Changes in Forest Structure and Biomass over Ten Years in a Lowland Amazonian Forest

Suwa, Rempei; Silva, Fernando de Carvalho da; Lima, Adriano José Nogueira; Pinto, Alberto Carlos Martins; Santos, Joaquim dos; Kajimoto, Tetsuya; Ishizuka, Moriyoshi; Higuchi, Níro

doi:10.6090/jarq.50.379

Cited by 2 publications

(2 citation statements)

References 18 publications

(28 reference statements)

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“…These restrictive conditions in Maracá have been highlighted as a probable environmental limitation acting on the increase in height as a function of stem diameter when compared to less-restrictive environments (Ramírez-Narváez 2017). Differences in tree height between forest types along a topographic gradient were also found in central Amazonia (Suwa et al 2016). However, although mathematical distinctions in the H:D relation may exist at the microscale for specific species in the different forest types in the ecotone zone, there is no doubt that, at the level of the major forest formation, the growth trajectories are governed by common environmental fluctuations.…”

Section: Discussionmentioning

confidence: 95%

Allometric models to estimate tree height in northern Amazonian ecotone forests

et al. 2019

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Allometric models defining the relationship between stem diameter and total tree height in the Amazon basin are important because they refine the estimates of tree carbon stocks and flow in the region. This study tests different allometric models to estimate the total tree height from the stem diameter in an ecotone zone between ombrophilous and seasonal forests in the Brazilian state of Roraima, in northern Amazonia. Stem diameter and total height were measured directly in 65 recently fallen trees (live or dead).Linear and nonlinear regressions were tested to represent the D:H relation in this specific ecotone zone. Criteria for model selection were the standard error of the estimate (S yx ) and the adjusted coefficient of determination (R² adj ), complemented by the Akaike Information Criterion (AIC). Analysis of residuals of the most parsimonious nonlinear models showed a tendency to overestimate the total tree height for trees in the 20-40 cm diameter range. Application of our best fitted model (Michaelis-Menten) indicated that previously published general equations for the tropics that use diameter as the independent variable can either overestimate tree height in the study area by 10-29% (Weibull models) or underestimate it by 8% (climate-based models). We concluded that our site-specific model can be used in the ecotone forests studied in Roraima because it realistically reflects the local biometric relationships between stem diameter and total tree height. Studies need to be expanded in peripheral areas of northern Amazonia in order to reduce uncertainties in biomass and carbon estimates that use the tree height as a variable in general models. Modelos alométricos para estimar altura de árvores em florestas ecotonais do norte da Amazônia RESUMOModelos alométricos que definem o relacionamento entre diâmetro do tronco e a altura total da árvore na bacia amazônica são importantes porque refinam as estimativas de fluxo e estoques de carbono arbóreo na região. Este estudo testou diferentes modelos alométricos para estimar a altura total de árvores a partir do diâmetro do tronco em uma zona de ecótono entre florestas ombrófilas e sazonais no estado de Roraima, norte da Amazônia. Diâmetro do tronco e altura total foram medidos de forma direta em 65 árvores tombadas recentemente (vivas e mortas). Regressões linear e não-linear foram testadas para representar a relação D:H nesta zona específica de ecótono. Os critérios de seleção dos modelos foram o erro padrão da estimativa (S yx ), o coeficiente de determinação ajustado (R² adj ) e o Critério de Informação de Akaike (AIC). A análise dos resíduos dos modelos não-lineares mais parcimoniosos mostrou uma tendência de superestimar a altura total para árvores entre 20-40 cm de diâmetro do tronco. A aplicação do modelo melhor ajustado (Michaelis-Menten) indicou que equações gerais publicadas previamente para os trópicos que usam diâmetro como variável independente podem superestimar em 10-29% (modelos Weibull) ou subestimar em 8% (modelos baseados no clima) a altura da...

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Section: Discussionmentioning

confidence: 95%

Allometric models to estimate tree height in northern Amazonian ecotone forests

et al. 2019

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“…2b). Suwa et al (2016) reported that the mortality of medium trees that are 40-50 cm dbh was higher than trees in the other size classes in the unlogged forest of ZF-2, in the central Amazon. The AGB increment due to the growth of surviving trees in the unlogged block Tab.…”

Section: Agb Stock In Unlogged Forest Blockmentioning

confidence: 99%

Recovery of above-ground tree biomass after moderate selective logging in a central Amazonian forest

Otani¹,

Lima²,

Suwa³

et al. 2018

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(4)We examined the recovery and dynamics of living tree above-ground biomass (AGB) after selective logging in an Amazonian terra firme forest managed by a private company. The forest consisted of 24 blocks (including one set aside for conservation) selectively logged in different years on a managed schedule. Trees ≥10 cm in diameter at breast height (dbh) were surveyed in 2006 in 192 0.25-ha plots, in 2010 in 119 plots, and in 2012-2013 in 54 plots. A logistic growth model factoring in logging dynamics and mean AGB of a block in these years was established. Referencing the mean AGB of the unlogged forest, the model indicated that the logged forest would take on average 14 years to regain its preharvest AGB after selective logging at 1.9 trees ha -1 (dbh > 50 cm). In 2010 and 2012-2013, the AGB increased significantly for small and large trees (10-20 cm and >60 cm dbh, respectively) in the logged forest. In contrast, it decreased significantly for medium-sized trees (30-50 cm dbh) in the unlogged forest. Comparisons with the previous studies mainly conducted in the other regions of Amazon suggested that the estimated AGB recovery period with moderate logging intensity was almost appropriate and likely acceptable to forest managers.

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Changes in Forest Structure and Biomass over Ten Years in a Lowland Amazonian Forest

Cited by 2 publications

References 18 publications

Allometric models to estimate tree height in northern Amazonian ecotone forests

Allometric models to estimate tree height in northern Amazonian ecotone forests

Recovery of above-ground tree biomass after moderate selective logging in a central Amazonian forest

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