Can fallen trees enhance aboveground biomass estimation? A proposal for the Brazilian Atlantic Forest / ¿Pueden los árboles caídos mejorar la estimación de la biomasa aérea? Una propuesta para el bosque atlántico brasileño

Introduction: Estimating aboveground biomass (AGB) in protected forests is a challenge, due to high costs and legal restrictions for direct assessments, and also to frequently weak estimation provided by general AGB equations. Objective: We propose a new approach that uses dead fallen trees (DFTs) to improve AGB estimation. We aim to analyse if the adjustment of allometric models based on DFTs provides a suitable local equation for AGB estimation or helps to validate existing pantropical or regional allometric equations. Methods: The study was carried out at the Dois Irmãos State Park (PEDI), Pernambuco, Northeast Brazil. Along 4 000 m, using the line intersect technique, we sampled 37 recent dead fallen trees ranging from 7.6 to 92.3 cm in diameter and from 8.6 to 29.4 m in height. Nine models were adjusted, and the best equation (local) was compared to regional and pantropical equations. Results: Oneequation (AGBkg= 1.5292* DBH2.0601*TH-0.2187) produced biomass estimates which did not differ from the observed values (P > 0.05). Differently from the others, this equation overestimated AGB in only 2.8 % and, along with other parameters of analysis (R2 adj and Syx %) had the best overall performance. Analysing the performance of the local equationversusavailable equations for estimating AGB, we found that only the local and the pantropical equations by Pearson et al. (2005) estimated values that were not significantly different from observed values. However, the local equation is more appropriate for local estimation of AGB, since it has the lowest RSME and CV. Conclusions: Based on the proposed approach, we were able to offer a local equation for tree AGB estimation based on fallen trees. The DFT method is efficient regarding time and costs, avoiding tree logging in protected forests and helps to guide the choice of a proper equation for forest AGB demands.

Introducción: La estimación de la biomasa aérea (AGB) en los bosques protegidos es un desafío, debido a los altos costos y las restricciones legales para las evaluaciones directas, y también a una estimación con frecuencia débil proporcionada por las ecuaciones generales de AGB. Objetivo: Proponemos un nuevo enfoque que utiliza los árboles muertos caídos (DFT) para mejorar la estimación de AGB. Nuestro objetivo es responder si el ajuste de modelos alométricos basados en DFT proporciona una ecuación local adecuada para la estimación de AGB o ayuda a validar las ecuaciones alométricas pantropicales o regionales existentes. Métodos: El estudio se realizó en el Parque Estatal Dois Irmãos (PEDI), Pernambuco, Nordeste de Brasil. En el espacio de 4 000 m, utilizando la técnica de intersección de líneas, se tomaron muestras de 37 árboles muertos recientemente que van desde 7.6 a 92.3 cm de diámetro y 8.6 a 29.4 m de altura. Se ajustaron nueve modelos y se comparó la mejor ecuación (local) con las ecuaciones regionales y pantropicales. Resultados: Una ecuación (AGBkg = 1.5292 * DBH2.0601 * TH-0.2187) determinó estimaciones de biomasa que no diferían de los valores observados (p> 0.05). A diferencia de las otras, esta ecuación sobreestimó AGB en solo 2.8 % y, junto con otros parámetros de análisis (R2 adj y Syx %), presentó el mejor rendimiento general. Analizando el rendimiento de la ecuación local versus las ecuaciones disponibles para estimar AGB, encontramos que solo las ecuaciones locales y pantropicales de Pearson et al. (2005) estimaron valores que no fueron significativamente diferentes de los valores observados. Sin embargo, la ecuación local es más apropiada para la estimación local de AGB, ya que tiene el RSME y CV más bajos. Conclusiones: Con base en el enfoque propuesto, pudimos proponer una ecuación local para la estimación de AGB basada en árboles caídos. La estimación basada en DFT es eficiente en términos de tiempo y costo, evita la tala de árboles en bosques protegidos y ayuda a guiar la elección de una ecuación adecuada para las demandas de AGB forestales.

Teor de umidade e densidade básica da madeira de nove espécies comerciais amazônicas / Moisture content and basic wood density of nine commercial Amazonian tree species

The aim of this work was to group species with similar moisture content and basic wood density in order to compose mixed species loads for industrial kiln drying. Nine tree species with three repetitions each were sampled at an Upland Forest in Central Amazonia. For all the species the moisture content was the same for top and base portions of the trunk, which gives stability during wood drying processes. The basic wood density values varied from 0,561 to 0,904 g cm-3. The species were divided in three groups based on basic density and moisture content; the first one included the species Minquartia guianensis, Lecythis poiteaui, Mezilaurus itauba, Manilkara huberi and Brosimum rubescens which are considered dificult or slow drying heavy woods (density ranging between 0,835 to 0,904 g cm-3). The second group was composed with the species Clarisia racemosa and Ocotea rubra (avarage density of 0,665 and 0,720 g cm-3, respectively), the third group includes Parkia paraensis and Brasimum parinarioides that showed average density and were considered fast drying woods (density of 0,561 e 0,588 g cm-3, respectively).

