scholarly journals Contribution of some Acacia Species on Carbon Sequestration in Blue Nile State, Sudan

2021 ◽  
pp. 97-105
Keyword(s):  
Carbon Sequestration ◽  
Wood Density ◽  
Carbon Stock ◽  
Tree Height ◽  
Biomass Estimation ◽  
Expansion Factor ◽  
Wood Volume ◽  
Crown Diameter ◽  
Breast Height ◽  
Acacia Seyal

Background: The current challenge is to reduce the uncertainties in obtaining accurate and reliable data of carbon stock changes and emission factors essential for reporting national inventories. Improvements in above ground biomass estimation can also help account for changes in carbon stock in forest areas that may potentially participate in the Reducing emissions from deforestation and forest degradation and other initiatives. Current objectives for such estimates need a unified approach which can be measurable, reportable, and verifiable. This might result to a geographically referenced biomass density database for Sudanese forests that would reduce uncertainties in estimating forest aboveground biomass. The main objective: of this study is to assess potential of some selected forest variables for modeling carbon sequestration for Acacia seyal, vr. Seyal, Acacia seyal, vr. fistula, Acacia Senegal. The specific objectives include development of empirical allometric models for forest biomass estimation, estimation of carbon sequestration for these tree species, estimation of carbon sequestration per hectare and comparing the amount with that reported to the region. A total of 10 sample trees for biomass and carbon determination were selected for each of the three species from El Nour Natural Forest Reserve of the Blue Nile State, Sudan. Data of diameter at breast height, total tree height, tree crown diameter, crown height, and upper stem diameters were measured. Then sample trees were felled and sectioned to their components, and weighed. Subsamples were selected from each component for oven drying at 105 ˚C. Finally allometric models were developed and the aboveground dry weight (dwt) and carbon sequestered per hector were calculated. The results: presents biomass equations, biomass expansion factor and wood density that developed for the trees. In case of inventoried wood volume, corrections for biomass expansion factor and wood density value were done, and new values are suggested for use to convert wood volume to biomass estimates. The results also, indicate that diameter at breast height, crown diameter and tree height are good predictors for estimation of tree dwt and carbon stock. Conclusion: The developed allometric equations in this study gave better estimation of dwt than default value. The average carbon stock was found to be 22.57 t/ha.

scholarly journals Contribution of some Savannah tree species in carbon sequestration

2021 ◽  
pp. 69-82
Keyword(s):  
Carbon Sequestration ◽  
Wood Density ◽  
Carbon Stock ◽  
Tree Height ◽  
Expansion Factor ◽  
Wood Volume ◽  
Biomass Expansion Factor ◽  
Diameter At Breast Height ◽  
Crown Diameter ◽  
Breast Height

Improvements in above ground biomass estimation can help account for changes in carbon stock in forest areas that may potentially participate in the clean development mechanism. The main objective of this study was to assess potential of some selected forest variables for modeling carbon sequestration for Combretum hartmannianum, Terminalia brownii, and Lanea fruitcosa. A total of 10 sample trees for Lanea fruitcosa and 8 sample trees for each of the other two species were selected for biomass and carbon determination were selected from El Nour Natural Forest Reserve of the Blue Nile State, Sudan. Data of diameter at breast height, total tree height, tree crown diameter, crown height, and upper stem diameters were measured. Then sample trees were felled and sectioned to their components and weighed. Subsamples were selected from each component for oven drying at 105 ˚C. Finally, allometric models were developed and the aboveground dry weight (dwt) and carbon sequestered per hector were calculated. The results presented biomass equations, biomass expansion factor and wood density that developed for the trees. In case of inventoried wood volume, corrections for biomass expansion factor and wood density value were done, and new values are suggested for use to convert wood volume to biomass estimates. The results also, indicate that diameter at breast height, crown diameter and tree height are good predictors for estimation of tree dwt and carbon stock. The developed allometric equations in this study gave better estimation of dwt than default value. The average carbon stock was found to be 22.57 t/ha.

scholarly journals Reproductive phenology of Uspí tree Couepia polyandra (Kunth) Rose (Chrysobalanaceae) in Campeche, Mexico

2020 ◽  
Vol 13 (10) ◽  
Author(s):  
Sol de Mayo A. Mejenes-López ◽  
Gustavo E. Mendoza-Arroyo ◽  
Manuel Marín-Quintero ◽  
Ricardo Antonio Chiquini-Medina
Keyword(s):  
Digital Camera ◽  
Tree Height ◽  
Reproductive Phenology ◽  
Ripe Fruit ◽  
Flower Buds ◽  
Phenological Stages ◽  
Diameter At Breast Height ◽  
Crown Diameter ◽  
Breast Height ◽  
Dependent Variables

