Wood density, phytomass variations within and among trees, and allometric equations in a tropical rainforest of Africa

Abstract• Key message Improving the precision of forest biomass estimates requires prioritizing the different sources of errors. In a tropical moist forest in central Africa, the choice of the allometric equation was found to be the main source of error.• Context When estimating the forest biomass at the landscape level using forest inventory data and allometric models, there is a chain of propagation of errors including the measurement errors, the models' prediction error, the error due to the model choice, and the sampling error.• Aims This study aims at comparing the contributions of these different sources of error to the total error, to prioritize them, and improve the precision of biomass estimates. • Methods Using a 9-ha permanent sample plot in a moist forest near Kisangani in the Democratic Republic of Congo and seven competing allometric models, we estimated the contributions of the different sources of error to the total error of the per hectare biomass estimate, for plot sizes ranging from 0.04 to 1 ha.• Results When there was no a priori on which model being the best and for 1-ha plots, the error due to the model choice was the largest source of error (76 % of the total error). Using weights to combine the predictions of the different models into a single ensemble prediction strongly reduced this error.• Conclusion Collecting training data sets on tree biomass at many sites would be needed to improve the precision of forest biomass estimates in central Africa.

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“…For all subsequent calculations, we used an average wood density of 0.6 g cm −3 (Chave et al 2005;Henry et al 2010). …”

Section: Biomass Datamentioning

confidence: 99%

Reducing the error in biomass estimates strongly depends on model selection

Picard

Bosela

Rossi

2014

Annals of Forest Science

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“…Usually allometric models are adjusted using three basic sources of information: dry samples of different tree compartments, the bulk density and the volume of the wood. Based on this data one obtains the total dry mass which is usually related to the diameter at breast height (dbh) and the height of the tree by an allometric relationship (HENRY et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Aboveground and Belowground Biomass and Carbon Estimates for Clonal Eucalyptus Trees in Southeast Brazil

et al. 2015

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-Eucalyptus plantations represent a short term and cost efficient alternative for sequestrating carbon dioxide from the atmosphere. Despite the known potential of forest plantations of fast growing species to store carbon in the biomass, there are relatively few studies including precise estimates of the amount of carbon in these plantations. In this study it was determined the carbon content in the stems, branches, leaves and roots of a clonal Eucalyptus grandis plantation in the Southeast of Brazil. We developed allometric equations to estimate the total amount of carbon and total biomass, and produced an estimate of the carbon stock in the stand level. Altogether, 23 sample trees were selected for aboveground biomass assessment. The roots of 9 of the 23 sampled trees were partially excavated to assess the belowground biomass at a singletree level. Two models with DBH, H and DBH 2 H were tested. The average relative share of carbon content in the stem, branch, leaf and root compartments was 44.6%, 43.0%, 46.1% and 37.8%, respectively, which is smaller than the generic value commonly used (50%). The best-fit allometric equations to estimate the total amount of carbon and total biomass had DBH 2 H as independent variable. The root-to-shoot ratio was relatively stable (C.V. = 27.5%) probably because the sub-sample was composed of clones. Total stand carbon stock in the Eucalyptus plantation was estimated to be 73.38 MgC ha -1 , which is within the carbon stock range for Eucalyptus plantations.Keywords: Carbon stock; Allometric equation; Carbon content. BIOMASSA ACIMA E ABAIXO DO SOLO E ESTIMATIVAS DE CARBONO PARA UM PLANTIO CLONAL DE EUCALIPTO NO SUDESTE DO BRASIL

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“…The DBH and tree height were directly measured, wood density of species was obtained from other studies and databases [22,23]. Average wood density value of the known species was used for species which wood density was not found which was 0.6 g/cm 3 that was equivalent to average value reported for wood density of trees in Africa ranges between 0.58 and 0.67 g/cm 3 [24]. According to IPCC [25], the biomass stock density of a sampling plot is converted to carbon stock densities by default carbon fraction of 0.47, as the dry biomass contains 47% organic carbon in the tropical and sub-tropical region.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Age of Exclosures and Aspect on Aboveground Carbon of Boswellia papyrifera Dominated Woodland of Kafta Humera, Western Tigray, Northern Ethiopia

Gebrewahid¹

2017

J Ecosyst Ecogr

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This study was conducted in Boswellia dominated woodland at Kafta Humera to estimate the amount of carbon stored in different age of exclosures and along different aspects. Ages of exclosures (eight, four, two and zero year) were used, and the aspects were classified in to east, west, north and south aspects. One hundred twenty eight (128) sampling quadrants having an area of 20 m × 20 m, were systematically laid using four transect lines at different distance. The aboveground carbon was analyzed using two-way analysis of variance. A total of twenty one (21) woody spices belongs to thirteen (13) families were identified and documented. There were significantly different (P<0.05) among age of exclosures. Eight-year exclosure was significantly higher in aboveground biomass (88.57 Mg/ha) and aboveground carbon (41.63 Mg/ha) followed by four, two and zero years of exclosure. Despite no significant differences (P<0.05) was seen between aspect for aboveground biomass and carbon. It had the order of west>east>south>north aspects. The results confirmed that exclosures plays a major role in the conservation of native woody species. However, more afforestation and reforestation are needed for better carbon storage in all exclosures.

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Wood density, phytomass variations within and among trees, and allometric equations in a tropical rainforest of Africa

Cited by 286 publications

References 48 publications

Reducing the error in biomass estimates strongly depends on model selection

Reducing the error in biomass estimates strongly depends on model selection

Aboveground and Belowground Biomass and Carbon Estimates for Clonal Eucalyptus Trees in Southeast Brazil

The Effect of Age of Exclosures and Aspect on Aboveground Carbon of Boswellia papyrifera Dominated Woodland of Kafta Humera, Western Tigray, Northern Ethiopia

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