scholarly journals Modelling height-diameter relationship for Chir pine trees

1970 ◽  
Vol 19 (2) ◽  
pp. 3-9 ◽  
Author(s):  
RP Sharma
Keyword(s):  
Linear Models ◽  
Tree Height ◽  
Study Data ◽  
Growth And Yield ◽  
Pinus Roxburghii ◽  
Pine Trees ◽  
Important Input ◽  
Regression Techniques ◽  
Stand Attributes ◽  
Chir Pine

Tree height-diameter relationship can be used as an important input component in growth and yield models, and description of stand dynamics. This study aims at establishing robust height-diameter models for Chir pine (Pinus roxburghii) trees using regression techniques. Among the twelve non-linear models fitted to height-diameter data from twentythree Chir pine stands in Parbat and Shyangja districts, Hossfeld's model accounted for the largest proportion of height variations (R2adj = 86%), and appeared to be biologically most realistic. This model can be applied to similar stand conditions from where study data were procured. Keywords: Chir pine; height-diameter models; model evaluation; stand attributes DOI: 10.3126/banko.v19i2.2978 Banko Janakari, Vol. 19, No.2 2009 pp.3-9  

scholarly journals Integration ofAndrographis paniculataas Potential Medicinal Plant in Chir Pine (Pinus roxburghiiSarg.) Plantation of North-Western Himalaya

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Chandra Shekher Sanwal ◽  
Raj Kumar ◽  
S. D. Bhardwaj
Keyword(s):  
Plant Height ◽  
Growth Parameters ◽  
Andrographis Paniculata ◽  
Growth And Yield ◽  
Economic Viability ◽  
Pinus Roxburghii ◽  
Area Index ◽  
Net Returns ◽  
Chir Pine ◽  
North Western

The integration ofAndrographis paniculataunderPinus roxburghii(Chir pine) plantation has been studied to evaluate the growth and yield for its economic viability and conservation. It was grown on three topographical aspects, namely, northern, north-western, and western, at a spacing of 30 cm × 30 cm, followed by three tillage depths, namely, minimum (0 cm), medium (up to 10 cm), and deep (up to 15 cm) tillage. The growth parameters, namely, plant height and number of branches per plant, were recorded as significantly higher on western aspect and lowest on northern aspect except for leaf area index which was found nonsignificant. However under all tillage practices all the growth parameters in both understorey and open conditions were found to be nonsignificant except for plant height which was found to be significantly highest under deep tillage and lowest under minimum tillage. The study of net returns forAndrographis paniculatarevealed that it had positive average annual returns even in understorey conditions which indicate its possible economic viability under integration of Chir pine plantations. Hence net returns can be enhanced by integratingAndrographis paniculataand this silvimedicinal system can be suggested which will help utilizing an unutilized part of land and increase total productivity from such lands besides conservation of theA. paniculata in situ.

scholarly journals Modelling height-diameter relationship for Pinus wallichiana trees for Lete and Kunjo of Mustang district

2013 ◽  
Vol 21 (2) ◽  
pp. 13-23
Author(s):  
B. H. Wagle ◽  
R. P. Sharma
Keyword(s):  
Linear Models ◽  
Weibull Model ◽  
Growth And Yield ◽  
Height Variation ◽  
Growth Simulation ◽  
Pinus Wallichiana ◽  
Pine Trees ◽  
Tree Data ◽  
Growth And Yield Models ◽  
Simulation Systems

Quantifi cation of height-diameter relationship helps in better understanding of stand dynamics. Height-diameter models can be used as necessary inputs to growth and yield models and growth simulation systems. The researchers developed height-diameter models with 364 Blue pine (Pinus wallichiana) tree data from Lete and Kunjo Village Development Committees (VDCs) of Mustang district. Eighteen non-linear models were calibrated, among which, Weibull model described the largest proportion of height variation (R2 adj = 0. 9362). Gunary and Chapman-Richards’ models also appeared almost identical to Weibull model in terms of fi t statistics and graphical appearance. The researchers recommend Weibull model for predicting total heights of Blue pine trees for the VDCs covered by the study.DOI: http://dx.doi.org/10.3126/banko.v21i2.9125Banko Janakari Vol. 21, NO. 2, 2011 Page: 13-23 Uploaded date: 10 November, 2013 

An ecological appraisal of Pinus roxburghii Sarg. (Chir pine) and Shorea robusta Gaertn. (Sal) plantations in Doon valley

