O problema das espécies arbóreas exóticas comercializadas nos viveiros florestais: Estudo de caso no município de Juiz de Fora (MG)

O comércio de mudas florestais para a recuperação de áreas degradadas e reflorestamento é crescente e a demanda de cada vez mais conhecimentos sobre práticas de manejo na produção de essências nativas, adequadas aos padrões ecológicos locais e à legislação ambiental vigente. Entretanto, a comercialização de mudas exóticas ainda é prática comum nos viveiros florestais, não existindo, para a microrregião de Juiz de Fora, MG, informações sobre os tipos de mudas comercializadosnos viveiros florestais. Neste estudo foram levantadas as espécies florestais comercializadas em oito viveiros florestais no município de Juiz de Fora, MG, e que abastecem os projetos de reflorestamento na região. As espécies foram identificadas e categorizadas em nativas da Mata Atlântica ou exóticas.Foram encontradas ao todo 147 espécies. Destas, 64 (43,5% do total) foram exóticas, sendo encontradas, com grande frequência (>50%) entre os viveiros, englobando espécies frutíferas com perfiltipicamente comercial, como goiaba (Psidium guaja), abacate (Persea americana), amora (Morus nigra) e cítricas – laranja, limão e tangerina (Citrus spp.). A presente análise evidencia uma grandeprodução e comercialização de espécies exóticas de mudas florestais do município, o que não condiz com a legislação florestal vigente e ainda pode ser considerado como grande risco em potencial para invasão biológica

Ecological aspects of arboreal community in Forest fragment Atlantic with predominantly palmito-juçara (Euterpe edulis)

The Botanic Garden - UFJF area has a history of coffee culture, and its decay and neglect in the 1930s, the forest is regenerating naturally. There is a mosaic of secondary forests in JB - UFJF, populations of Euterpe edulis are more frequent in wet soils, this species being characteristic of more advanced areas in terms of succession. The objective was to diagnose the tree community of a stretch of secondary forest JB - UFJF dominated by E. edulis, to obtain detailed information on the structure and floristic diversity, and demonstrate the importance of the JB - UFJF in biodiversity conservation of the regional flora. A stretch of approximately 20 ha of regenerated forest was selected after discontinuation of caffeine (~ 70 in), with dominance of palm (E. edulis), where 25 plots of 20 x 20 m (total 1 ha) were allocated. All trees (dbh ≥ 5 cm) live and dead standing were sampled, identified and measured (DBH). We sampled 1926 individual, with 1837 living individuals belonging to 116 species. The most important species in the community were E. edulis (22.9 % VI), Piptadenia gonoacantha (16.5%), Xylopia sericea (5.7 %), Annona cacans (3.5 %) and Syagrus romanzoffiana (3.3 %), which together amounted to 51.9 % of VI. Highlight for E. edulis, with relative density of 41.2 % and a presence in all plots. The 89 dead trees represent 4.6% of all subjects, the lowest value when compared with other secondary forests in the region, which exceeded 15 %. The diameter distribution of the community was "reverse - J", with a large concentration of individuals in the first classes, showing good regenerative capacity. However, the population of P. gonoacantha, a pioneer of long life cycle, presented unbalanced distribution, with a decrease of individuals in the first classes, indicating a trend of progressive output community. Owing the dominance of E. edulis, the index value of species diversity (Shannon H '= 2.98 nats / ind) was close to that of secondary forests in the region. However, with the exclusion of species calculations, the index value has substantially increased (H '= 3.89 nats / ind) being the highest so far in the region's forests, showing that the fragment has high tree diversity. The results show a more mature tree community in relation to other studied secondary forests in the region with high species richness and species diversity, high density and low basal area of dead, indicating frank "construction phase". Additionally, the area has a high density of E. edulis and the presence of other endangered species, and species characteristics of families of mature forest (Lauraceae, Myrtaceae, Sapotaceae) with good representation, showing great importance to the preservation of regional floristic biodiversity.A área JB-UFJF apresenta um histórico de cultura cafeeira, e com sua decadência e abandono na década de 1930, a floresta vem se regenerando naturalmente. Dentro do mosaico de florestas secundárias no JB-UFJF, populações de Euterpe edulis são frequentes em solos mais úmidos, sendo esta espécie característica de áreas mais avançadas em termos de sucessão. O objetivo foi realizar o diagnóstico da comunidade arbórea de um trecho de floresta secundária do JB-UFJF dominado por E. edulis, para se obter informações detalhadas sobre a estrutura e diversidade florística, e demonstrar a importância do JB-UFJF na conservação da biodiversidade da flora regional. Foi selecionado um trecho de aproximadamente 20 ha de floresta regenerada após abandono da cafeicultura (~70 nos), com dominância de palmito (E. edulis), onde foram alocadas 25 parcelas de 20 x 20 m (total 1 ha). Todas as árvores (DAP ≥ 5 cm) vivas e mortas em pé foram amostradas, identificadas e mensuradas (DAP). Os parâmetros fitossociológicos e de diversidade foram calculados. Foram amostrados 1926 indivíduos, sendo 1837 indivíduos vivos pertencentes a 116 espécies. As espécies mais importantes na comunidade foram E.edulis (22,9% VI), Piptadenia gonoacantha (16,5%), Xylopia sericea (5,7%), Annona cacans (3,5%) e Syagrus romanzoffiana (3,3%), que juntas somaram 51,9% do VI. Destaque para E. edulis, com densidade relativa de 41,2% e presença em todas as parcelas. As 89 árvores mortas representam 4,6% do total de indivíduos, o valor mais baixo quando comparado com outras florestas secundárias da região, que ultrapassam 15%. A distribuição diamétrica da comunidade foi “J-reverso”, com grande concentração de indivíduos nas primeiras classes, mostrando boa capacidade regenerativa. No entanto, a população de P. gonoacantha, uma pioneira de ciclo de vida longo, apresentou distribuição desbalanceada, com decréscimo de indivíduos nas primeiras classes, indicando tendência de saída progressiva do sistema.Devido à dominância de E. edulis, o valor do índice de diversidade de espécies de Shannon (H’ = 2,98 nats/ind) foi próximo ao das florestas secundárias da região. Entretanto, com a exclusão da espécie dos cálculos, o valor do índice aumentou substancialmente (H’ = 3,89 nats/ind) sendo o mais elevado até o momento nas florestas da região, mostrando que o fragmento apresenta elevada diversidade arbórea. Os resultados mostram uma comunidade arbórea mais madura em relação a outras florestas secundárias estudadas na região, com elevada riqueza e diversidade de espécies, elevada área basal e baixa densidade de mortas, indicando franca “fase de construção”. Adicionalmente, a área possui grande densidade de E. edulis e presença de outras ameaçadas de extinção, e espécies de famílias características de floresta madura (ex. Lauraceae, Myrtaceae, Sapotaceae) com boa representatividade, demonstrando grande importância para a preservação da biodiversidade florística regional.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Comparisons of the relative basal area, density and frequency of coffee between shaded and unshaded systems that were abandoned (>70 years) and now are secondary forests in Juiz de Fora, Minas Gerais, Brazil.

