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Deforestation in the Amazon has resulted in large areas of depleted soils on abandoned pastures and agricultural sites that present a restoration challenge central to protecting biodiversity and ecosystem function in the region. Biochar - charcoal made from waste materials - can improve soil physical, chemical, and biological properties, but the few tropical field trials to date do not give consistent results regarding tree growth. This study presents three years of soil performance and tree growth of a secondary forest shading nontimber forest product (NTFP) plantations of Ocotea quixos (Lauraceae), Myroxylon balsamum (Fabaceae), and their mixture. Open kiln and traditional mound biochars were added at 10 t ha-1 at two sites with contrasting soil types. Biochar additions resulted in pronounced effects on soil properties that varied over time and with depth in the soil profile. Biochar additions generally increased soil organic matter, electrical conductivity, and plant nutrients (in particular K, Ca, and N), but there were interactive effects of NTFP treatments, and stronger responses on the poorer soil type. Biochar amendments resulted in increased tree growth, with a 29 ± 12% increase in aboveground biomass (AGB) on plots amended with kiln biochar and a 23 ± 9% increase in plots with mound biochar compared to controls. Tree species also varied in growth responses to biochar additions, with the largest increases observed in Jaccaranda copaia and Piptocoma discolor. Significant interactions between biochar and NTFP treatments were also seen for tree growth responses, such as Cecropia spp., which only showed increased biomass on mound biochar plots planted with Ocotea quixos. Overall, our results demonstrate a stronger effect of biochar in less favorable soil conditions, and an overriding effect of the legume NTFP in richer soils, and suggest that additions of biochar and legumes are important options to increase productivity and ecological resilience in tropical forest restoration.

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BACKGROUND: Rapid non-destructive measurements to predict cassava root yield over the full growing season through large numbers of germplasm and multiple environments is a huge challenge in Cassava breeding programs. As opposed to waiting until the harvest season, multispectral imagery using unmanned aerial vehicles (UAV) are capable of measuring the canopy metrics and vegetation indices (VIs) traits at different time points of the growth cycle. This resourceful time series aerial image processing with appropriate analytical framework is very important for the automatic extraction of phenotypic features from the image data. Many studies have demonstrated the usefulness of advanced remote sensing technologies coupled with machine learning (ML) approaches for accurate prediction of valuable crop traits. Until now, Cassava has received little to no attention in aerial image-based phenotyping and ML model testing. RESULTS: To accelerate image processing, an automated image-analysis framework called CIAT Pheno-i was developed to extract plot level vegetation indices/canopy metrics. Multiple linear regression models were constructed at different key growth stages of cassava, using ground-truth data and vegetation indices obtained from a multispectral sensor. Henceforth, the spectral indices/features were combined to develop models and predict cassava root yield using different Machine learning techniques. Our results showed that (1) Developed CIAT pheno-i image analysis framework was found to be easier and more rapid than manual methods. (2) The correlation analysis of four phenological stages of cassava revealed that elongation (EL) and late bulking (LBK) were the most useful stages to estimate above-ground biomass (AGB), below-ground biomass (BGB) and canopy height (CH). (3) The multi-temporal analysis revealed that cumulative image feature information of EL + early bulky (EBK) stages showed a higher significant correlation (r = 0.77) for Green Normalized Difference Vegetation indices (GNDVI) with BGB than individual time points. Canopy height measured on the ground correlated well with UAV (CHuav)-based measurements (r = 0.92) at late bulking (LBK) stage. Among different image features, normalized difference red edge index (NDRE) data were found to be consistently highly correlated (r = 0.65 to 0.84) with AGB at LBK stage. (4) Among the four ML algorithms used in this study, k-Nearest Neighbours (kNN), Random Forest (RF) and Support Vector Machine (SVM) showed the best performance for root yield prediction with the highest accuracy of R2 = 0.67, 0.66 and 0.64, respectively. CONCLUSION: UAV platforms, time series image acquisition, automated image analytical framework (CIAT Pheno-i), and key vegetation indices (VIs) to estimate phenotyping traits and root yield described in this work have great potential for use as a selection tool in the modern cassava breeding programs around the world to accelerate germplasm and varietal selection. The image analysis software (CIAT Pheno-i) developed from this study can be widely applicable to any other crop to extract phenotypic information rapidly.