Este trabalho teve como objetivo agrupar espécies com características de teor de umidade e densidade básica da madeira semelhantes para compor cargas mistas de espécies para secagem em câmaras industriais de secagem da madeira. Foram amostradas nove espécies em floresta de terra firme na Amazônia Central com três repetições por espécie. Em todas as espécies os teores de umidade não diferiram entre base e topo do tronco, o que confere estabilidade da madeira durante o processo de secagem. Os valores de densidade básica variaram de 0,561 a 0,904 g cm-3. A partir do presente estudo foi possível separar as espécies em três grupos com base na densidade básica e teor de umidade, o primeiro com as espécies Minquartia guianensis, Lecythis poiteaui, Mezilaurus itauba, Manilkara huberi e Brosimum rubescens que são consideradas madeiras pesadas (densidade variando de 0,835 a 0,904 g cm-3) , de secagem mais lenta ou difícil. O segundo grupo contem as espécies Clarisia racemosa e Ocotea rubra (densidade média de 0,665 e 0,720 g cm-3, respectivamente) e o terceiro grupo com as espécies Parkia paraensis e Brasimum parinarioides que apresentam densidade média e secagem rápida (densidade de 0,561 e 0,588 g cm-3, respectivamente).

Microsatellite markers in candidate genes for wood properties and its application in functional diversity assessment in eucalyptus globulus

Background: Functional genetic markers have important implications for genetic analysis by providing direct estimation of functional diversity. Although high throughput sequencing techniques for functional diversity analysis are being developed nowadays, the use of already well established variable markers present in candidate genes is still an interesting alternative for mapping purposes and functional diversity studies. SSR markers are routinely used in most plant and animal breeding programs for many species including Eucalyptus. SSR markers derived from candidate genes (SSR-CG) can be used effectively in co-segregation studies and marker-assisted diversity management. Results: In the present study, eight new non reported SSRs were identified in seven candidate genes for wood properties in Eucalyptus globulus: cinnamoyl CoA reductase (CCR), homocysteine S-methyltransferase (HMT), shikimate kinase (SK), xyloglucan endotransglycosylase 2 (XTH2), cellulose synthase 3 (CesA3), glutathione S-transferase (GST) and the transcription factor LIM1. Microsatellites were located in promoters, introns and exons, being most of them CT dinucleotide repeats. Genetic diversity of these eight CG-derived SSR-markers was explored in 54 unrelated genotypes. Except for XTH2, high levels of polymorphism were detected: 93 alleles (mean of 13.1 sd 1.6 alleles per locus), a mean effective number of alleles (Ne) of 5.4 (sd 1.6), polymorphic information content values (PIC) from 0.617 to 0.855 and probability of Identity (PI) ranging from 0.030 to 0.151. Conclusions: This is the first report on the identification, characterization and diversity analysis of microsatellite markers located inside wood quality candidate genes (CG) from Eucalyptus globulus...

Allometry of the babassu palm growing on a slash-and-burn agroecosystem of the eastern periphery of Amazonia / Allometria da palmeira babaçu em um agroecossistema de derruba-e-queima na periferia este da Amazônia

Babassu (Attalea speciosa C.Martius, Arecaceae) is a palm with extraordinary socioeconomic and ecologic importance in large areas of tropical Brazil, especially in frequently burned and degraded landscapes. Nevertheless, surprisingly little is known about this keystone species. This paper investigates the allometry of babassu, in order to improve understanding on palm architecture and to provide researchers with an efficient tool for aboveground biomass estimation of juvenile and adult palms. Juvenile leaf biomass can be accurately predicted with the easily measurable minimum diameter of rachis at 30 cm extension. Adult palm biomass can be estimated based on woody stem height, a variable fairly easily measurable on-field. Leaf biomass of adult palms was highly variable, averaged 31.7 percent of aboveground biomass and can be estimated only indirectly through the relationships between wood:leaf-ratio and total aboveground biomass. Carbon contents varied little in the babassu palm, without size- or growth-stage related differences, suggesting the general applicability of values (42.5 percent C for stems, 39.8 percent C for leaves). As a consequence of the limited secondary diameter growth inherent to palms, stem diameter of adult palms is unrelated to palm height and biomass. Stem tapering decreases with increasing palm height. This is partially compensated by increasing wood density in near cylindrical stems. Nevertheless, maximum babassu palm height of about 30 meters appears to be dictated by mechanical stability constraints. All allometric relationships of babassu described in this study are not affected by vegetation stand age, indicating the general applicability of these relationships.

