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 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 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 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 Height-Diameter Models for Mixed-Species Forests Consisting of Spruce, Fir, and Beech

2014 ◽  
Vol 56 (2) ◽  
pp. 93-104 ◽  
Author(s):  
Rudolf Petráš ◽  
Michal Bošeľa ◽  
Julian Mecko ◽  
Julius Oszlányi ◽  
Ionel Popa
Keyword(s):  
Goodness Of Fit ◽  
Abies Alba ◽  
Tree Height ◽  
European Beech ◽  
Coefficient Of Determination ◽  
Stand Age ◽  
Silver Fir ◽  
Mathematical Form ◽  
Mixed Species ◽  
Regression Parameters

AbstractHeight-diameter models define the general relationship between the tree height and diameter at each growth stage of the forest stand. This paper presents generalized height-diameter models for mixed-species forest stands consisting of Norway spruce (Picea abies Karst.), Silver fir (Abies alba L.), and European beech (Fagus sylvatica L.) from Slovakia. The models were derived using two growth functions from the exponential family: the two-parameter Michailoff and three-parameter Korf functions. Generalized height-diameter functions must normally be constrained to pass through the mean stand diameter and height, and then the final growth model has only one or two parameters to be estimated. These “free” parameters are then expressed over the quadratic mean diameter, height and stand age and the final mathematical form of the model is obtained. The study material included 50 long-term experimental plots located in the Western Carpathians. The plots were established 40-50 years ago and have been repeatedly measured at 5 to 10-year intervals. The dataset includes 7,950 height measurements of spruce, 21,661 of fir and 5,794 of beech. As many as 9 regression models were derived for each species. Although the “goodness of fit” of all models showed that they were generally well suited for the data, the best results were obtained for silver fir. The coefficient of determination ranged from 0.946 to 0.948, RMSE (m) was in the interval 1.94-1.97 and the bias (m) was -0.031 to 0.063. Although slightly imprecise parameter estimation was established for spruce, the estimations of the regression parameters obtained for beech were quite less precise. The coefficient of determination for beech was 0.854-0.860, RMSE (m) 2.67-2.72, and the bias (m) ranged from -0.144 to -0.056. The majority of models using Korf’s formula produced slightly better estimations than Michailoff’s, and it proved immaterial which estimated parameter was fixed and which parameters were free

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 Models for Measuring Height-Diameter Relationships for Agarwood (AquilariamalaccensisLamk) Plantations in Bangladesh

2019 ◽  
Vol 8 (2) ◽  
Author(s):  
S.M.Z. Islam ◽  
M.A.M. Chowdhury ◽  
K. Misbahuzzaman
Keyword(s):  
Goodness Of Fit ◽  
Linear Models ◽  
Mean Squared Error ◽  
Tree Height ◽  
Information Criterion ◽  
Growth And Yield ◽  
Coefficient Of Determination ◽  
Regression Parameters ◽  
Forest Division ◽  
Watson Statistic

The relationship between tree height and diameter is an important element in growth and yield models, in carbon stock estimation and timber volume models, and in the description of stand dynamics.In this paper considered18 functional models and evaluated the performance that predict total tree height from diameter at breast height of agarwood. The models were applied to A.malaccensisLamk (Agarwood) which is economically important tree species planted in some potential forest areas of Bangladesh.A total of 5,866 tree heights and corresponding diameters at breast heights were extracted from many forest areas in Sylhet, Chittagong, Cox's Bazar and Chittagong Hill Tracts (Rangamati) forest division. The model goodness of fit values were evaluated in terms of adjusted coefficient of determination (R2), root mean squared error (RMSE), Akaike’s information criterion (AIC),Durbin-Watson statistic value,homogeneity of the residuals and significance of the regression parameters. The results of the study indicated that the height-diameter relationship can best be described by non-linear models. The best three models selected for the species with ranking in terms of goodness of fit. The Gompertz ; Parabolic and Logistic  with R2=0.91 were height-diameter models performed better than other models.

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