Objective. To describe reproductive phenological stages, since the formation of flower buds, flowering, fruiting, up to the formation of the ripe fruit and foliation of 21 Couepia polyandra trees; and correlation of allometric data of tree height, diameter at breast height (DBH) and crown diameter, as well as the correlation of precipitation with reproductive phenology data. Methodology. The description of the reproductive phenology (foliage, formation of flower buds, flowers, fruits) was done by direct monthly observation with a digital camera (Canon SX60HS, 65). The correlation among precipitation, allometry, and types of soils where the trees grow was calculated by recording data from each tree by measuring height, diameter at breast height (DBH) and foliage. Results. The highest tree was 21.0 m; the widest DBH measured 68 cm; and the greater crown diameter was 34.45 m; the overall averages were 10.38 m, 33.17 cm and 9.37 m, respectively. A significant correlation was found between height and DBH (r=0.91, p<0.05); the correlations for the variables Height-Crown and DBH-Crown were not significant (p>0.05). Conclusions. Water as a factor is responsible for the formation of inflorescence and fruit; determining that these phenological events are dependent variables with precipitation, highlighting a mean positive relation with the growth of flowers.

scholarly journals ABOVEGROUND DENDROMASS ESTIMATION OF JUVENILE PAULOWNIA SP.

2017 ◽  
Vol 1 (24) ◽  
Author(s):  
Tatiana Stankova ◽  
Veselka Gyuleva ◽  
Dimitar Dimitrov ◽  
Hristina Hristova ◽  
Ekaterina Andonova
Keyword(s):  
Regression Models ◽  
Goodness Of Fit ◽  
Tree Height ◽  
Early Growth ◽  
Biomass Estimation ◽  
Allometric Relationships ◽  
Tree Diameter ◽  
Breast Height ◽  
Ornamental Trees ◽  
Total Tree

Species of the genus Paulownia have been introduced to Bulgaria since the beginning of the XXthcentury and their multipurpose uses - as ornamental trees, for wood and biomass production- have been tested ever since. We present a study, which examines the early growth of four Paulowniaclones at southern locations in Bulgaria and derives biometric models for dendromass estimationof juvenile Paulownia trees.The data originated from two experimental plantations established on nursery land using one-yearoldin vitro propagated plant material. Forty six, 1 to 3 year-old saplings from two clones of P. tomentosaand two P. elongata × P. fortunei hybrids were sampled. Their stem biomass was modeledas a function of the breast height tree diameter and total tree height or the stem diameter aloneand a set of goodness-of-fit criteria was applied to select the most adequate among the 29 testedformulations. The regression models were fitted in log-transformed form to the logarithm of thestem biomass and MM correction factor for bias was applied to the back-transformed predictiondata. Two allometric relationships were derived, which adequately assess stem dendromass ofyoung Paulownia sp. from easily measurable tree characteristics. Both models are applicable forstem biomass estimation of juvenile Paulownia trees of diameter up to 5 cm and total height upto 3.5 m.

scholarly journals MANGROVE ABOVE GROUND BIOMASS ESTIMATION USING COMBINATION OF LANDSAT 8 AND ALOS PALSAR DATA

2017 ◽  
Vol 12 (2) ◽  
pp. 85 ◽  
Author(s):  
Gathot Winarso ◽  
Yenni Vetrita ◽  
Anang D. Purwanto ◽  
Nanin Anggraini ◽  
Soni Darmawan ◽  
...  
Keyword(s):  
Carbon Stock ◽  
Vegetation Indices ◽  
Emission Trading ◽  
Remote Sensing Data ◽  
Tree Height ◽  
Biomass Estimation ◽  
Landsat 8 ◽  
Alos Palsar ◽  
Sar Data ◽  
Estimation Models

Mangrove ecosystem is important coastal ecosystem, both ecologically and economically. Mangrove provides rich-carbon stock, most carbon-rich forest among ecosystems of tropical forest. It is very important for the country to have a large mangrove area in the context of global community of climate change policy related to emission trading in the Kyoto Protocol. Estimation of mangrove carbon-stock using remote sensing data plays an important role in emission trading in the future. Estimation models of above ground mangrove biomass are still limited and based on common forest biomass estimation models that already have been developed. Vegetation indices are commonly used in the biomass estimation models, but they have low correlation results according to several studies. Synthetic Aperture Radar (SAR) data with capability in detecting volume scattering has potential applications for biomass estimation with better correlation. This paper describes a new model which was developed using a combination of optical and SAR data. Biomass is volume dimension related to canopy and height of the trees. Vegetation indices could provide two dimensional information on biomass by recording the vegetation canopy density and could be well estimated using optical remote sensing data. One more dimension to be 3 dimensional feature is height of three which could be provided from SAR data. Vegetation Indices used in this research was NDVI extracted from Landsat 8 data and height of tree estimated from ALOS PALSAR data. Calculation of field biomass data was done using non-decstructive allometric based on biomass estimation at 2 different locations that are Segara Anakan Cilacap and Alas Purwo Banyuwangi, Indonesia. Correlation between vegetation indices and field biomass with ALOS PALSAR-based biomass estimation was low. However, multiplication of NDVI and tree height with field biomass correlation resulted R2 0.815 at Alas Purwo and R2 0.081 at Segara Anakan.  Low correlation at Segara anakan was due to failed estimation of tree height. It seems that ALOS PALSAR height was not accurate for determination of areas dominated by relative short trees as we found at Segara Anakan Cilacap, but the result was quite good for areas dominated by high trees. To improve the accuracy of tree height estimation, this method still needs validation using more data.