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ABSTRACT Dry tropical forests are a key component in the global carbon cycle and their biomass estimates depend almost exclusively of fitted equations for multi-species or individual species data. Therefore, a systematic evaluation of statistical models through validation of estimates of aboveground biomass stocks is justifiable. In this study was analyzed the capacity of generic and specific equations obtained from different locations in Mexico and Brazil, to estimate aboveground biomass at multi-species levels and for four different species. Generic equations developed in Mexico and Brazil performed better in estimating tree biomass for multi-species data. For Poincianella bracteosa and Mimosa ophthalmocentra, only the Sampaio and Silva (2005) generic equation was the most recommended. These equations indicate lower tendency and lower bias, and biomass estimates for these equations are similar. For the species Mimosa tenuiflora, Aspidosperma pyrifolium and for the genus Croton the specific regional equations are more recommended, although the generic equation of Sampaio and Silva (2005) is not discarded for biomass estimates. Models considering gender, families, successional groups, climatic variables and wood specific gravity should be adjusted, tested and the resulting equations should be validated at both local and regional levels as well as on the scales of tropics with dry forest dominance.

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ResumenLa distribución de carbono azul en los ecosistemas, entre los que se cuentan los manglares, es poco conocida en comparación con los grandes avances que existen para los ecosistemas forestales terrestres, a pesar de que su alta productividad y capacidad de almacenamiento de carbono es reconocida. Este estudio, tuvo por objetivo, analizar la biomasa aérea de las especies Rhizophora mangle y Avicennia germinans en el ecosistema de manglar localizado en el área marina protegida denominada Distrito de Manejo Integrado (DMI) Cispatá-Tinajones-La Balsa en el Caribe colombiano. Para ello, con la debida autorización oficial, se cosecharon 30 individuos de cada especie, con el fin de generar modelos alométricos que permitieran estimaciones de biomasa aérea con bajos niveles de incertidumbre. Los resultados indican que la biomasa aérea de los bosques de manglar del Caribe colombiano en el DMI, es de 129.69 ± 20.24 Mg/ha, es decir, que almacenan 64.85 ± 10.12 MgC/ ha. Teniendo en cuenta que el DMI presenta un área de 8 570.9 ha en bosques de manglar, se estima que el carbono total potencialmente almacenado por este ecosistema es de aproximadamente 555 795.93 MgC. Las ecuaciones generadas en este estudio se pueden considerar como una opción alternativa para la evaluación de las reservas de carbono en la biomasa aérea de los bosques de manglar en del Caribe colombiano, dado que otros modelos disponibles para la estimación de la biomasa aérea no discriminan a los bosques de manglar, a pesar de ser ecosistemas particulares. Los modelos pueden ser empleados como una opción para apoyar las estrategias de conservación de bosques y la reducción de emisiones. En general, el potencial de almacenamiento de carbono en los bosques de manglar del Caribe colombiano, es importante, y podría posesionar al país en la conservación de bosques y la reducción de emisiones a través de la conservación del carbono azul almacenado.

AbstractThe distribution of carbon in “Blue Carbon” ecosystems such as mangroves is little known, when compared with the highly known terrestrial forests, despite its particular and recognized high productivity and carbon storage capacity. The objective of this study was to analyze the above ground biomass (AGB) of the species Rhizophora mangle and Avicennia germinans from the Marine Protected Area of Distrito de Manejo Integrado (DMI), Cispatá-Tinajones-La Balsa, Caribbean Colombian coast. With official authorization, we harvested and studied 30 individuals of each species, and built allometric models in order to estimate AGB. Our AGB results indicated that the studied mangrove forests of the DMI Colombian Caribbean was of 129.69 ± 20.24 Mg/ha, equivalent to 64.85 ± 10.12 MgC/ha. The DMI has an area of 8 570.9 ha in mangrove forests, and we estimated that the total carbon potential stored was about 555 795.93 Mg C. The equations generated in this study can be considered as an alternative for the assessment of carbon stocks in AGB of mangrove forests in Colombia; as other available AGB allometric models do not discriminate mangrove forests, despite being particular ecosystems. They can be used for analysis at a more detailed scale and are considered useful to determine the carbon storage potential of mangrove forests, as a country alternative to support forest conservation and emission reduction strategies. In general, the potential of carbon storage from Colombian Caribbean mangrove forests is important and could promote the country leadership of the “blue carbon” stored. Rev. Biol. Trop. 64 (2): 913-926. Epub 2016 June 01.

