RESUMOAs três parcelas permanentes usadas neste estudo são testemunhas (não perturbadas) de um experimento de manejo florestal do Instituto Nacional de Pesquisas da Amazônia, no município de Manaus (AM). Essas parcelas têm sido monitoradas desde 1980, mas para efeito deste estudo, foram consideradas 12 medições repetidas no período 1986-2000. Durante este período, o fenômeno El Niño (seca anormal na região) ocorreu em duas ocasiões, em 1992-93 e 1997-98, sendo que o último foi seguido do La Niña (chuva anormal na região), em 1999. Devido a esses fenômenos, as taxas de recrutamento e mortalidade foram iguais, 0,7%, durante o período observado. No entanto, a acumulação (fixação na árvore) de carbono, foi de 16 toneladas métricas, dando um incremento periódico anual significativo (p = 0,039), em torno de 1,2 t/ha/ano. Palavras-chave: biomassa, parcelas permanentes, mudanças climáticas CARBON BALANCE AND DYNAMICS OF PRIMARY VEGETATION IN THE CENTRAL AMAZON ABSTRACTThe three permanent forest inventory plots used for this study were control plots (not disturbed) from a forest management project of the National Institute of Amazon Research (INPA) in the Brazilian State of Amazonas. These plots have been monitored since 1980, although for this study the period from 1986-2000 was considered. During this period, the El Niño phenomenon, which causes increased drought in the region, occurred on two occasions (1992-93 and 1997-98), followed by La Niña which causes increased precipitation in the region (1999)(2000). Despite of this change in climate, recruitment and mortality rates were equal throughout the period at 0.7% yr-1. During the same period, carbon accumulation in forest biomass was 16 Mg, resulting in a statistically significant (p = 0.039) increase of about 1.2 Mg biomass ha-1 yr-1.
Procurou-se identificar, qualificar e quantificar a intensidade de danos causados pela colheita florestal em uma área com floresta primária explorada (FPE), tendo com testemunha uma área com floresta primária não-explorada (FPNE), com 202 e 204 ha, respectivamente. Na FPNE, foram avaliados os danos decorrentes de causas naturais. As áreas de FPE e de FPNE localizam-se no município de Manicoré, Estado do Amazonas. Realizou-se o inventário utilizando o método de amostragem aleatória, em ambas as áreas. As amostragens foram executadas em dois níveis de inclusão de DAP. No nível I foram instaladas cinco parcelas de 100 x 100 m (1 ha), onde foram inventariadas todas as árvores com DAP > ou = 15 cm. No nível II, as parcelas do nível I foram divididas sistematicamente em subparcelas de 10 x 10 m (100 m²), tendo sido amostradas aleatoriamente cinco subparcelas por parcela do nível I, totalizando 2.500 m², onde foram inventariados todos os indivíduos (varejões) com 5,0 <= DAP < 15 cm. As análises dos danos decorrentes de causas naturais indicaram que na FPNE apenas 10% da vegetação adulta remanescente apresentou danos. Na FPE, os danos causados pelas operações de colheita florestal, incluindo-se o corte e o arraste de toras, totalizaram 29%. As modificações na estrutura diamétrica da FPE foram maiores nas maiores classes de DAP, em que, em geral, foram constatadas reduções de 27, 29 e 30%, respectivamente, no número de árvores (n/ha), na área basal (m²/ha) e no volume (m³/ha). Essa redução de estoque foi considerada normal, uma vez que a amostragem foi realizada imediatamente após a execução das operações de colheita florestal.
SANTOS 6 e Niro HIGUCHI 6 RESUMO: Este trabalho tem como objetivo analisar padrões de crescimento individual de diversas árvores que ocorrem em duas toposseqüências (direções Norte-Sul e Leste-Oeste), de uma amostra representativa da floresta de terra-firme na Amazônia Central. Foram selecionados de forma aleatória, aproximadamente, 300 indivíduos, sendo 150 em cada toposseqüência, distribuídos em mesmas proporções nas três classes topográficas (platô, encosta e baixio) e nas três classes de diâmetro (10 < DAP < 30 cm; 30 < DAP< 50 cm e DAP> 50 cm). Em cada uma dessas árvores foi instalada uma fita metálica, com extremidades parcialmente sobrepostas e ligadas por uma mola; o avanço de uma das pontas, dentro de uma abertura, representa o crescimento em circunferência, que foi medido com um paquímetro digital.
(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.