<p>Area size was included as random effect to account for the possible confounding effect of patch size in our results and SAR models were performed to reduce spatial autocorrelation between plots. Different letters indicate significant differences between shaded and unshaded systems (p<0.05).</p

Simultaneous autoregressive (SAR) models between coffee basal area and native density (individuals.plot^-1), basal area (cm².plot^-1), absolute species richness (species.plot^-1), rarefied species richness (species.ind^-1), Shannon diversity (H’.plot^-1) of tree and sapling components.

<p>Moran’s I p-values > 0.05 indicate no spatial correlation among plots. The SAR models intercept, β coefficient, p-value and Nagelkerke R squared are given.</p

Bivariate relationships between coffee basal area and native community parameters of sapling and tree components.

<p>a) sapling basal area; b) tree basal area; c) sapling density; d) tree density; e) absolute species richness of saplings; f) absolute species richness of trees; g) rarefied species richness of saplings; h) rarefied species richness of trees; i) Shannon diversity of saplings; j) Shannon diversity of trees; k) percentage of pioneer saplings; l) percentage of pioneer trees. Only shaded systems were included because coffee was absent in most unshaded system plots (22 of 25 plots). Regression lines, confidence interval (95%) and Nagelkerke R² of SAR models are given for both shaded sites (BGJF-1 –solid symbols, N = 25; and MPP–open symbols, N = 10). Sites were included as random effect to account for the nestedness of the plots within sites, and SAR models were performed to reduce spatial autocorrelation among plots.</p

Persistence of <i>Coffea arabica</i> and its relationship with the structure, species diversity and composition of a secondary forest in Brazil

<div><p>Understanding the relationships between <i>Coffea arabica</i> L. and the native tree community of secondary forests regrowing after the abandonment of coffee plantations is important because, as a non-native species in the Neotropics, coffee can outcompete native species, reducing diversity and forests ecosystem services. We aimed to answer three questions: 1) Does coffee regeneration in secondary forests differ between shaded and unshaded abandoned plantations?; 2) How is coffee basal area related to structural attributes, species diversity and composition of the native community?; and 3) Do the relationships between coffee and native community differ between tree and sapling components? We sampled the tree and sapling components in a seasonal tropical dry forest that were previously used as shaded and unshaded coffee plantations. Coffee was the most important species in the sapling component of shaded systems, but was almost absent in unshaded ones. Coffee basal area was negatively related with the native density and absolute species richness of the sapling component; and was negatively related with tree density, and positively related with the percentage of pioneer individuals of the native tree component. Our results indicate that coffee persists in secondary forest communities even after more than 70 years of shaded-coffee plantations were abandoned, potentially reducing density and diversity of native species. Despite limitations, which hinder more general conclusions on coffee invasiveness in Brazilian secondary tropical forests, our results indicate that coffee is a strong competitor in the studied secondary forests and provide important insights for future research on this topic.</p></div