scholarly journals Seemingly Unrelated Mixed-Effects Biomass Models for Young Silver Birch Stands on Post-Agricultural Lands

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 381
Author(s):  
Karol Bronisz ◽  
Lauri Mehtätalo
Keyword(s):  
Tree Height ◽  
Mixed Effects ◽  
Model System ◽  
Silver Birch ◽  
Estimation Methods ◽  
Biomass Estimation ◽  
Agricultural Lands ◽  
Cross Model ◽  
Diameter At Breast Height ◽  
Breast Height

Secondary succession that occurs on abandoned farmlands is an important source of biomass carbon stocks. Both direct and indirect tree biomass estimation methods are applied on forest lands. Using empirical data from 148 uprooted trees, we developed a seemingly unrelated mixed-effects models system for the young silver birch that grows on post agricultural lands in central Poland. Tree height, biomass of stem, branches, foliage, and roots are used as dependent variables; the diameter at breast height is used as the independent variable. During model elaboration we used restricted cubic spline: 5 knots at the quantiles (0.05, 0.275, 0.5, 0.725, and 0.95) of diameter at breast height provided sufficiently flexible curves for all biomass components. In this study, we demonstrate the use of the model system through cross-model calibration of the biomass component model using tree height measured from 0, 2, 3, and 4 available extreme trees feature in the plot in question. A different number of extreme trees were measured for final model system and our results indicated that for all analyzed components, random-effect predictions are characterized by higher accuracy than fixed-effects predictions.

scholarly journals Evaluation of Different Calibration Approaches for Merchantable Volume Predictions of Norway Spruce Using Nonlinear Mixed Effects Model

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1104
Author(s):  
Zdeněk Adamec ◽  
Radim Adolt ◽  
Karel Drápela ◽  
Jiří Závodský
Keyword(s):  
Norway Spruce ◽  
Tree Height ◽  
Mixed Effects ◽  
Mixed Effects Model ◽  
Wood Volume ◽  
Nonlinear Mixed Effects Model ◽  
Breast Height ◽  
Stem Taper ◽  
Total Tree

Research Highlights: Determination of merchantable wood volume is one of the key preconditions for sustainable forest management. This study explores accuracy of calibrated predictions of merchantable wood volume of Norway spruce (Picea abies (L.) H. Karst.) using stem taper curves (STC) in a form of a mixed model. Background and Objectives: The study is devoted to the determination of merchantable wood volume (over bark) of individual standing stems based on the integration of an STC model calibrated using upper diameter measurements. Various options of upper diameter measurement were tested and their impact on the accuracy of merchantable wood volume prediction was evaluated. Materials and Methods: To model stem taper curves, a Kozak 02 function was applied in a form of a nonlinear, mixed effects model. Accuracies of calibrated merchantable wood volume predictions obtained through remote (optical) upper diameter measurements were compared to accuracies corresponding to contact measurements by a caliper. The performance of two alternative methods used in the Czech National Forest Inventory (NFI) and forestry practice, involving diameter at breast height and total tree height as the only predictors, were also tested. The contact measurements were performed at identical stem positions after felling the respective sample tree. The calibration was done in order to account for factors inherent in particular location, and, optionally, also in a particular sample stem (within the respective location). Input data was sourced as part of a dedicated survey involving the entire territory of the Czech Republic. In total, 716 individual spruce trees were measured, felled and analysed at 169 locations. Results: In general, the best merchantable volume predictions were obtained by integrating the STC fitted (and calibrated) by minimising errors of stem cross-sectional areas instead of diameters. In terms of calibrated predictions, using single-directional, caliper measurement of upper diameter at 7 m (after felling) led to the best accuracy. In this case, the observed mean bias of merchantable volume prediction was only 0.63%, indicating underestimation. The best optical calibration strategy involved upper diameter measurements at two heights (5 and 7 m) simultaneously. Bias of this volume prediction approach was estimated at 2.1%, indicating underestimation. Conclusions: Concerning the prediction of merchantable stem volume of standing Norway spruce trees, STC calibration using two optical upper diameter measurements (at 5 and 7 m) was found to be practically applicable, provided a bias up to 3.7% can be accepted. This method was found to be more accurate than the existing national alternatives using diameter at breast height and the total tree height as the only predictors.