2021 ◽  
Vol 43 (2) ◽  
pp. 107-113
Author(s):  
Subramanian Sivaranjani ◽  
◽  
Vijender Pal Panwar ◽  
Keyword(s):  
Sandy Loam ◽  
Lantana Camara ◽  
Pine Plantation ◽  
Broussonetia Papyrifera ◽  
Pinus Roxburghii ◽  
Shorea Robusta ◽  
Physico Chemical ◽  
Pine Trees ◽  
Chemical Attributes ◽  
Chir Pine

The present study focused on phyto-sociological and physico-chemical attributes of soil in Pinus roxburghii (Chir pine) and Shorea robusta (Sal) plantations in a reserved estate of New Forest, Dehradun. A total of 33 plant species comprising of 18 trees, 10 shrubs and five herbs were recorded from the study area. The tree density, in chir pine was lower 950 individuals/ ha as compared to 1073 individuals/ ha in sal vegetation. In saplings, high density was observed for Syzygium cumini (20 individuals/ 100m2) in sal followed by Broussonetia papyrifera (19 individuals/100m2) in chir pine plantation. Lantana camara, marked its presence with highest density (49 individuals/100 m2) in chir pine followed by Clerodendrum infortunatum (18 individuals/100 m2) in sal plantation. Higher tree basal cover (51 m2/ha) was recorded in sal than chir pine (19 m2/ha). Similarly, the tree diversity in sal was recorded higher (1.68) as compared to chir pine (1.51) plantation. Contrarily, sapling diversity was higher (2.81) in chir pine as compared to sal (2.52) plantation. Herbaceous flora was completely absent in sal plantation. Analysis of size class distribution revealed that sal trees (~ 29%) attained 21-30 cm diameter whereas chir pine trees (68%) were under 11-20 cm diameter class mainly due to preferred growing zone of the species and habitat suitability. The soil under chir pine was slightly acidic (5.98) with sandy loam texture. Soil was comparatively good with higher soil organic carbon (2.71%) under sal plantation mainly due to high humus deposition. It is suggested to restrict wide spread of Lantana camara in chir pine plantation for the better growth of the species and enhance nutrient availability.

scholarly journals An Individual-Tree Growth and Yield Prediction System for Even-Aged Natural Shortleaf Pine Forests

1999 ◽  
Vol 23 (4) ◽  
pp. 203-211 ◽  
Author(s):  
Thomas B. Lynch ◽  
Kenneth L. Hitch ◽  
Michael M. Huebschmann ◽  
Paul A. Murphy
Keyword(s):  
Basal Area ◽  
Pine Forests ◽  
Growth And Yield ◽  
Prediction System ◽  
Pinus Echinata ◽  
Shortleaf Pine ◽  
Individual Tree ◽  
Pine Trees ◽  
Computer Simulation Program ◽  
Stand Attributes

Abstract The development of a system of equations that model the growth and development of even-aged natural shortleaf (Pinus echinata Mill.) pine forests is described. The growth prediction system is a distance-independent individual-tree simulator containing equations that predict basal-area growth, survival, total and merchantable heights, and total and merchantable volumes for shortleaf pine trees. These equations were combined into a computer simulation program that predicts future states of shortleaf pine stands from initial stand descriptions. Comparisons of observed and predicted ending stand conditions in shortleaf pine research plots indicate the simulator makes acceptable forecasts of final stand attributes. South. J. Appl. For. 23(4):203-211.

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.

scholarly journals Criterios y modelos estadísticos de eficacia escolar

2020 ◽  
Vol 38 (2) ◽  
pp. 311-327
Author(s):  
Luis Lizasoain Hernández
Keyword(s):  
Effective Schools ◽  
School Effectiveness ◽  
Linear Models ◽  
Basque Country ◽  
Outcome Variable ◽  
Multilevel Regression ◽  
School Effectiveness Research ◽  
Regression Techniques ◽  
Pais Vasco ◽  
Selection Of

El objetivo de este artículo es presentar los criterios y modelos estadísticos empleados en un estudio de eficacia escolar desarrollado en la Comunidad Autónoma del País Vasco empleando como variable criterio los resultados en matemáticas, comprensión lectora en lengua castellana y en lengua vasca, resultantes de las evaluaciones de Diagnóstico aplicadas en cinco años. Se definen cuatro criterios de eficacia escolar: puntuaciones extremas, residuos extremos, crecimiento de puntuaciones y crecimiento de residuos. Para ello se han aplicado técnicas de regresión multinivel empleando modelos jerárquicos lineales. Los resultados permiten una selección de centros tanto de alta como de baja eficacia que se basa en cuatro enfoques distintos y complementarios de la eficacia (o ineficacia) escolar. The aim of this paper is to present the statistical criteria and models used in a school effectiveness research carried out in the Basque Country Autonomous Community using as outcome variable the mathematics, spanish language and basque language scores. These scores come from the Diagnosis Assessments applied for five years. Four school effectiveness criteria are defined: extreme scores, extreme residuals, scores growth and residuals growth. Multilevel regression techniques have been applied using hierarchical linear models (HLM). Results have permitted a selection of both high and low effective schools based on four different and complementary school effectiveness approaches.

