scholarly journals Evaluation of Compatible Taper and Volume Models for Combretum hartmannianum and Lonchocarpus laxiflorus Tree Species.

2021 ◽  
pp. 50-70
Keyword(s):  
Tree Species ◽  
Tree Height ◽  
Coefficient Of Determination ◽  
Accurate Estimation ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Regression Parameters ◽  
Absolute Residual ◽  
Total Tree ◽  
Volume Models

This paper developed and evaluated the performance of the current functional tree taper and volume models. The models were applied to some selected economically important natural tree species common to central Sudan, namely, Combretum hartmannianum and, Lonchocarpus Laxiflorus. The tree variables measured were the diameter at breast height (DBH, cm), diameter at the base of the tree (d0, cm), upper stem diameters (di), total tree height (H), and height to the base of the crown (Hb). In total, 19 taper and 32 volume models were tested and evaluated (22 models were two-variable models (Diameter at breast height and total tree height or bole height) and 10 were three-variable models (Diameter at ground level, Diameter at breast height and total tree height or bole height). The model goodness of fit was evaluated in terms of adjusted coefficient of determination (Ra2), standard error (SE), mean absolute residual (MAR), bias (BI) Akaike’s information criterion (AIC), homogeneity of the residuals and significance of the regression parameters. As far as taper models is concerned, Models, some of the models were found to yield satisfactory results for the tow selected species with R2 range of 0.94 – 0.96. For the within species variation of models on the basis of the AIC values, the ranking of the models (smaller AIC first) were in consistant with the rankings due to SE and Ra2 values although AIC penalizes models in proportion to the number regression parameters. In general the results of the study indicated that higher residuals valuse are in most of the cases associated with the lower parts of the bole, the butress portion of the stem. This suggests that care should be taken during the application of such models for hardwood species, especially in open woodlands where butress is a common characteristic.The results for volume models revealed differences in the behaviour of different models for each species as the degree of significance of the regression parameters varies between tree species. However, the replacement of the total tree height by the bole height (merchantable height) improves both the level of parameter significance and the coefficient of determination. The results also reveal that inclusion of diameter at grown level to the original two variables (DBH, Ht) and the replacement of the original model total height with the bale height results in quite significant improvement of the Ra2 values. In general, the study concluded that taper and volume models can provide precise and accurate estimation of tree growth variables for the studied species with reasonable cost and time, but care should be taken when dealing with same model for the same species across varying growth and management condition, or when dealing with different species. country.

scholarly journals Taper and Volume Models for Some Terminalia Tree Species

2021 ◽  
pp. 106-125
Keyword(s):  
Tree Species ◽  
Goodness Of Fit ◽  
Tree Height ◽  
Coefficient Of Determination ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Regression Parameters ◽  
Absolute Residual ◽  
Total Tree ◽  
Volume Models

The paper evaluated the performance of the current functional tree taper and volume models. The models were applied to some selected economically important natural Terminalia tree species common to central Sudan, namely, Terminalia laxiflora and, Terminalia brownii. 22 two-variable models (Diameter at breast height and total tree height or bole height) and 10 three-variables models (Diameter at ground level, Diameter at breast height and total tree height or bole height) were evaluated. The tree variables measured were the diameter at breast height (DBH, cm), diameter at the base of the tree (d0, cm), upper stem diameters (di), total tree height (H), and height to the base of the crown (Hb). Data were extracted from a natural reserved forest in the Blue Nile state. The models goodness of fit were evaluated in terms of adjusted coefficient of determination (Ra2), standard error (SE), mean absolute residual (MAR), bias (BI) Akaike’s information criterion (AIC), homogeneity of the residuals and significance of the regression parameters. Taper-17 and Taper-19 were found to be among the best two models for the two species with R2 range of 0.94 – 0.93, but with different rankings for each species. Comparison of the range of data for the tow studied species suggested that representation of various diameter at breast height (DBH, cm), diameter at the base of the tree (d0, cm), upper stem diameters (di), total tree height (H), and height to the base of the crown (Hb), had significant influence on the accuracy of prediction outside the range of the fitted data. This implies that application of the selected models is only useful at local stand level or at best in similar biological and stand structure conditions. For volume models, The results indicated that individual equations act differently in each species as there were great variations in the values of the same parameter of a given model accross the species. Some regression parameters of a given model were found to be significant in some species and insignificant in others. Comparison between the two versions of each group reveals that the replacement of the total tree height by the bole height (merchantable height) improves both the level of parameter significance and the coefficient of determination. From the first, the regression parameters of only 5 models (VOL-1, VOL-5, VOL-8, VOL-17, and VOL-20) were found to be significant at 0.05 probability level for all the tow species. The results also reveal that inclusion of variable D0 to the original two variables (DBH, Ht) to the volume equations results in insignificant improvement of the Ra2 values, while the replacement of the original model Ht variable with the Hb results in quite significant improvement of the Ra2 values. However, substantial improvement of the Ra2 values were obtained when both D0 and Hb were added. For this group of models, VOL-23, VOL-25- VOL-29 VOL30- and VOL-31were found to be the best for almost all the tow species. In general, the study concluded that taper and volume models can provide precise and accurate tree growth variables for the studied species with reasonable cost and time, but care should be taken when dealing with same model for the same species across the varying growth and management condition.

