scholarly journals Site-Specific Allometric Models for Prediction of Above-and Belowground Biomass of Subtropical Forests in Guangzhou, Southern China

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 862 ◽  
Author(s):  
Zhao ◽  
Li ◽  
Zhou ◽  
Qiu ◽  
Wu
Keyword(s):  
Southern China ◽  
Belowground Biomass ◽  
Subtropical Forest ◽  
Forest Carbon ◽  
Total Biomass ◽  
Carbon Sinks ◽  
Site Specific ◽  
Subtropical Forests ◽  
Allometric Models ◽  
Biomass Models

Tree allometric models that are used to predict the biomass of individual tree are critical to forest carbon accounting and ecosystem service modeling. To enhance the accuracy of such predictions, the development of site-specific, rather than generalized, allometric models is advised whenever possible. Subtropical forests are important carbon sinks and have a huge potential for mitigating climate change. However, few biomass models compared to the diversity of forest ecosystems are currently available for the subtropical forests of China. This study developed site-specific allometric models to estimate the aboveground and the belowground biomass for south subtropical humid forest in Guangzhou, Southern China. Destructive methods were used to measure the aboveground biomass with a sample of 144 trees from 26 species, and the belowground biomass was measured with a subsample of 116 of them. Linear regression with logarithmic transformation was used to model biomass according to dendrometric parameters. The mixed-species regressions with diameter at breast height (DBH) as a single predictor were able to adequately estimate aboveground, belowground and total biomass. The coefficients of determination (R2) were 0.955, 0.914 and 0.954, respectively, and the mean prediction errors were −1.96, −5.84 and 2.26%, respectively. Adding tree height (H) compounded with DBH as one variable (DBH2H) did not improve model performance. Using H as a second variable in the equation can improve the model fitness in estimation of belowground biomass, but there are collinearity effects, resulting in an increased standard error of regression coefficients. Therefore, it is not recommended to add H in the allometric models. Adding wood density (WD) compounded with DBH as one variable (DBH2WD) slightly improved model fitness for prediction of belowground biomass, but there was no positive effect on the prediction of aboveground and total biomass. Using WD as a second variable in the equation, the best-fitting allometric relationship for biomass estimation of the aboveground, belowground, and total biomass was given, indicating that WD is a crucial factor in biomass models of subtropical forest. Root-shoot ratio of subtropical forest in this study varies with species and tree size, and it is not suitable to apply it to estimate belowground biomass. These findings are of great significance for accurately measuring regional forest carbon sinks, and having reference value for forest management.

scholarly journals Wetter is Better: Rewetting of Minerotrophic Peatlands Increases Plant Production and Moves Them Towards Carbon Sinks in a Dry Year

Ecosystems ◽  
2020 ◽  
Author(s):  
Sarah Schwieger ◽  
Juergen Kreyling ◽  
John Couwenberg ◽  
Marko Smiljanić ◽  
Robert Weigel ◽  
...  
Keyword(s):  
Organic Matter ◽  
Biomass Production ◽  
Plant Material ◽  
Carbon Sink ◽  
Belowground Biomass ◽  
Plant Production ◽  
Total Biomass ◽  
Carbon Sinks ◽  
Alder Forest ◽  
Organic Matter Accumulation

Abstract Peatlands are effective carbon sinks as more biomass is produced than decomposed under the prevalent anoxic conditions. Draining peatlands coupled with warming releases stored carbon, and subsequent rewetting may or may not restore the original carbon sink. Yet, patterns of plant production and decomposition in rewetted peatlands and how they compare to drained conditions remain largely unexplored. Here, we measured annual above- and belowground biomass production and decomposition in three different drained and rewetted peatland types: alder forest, percolation fen and coastal fen during an exceptionally dry year. We also used standard plant material to compare decomposition between the sites, regardless of the decomposability of the local plant material. Rewetted sites showed higher root and shoot production in the percolation fen and higher root production in the coastal fen, but similar root and leaf production in the alder forest. Decomposition rates were generally similar in drained and rewetted sites, only in the percolation fen and alder forest did aboveground litter decompose faster in the drained sites. The rewetted percolation fen and the two coastal sites had the highest projected potential for organic matter accumulation. Roots accounted for 23–66% of total biomass production, and belowground biomass, rather than aboveground biomass, was particularly important for organic matter accumulation in the coastal fens. This highlights the significance of roots as main peat-forming element in these graminoid-dominated fen peatlands and their crucial role in carbon cycling, and shows that high biomass production supported the peatlands’ function as carbon sink even during a dry year.

scholarly journals ALOCAÇÃO E MODELAGEM DA BIOMASSA EM Dendrocalamus asper

FLORESTA ◽  
2014 ◽  
Vol 45 (1) ◽  
pp. 1 ◽  
Author(s):  
Francelo Mognon ◽  
Aurélio Lourenço Rodrigues ◽  
Carlos Roberto Sanquetta ◽  
Ana Paula Dalla Corte ◽  
Adalberto Brito De Novaes ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Total Biomass ◽  
Major Fraction ◽  
Allometric Models ◽  
Stem Biomass ◽  
Breast Height ◽  
Biomass Models ◽  
Independent Variable ◽  
Collar Diameter ◽  
Dendrocalamus Asper