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The tropical montane forests in the Colombian Andean region are located above 1 500m, and have been heavily deforested. Despite the general presumption that productivity and hence carbon stocks in these ecosystems are low, studies in this regard are scarce. This study aimed to i) to estimate Above Ground Biomass (AGB) in forests located in the South of the Colombian Andean region, ii) to identify the carbon storage potential of tropical montane forests dominated by the black oak Colombobalanus excelsa and to identify the relationship between AGB and altitude, and iii) to analyze the role of tropical mountain forests in conservation mechanisms such as Payment for Environmental Services (PES) and Reducing Emissions from Deforestation and Degradation (REDD+). Twenty six 0.25ha plots were randomly distributed in the forests and all trees with D≥10cm were measured. The results provided important elements for understanding the role of tropical montane forests as carbon sinks. The information produced can be used in subnational initiatives, which seek to mitigate or reduce the effects of deforestation through management or conservation of these ecosystems, like REDD+ or PES. The AGB and carbon stocks results obtained were similar to those reported for lowland tropical forests. These could be explained by the dominance and abundance of C. excelsa, which accounted for over 81% of AGB/carbon. The error associated with the estimates of AGB/carbon was 10.58%. We found a negative and significant relationship between AGB and altitude, but the higher AGB values were in middle altitudes (≈1 700-1 800m), where the environmental conditions could be favorable to their growth. The carbon storage potential of these forests was higher. However, if the historical rate of the deforestation in the study area continues, the gross emissions of CO2e to the atmosphere could turn these forests in to an important emissions source. Nowadays, it is clear that tropical montane forests are vulnerable to deforestation, especially black Oak forests due to their commercial value. Given their high carbon storage potential, the presence of endemic species and the strategic functions of these ecosystems, we recommend that they should be considered relevant during REDD+, PES or any other conservation assessment. Rev. Biol. Trop. 63 (1): 69-82. Epub 2015 March 01.

Los bosques tropicales de montaña (BTM) en la región Andina de Colombia se encuentran por encima de 1 500m, y han sido fuertemente deforestados. A pesar de la presunción general de que la productividad y las reservas de carbono en estos ecosistemas son bajas, los estudios al respecto son escasos. Este estudio tuvo por objetivo i) estimar la biomasa aérea (BA) de los bosques localizados en el sur de la región Andina colombiana, ii) identificar el potencial de almacenamiento de carbono en bosques dominados por el roble negro Colombobalanus excelsa e identificar la relación entre la BA y la altitud, y iii) analizar su papel en mecanismos de conservación, como el Pago por Servicios Ambientales (PSA) y la Reducción de Emisiones por deforestación y Degradación (REDD+). Veintiséis parcelas de 0.25ha fueron distribuidas al azar, y se midieron todos los árboles con D≥10cm. Los resultados obtenidos de BA y carbono almacenado fueron similares a los reportados para bosques tropicales de tierras bajas. Esto se puede explicar por la abundancia y dominancia de C. excelsa, que contribuye con más del 81% de la BA/carbono; el error asociado a las estimaciones fue de 10.58%. Se encontró una relación negativa y significativa entre la BA y la altitud, pero los valores más altos de BA estuvieron en las altitudes medias (≈1 700-1 800m), donde las condiciones ambientales podrían ser favorables para su crecimiento. El potencial de almacenamiento de carbono de estos bosques fue alto. Los resultados permiten tener elementos importantes para entender el papel de los BTM como sumideros de carbono. Sin embargo, si la tasa histórica de deforestación en el área de estudio continúa, las emisiones brutas de CO2e a la atmósfera podrían convertirlos en una fuente de emisiones importante. Actualmente, los BTM son vulnerables a la deforestación, especialmente los bosques de roble negro debido a su valor comercial. Teniendo en cuenta el alto potencial de almacenamiento de carbono, la presencia de especies endémicas, y las funciones estratégicas que pueden desempeñar estos ecosistemas, se recomienda que sean considerados relevantes para REDD+, PSA u otra estrategia de conservación.

