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 

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 Diameter-height models for the Terai tree species

2015 ◽  
Vol 25 (1) ◽  
pp. 50-54 ◽  
Author(s):  
A. Khadka ◽  
T. Subedi ◽  
M. Ghimire ◽  
B. P. Dhakal ◽  
H. Parikka
Keyword(s):  
Tree Species ◽  
Linear Models ◽  
Resource Assessment ◽  
Forest Growth ◽  
Growth And Yield ◽  
Forest Resource ◽  
Linear Mixed Effects ◽  
Shorea Robusta ◽  
Non Linear ◽  
Growth And Yield Models

Tree diameter-height relationship can be used as a key input component in forest growth and yield models, and description of stand dynamics. Various models of stem diameter and height relation were developed. Those were formulated and implemented during Terai forest inventory data calculations in the Forest Resource Assessment (FRA) Nepal Project. The field inventory was conducted from December, 2010 to March, 2011. The Concentric Circular Sample Plot was designed where the diameters at breast height of all the tallied trees and the heights of the sampled trees were measured. The data were handled with R-script in R Programme to generate non-linear mixed effects models in ‘lmfor’ package of forest biometrics functions of Mehtatalo. Different non-linear models were used to fit the diameter-height relation, which performed well in describing the relationships between the diameters and the heights of the Terai tree species depending on the sample size. The models were selected as the best fitted based on the statistical results such as standard error, Adjusted R2, RMSE and residuals. The best models for Shorea robusta and Terminalia alata were generated using Wykoff’s and Naslund’s functions, respectively.Banko Janakari, A Journal of Forestry Information for NepalVol. 25, No. 1Page: 50-54

Deriving Tree Diameter Growth and Probability of Survival Equations from Successive Diameter Distributions

2008 ◽  
Vol 54 (1) ◽  
pp. 31-35
Author(s):  
Thomas G. Matney ◽  
Emily B. Schultz
Keyword(s):  
General Procedure ◽  
Growth And Yield ◽  
Diameter Distribution ◽  
Diameter Growth ◽  
Individual Tree ◽  
Statistical Probability ◽  
Growth And Survival ◽  
Tree Diameter ◽  
Growth And Yield Models ◽  
Diameter Distributions

Abstract Many growth and yield models have used statistical probability distributions to estimate the diameter distribution of a stand at any age. Equations for approximating individual tree diameter growth and survival probabilities from dbh can be derived from these models. A general procedure for determining the functions is discussed and illustrated using a loblolly pine spacing study. The results from the spacing study show that it is possible to define tree diameter growth and survival probability functions from diameter distributions with an accuracy sufficient to obtain a link between the individual tree and diameter growth and yield models.

scholarly journals Spatial Tree Mapping Using Photography

2010 ◽  
Vol 27 (2) ◽  
pp. 68-74 ◽  
Author(s):  
Adam R. Dick ◽  
John A. Kershaw ◽  
David A. MacLean
Keyword(s):  
Spatial Location ◽  
Growth And Yield ◽  
Absolute Distance ◽  
Widespread Application ◽  
Visualization Software ◽  
Dependent Growth ◽  
Spatial Locations ◽  
Growth And Yield Models ◽  
Field Plots ◽  
Forest Conditions

Abstract Stem maps describing the spatial location of trees sampled in a forest inventory are used increasingly to model relationships between neighboring trees in distance-dependent growth and yield models, as well as in stand visualization software. Current techniques and equipment available to acquire tree spatial locations prohibit widespread application because they are time-consuming, costly, and prone to measurement error. In this report, we present a technique to derive stem maps from a series of digital photographs processed to form a seamless 360° panorama plot image. Processes are described to derive distance from plot center and azimuth to each plot tree. The technique was tested on 46 field plots (1,398 sample trees) under a range of forest conditions and compared with traditional methods. Average absolute distance error was 0.38 ± 0.44 m, and average absolute azimuth error was 2.3 ± 2.5°. Computed average horizontal accuracy was 0.40 ± 0.42 m, with 85% of measured trees being within 0.5 m of the field-measured tree location.

scholarly journals Loblolly and Slash Pine Growth and Yield Prediction for Regional Timber Supply Projection Algorithms

1999 ◽  
Vol 23 (4) ◽  
pp. 230-237
Author(s):  
Bruce E. Borders ◽  
Jeffrey B. Jordan
Keyword(s):  
Loblolly Pine ◽  
Analysis Data ◽  
Growth And Yield ◽  
Yield Prediction ◽  
Projection Algorithms ◽  
Timber Supply ◽  
Usda Forest Service ◽  
Forest Inventory And Analysis ◽  
Pine Stands ◽  
Growth And Yield Models