† These authors contributed equally to this work. AbstractThe topographic effects on biomass and its increment were evaluated for a terra-firme forest near Manaus, Brazil. We established three plots (60 × 60 m) on a plateau and at the bottom of a valley (namely baixio), and measured stem diameter at breast height D (> 10 cm) for tree and palm species in 2002 and 2012. Small trees (10 cm > D > 5 cm) were measured in subplots (20 × 60 m) within each plot. We also estimated tree height with the D -tree height H relationship model based on a hundred samples of the tree species in each topography. The aboveground biomass AGB was estimated as 315.4 ± 33.2 (average ± SE) Mg ha -1 on the plateau, which was higher than 224.2 ± 20.3 Mg ha -1 in baixio though the difference was statistically marginal (p = 0.09). The difference in AGB was partly ascribed to the decrease of H for large trees and a lack of large trees whose D > 80 cm at the baixio site. The AGB of palm species in baixio was 2.7 ± 0.87 Mg ha -1 , which was higher than 0.24 ± 0.08 Mg ha -1 on the plateau though the difference was statistically insignificant (p = 0.11). On the other hand, the increment of AGB did not differ significantly between the two sites (p > 0.05), and the variation of AGB increment among the plots was mainly ascribed to the variation of biomass loss caused by mortality.Discipline: Forestry and forest products Additional key words: biomass increment, topography, AmazonThis study was conducted as a part of an international cooperative research project between Japan and Brazil
Every year, logging in the world’s largest tropical forest, located within the Amazon biome, continues unabated. Although it is a preferred alternative to deforestation, the residual stand and site are impacted by logging. The objective of this review was to determine and assess the current state of research throughout Amazonia on the subject of logging impacts. To achieve this goal, a systematic approach was utilized to gather, assess and categorize research articles conducted in the Amazon biome over the last decade. Eligibility for inclusion of articles required demonstration of a direct impact from logging operations. A total of 121 articles were determined to meet the eligibility requirements and were included in this review. Articles were subdivided into three environmental categories: forest (n = 85), wildlife (n = 24) and streams (n = 12). The results of this review demonstrated that impacts from logging activities to the forest site were a direct result of the logging cycle (e.g., how often logging occurs) or logging intensity (e.g., how many trees are felled). The impacts to wildlife varied dependent on species, whereas impacts to streams were affected more by the logging system. Overall, research suggested that to attain sustainability and diminish the impacts from logging, a lower logging intensity of 10–15 m3 ha−1 and a longer logging cycle of 40–60 years would be essential for the long-term viability of forest management in Amazonia.
O manejo em pequena escala é uma alternativa de uso dos recursos madeireiros para pequenos produtores no estado do Amazonas. Estudos florísticos são importantes para o conhecimento da flora regional e seus potenciais diversos. O objetivo deste estudo foi avaliar a composição florística e estrutura florestal em planos de manejo em pequena escala a fim de se conhecer quais espécies tem sido mais visada pelos pequenos produtores rurais do Amazonas e verificar se a diversidade de espécies dessas áreas condiz com o esperado para a região Amazônica. Foram utilizadas planilhas de inventário florestal de planos de manejo licenciados no ano de 2013. Foi realizada a análise da estrutura horizontal considerando os parâmetros de densidade, dominância, frequência e valor de importância das espécies. A diversidade da vegetação foi avaliada a partir dos índices de diversidade de Shannon-Wiener (H') e equabilidade de Pielou (J). Houve um total de 5716 indivíduos mensurados, representando 158 espécies e 35 famílias botânicas. As 10 famílias com maior riqueza de espécies foram Fabaceae (37), Lauraceae (18), Lecythidaceae (15), Sapotaceae (9), Moraceae (9), Chrysobalanaceae (8), Malvaceae (7) Myristicaceae (6), Anacardiaceae (5) e Caryocaraceae (4). As 10 espécies com maior valor de importância foram Micropholis williamii, Goupia glabra, Couratari tauari, Chrysophyllum L., Scleronema micranthum, Licania heteromorfa, Couepia subcordata, Tachigali paniculata, Peltogyne densiflora e Dipteryx odorata. A diversidade de espécies em planos de manejo em pequena escala condiz com o esperado para a ragião amazônica, sendo considerada alta.
The sustainable use of forestry resources has an intrinsic relationship with log yield in sawmills, because the knowledge of this variable can optimize the processed wood production. Thus, the objective of this work was to determine the percentage yield in the sawing of Sucupira-Vermelha (Andira parviflora Ducke.) logs in different diameter classes and to adjust mathematical models to estimate processed wood. It was sampled 56 logs with diameters between 31 and 69 cm grouped into 4 diameter classes. Afterwards the sawing was performed obtaining various pieces of wood which were cubed to determine the yielding percentage. The increase in diameter classes provided an increase in sawn wood yield, which showed a significant difference only between the diameter class 1 and the others studied. Twelve mathematical models, 6 linear and 6 nonlinear, were evaluated. The models quality adjustment and selection was based on the highest adjusted determination coefficient (R²adj), lowest estimation standard error (Syx) and variation coefficient (VC%) and, most homogeneous residues graphic distribution. The nonlinear models of single entry (diameter) and double entry (diameter and length) were the most accurate to estimate the sawn wood yield of Sucupira-Vermelha species.
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