Phosphorus (P) fertilization and liming can reduce negative effects caused by a sudden increase in light availability after thinning of forest plantations. In this study, immediately after thinning, photochemical performance (quantum yield of PSII and performance index) decreased, however, liming and P fertilization reduced the negative effects caused by thinning and accelerated the recovery of Bertholletia excelsa trees. After thinning, the remaining trees increased J-I phase with the formation of a positive K-band which occurred exclusively in unfertilized (no liming or no P) individuals. Additionally, enhanced effective dissipation (DI0/RC) values (140%) were found in individuals without liming or P after thinning, while plants under liming and P increased DI0/RC values by 47 and 79%, respectively. Photochemical performance of B. excelsa was positively correlated to iron, zinc, and manganese. Thus, P fertilization and liming are recommended for alleviating the stress caused by high irradiance after thinning in B. excelsa plantations.

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Energy forests emerge as an alternative to fossil fuels for energy production. The good performance of these forests should consider the selection of fast-growing species, high biomass productivity and energy yield. The aim was to investigate growth and energy yield of Acacia auriculiformis and Acacia mangium in a short-rotation plantation in the Amazonas. The energy yield was determined on 12 trees per species, from the results of biomass, calorific value and basic density. When 9 years-old, A. mangium had the highest growth rates in height (1.9 m yr-1) and DBH (2.5 cm yr-1). The greatest biomass productivity was observed in A. mangium (33.4 Mg ha-1 yr-1), which was 84% higher than A. auriculiformis (18.1 Mg ha-1 yr-1). Basic density (0.54 g cm-3) and calorific value (4,400 kcal kg-1) showed no significant differences between species. The energy yield of A. mangium (1,317 Gcal ha-1) was twice as of A. auriculiformis (684 Gcal ha-1). A. mangium has better energy performance, compared to the A. auriculiformis, and therefore could the most recommended for the formation of energy forests in disturbed areas in the state of Amazonas. ResumoBiomassa e produtividade energética de leguminosas arbóreas cultivadas no Amazonas. As florestas energéticas representam alternativa à dependência do uso de combustíveis fósseis para a produção de energia. O bom desempenho dessas florestas deve considerar a seleção de espécies de rápido crescimento, alta produtividade em biomassa e rendimento energético. O objetivo foi investigar o crescimento e a produtividade energética de Acacia auriculiformis e Acacia mangium em plantios florestais de curta rotação no Amazonas. A produtividade energética foi determinada em 12 árvores de cada espécie, a partir dos resultados de biomassa, poder calorífico e densidade básica. Aos 9 anos, A. mangium teve as maiores taxas de crescimento em altura (1,9 m ano-1) e DAP (2,5 cm ano-1). A maior produtividade de biomassa foi observada em A. mangium (33,4 Mg ha-1 ano-1), que foi 84% superior a de A. auriculiformis (18,1 Mg ha-1 ano-1). A densidade básica (0,54 g cm-3) e o poder calorífico (4.400 kcal kg-1) não apresentaram diferenças significativas entre as espécies. A produtividade energética de A. mangium (1.317 Gcal ha-1) foi duas vezes maior que a de A. auriculiformis (684 Gcal ha-1). Acacia mangium tem melhor desempenho energético quando comparada à A. auriculiformis, sendo portanto mais recomendada para a formação de florestas energéticas em áreas alteradas no estado do Amazonas.Palavras-chave: Acacia mangium; Acacia auriculiformis; plantios de curta rotação.

As estratégias de distribuição de biomassa e nutrientes utilizadas pelas espécies florestais podem refletir sua capacidade de sobrevivência em plantios sobre áreas degradadas. O objetivo deste estudo foi quantificar os estoques de biomassa e nutrientes nos compartimentos arbóreos de Parkia multijuga, Parkia nitida e Parkia pendula em plantios sobre área degradada em Manaus, AM. A biomassa foi determinada pelo método destrutivo em seis árvores de cada espécie, que foram compartimentadas em: folhas, galhos finos (Ø <10 cm), galhos grossos (Ø ≥10 cm), fuste, raízes médias (2 mm ≤ Ø <5 cm) e raízes grossas (Ø ≥5 cm). Aos quatro anos, Parkia multijuga exibiu 60% do total de biomassa nos compartimentos aéreos e 40% nos subterrâneos. Parkia nitida exibiu 84% nos compartimentos aéreos e apenas 16% nos subterrâneos. Parkia pendula exibiu 67% nos compartimentos aéreos e 33% nos subterrâneos. A ordem de acúmulo de macronutrientes nos compartimentos foi: N > Ca > K > Mg > P. O fato de Parkia multijuga adotar estratégias de alocação de biomassa e nutrientes que favorecerão seu desempenho sobre sítios com baixa disponibilidade de recursos sustenta sua indicação para a composição de programas de reflorestamento em áreas degradadas na Amazônia.Palavras-chave: Espécies florestais nativas; nutrição florestal; reflorestamento; restauração. AbstractBiomass and nutrients in three species of Parkia plantings on degraded area in Central Amazon. Biomass and nutrients partitioning strategies in tree species may reflect their ability to survive in plantations on degraded areas. The objective of this study was to investigate the content of biomass and nutrients in tree components of Parkia multijuga, Parkia nitida and Parkia pendula on plantings in degraded area in Manaus, AM. The biomass was determined by the harvest method in six trees of each species, which were subdivided into leaves, fine branches (Ø < 10 cm), coarse branches (Ø ≥10 cm), stem wood, medium roots (≤ 2 mm Ø < 5 cm ) and coarse roots (Ø ≥ 5 cm). At 4 years, Parkia multijuga allocated 60% of the total biomass to above-ground components and 40% to below-ground. Parkia nitida allocated 84% to above-ground and 16% to below-ground. Parkia pendula allocated 67% to above-ground components and 33% to below-ground. The order of the nutrient accumulation in tree compartments was: N > Ca > K > Mg > P. Parkia multijuga, by adopting better strategies of distribution of biomass and nutrients, it is a recommended species for reforestation programs on degraded sites in the Amazon.Keywords: Native forest species; forest nutrition; reforestation; restoration.