A palmeira babaçu (Attalea speciosa C.Martius, Arecaceae) tem grande importância socioeconômica e ecológica em grande parte da área tropical brasileira, especialmente em áreas degradadas por queimadas freqüentes na Amazônia. No entanto, ainda pouco se sabe sobre as características ecológicas desta espécie-chave. Este estudo investiga a alometria do babaçu com o objetivo de estabelecer uma metodologia eficiente na estimativa da biomassa aérea de palmeiras juvenis e adultas e para um melhor entendimento da sua arquitetura. A biomassa de palmeiras juvenis pode ser estimada facilmente e com precisão com o diâmetro mínimo das ráquis das folhas a 30 cm de extensão. A biomassa de palmeiras adultas pode ser estimada com base na altura do tronco lenhoso, também relativamente de fácil medição em campo. A biomassa foliar das palmeiras adultas foi em media 31,7 por cento da biomassa aérea, porém houve uma alta variação e, portanto, somente pode ser estimada indiretamente através da relação entre a razão madeira:folha e biomassa aérea total. Os teores de carbono no babaçu apresentaram baixa variação, sem diferenças sistemáticas em relação ao tamanho ou estágio de crescimento, o que aponta à aplicabilidade geral dos valores 42.5 por cento C para troncos, 39.8 por cento C para folhas. Em conseqüência do limitado crescimento secundário do diâmetro inerente de palmeiras, não houve relação do diâmetro de tronco com a altura e a biomassa das palmeiras adultas. Observou-se que o afilamento do caule diminui com o aumento da altura das palmeiras, o que é parcialmente compensado pelo incremento da densidade de madeira em troncos quase-cilíndricos. No entanto, a altura máxima do babaçu, de cerca de 30 metros, aparentemente está definida por limitações na estabilidade mecânica. Todas as relações alométricas aqui descritas são independentes da idade da vegetação, indicando a aplicabilidade geral das relações encontradas.

A Comparison of Sap Flow Measurements and Potometry in Two Tropical Lowland Tree Species with Contrasting Wood Properties

We evaluated the performance of the Heat Dissipation Technique (HDT) to measure sap flow in whole trees by comparison with potometric water uptake. Two tropical lowland species, Ochroma lagopus (balsa), a pioneer species with light wood and Hyeronima alchorneoides (pilón), a late-successional species with hard wood were examined. Diurnal courses of sap flow measured with the HDT showed good agreement with potometry. At the low sap flow rates (below 1 Kg h-1) occurring during nocturnal recharge HDT consistently underestimated sap flow rates. This resulted in the failure of the current version of the HDT to measure nocturnal water uptake, an important component of the water budget of at least one of the two species examined.

Wood density of trees in black water floodplains of Rio Jaú National Park, Amazonia, Brazil

The Jaú National Park is the largest protected forested area in the world. The Vitória Amazônica Foundation is working towards understanding its ecosystem, to which this paper contributes. Wood density was analysed in 27 common tree species growing in the blackwater flood-plains of the Rio Jaú, an affluent of the Rio Negro (Amazonia, Brazil). Wood was sampled with an increment borer. Mean wood density of the analysed species ranged from 0.35 to 0.87 g cm-3. The mean of all sampled species was 0.67 g cm-3 (st. dev. 0.13). Lowest density was found for Hevea spruceana with 0.32 g cm-3 and highest for Crudia amazonica with 0.9 g cm-3.

O Parque Nacional do Jaú é a maior área protegida do mundo completamente coberta por floresta. Este trabalho contribui para o conhecimento deste ecossistema, em colaboração com a Fundação Vitória Amazônica. A densidade da madeira de 27 espécies de árvores comuns nas áreas inundáveis do Rio Jaú, um afluente do Rio Negro, foi determinada com o método não destrutivo do trado. A densidade média das espécies analisadas variou entre 0.35 e 0.87 g cm-3. A média de todas as espécies foi de 0.67 g cm-3 (st. dev. 0.13). A menor densidade medida foi em Hevea spruceana com 0.32 g cm-3 e a maior em Crudia amazonica com 0.9 g cm-3.