scholarly journals Growth and yield of teak stands at different spacing

2018 ◽  
Vol 53 (10) ◽  
pp. 1109-1118
Author(s):  
Reginaldo Antonio Medeiros ◽  
Haroldo Nogueira de Paiva ◽  
Flávio Siqueira D’Ávila ◽  
Helio Garcia Leite
Keyword(s):  
Growth Rate ◽  
Basal Area ◽  
Tree Height ◽  
Tectona Grandis ◽  
Growth And Yield ◽  
Mean Square ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Total Tree

Abstract: The objective of this work was to evaluate the growth and yield of teak (Tectona grandis) stands at different spacing and in different soil classes. Twelve spacing were evaluated in an Inceptisol and Oxisol, in plots with an area of 1,505 or 1,548 m2, arranged in a completely randomized design with nine replicates. The teak trees were measured at 26, 42, 50, and 78 months of age. Total tree height was less affected by spacing. Mean square diameter was greater in wider spacing, whereas basal area and total volume with bark were greater in closer spacing. An increase in volume with bark per tree was observed with the increase of useful area per plant. For teak trees, growth stagnation happens earlier, the growth rate is higher in closer spacing, and the plants grow more in the Inceptisol than in the Oxisol.

Within-ring δ13C spatial variability and interannual variations in wood cellulose of two contrasting provenances of Pinus pinaster

1998 ◽  
Vol 28 (5) ◽  
pp. 766-773 ◽  
Author(s):  
Anne Nguyen-Queyrens ◽  
André Ferhi ◽  
Denis Loustau ◽  
Jean-Marc Guehl
Keyword(s):  
Spatial Variability ◽  
Pinus Pinaster ◽  
Isotope Composition ◽  
Tree Height ◽  
Stress Index ◽  
Mature Stage ◽  
Water Stress Index ◽  
Pinus Pinaster Ait ◽  
Pine Trees ◽  
Drought Resistant

The carbon isotope composition (δ13C) of cellulose extracted from wood samples was measured on 26-year-old maritime pine trees (Pinus pinaster Ait.) of the mesic French provenance Landes and of the drought-resistant Moroccan provenance Tamjoute, all growing at the same location in France. Analysis of spatial variability revealed that intra-ring δ13C values varied over a range of about 0.5%o (mean SD = 0.12%o) for circumference and of about 1%o (mean SD = 0.22%o) for height and that interannual variability of δ13C was 3%o. The successive year-to-year δ13C values on four trees (from 1972 to 1991) were found to roughly parallel the variations of a water stress index, calculated by taking into account climatic variables as well as the level of the water table in the soil: δ13C increased with drought. The two provenances (30 trees per provenance) were compared at a juvenile stage (old rings) and at a mature stage (recent rings). The drought-resistant provenance (Tamjoute) presented lower δ13C values, independent of ring age. Relationships between δ13C and tree height are discussed both at the within- and between-provenance levels.

scholarly journals Height-Diameter Equations for Thirteen Midwestern Bottomland Hardwood Species

2002 ◽  
Vol 19 (4) ◽  
pp. 171-176 ◽  
Author(s):  
Kenneth C. Colbert ◽  
David R. Larsen ◽  
James R. Lootens
Keyword(s):  
Tree Height ◽  
Average Height ◽  
Bottomland Hardwood ◽  
Bottomland Hardwood Forests ◽  
Des Moines ◽  
Hardwood Species ◽  
Riparian Tree ◽  
Regression Techniques ◽  
Using Data ◽  
Total Tree

Abstract Height-diameter equations are often used to predict the mean total tree height for trees when only diameter at breast height (dbh) is measured. Measuring dbh is much easier and is subject to less measurement error than total tree height. However, predicted heights only reflect the average height for trees of a particular diameter. In this study, we present a set of height-diameter equations for 13 riparian tree species using data obtained from bottomland hardwood forests along the Mississippi, Missouri, Illinois, and Des Moines rivers. Nonlinear regression techniques were used to develop the equations. The resulting equations provide a reasonable means of predicting unknown tree heights, given dbh, for these species.

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