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Restoration of Atlantic Forests is receiving increasing attention because of its role in both biodiversity conservation and carbon sequestration for global climate change mitigation. This study was carried out in an Atlantic Forest restoration project in the south-central region of São Paulo State - Brazil to develop allometric equations to estimate tree biomass of indigenous tree species in mixed plantations. Above and below-ground biomass (AGB and BGB, respectively), stem diameter (DBH: diameter at 1.3 m height), tree height (H: total height) and specific wood density (WD) were measured for 60 trees of 19 species. Different biomass equations (linear and nonlinear-transformed) were adjusted to estimate AGB and BGB as a function of DBH, H and WD. For estimating AGB and BGB, the linear biomass equation models were the least accurate. The transformed nonlinear biomass equation that used log DBH2, log H and log WD as predictor variables were the most accurate for AGB and the transformed nonlinear biomass equations that used log DBH2*WD as predictor variables were the most accurate for BGB. It is concluded that these adjusted equations can be used to estimate the AGB and BGB in areas of the studied project. The adjusted equations can be recommended for use elsewhere in the region for forest stands of similar age, tree size ranges, species composition and site characteristics.

A restauração da Mata Atlântica vem recebendo aumento na atenção por causa do papel na conservação da biodiversidade e sequestro de carbono para a mitigação da mudança global do clima. Este estudo foi conduzido em um projeto de restauração da Mata Atlântica na região centro-sul do Estado de São Paulo - Brasil e buscou desenvolver equações alométricas para estimar a biomassa arbórea de espécies nativas em plantios mistos. Em 60 árvores de 19 espécies foram medidas a biomassa acima e abaixo do solo, o diâmetro do tronco (DAP: diâmetro a 1,3 m de altura), altura (H) e densidade específica da madeira (Ds). Diferentes equações de biomassa (linear e não linear) foram ajustadas para estimar a biomassa acima e abaixo do solo, utilizando DAP, H e Ds como variáveis preditoras. As equações de biomassa lineares foram as menos acuradas para a estimativa da biomassa acima e abaixo do solo. As equações de biomassa não lineares que usaram log DAP2, log H e log Ds como variáveis preditoras foram mais acuradas para a estimativa da biomassa acima do solo e as não lineares que usaram log DBH2*WD como variáveis preditoras foram as mais acuradas para a estimativa da biomassa abaixo do solo. Conclui-se que estas equações ajustadas podem ser usadas na estimativa da biomassa acima e abaixo do solo nas áreas do projeto estudado. Também pode ser considerado o uso destas equações ajustadas em outras áreas restauradas da Mata Atlântica com idade do povoamento, classes de tamanho das árvores, composição de espécies e características das áreas similares ao deste estudo, desde que árvores sejam avaliadas para verificar a eficácia da equação a ser usada.

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Diversity and dynamics of a high sub-Andean forest from Northern Andes, Colombia. The sub-Andean forests are characterized by a high biodiversity, but little is known about their natural dynamics. In order to generate new information, this study assessed two permanent plots of one hectare each, in the Northern Andean area of the Western Cordillera, Colombia. Methodology included the evaluation of diversity patterns, above ground biomass (AGB) dynamics, and mortality and recruitment rates. Besides, we used the Fisher´s Alpha index to calculate species diversity. Forest dynamics and AGB were evaluated in both plots by means of three censuses carried out within a nine years period. In total, we found 1 664 individuals with diameter at breast height (DBH)≥10cm belonging to 222 species, 113 genera and 60 families. Mean species richness was of 156 species/ha and a mean Fisher´s Alpha index of 56.2/ha. The mortality rate was 0.88% and recruitment was 1.16%, which did not allow to lay any external effect of global warming or climate change on individual forest dynamics. However, the mean AGB was 243.44±9.82t/ha, with an annual average increase of 2.9t/ha, a higher value than the one reported in other studies of high sub-Andean forests, which suggests that equilibrium in terms of the AGB have not yet been reached. Besides, according to field observations, a recovery process, from a disturbance that occurred in the past, might be on his way. Rev. Biol. Trop. 60 (2): 943-952. Epub 2012 June 01.