scholarly journals Unexplained Relationships of Height-Diameter of Three Tree Species in a Tropical Forest.

2013 ◽  
Vol 6 (3) ◽  
pp. 196-204
Keyword(s):  
Tree Species ◽  
Coefficient Of Determination ◽  
Multivariate Models ◽  
Forest Reserve ◽  
Permanent Sample Plots ◽  
Tree Distance ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Bivariate Models

Associations between bivariate variables relative to the unexplained relationships of height-Dbh (diameter at breast height) models were investigated. Seven permanent sample plots measuring 40m by 250m at Omo Forest Reserve were used to assess the relationships between height and diameter at breast height of three tree species as affected by the variables of neighbouring trees. The result showed differences in the coefficient of determination of the bivariate models and multivariate models. The models arrived at for each of the species and for the bivariate models are: Scottelia coriaceae: Ht = 2.59 + 0.473D+ 0.0012D2 for 5cm ≤ D ≤100cm (R2 = 0.70) Sterculia rhinopetala: Ht = 5.96 + 0.467D+ 0.00296D2 for 5cm ≤ D ≤100cm (R2 = 0.77) Strombosia pustulata: Ht = 2.02 + 0.722D+ 0.00581D2 for 5cm ≤ D ≤ 60cm (R2 = 0.81) Where both Ht and D are height and Diameter at breast height. While on the other hand the multivariate models that considered the effect of neighbouring trees are: Scottelia coriaceae: 2 1 2 3 4 Ht = 3.74 + 0.41x −1.14x + 0.205x +1.278x (R = 0.723) Sterculia rhnopetala: 2 1 2 3 4 Ht = 6.18 + 0.2601x +1.163x + 0.438x − 0.442x (R = 0.608) Strombosia pustalata: 2 1 2 3 4 Ht = 6.84 + 0.399x − 0.318x − 0.138x − 0.838x (R = 0.650) x1 = diameter at breast height, x2 = Mean neighbouring tree distance, x3 = Frequency of the neighbouring tree and x4 = Position of the crown.

scholarly journals Allometric Equations for Estimating Aboveground Biomass of Eucalyptus urophylla S.T. Blake in East Nusa Tenggara

2021 ◽  
Vol 27 (1) ◽  
pp. 24-31
Author(s):  
R Sadono ◽  
◽  
W Wahyu ◽  
F Idris
Keyword(s):  
Aboveground Biomass ◽  
Tree Height ◽  
Allometric Equation ◽  
Allometric Equations ◽  
Accurate Estimation ◽  
Eucalyptus Urophylla ◽  
Individual Tree ◽  
Eucalyptus Plantation ◽  
Diameter At Breast Height ◽  
Breast Height

Understanding the essential contribution of eucalyptus plantation for industry development and climate change mitigation requires the accurate quantification of aboveground biomass at the individual tree species level. However, the direct measurement of aboveground biomass by destructive method is high cost and time consuming. Therefore, developing allometric equations is necessary to facilitate this effort. This study was designed to construct the specific allometric models for estimating aboveground biomass of Eucalyptus urophylla in East Nusa Tenggara. Forty two sample trees were utilized to develop allometric equations using regression analysis. Several parameters were selected as predictor variables, i.e. diameter at breast height (D), quadrat diameter at breast height combined with tree height (D2H), as well as D and H separately. Results showed that the mean aboveground biomass of E. urophylla was 143.9 ± 19.44 kg tree-1. The highest biomass were noted in stem (80.06%), followed by bark (11.89%), branch (4.69%), and foliage (3.36%). The relative contribution of stem to total aboveground biomass improved with the increasing of diameter class while the opposite trend was recorded in bark, branch, and foliage. The equation lnŶ = lna + b lnD was best and reliable for estimating the aboveground biomass of E. urophylla since it provided the highest accurate estimation (91.3%) and more practical than other models. Referring to these findings, this study concluded the use of allometric equation was reliable to support more efficient forest mensuration in E. urophylla plantation.