Comparison of linear and mixed-effect regression models and a k-nearest neighbour approach for estimation of single-tree biomass

2008 ◽  
Vol 38 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Lutz Fehrmann ◽  
Aleksi Lehtonen ◽  
Christoph Kleinn ◽  
Erkki Tomppo
Keyword(s):  
Mixed Models ◽  
Regression Models ◽  
Tree Height ◽  
Biomass Estimation ◽  
Data Sets ◽  
Tree Biomass ◽  
Mixed Effect ◽  
Single Tree ◽  
Breast Height ◽  
Effect Regression

Allometric biomass models for individual trees are typically specific to site conditions and species. They are often based on a low number of easily measured independent variables, such as diameter in breast height and tree height. A prevalence of small data sets and few study sites limit their application domain. One challenge in the context of the actual climate change discussion is to find more general approaches for reliable biomass estimation. Therefore, nonparametric approaches can be seen as an alternative to commonly used regression models. In this pilot study, we compare a nonparametric instance-based k-nearest neighbour (k-NN) approach to estimate single-tree biomass with predictions from linear mixed-effect regression models and subsidiary linear models using data sets of Norway spruce ( Picea abies (L.) Karst.) and Scots pine ( Pinus sylvestris L.) from the National Forest Inventory of Finland. For all trees, the predictor variables diameter at breast height and tree height are known. The data sets were split randomly into a modelling and a test subset for each species. The test subsets were not considered for the estimation of regression coefficients nor as training data for the k-NN imputation. The relative root mean square errors of linear mixed models and k-NN estimations are slightly lower than those of an ordinary least squares regression model. Relative prediction errors of the k-NN approach are 16.4% for spruce and 14.5% for pine. Errors of the linear mixed models are 17.4% for spruce and 15.0% for pine. Our results show that nonparametric methods are suitable in the context of single-tree biomass estimation.

scholarly journals Biomass functions applicable to European beech

2012 ◽  
Vol 51 (No. 4) ◽  
pp. 147-154 ◽  
Author(s):  
E. Cienciala ◽  
M. Černý ◽  
J. Apltauer ◽  
Z. Exnerová
Keyword(s):  
Tree Height ◽  
European Beech ◽  
Biomass Estimation ◽  
Managed Forests ◽  
Independent Variables ◽  
Breast Height ◽  
Allometric Functions ◽  
Branch Biomass ◽  
Independent Variable ◽  
Total Tree

This material describes parameterization of allometric functions applicable to biomass estimation of European beech trees. It is based on field data from destructive measurements of 20 full-grown trees with diameter at breast height (dbh) from 5.7 to 62.1 cm. The parameterization was performed for total tree aboveground biomass (AB; besides stump), stem and branch biomass, respectively. The allometric functions contained two or three parameters and used dbh either as a single independent variable or in combination with tree height (H). These functions explained 97 to 99% of the variability in the measured AB. The most successful equation was that using both dbh and H as independent variables in combination with three fitted parameters. H, as the second independent variable, had rather a small effect on improving the estimation: in the case of AB, H as independent variable improved prediction accuracy by 1&ndash;2% whereas in the case of branch biomass by about 5%. The parameterized biomass equations are applicable to tree specimens of European beech grown in typically managed forests.

Variation of Wood Density in Larch in Northeast of China

2012 ◽  
Vol 487 ◽  
pp. 38-42
Author(s):  
Ming Yu Liu ◽  
Yin Bang Liu ◽  
Li Chun Jiang
Keyword(s):  
Wood Density ◽  
Significant Variation ◽  
Tree Height ◽  
Northeastern China ◽  
Dahurian Larch ◽  
Displacement Method ◽  
Water Displacement ◽  
Breast Height ◽  
Equal Distance ◽  
Northeast Of China

Wood density was investigated in seven dahurian larch (Larix gmelinii Rupr.) trees grown in northeastern China. Six discs (about 5 cm thick) were cut from each tree (i.e. from the root stem, at breast height (1.3m), and at 20%, 40%, 60%, and 80% of the total height). For each disc, a thick sliver with parallel sides was cut out along the diameter of the disc. The sliver was about 40-mm thick, with the pith located in the middle. Eight small pieces were cut from the sliver with equal distance from pith to bark. Wood density of small piece was obtained using water displacement method. Significant variation in wood density was observed among sections for different heights. Wood density increases from pith to bark for all height categories and decreases from the stump to top of the tree height.

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