O objetivo deste trabalho foi quantificar a biomassa seca total individual de plantas de bambu da espécie Dendrocalamus asper (Schult. & Schult. f.) Backer ex K. Heyne, visando conhecer a sua distribuição nos diferentes compartimentos, bem como avaliar modelos de biomassa em função de variáveis biométricas das plantas. Foram avaliados 20 indivíduos, coletados em Bauru, SP. As plantas amostradas foram medidas, abatidas e pesadas. A maior fração da biomassa foi observada na parte aérea, com 86%, sendo 64% para o compartimento colmo, 16% para os galhos e 6% para as folhas. Os rizomas representaram 14% da biomassa total. As variáveis biométricas (diâmetro à altura do peito – DAP, altura total – ht e diâmetro de colo – Dcolo) correlacionaram-se significativamente com as biomassas total e do colmo. O modelo que apresentou o melhor desempenho para a biomassa total teve como variável independente apenas o DAP, enquanto que para a biomassa dos colmos foi a variável combinada dap0,5*lndap. Os ajustes para os demais compartimentos não geraram resultados satisfatórios, em função da baixa correlação entre as variáveis biométricas e suas biomassas. Concluiu-se que é possível expressar a biomassa seca total e do colmo do bambu por meio de modelos alométricos, porém o mesmo não se aplica aos demais compartimentos.Palavras-chave: Bambu; fitomassa; modelos alométricos. AbstractAllocation and modeling of biomass of Dendrocalamus asper. The aim of this research was to quantify the total individual biomass of bamboo plants of the species Dendrocalamus asper (Schult. & Schult. f.) Backer ex K. Heyne, in order to understand its distribution along different compartments, as well as evaluat biomass models according to biometric variables. Twenty individuals collected in Bauru, SP were evaluated. The plants were measured, cut and weighed. The aboveground biomass accounted for the major fraction, representing 86%. The stem compartment represented 64% of total biomass, followed by the branches, with 16% and leaves, with 6%. Rhizomes accounted for 14% of the total biomass. The biometric variables (diameter at breast height - dbh, total height – ht, and collar diameter - dcollar) were significantly correlated with total and stem biomass. The model that revealed best performance for total biomass had only dap as independent variable, for the stems biomass the combined variable was dap0,5*lndap. The adjustments for other compartments were not satisfactory due to low correlation between the biometric variables and their biomass. As conclusion, it is possible to express the total  dry stem biomass and culm mass of bamboo using allometric models, however, the same does not apply to other compartments.Keywords: Bamboo; phytomass; allometric models.

scholarly journals Allometric models for estimating aboveground biomass and carbon stock for Diospyros mespiliformis in West Africa

Silva Fennica ◽  
2020 ◽  
Vol 54 (1) ◽  
Author(s):  
Korotimi Ouédraogo ◽  
Kangbéni Dimobe ◽  
Adjima Thiombiano
Keyword(s):  
Burkina Faso ◽  
Carbon Content ◽  
Aboveground Biomass ◽  
Direct Method ◽  
Scientific Information ◽  
Leaf Biomass ◽  
Basal Diameter ◽  
Site Specific ◽  
Allometric Models ◽  
Biomass Models

Accurate estimates of aboveground biomass (AGB) strongly depend on the suitability and precision of allometric models. Hochst. ex A. DC. is a key component of most sub-Sahara agroforestry systems and, one of the most economically important trees in Africa. Despite its importance, very few scientific information exists regarding its biomass and carbon storage potential. In this study direct method was used to develop site-specific biomass models for tree components in Burkina Faso. Allometric models were developed for stem, branch and leaf biomass using data from 39 tree harvested in Sudanian savannas of Burkina Faso. Diameter at breast height (DBH), tree height, crown diameter (CD) and basal diameter (D) were regressed on biomass component using non-linear models with DBH alone, and DBH in combination with height and/or CD as predictor variables. Carbon content was estimated for each tree component using the ash method. Allometric models differed between the experimental sites, except for branch biomass models. Site-specific models developed in this study exhibited good model fit and performance, with explained variance of 81–98%. Using models developed from other areas would have underestimated or overestimated biomass by between –72% and +98%. Carbon content in aboveground components of in Tiogo, Boulon and Tapoa-Boopo was 55.40% ± 1.50, 55.52% ± 1.06 and 55.63% ± 1.00, respectively, and did not vary significantly (-value = 0.909). Site-specific models developed in this study are useful tool for estimating carbon stocks and can be used to accurately estimate tree components biomass in vegetation growing under similar conditions.Diospyros mespiliformisD. mespiliformis20D. mespiliformisP

scholarly journals The Variation Driven by Differences between Species and between Sites in Allometric Biomass Models

