥ 5.0 cm were sampled in sixty-two plots measuring 10 m × 10 m, which were systematically installed in the forest. Three floristic groups were found: Middle Stage, including 54 species, with Casearia sylvestris as an indicator species; Advanced Stage, with 38 species and Pilocarpus pennatifolius as the indicator species; and Altered Forest, with 27 species and Apuleia leiocarpa, Helietta apiculata, and Machaerium paraguariense as indicator species. A higher proportion of climax light-demanding individuals was reported in the Middle Stage and Altered Forest groups, contrasting with the Advanced Stage group, in which climax shade-tolerant species were predominant. In addition, the groups were differentiated according to their dispersion strategy, with specific syndromes occurring in each group (Middle Stage: zoochory; Advanced Stage: autochory; Altered Forest: anemochory).

A diversidade de ambientes encontrados em florestas naturais pode influenciar na regeneração natural e futuramente na dinâmica sucessional. Nesse contexto, objetivou-se avaliar a regeneração natural de espécies arbóreas em diferentes comunidades (grupos florísticos) de uma Floresta Ombrófila Mista. Foram amostradas 69 parcelas com dimensões de 10m x 10m, onde foram medidos os indivíduos com 3,0cm ≤ circunferência à altura do peito (CAP) >30,0cm. Em subparcelas de 3,16m x 3,16m, foram medidos os indivíduos com CAP >3,0cm e altura ≥50cm. As espécies com maior potencial de regeneração natural nas comunidades avaliadas foram Sebastiania brasiliensis e Stillingia oppositifolia (Grupo 1), Myrceugenia cucullata e Allophylus guaraniticus (Grupo 2) e Stillingia oppositifolia e Myrceugenia miersiana (Grupo 3). Destaca-se que as espécies Allophylus edulis, Blepharocalyx salicifolius, Justicia sp., Myrceugenia cucullata e Stillingia oppositifolia estiveram entre as 10 principais espécies nas três comunidades, mostrando elevado potencial de regeneração. As três comunidades favoreceram a ocorrência de elevada riqueza de espécies (Grupo 1=101; Grupo 2=98; Grupo 3=101). Todavia, as espécies secundárias tardias e secundárias iniciais mostraram maior adaptação aos diferentes locais da floresta, com densidade superior às espécies pioneiras.

The diversity of environments found in natural forests can influence the natural regeneration and dynamics of succession in the future. The goal of this study was to evaluate the natural regeneration of arboreal species in different communities (floristic groups) of a mixed ombrophylous forest. It was sampled 69 plots with dimensions 10m x 10m, where individuals with 3.0cm ≤ circumference at breast height (CBH) >30.0cm were measured. The individuals with CBH >3.0cm and height ≥50cm in subunits of 3.16m x 3.16m were measured. The species with the greatest potential for natural regeneration in the evaluated communities were Sebastiania brasiliensis and Stillingia oppositifolia (Group 1), Myrceugenia cucullata and Allophylus guaraniticus (Group 2) and Stillingia oppositifolia and Myrceugenia miersiana (Group 3). The species Allophylus edulis, Blepharocalyx salicifolius, Justicia sp., Myrceugenia cucullata and Stillingia oppositifolia were among the top 10 species in all three communities, showing a high potential for regeneration. The three communities have facilitated the occurrence of high species richness (Group 1=101; Group 2= 98; Group 3=101). However, early secondary and late secondary species showed greater adaptation to different forest sites with higher density compared to pioneer species.

O presente trabalho teve como objetivo diagnosticar variações estruturais entre os grupos florísticos de uma Floresta Ombrófila Mista Montana, em Nova Prata - RS. Para isso, foram inventariadas 71 parcelas de 10 x 100 m, distribuídas pelo processo de Amostragem Sistemática em Dois Estágios. Foram mensurados todos os indivíduos com circunferência a altura do peito igual ou superior a 30,0 cm. A análise de agrupamento, baseada na abundância das espécies em cada parcela, foi realizada utilizando o método de ligação Ward e a distância euclidiana como medida de parecença, a qual permitiu classificar as parcelas em quatro grupos florísticos distintos. Os grupos Estágio Intermediário, Floresta de Borda, Estágio Avançado e Floresta Degradada apresentaram Matayba elaeagnoides Radlk., Lithraea brasiliensis Marchand, Campomanesia xanthocarpa O.Berg e Myrciaria floribunda (West ex Willd.) O. Berg, respectivamente, como espécies mais características. Foi encontrada maior variação da proporção de espécies de sub-bosque e pioneiras. Constatou-se o maior número de espécies com o padrão de distribuição espacial agregado. As estruturas diamétrica e hipsométrica indicaram que os grupos possuem boa capacidade de renovação e um dossel inferior mais denso, porém, distinguindo-se em algumas características. Em síntese, os grupos apresentaram variações estruturais que evidenciam a necessidade de se considerar os agrupamentos no caso de intervenção na floresta.

This study aimed to diagnosis structural variations between floristic groups in a remnant of Montane Mixed Ombrophylous Forest in Nova Prata, RS state. To do so, 71 plots with dimensions of 10 x 100 m were inventoried, distributed by the process of systematic sampling in Two Stages. All individuals with circumference at breast height equal to or above 30.0 cm were measured. The cluster analysis based on the abundance of species in each plot was conducted by using Ward connection method and it allowed classifying the plots in four distinct floristic groups. Intermediate Stage, Border Forest, Advanced Stage and Degraded Forest Groups presented Matayba elaeagnoides Radlk, Lithrea brasiliensis Marchand, Campomanesia xanthocarpa O.Berg and Myrciaria floribunda floribunda (West ex Willd.) O. Berg, respectively, as the most characteristic species. Greater variation in the proportion of understory species and pioneers was found. The highest number of species with the aggregated spatial distribution pattern was observed. The diameter and hypsometric structures indicated the groups have a good renewal capacity and a denser bottom canopy, respectively, although they have some different characteristics. In summary, the groups presented structural variations that evidenced the need to consider the clusters in the event of intervention in the forest.