scholarly journals Determining the Age of Streetside Trees with Diameter at Breast Height-based Multifactorial Model

2008 ◽  
Vol 34 (3) ◽  
pp. 137-143
Author(s):  
Jan Lukaszkiewicz ◽  
Marek Kosmala
Keyword(s):  
Regression Coefficient ◽  
Tree Height ◽  
Tree Age ◽  
Multifactorial Model ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
R Value ◽  
The Difference ◽  
Individual Trees ◽  
Total Tree

This article evaluates the possibility of determining tree age based simultaneously on diameter at breast height (dbh) (1.3 m [4.3 ft]) and total tree height using common lime, common ash, and horsechestnut species. The first step was the identification and measuring groups of trees growing in similar conditions (streetside trees in Warsaw area, Poland) in which planting ages were known (mainly from archives). Next, multifactorial regression model was developed describing the growth of both tree parameters (dbh and height) over time. In the majority of cases, plotting tree age against diameter and height yielded a regression coefficient r value and determination coefficient r 2value above 0.9. For graphic interpretation of elaborated multifactorial models, nomograms were applied. This kind of graph allows explaining tree age based on both dbh and height of trees. Another step was verification. The resulting model was applied to unrelated groups of trees of known age. Mean bias values were established for each model. The difference between the actual age and mean age calculated with the model was less than ±15%. Presented model, although not meant for application to individual trees, might be useful to determine the age of groups of trees growing along streets and roads.

scholarly journals Verification of bi-parameter models of dependence diameter on breast height in birch stands

2020 ◽  
Author(s):  
А.В. Лебедев ◽  
В.В. Кузьмичев
Keyword(s):  
Standard Error ◽  
Research Work ◽  
Tree Height ◽  
Information Criterion ◽  
Coefficient Of Determination ◽  
Model Parameters ◽  
Statistical Point ◽  
Diameter At Breast Height ◽  
Breast Height

Важное значение как в лесохозяйственных работах, так и при проведении научных исследований имеет точность определения высоты деревьев. Высота обычно определяется с использованием конкретных моделей, где она является функцией от диаметра дерева на высоте груди. Наиболее простыми моделями зависимости высоты деревьев от диаметра на высоте груди являются двухпараметрические, и они находят широкое применение в лесотаксационных работах. На материалах 23 пробных площадей с измерением модельных деревьев, заложенных в березовых древостоях Лесной опытной дачи Тимирязевской сельскохозяйственной академии, проводилось определение параметров для 14 двухпараметрических моделей, наиболее часто встречающихся в литературных источниках. Параметры моделей вычислялись путем минимизации среднеквадратической ошибки. Качество моделей оценивалось по следующим метрикам: квадратный корень из среднеквадратической ошибки, коэффициент детерминации, информационный критерий Акаике, информационный критерий Байеса. Полученные результаты подтвердили целесообразность использования на практике ряда уравнений, которые среди двухпараметрических моделей показывают приемлемое качество. Результаты анализа данных показывают, что со статистической точки зрения полученные различия в качестве моделей не являются значимыми на 5-м уровне (t-тест). Обоснованные в качестве лучших модели зависимости высоты от диаметра на высоте груди могут быть использованы на практике при выполнении лесохозяйственных и научно-исследовательских работ в березовых древостоях, произрастающих в центральных регионах европейской части России. Методика проведенного исследования позволяет повторить аналогичную работу для древесных пород и лесорастительных условий, для которых информация о характере связи высоты с таксационным диаметром является неполной или отсутствует. The accuracy of determining the height of trees is important both in forestry and in scientific research. Height is usually determined using specific models, where it is a function of the diameter at breast height. The simplest models of the dependence of tree height on diameter at breast height are two-parameter, and they are widely used in forest taxation researches. On the materials of 23 sample plots with the measurement of model trees laid in birch stands of the Forest Experimental District of the Timiryazev Agricultural Academy, the parameters were determined for the 14 bi-parameter models that are most often found in literary sources. Model parameters were calculated by minimizing the standard error. The quality of the models was evaluated by the following metrics: the square root of the standard error, the coefficient of determination, the Akaike information criterion, the Bayes information criterion. The obtained results confirmed the feasibility of using in practice several equations, which among the biparameter models show acceptable quality. The results of data analysis show that, from a statistical point of view, the differences obtained in the quality of models are not significant at the 5 level (t-test). Substantiated as the best models of the dependence of height on diameter at breast height can be used in practice when performing forestry and research work in birch stands growing in the central regions of the European part of Russia. The methodology of the study allows you to repeat the same work for tree species and forest conditions, for which information about the nature of the relationship of height with the diameter at breast height is incomplete or absent.