Los bosques sub-Andinos poseen alta diversidad biológica, de los cuales poco se conoce sobre su dinámica natural. Se evaluaron patrones de diversidad y biomasa, tasas de mortalidad y reclutamiento en dos parcelas permanentes de una hectárea cada una, establecidas en bosques en altitudes entre los 2 000-2 200msnm, en la vertiente Oriental de la cordillera Occidental del norte de los Andes en Colombia. Se determino diversidad de especies mediante el índice alpha de Fisher, la dinámica del bosque se evaluó mediante tres censos durante nueve anos. En total, se hallaron 1 964 individuos con un diámetro a la altura del pecho DAP≥10cm. pertenecientes a 222 especies, 113 géneros y 60 familias. La riqueza media de especies fue de 156 especies por hectárea y un índice alpha medio de Fisher de 56.2/h. Las tasas de mortalidad y reclutamiento fueron de 0.88% y 1.16% respectivamente, lo cual no indica que se presente un efecto externo proveniente del calentamiento global sobre la dinámica del bosque. La biomasa aérea promedio fue de 243.44±9.82tn/ha con un incremento anual promedio de 2.9ton/ha, valor superior a los reportados, lo cual sugiere que el equilibrio para este bosque no se ha alcanzado. De acuerdo con las observaciones de campo, este bosque parece estar recuperándose de una alteración pasada.

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Structural recovering in Andean successional forests from Porce (Antioquia, Colombia). Places subjected to natural or human disturbance can recover forest through an ecological process called secondary succession. Tropical succession is affected by factors such as disturbances, distance from original forest, surface configuration and local climate. These factors determine the composition of species and the time trend of the succession itself. We studied succession in soils used for cattle ranching over various decades in the Porce Region of Colombia (Andean Colombian forests). A set of twenty five permanent plots was measured, including nine plots (20x50m) in primary forests and sixteen (20x25m) in secondary forests. All trees with diameter ≥1.0cm were measured. We analyzed stem density, basal area, above-ground biomass and species richness, in a successional process of ca. 43 years, and in primary forests. The secondary forests’ age was estimated in previous studies, using radiocarbon dating, aerial photographs and a high-resolution satellite image analysis (7 to >43 years). In total, 1 143 and 1 766 stems were measured in primary and secondary forests, respectively. Basal area (5.7 to 85.4m²ha-1), above-ground biomass (19.1 to 1 011.5 t ha-1) and species richness (4 to 69) directly increased with site age, while steam density decreased (3 180 to 590). Diametric distributions were "J-inverted" for primary forests and even-aged size-class structures for secondary forests. Three species of palms were abundant and exclusive in old secondary forests and primary forests: Oenocarpus mapora, Euterpe precatoria and Oenocarpus bataua. These palms happened in cohorts after forest disturbances. Secondary forest structure was 40% in more than 43 years of forest succession and indicate that many factors are interacting and affecting the forests succession in the area (e.g. agriculture, cattle ranching, mining, etc.). Rev. Biol. Trop. 58 (1): 427-445. Epub 2010 March 01.

Lugares susceptibles a perturbaciones naturales o antrópicas pueden recuperar la cobertura boscosa. La sucesión tropical puede ser afectada por factores tales como perturbaciones, distancia al bosque original, topografía y clima local. Estos factores determinan la composición de especies y la tasa de recuperación de los sitios. Se estudió la sucesión en suelos que habían sido usados para el establecimiento de pasturas ganaderas por varias décadas en la Región Porce de Colombia (bosques Colombianos de los Andes). Se midieron un total de veinticinco parcelas, incluyendo nueve parcelas (20x50m) en bosques primarios y dieciséis (20x25m) en bosques secundarios. Se midieron todos los árboles con un diámetro ≥1.0cm. Se analizó la densidad, área basal, biomasa aérea y riqueza de especies, en un bosque con un proceso sucesional de ca. 43 años y en un bosque primario. Las edades de los bosques secundarios fueron obtenidas en estudios previos usando la datación con carbono catorce (C14), fotografías aéreas y el análisis de imágenes de satélite de alta resolución (entre 7 y >43 años). En total, 1 143 y 1 766 individuos se midieron en bosque primario y secundario, respectivamente. El área basal (5.7 a 85.4m²ha-1), la biomasa aérea (19.1 a 1 011.5 t ha-1) y la riqueza de especies (4 a 69) aumentaron directamente con la edad de los sitios, mientras que la densidad de árboles disminuyó (3 180 a 590). Las distribuciones diamétricas fueron en J-invertida para los bosques primarios y unimodal para los secundarios. Tres especies de palmas fueron abundantes y exclusivas de bosques secundarios viejos y bosques primarios: Oenocarpus mapora, Euterpe precatoria y Oenocarpus bataua. Cohortes de estas palmas aparecieron después de perturbaciones del bosque. La recuperación de la estructura de los bosques secundarios en más de 43 años de sucesión fue 40% e indica que varios factores están interactuando y afectando la sucesión de los bosques en el área (e.g. agricultura, ganadería extensiva, minería, etc.).