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 976 ◽  
Author(s):  
Dutcă
Keyword(s):  
Aboveground Biomass ◽  
Tree Height ◽  
Site Specific ◽  
Allometric Models ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Biomass Models ◽  
Anova Model ◽  
Species Specific ◽  
Variance Explained

Background and Objectives: It is commonly assumed that allometric biomass models are species-specific and site-specific. However, the magnitude of species and site dependency in these models is not well-known. This study aims to investigate the variation in allometric models (i.e., aboveground biomass predicted by diameter at breast height and tree height) that has originated from the differences between tree species and between sites, thereby contributing to a better understanding of species and site-specificity issue in these models. Materials and Methods: The study is based on two large biomass datasets of 4921 and 5199 trees, from Eurasia and Canada. Using a nested ANOVA model on relative aboveground biomass residuals (with species and site as random effects), the proportion of variance explained by species or site was assessed by means of Variance Partition Coefficient (VPC). Results: The proportion of variance explained by species (VPCspecies = 42.56%, SE = 6.10% for Dataset 1 and VPCspecies = 47.54%, SE = 6.07% for Dataset 2) was larger than that explained by site (VPCsite = 20.08%, SE = 3.35% for Dataset 1 and VPCsite = 8.27%, SE = 1.38% for Dataset 2). The proportion of variance explained by site decreased by 24%–44% and the proportion of variance explained by species changed only slightly, when height is included in the allometric biomass models (i.e., models based on diameter at breast height alone, compared to models based on diameter at breast height and tree height). Conclusions: Allometric biomass models were more species-specific than they were site-specific. Therefore, the species (i.e., differences between species) seems to be a more important driver of variability in allometric models compared to site (i.e., differences between sites). Including height in allometric biomass models helped reduce the dependency of these models, on sites only.

Old-growth forest carbon sinks overestimated

Nature ◽  
2021 ◽  
Vol 591 (7851) ◽  
pp. E21-E23
Author(s):  
Per Gundersen ◽  
Emil E. Thybring ◽  
Thomas Nord-Larsen ◽  
Lars Vesterdal ◽  
Knute J. Nadelhoffer ◽  
...  
Keyword(s):  
Forest Carbon ◽  
Carbon Sinks ◽  
Old Growth ◽  
Old Growth Forest

SolicorynesporaSpecies Associated with Dead Branches of Subtropical Forests in Southern China

2016 ◽  
Vol 37 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Jian Ma ◽  
Ji-Wen Xia ◽  
Xiu-Guo Zhang ◽  
You-Qiang Luo ◽  
Rafael F. Castañeda-Ruíz
Keyword(s):  
Southern China ◽  
Subtropical Forests

scholarly journals Closing a gap in tropical forest biomass estimation: taking crown mass variation into account in pantropical allometries

2016 ◽  
Vol 13 (5) ◽  
pp. 1571-1585 ◽  
Author(s):  
Pierre Ploton ◽  
Nicolas Barbier ◽  
Stéphane Takoudjou Momo ◽  
Maxime Réjou-Méchain ◽  
Faustin Boyemba Bosela ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Reference Model ◽  
Original Data ◽  
Carbon Stocks ◽  
Forest Carbon ◽  
Biomass Estimation ◽  
Systematic Bias ◽  
Data Set ◽  
Allometric Models ◽  
Large Trees

Abstract. Accurately monitoring tropical forest carbon stocks is a challenge that remains outstanding. Allometric models that consider tree diameter, height and wood density as predictors are currently used in most tropical forest carbon studies. In particular, a pantropical biomass model has been widely used for approximately a decade, and its most recent version will certainly constitute a reference model in the coming years. However, this reference model shows a systematic bias towards the largest trees. Because large trees are key drivers of forest carbon stocks and dynamics, understanding the origin and the consequences of this bias is of utmost concern. In this study, we compiled a unique tree mass data set of 673 trees destructively sampled in five tropical countries (101 trees > 100 cm in diameter) and an original data set of 130 forest plots (1 ha) from central Africa to quantify the prediction error of biomass allometric models at the individual and plot levels when explicitly taking crown mass variations into account or not doing so. We first showed that the proportion of crown to total tree aboveground biomass is highly variable among trees, ranging from 3 to 88 %. This proportion was constant on average for trees < 10 Mg (mean of 34 %) but, above this threshold, increased sharply with tree mass and exceeded 50 % on average for trees  ≥  45 Mg. This increase coincided with a progressive deviation between the pantropical biomass model estimations and actual tree mass. Taking a crown mass proxy into account in a newly developed model consistently removed the bias observed for large trees (> 1 Mg) and reduced the range of plot-level error (in %) from [−23; 16] to [0; 10]. The disproportionally higher allocation of large trees to crown mass may thus explain the bias observed recently in the reference pantropical model. This bias leads to far-from-negligible, but often overlooked, systematic errors at the plot level and may be easily corrected by taking a crown mass proxy for the largest trees in a stand into account, thus suggesting that the accuracy of forest carbon estimates can be significantly improved at a minimal cost.

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