Patterns in height-diameter relationships for selected tree species and sites in eastern Texas

1999 ◽  
Vol 29 (9) ◽  
pp. 1445-1448 ◽  
Author(s):  
Mark R Fulton
Keyword(s):  
Tree Species ◽  
Tree Height ◽  
Height Growth ◽  
Initial Slope ◽  
Maximum Height ◽  
Height Increment ◽  
Understory Species ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Two Parameter

Relationships between tree height and diameter at breast height were described for 15 species across a range of sites in eastern Texas using a two-parameter equation. Maximum height varied significantly from site to site within a species, but the ratio of initial slope to maximum height was generally constant. Sites favoring tall trees of one species tended to favor tall trees of all species, especially among species found in the overstory. The greatest rates of height growth for a given diameter at breast height increment were found among some midstory and understory species.

scholarly journals Estimation of Genetic Parameters and Wood Yield Selection Index in a Clonal Trial of Korean Pine (Pinus koraiensis) in Northeastern China

2021 ◽  
Vol 13 (8) ◽  
pp. 4167
Author(s):  
David Kombi Kaviriri ◽  
Huan-Zhen Liu ◽  
Xi-Yang Zhao
Keyword(s):  
Selection Index ◽  
Tree Height ◽  
Stem Volume ◽  
Korean Pine ◽  
Branch Number ◽  
Basal Diameter ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Stem Straightness ◽  
Clonal Trial

In order to determine suitable traits for selecting high-wood-yield Korean pine materials, eleven morphological characteristics (tree height, basal diameter, diameter at breast height, diameter at 3 meter height, stem straightness degree, crown breadth, crown height, branch angle, branch number per node, bark thickness, and stem volume) were investigated in a 38-year-old Korean pine clonal trial at Naozhi orchard. A statistical approach combining variance and regression analysis was used to extract appropriate traits for selecting elite clones. Results of variance analysis showed significant difference in variance sources in most of the traits, except for the stem straightness degree, which had a p-value of 0.94. Moderate to high coefficients of variation and clonal repeatability ranged from 10.73% to 35.45% and from 0.06% to 0.78%, respectively. Strong significant correlations on the phenotypic and genotypic levels were observed between the straightness traits and tree volume, but crown breadth was weakly correlated to the volume. Four principal components retaining up to 80% of the total variation were extracted, and stem volume, basal diameter, diameter at breast height, diameter at 3 meter height, tree height, and crown height displayed high correlation to these components (r ranged from 0.76 to 0.98). Based on the Type III sum of squares, tree height, diameter at breast height, and branch number showed significant information to explain the clonal variability based on stem volume. Using the extracted characteristics as the selection index, six clones (PK105, PK59, PK104, PK36, PK28, and K101) displayed the highest Qi values, with a selection rate of 5% corresponding to the genetic gain of 42.96% in stem volume. This study provides beneficial information for the selection of multiple traits for genetically improved genotypes of Korean pine.

scholarly journals Seemingly Unrelated Mixed-Effects Biomass Models for Black Locust in West Poland

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 380
Author(s):  
Karol Bronisz ◽  
Szymon Bijak ◽  
Rafał Wojtan ◽  
Robert Tomusiak ◽  
Agnieszka Bronisz ◽  
...  
Keyword(s):  
Black Locust ◽  
Random Effect ◽  
Tree Height ◽  
Cross Model ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Dependent Variables ◽  
Dry Biomass ◽  
Biomass Components ◽  
Independent Variable

Information about tree biomass is important not only in the assessment of wood resources but also in the process of preparing forest management plans, as well as for estimating carbon stocks and their flow in forest ecosystems. The study aimed to develop empirical models for determining the dry mass of the aboveground parts of black locust trees and their components (stem, branches, and leaves). The research was carried out based on data collected in 13 stands (a total of 38 sample trees) of black locust located in western Poland. The model system was developed based on multivariate mixed-effect models using two approaches. In the first approach, biomass components and tree height were defined as dependent variables, while diameter at breast height was used as an independent variable. In the second approach, biomass components and diameter at breast height were dependent variables and tree height was defined as the independent variable. Both approaches enable the fixed-effect and cross-model random-effect prediction of aboveground dry biomass components of black locust. Cross-model random-effect prediction was obtained using additional measurements of two extreme trees, defined as trees characterized by the smallest and largest diameter at breast height in sample plot. This type of prediction is more precise (root mean square error for stem dry biomass for both approaches equals 77.603 and 188.139, respectively) than that of fixed-effects prediction (root mean square error for stem dry biomass for both approaches equals 238.716 and 206.933, respectively). The use of height as an independent variable increases the possibility of the practical application of the proposed solutions using remote data sources.

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