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Medidas mensais da altura da pastagem, biomassa total, variações de biomassa viva e morta, a área específica foliar (SLA) e o Índice de Área de Folha (IAF) de fevereiro de 1999 a janeiro de 2005 na Fazenda Nossa Senhora (FNS) e em Rolim de Moura (RDM) entre Fevereiro a Março de 1999, Rondônia, Brasil. A pastagem predominante é Urochloa brizantha (Hochst. ex A. Rich) R. D. Webster (99 por cento na FNS e 76 por cento em RDM), com pequenas manchas de Urochloa humidicula (Rendle). A altura média anual da grama foi de ~0,16 m. Com o pastejo, o mínimo mensal foi de 0,09 m (estação seca) e máximo de 0,3 m sem pastejo (estação úmida). O IAF, biomassa total, material morto, vivo e SLA tiveram valores médios de 2,5 m² m-2 , 2202 kg ha-1, 2916 kg ha-1 e 19 m² kg-1 respectivamente. A média mensal da biomassa foi 4224 kg ha-1 em 2002 e 6667 kg ha-1 em 2003. Grande variação sazonal do material vivo e morto, sendo mais alto o vivo durante a estação úmida (3229 contra 2529 kg ha-1), sendo o morto maior durante a seca (2542 contra 1894 kg ha-1). O nível de água no solo variou de -3,1 a -6,5 m durante as estações. Em médias anuais os IAF foram de 1,4 em 2000 a 2,8 em 2003 e o SLA entre 16,3 m² kg-1 em 1999 e 20,4 m² kg-1 em 2001. As observações do Albedo variaram de 0,18 para 0,16 em relação aos altos valores de IAF.

Monthly measurements of the grass height, total above-ground biomass and the proportions of live and dead biomass, Specific Leaf Area (SLA) and Leaf Area Index (LAI) were made in one cattle ranch at the Fazenda Nossa Senhora (FNS) (February of 1999 to January of 2005) and also in Rolim de Moura (RDM) (February to March of 1999) in Rondônia state. The predominant grass species is Urochloa brizantha (Hochst. ex A. Rich) R. D. Webster (covering 99 percent of the area in FNS and 76 percent in RDM), with minor patches of Urochloa humidicula. This pasture was regularly grazed. The average grass height was 0.16 m but monthly value varied between 0.09 m after intensive grazing in the dry season to 0.32 m in a wet season without grazing. The LAI, total biomass, dead plant material, live above-ground plant material and SLA average 2,5 m² m-2, 2202 kg ha-1, 2916 kg ha-1 and 19 m² kg-1 respectively. The monthly average above-ground biomass showed little seasonal variation, but annual averages ranged from 4224 kg ha-1 in 2002 to 6667 kg ha-1 in 2003. Live biomass was significantly higher during the wet season than during the dry season (3229 versus 2529 kg ha-1) whereas dead biomass was higher during the dry season than during the wet season (2542 versus 1894 kg ha-1). The groundwater levels changes from -3.1 m to -6.5 m during the wet and dry seasons, respectively. The annual average of SLA was 16.3 m² kg-1 in 1999 and 20.4 m² kg-1 in 2001. And for LAI was 1.5 in 2000 to 2.8 in 2003. The Albedo changes from 0.18 down to 0.16 at higher values of LAI.

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Monthly measurements of the grass height, total above-ground biomass and the proportions of live and dead biomass, Specific Leaf Area (SLA) and Leaf Area Index (LAI) were made in one cattle ranch at the Fazenda Nossa Senhora (FNS) (February of 1999 to January of 2005) and also in Rolim de Moura (RDM) (February to March of 1999) in Rondônia state. The predominant grass species is Urochloa brizantha (Hochst. ex A. Rich) R. D. Webster (covering 99% of the area in FNS and 76% in RDM), with minor patches of Urochloa humidicula. This pasture was regularly grazed. The average grass height was 0.16 m but monthly value varied between 0.09 m after intensive grazing in the dry season to 0.32 m in a wet season without grazing. The LAI, total biomass, dead plant material, live above-ground plant material and SLA average 2,5 m² m-2, 2202 kg ha-1, 2916 kg ha-1 and 19 m² kg-1 respectively. The monthly average above-ground biomass showed little seasonal variation, but annual averages ranged from 4224 kg ha-1 in 2002 to 6667 kg ha-1 in 2003. Live biomass was significantly higher during the wet season than during the dry season (3229 versus 2529 kg ha-1) whereas dead biomass was higher during the dry season than during the wet season (2542 versus 1894 kg ha-1). The groundwater levels changes from -3.1 m to -6.5 m during the wet and dry seasons, respectively. The annual average of SLA was 16.3 m² kg-1 in 1999 and 20.4 m² kg-1 in 2001. And for LAI was 1.5 in 2000 to 2.8 in 2003. The Albedo changes from 0.18 down to 0.16 at higher values of LAI.