N-fixing leguminous species can reach atmospheric dinitrogen gas (N2), having an advantage under N-limited degraded environments. These N-fixers are constantly used as facilitative species. Chlorophyll a fluorescence (ChF) acknowledges how different species take up and use light energy during photosynthesis. These techniques assess stress and performance responses to photosynthesis and are used for the selection of species with potential for reforestation. Six Fabaceae species were selected for this study: three nonfixing species (Cenostigma tocantinum, Senna reticulata and Dipteryx odorata) and three N-fixing species (Clitoria fairchildiana, Inga edulis and Acacia spp.). Variations in chlorophyll fluorescence under high vs. low water and nutrient conditions were studied. Multivariate analysis was performed to detect the effects of seasonality and fertilization on dark-adapted ChF two years after the experiment was established. The correlation among ChF variables and growth, photosynthesis and foliar nutrient concentrations was evaluated. Under high water- and nutrient-availability conditions, plants exhibited an enhanced performance index on absorption basis values correlated with electron transport fluxes. Under drought and nutrient-poor conditions, most species exhibit increased energy dissipation as photoprotection. High interspecific variation was found; therefore, species-specific responses should be considered in future ChF studies. Corroborating the ability to colonize high-light environments, N-fixers showed an increased performance index correlated with electron transport and Zn and N foliar concentrations. Negative correlations were found between photosynthesis and trapped fluxes. Diameter growth was positively correlated with electron transport fluxes. Given the different responses among species, ChF is an effective technique to screen for seasonality, fertilization and species effects and should be considered for use during forest restoration. Finally, the addition of fertilization treatments may facilitate tropical forest restoration due to the importance of nutrients in physiological processes. N-fixers showed high photochemical performance and tolerance to abiotic stress in degraded areas and therefore should be included to support ecosystem biomass restoration.

ResumoFotossíntese de espécies de Anibae em resposta à exposição a ambientes contrastantes de luz. Características ecofisiológicas e o ambiente de luz têm implicações sobre o estabelecimento de plantios florestais. O objetivo desse estudo foi investigar a fotossíntese de Aniba canelilla e A. rosaeodora em resposta à disponibilidade de luz no campo. As trocas gasosas, conteúdo de clorofilas (ICC) e desempenho fotoquímico (F V /F M ) foram medidos em folhas aclimatadas (sombra durante 300 dias), a pleno sol (28 dias) e novamente à sombra durante 28 dias. A fotossíntese, ICC e F V /F M de A. canelilla e A. rosaeodora foram afetadas negativamente a pleno sol, mas se recuperaram quando submetidas à sombra. A fotossíntese, ICC e F V /F M foram duas vezes superiores nas plantas de sombra. Aniba rosaeodora apresentou desempenho fotossintético duas vezes superior a A. canelilla. As diferenças nas respostas fotossintéticas à luz sugerem que as espécies poderiam ocupar "nichos" de sucessão diferentes em plantios de enriquecimento e, a plasticidade (mediada pela recuperação) implica aclimatação em ambientes de luz variável. O fato das espécies de Anibae estudadas possuírem diferenças de plasticidade para luz deve ser visto com cautela para sugerir plantios convencionais, mas reforça a indicação para plantios de enriquecimento em sítios florestais com variações na disponibilidade de luz. Palavras-chave: Aniba canelilla, Aniba rosaeodora, fluorescência da clorofila a, plantios florestais, trocas gasosas. AbstractPhotosynthesis of species of Anibae in response to the exposure to contrasting light environments. Ecophysiological traits and the light environment have implications for the establishment of forest plantations. The aim of this study was to investigate the photosynthetic activity of Aniba canelilla and A. rosaeodora in response to changes in the availability of light in the field. Gas exchange, content of chlorophylls (ICC) and photochemical performance (F V /F M ) were measured in leaves acclimated in the shade during 300 days, after in the full sun (28 days) and again in the shade by 28 days. The photosynthesis, ICC and F V /F M of A. canelilla and A. rosaeodora were negatively affected in full sunlight, but the plants recovered when submitted to shade. Photosynthesis, ICC and F V /F M were twice as high in shade plants. Aniba rosaeodora presented photosynthetic performance twice higher than A. canelilla. Differences in photosynthetic responses to light suggest that species could occupy different succession "niches" in enrichment plantation, and plasticity (recovery-mediated) implies acclimatization under variable light environments. The fact that the studied species of Anibae have differences in plasticity for light should be viewed with caution to suggest conventional plantations, but it reinforce the indication for enrichment plantations in forest sites with variations in the availability of light.

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