Silvicultural performance of five forest species in the central Brazilian Amazon / Desempenho silvicultural de cinco espécies florestais na Amazônia central brasileira

ABSTRACT Planting of forest species of timber interest helps to reduce the deforestation pressure on the Amazon forest, promotes sustainable development of the producing region and generates ecological benefits. The objective of this work was to evaluate the survival rate and growth of four native (Swietenia macrophylla, Parkia decussata, Dipteryx odorata and Jacaranda copaia) and one exotic (Acacia mangium) species in monospecific plantations (spacing of 2 x 2 m) established on areas previously used for grazing, in Itacoatiara, State of Amazonas, Brazil. When the trees were four years old, we collected biometric data [height at 1.30 m (DBH, cm), crown projection area (CPA, m2), total height (Ht, m), commercial cylinder volume (Vcyl, m3 ha-1)], and qualitative data from visual diagnosis [survival rate (S, %), nutritional status (NS, G = good, D = deficient, %), and phytosanitary status (PS, S = satisfactory, N = non-satisfactory, %)]. Three plots of 128 m2, with 32 plants each, were evaluated for each species. Jacaranda copaia, followed by Dipteryx odorata and Parkia decussata, were the recommended species for planting in areas with edaphoclimatic conditions similar to those of the present work, due to their better performance according to most of the variables.

RESUMO Plantios de espécies florestais de interesse madeireiro contribuem para diminuir a pressão sobre a floresta amazônica, proporcionam o desenvolvimento sustentável na região e geram benefícios ecológicos. Este estudo objetivou avaliar a sobrevivência e o crescimento de quatro espécies nativas (Swietenia macrophylla, Parkia decussata, Dipteryx odorata e Jacaranda copaia) e uma exótica (Acacia mangium), em plantios monoespecíficos (espaçamento de 2 x 2 m) estabelecidos em áreas anteriormente ocupadas por pastagem, em Itacoatiara, Amazonas. Aos quatro anos de idade, foram obtidos dados biométricos [diâmetro à altura de 1,30 m do solo (DBH, cm), área de projeção de copa (CPA, m2), altura total (Ht, m), volume comercial do cilindro (Vcyl, m3 ha-1)], e dados qualitativos obtidos por diagnose visual [taxa de sobrevivência (S; %), estado nutricional (NS, G: bom; D: deficiente; %) e estado fitossanitário (PS, S: satisfatório; NS: não-satisfatório; %). Para cada espécie considerou-se três parcelas de 128 m2, cada uma com 32 plantas. Jacaranda copaia, seguida de Dipteryx odorata e Parkia decussata, foram as espécies mais recomendadas para o plantio em áreas com condições edafoclimáticas semelhantes às do presente trabalho, devido ao seu melhor desempenho para a maioria das variáveis.

Regression models for estimating leaf area of seedlings and adult individuals of Neotropical rainforest tree species / Modelos de regressão para estimativa da área foliar de indivíduos jovens e adultos de espécies arbóreas de floresta neotropical

Abstract Individual leaf area (LA) is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length – L and width – W) of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx) with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx) had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.

Resumo Área foliar individual (AF) é uma variável chave em estudos sobre a ecofisiologia de arbóreas, porque influencia diretamente a interceptação de luz, a fotossíntese e a evapotranspiração das árvores adultas e das mudas. Foram analisadas as dimensões foliares (comprimento - C e largura - L) de indivíduos adultos e de mudas de sete espécies arbóreas de florestas neotropicais (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera e Tabebuia stenocalyx), com o objetivo de testar a viabilidade de modelos de regressão linear para estimar a AF de indivíduos adultos e mudas. No sul da Bahia, Brasil, um primeiro conjunto de dados foi coletado entre março e outubro de 2012. A partir das sete espécies analisadas, apenas duas (P. cattleyanum e T. stenocalyx) apresentaram relações muito semelhantes entre e AF e CL, em ambos os estádios ontogenéticos. Para estas duas espécies, um segundo conjunto de dados foi coletado em agosto de 2014, a fim de validar os modelos únicos que englobam folhas de indivíduos adultos e mudas. Nossos resultados mostram a possibilidade de desenvolvimento de modelos para a predição da área foliar, abrangendo diferentes estádios ontogenéticos para espécies arbóreas tropicais. O desenvolvimento destes modelos foi mais dependente das espécies do que das diferenças entre o tamanho das folhas de mudas e de indivíduos adultos.

Growth response of Lebanon cedar (Cedrus libani ) plantations to thinning intensity in Western Turkey.

This paper presents the growth response of 25 yr old Lebanon cedar (Cedrus libani A. Rich.) plantation to thinnings of different intensities in Isparta in western Turkey. The thinning intensity was measured by using the residual basal area (%) as parameter. In spring of 2005, three treatments were tested; light, moderate and heavy thinning with respectively 10, 25 and 35% of basal area removed. The statistical design of the experiment was a randomized incomplete block with two blocks and three treatments. Variables such as diameter at breast height (diameter) and height were measured. Growth rate ratios of diameter in moderately thinned and heavily thinned stands were 1.02 and 1.03, respectively. Basal area growth rates in moderately thinned and heavily thinned plots were 0.93 and 1.05, respectively. The largest values for the mean tree were observed with the heaviest thinning treatment. Absolute diameter increment was positively correlated with initial diameter in all plots. Relative diameter growth was negatively correlated with initial diameter. Growth rate interpretations were supported by analysis of variance using Duncan’s test of range multiple. The results obtained show significant differences between treatments for tree height growth, for the two inventories carried out (2005, 2008). However, diameter, basal area and volume were no found between treatments for tree.