Medidas mensais da altura da pastagem, biomassa total, variações de biomassa viva e morta, a área específica foliar (SLA) e o Índice de Área de Folha (IAF) de fevereiro de 1999 a janeiro de 2005 na Fazenda Nossa Senhora (FNS) e em Rolim de Moura (RDM) entre Fevereiro a Março de 1999, Rondônia, Brasil. A pastagem predominante é Urochloa brizantha (Hochst. ex A. Rich) R. D. Webster (99% na FNS e 76% em RDM), com pequenas manchas de Urochloa humidicula (Rendle). A altura média anual da grama foi de ~0,16 m. Com o pastejo, o mínimo mensal foi de 0,09 m (estação seca) e máximo de 0,3 m sem pastejo (estação úmida). O IAF, biomassa total, material morto, vivo e SLA tiveram valores médios de 2,5 m² m-2 , 2202 kg ha-1, 2916 kg ha-1 e 19 m² kg-1 respectivamente. A média mensal da biomassa foi 4224 kg ha-1 em 2002 e 6667 kg ha-1 em 2003. Grande variação sazonal do material vivo e morto, sendo mais alto o vivo durante a estação úmida (3229 contra 2529 kg ha-1), sendo o morto maior durante a seca (2542 contra 1894 kg ha-1). O nível de água no solo variou de -3,1 a -6,5 m durante as estações. Em médias anuais os IAF foram de 1,4 em 2000 a 2,8 em 2003 e o SLA entre 16,3 m² kg-1 em 1999 e 20,4 m² kg-1 em 2001. As observações do Albedo variaram de 0,18 para 0,16 em relação aos altos valores de IAF.

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The main objective of this paper is to present and discuss the best methods to estimate live above ground biomass in the Atlantic Forest. The methods presented and conclusions are the products of a workshop entitled "Estimation of Biomass and Carbon Stocks: the Case of Atlantic Rain Forest". Aboveground biomass (AGB) in tropical forests is mainly contained in trees. Tree biomass is a function of wood volume, obtained from the diameter and height, architecture and wood density (dry weight per unit volume of fresh wood). It can be quantified by the direct (destructive) or indirect method where the biomass quantification is estimated using mathematical models. The allometric model can be site specific when elaborated to a particular ecosystem or general that can be used in different sites. For the Atlantic Forest, despite the importance of it, there are only two direct measurements of tree biomass, resulting in allometric models specific for this ecosystem. To select one or other of the available models in the literature to estimate AGB it is necessary take into account what is the main question to be answered and the ease with which it is possible to measure the independent variables in the model. Models that present more accurate estimates should be preferred. However, more simple models...

O principal objetivo deste artigo é apresentar e discutir a melhor forma para estimar a biomassa viva acima do solo (BVS) na Mata Atlântica. A biomassa viva acima do solo em florestas tropicais esta contida principalmente nas árvores. A biomassa das árvores é uma função do seu volume de madeira, obtido do diâmetro e da altura, de sua arquitetura e da densidade de sua madeira (peso seco por unidade de volume fresco). Ela pode ser quantificada pelo método direto (destrutivo) ou pelo método indireto onde a quantificação da biomassa é feita através de modelos matemáticos. Os modelos alométricos podem ser específicos para um determinado local, quando elaborado para um ecossistema particular, ou gerais, que podem ser utilizados em para estimar a biomassa em diferentes locais. Para a Mata Atlântica, a despeito de sua importância, existem somente duas medidas diretas de biomassa de árvores, que resultaram em modelos alométricos específicos para essas florestas. Para selecionar um ou outro modelo alométrico para estimar BVS, disponível na literatura, é necessário levar em conta o a questão a ser respondida e a facilidade com a qual é possível medir as variáveis independentes do modelo. Preferencialmente, deve-se utilizar modelos...

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