Abstract Regional and national timber supply models require standing inventory update procedures. To date, most inventory update procedures used in regional timber supply algorithms have not made use of growth and yield methodology. We present growth and yield models to update standing inventories for natural and planted slash and loblolly pine stands in Georgia. These models were fitted to USDA Forest Service Forest Inventory and Analysis data obtained from the sixth survey of Georgia and should prove useful in regional timber supply projection algorithms. South. J. Appl. For. 23(4):230-237.

scholarly journals Growth and yield models for eucalyptus stands obtained by differential equations

2017 ◽  
Vol 74 (5) ◽  
pp. 364-370
Author(s):  
Adriano Ribeiro de Mendonça ◽  
Natalino Calegario ◽  
Gilson Fernandes da Silva ◽  
Samuel de Pádua Chaves e Carvalho
Keyword(s):  
Differential Equations ◽  
Growth And Yield ◽  
Growth And Yield Models

scholarly journals Compatible Stem Taper, Volume, and Weight Equations for Young Longleaf Pine Plantations in Southwest Georgia

2007 ◽  
Vol 31 (4) ◽  
pp. 187-191 ◽  
Author(s):  
John R. Brooks ◽  
Lichun Jiang ◽  
Alexander Clark
Keyword(s):  
Longleaf Pine ◽  
Pinus Palustris ◽  
Growth And Yield ◽  
Average Error ◽  
Nonlinear Fitting ◽  
Fitting Procedure ◽  
Stem Taper ◽  
Pine Trees ◽  
Intensively Managed ◽  
Generalized Newton

Abstract Outside and inside bark diameter measurements were recorded from tree disks obtained at 0-, 0.5-, 2.0-, 4.5-, 6.0-, 16.6-, and at 4-ft-height intervals above 6 ft to a 2-in. diameter outside bark top diameter on 42 longleaf pine trees selected from intensively managed longleaf pine (Pinus palustris Mill.) plantations in Dougherty and Worth Counties in southwest Georgia. Trees were sampled from unthinned, cutover stands in their 11th and 14th growing season, which are currently part of an existing growth and yield study. Sample trees ranged from 2 to 7 in. in diameter and from 18 to 40 ft in total height. Parameters for a segmented polynomial taper and compatible cubic foot volume and weight equation were simultaneously estimated using a seemingly unrelated nonlinear fitting procedure to volumes based on a generalized Newton formula and an overlapping bolt methodology. Average error was approximately 0.25 in., 0.04 ft3, and 2.5 lb for taper, volume, and weight estimation, respectively.

A simple growth and yield model for assessing changes in standing volume across Canada’s forests

2009 ◽  
Vol 85 (1) ◽  
pp. 57-64 ◽  
Author(s):  
C -H. Ung ◽  
P Y Bernier ◽  
X J Guo ◽  
M -C. Lambert
Keyword(s):  
Predictive Power ◽  
Robust Regression ◽  
Forest Growth ◽  
Growth Potential ◽  
Growth And Yield ◽  
Stand Age ◽  
Yield Model ◽  
Wood Volume ◽  
National Model ◽  
Growth And Yield Models

We have adjusted two growth and yield models to temporary sample plots from across Canada, and used climate variables in lieu of phytometric indices such as site index to represent, in part, the site-level variability in growth potential. Comparison of predicted increments in plot-level height, basal area and merchantable wood volume to increments of these variables measured in permanent sample plots shows a moderate to poor predictive ability. Comparison with the performance of four operational growth and yield models from different provinces across Canada shows comparable predictive power of this new model versus that of the provincial models. Based on these results, we suggest that the simplification of regional growth and yield models may be achieved without further loss of predictive power, and that the large error in the prediction of growth increment is mostly associated with the use of temporary sample plots which, by definition, contain little information on stand dynamics. We also suggest that, because of the empirical nature of these growth and yield models, the scale of application should determine the appropriate scale of the model. National estimates of forest growth are therefore less likely to be biased if obtained from a national model only than if obtained from a combination of regional models, where those exist, gap-filled with estimates from a national model. Key words: yield model, merchantable wood volume, stand age, climatic variables, simultaneous regression, robust regression

A Graphical Comparison of Loblolly Pine Growth-and-Yield Models

2013 ◽  
Vol 37 (3) ◽  
pp. 169-176 ◽  
Author(s):  
James E. Henderson ◽  
Scott D. Roberts ◽  
Donald L. Grebner ◽  
Ian A. Munn
Keyword(s):  
Loblolly Pine ◽  
Growth And Yield ◽  
Graphical Comparison ◽  
Growth And Yield Models
Sign in / Sign up

Export Citation Format

Share Document