Effects of adding tree, stand, and site variables to Kozak's variable-exponent taper equation

1994 ◽  
Vol 24 (2) ◽  
pp. 252-259 ◽  
Author(s):  
Charles K. Muhairwe ◽  
Valerie M. LeMay ◽  
Antal Kozak
Keyword(s):  
Variable Exponent ◽  
Lodgepole Pine ◽  
Site Class ◽  
Breast Height ◽  
Red Cedar ◽  
Taper Function ◽  
Quadratic Mean Diameter ◽  
Taper Equation ◽  
The Cost ◽  
Total Tree

Crown class, site class, and breast-height age were incorporated into Kozak's variable-exponent taper equation (A. Kozak. 1988. Can. J. For. Res. 18: 1363–1368) for three species: Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western red cedar (Thujaplicata Donn), and aspen (Populustremuloides Michx.). For lodgepole pine (Pinuscontorta Dougl.), crown ratio, breast-height age, and quadratic mean diameter were incorporated into Kozak's taper equation. The effects of adding these variables to the exponent part of the taper equation on the prediction abilities of the taper model were assessed for prediction of diameter inside bark along the stem, total tree volume, and tree merchantable height. It was found that apart from the use of crown ratio for lodgepole pine, the additional variables resulted in only marginal improvements to the published version of Kozak's taper function. Therefore, the cost of measuring these additional variables is not justifiable.

A variable-exponent taper equation

1988 ◽  
Vol 18 (11) ◽  
pp. 1363-1368 ◽  
Author(s):  
A. Kozak
Keyword(s):  
Variable Exponent ◽  
Computing Time ◽  
Variable Form ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Taper Function ◽  
Taper Equation ◽  
Taper Equations ◽  
Different Parts

A different approach to fitting taper equations has been developed, which eliminates the necessity of using several functions to predict diameter inside bark at different parts of the stem. The variable form taper function is easy to develop and saves computing time. For the data used in this study, it predicted tree profile as a function of height, diameter at breast height, and height from the ground with less bias than many of the taper-estimating systems found in the literature.

What factors should be accounted for when developing a generalized taper function for black wattle trees?

2020 ◽  
Vol 50 (11) ◽  
pp. 1113-1123
Author(s):  
Mateus Niroh Inoue Sanquetta ◽  
John Paul McTague ◽  
Henrique Ferraço Scolforo ◽  
Alexandre Behling ◽  
Carlos Roberto Sanquetta ◽  
...  
Keyword(s):  
Solid Wood ◽  
Auxiliary Variables ◽  
Stem Form ◽  
Mixed Effect ◽  
Individual Tree ◽  
Taper Function ◽  
Black Wattle ◽  
Taper Equation ◽  
Total Tree ◽  
Mixed Effect Modeling

Taper functions have been widely used for various purposes. Several functions were developed and successfully applied; however, most of these functions fail to account for the influence of stand-level and individual-tree effects of variation on the stem profile. Hence, we aimed in this study to assess how these factors influence the stem profile of black wattle (Acacia mearnsii De Wild.) trees in southern Brazil. There is a notable necessity for developing a domestic market for black wattle solid wood. The database was composed of 218 black wattle trees at age 10 years distributed across the state of Rio Grande do Sul, Brazil. A dimensionally compatible taper equation combined with the mixed-effect modeling approach was used. Additionally, auxiliary variables were included to build a generalized taper function that explains stem form variations. In general, all variables showed a significant influence on the stem profile, except the crown ratio. The inclusion of relative spacing and tree hierarchical position in the taper function resulted in higher accuracy when estimating stem diameters and total tree volume. This study indicates that accounting for attributes at the stand and individual-tree levels may improve stem profile predictions, as well as the biological soundness of the taper function.

Effects of upper stem measurements on the predictive ability of a variable-exponent taper equation

1998 ◽  
Vol 28 (7) ◽  
pp. 1078-1083 ◽  
Author(s):  
Antal Kozak
Keyword(s):  
Measurement Errors ◽  
Variable Exponent ◽  
Predictive Ability ◽  
Diameter Measurement ◽  
Breast Height ◽  
Taper Equation ◽  
Taper Equations

Like several other taper equations, the predictive ability of Kozak's (1988. Can. J. For. Res. 18: 1363-1368) variable-exponent taper equations can also be improved by an additional upper stem outside bark diameter measurement. This study indicated that improvements were small and were mainly restricted to increasing the precision of the estimates. Also, it was demonstrated that if additional diameter measurements are justified, they should be taken between 40 and 50% of the height above breast height for greatest improvement. Measurement errors in upper stem diameters and in their heights above breast height affected both the precision and bias of predictions.

Two new height models for volume estimation of lodgepole pine stands

1988 ◽  
Vol 18 (2) ◽  
pp. 195-201 ◽  
Author(s):  
W. T. Zakrzewski ◽  
I. E. Bella
Keyword(s):  
Lodgepole Pine ◽  
Tree Height ◽  
Practical Method ◽  
Volume Estimation ◽  
Data Set ◽  
Individual Tree ◽  
Pine Trees ◽  
Quadratic Mean Diameter ◽  
The Cost ◽  
Volume Estimates

To reduce the cost and increase the efficiency of obtaining individual tree height information required for sample plot volume estimation, two general height–diameter (H/D) regression models were developed using two-stage regression analysis and data from 96 lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) sample plots. The derived models were examined using an independent data set of 28 plots. In addition to diameter at breast height (D), these models also included two easily measurable stand parameters as independent variables: quadratic mean diameter (Dq) and the height of a tree with diameter Dq (Hq). With a practical method to estimate Hq (from up to three heights measured) and using these two new H/D models in conjunction with available regional standard volume equations (V = f (D,H)), the stand volume estimates, on the average, were 0.003% higher (SD 4.1%) for the first model and 1.081% lower (SD 4.6%) for the second model than those obtained using traditional H/D curves for each plot based on 30 or more height measurements. The new models are therefore recommended for use in height estimation of lodgepole pine trees within the range of conditions of the data. This approach may be applied to other species and regions.

Development of comandra blister rust on lodgepole pine

1990 ◽  
Vol 20 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Brian W. Geils ◽  
William R. Jacobi
Keyword(s):  
Lodgepole Pine ◽  
Tree Height ◽  
Infection Site ◽  
Canker Disease ◽  
Susceptibility To Infection ◽  
Blister Rust ◽  
The Mean ◽  
Central Rocky Mountains ◽  
Stem Cankers ◽  
Total Tree

The comandra blister rust parasite (Cronartiumcomandrae Pk.) causes a serious canker disease of lodgepole pine (Pinuscontorta Dougl. ex Loud. ssp. latifolia (Engelm.) Critch.) in the central Rocky Mountains. The expansion, longevity, and distribution of comandra blister rust cankers were studied by annual monitoring, reconstructing canker histories, and random sampling. In saplings, infections occur throughout the lower 80% of the crown; and branch cankers expand toward the bole at 2.5 cm•year−1, regardless of temperature, age, position, tree size, vigor, or susceptibility to infection. The proportion of branch cankers that develop into stem cankers decreases logistically both with distance from infection site to bole and with time since infection. Fewer than 50% of branch cankers that are farther than 20 cm from the bole or more than 8 years old are expected to establish stem cankers. The proportion of branch cankers that become stem cankers decreases with distance more rapidly for comandra blister rust than for other stem rusts. The mean height of stem cankers increases with total tree height, but cankers are uncommon at the top of the crown and low on the trunk of larger trees. The number of years for a canker to girdle its host equals the diameter of the stem at the center of the canker measured in centimetres. Because girdling cankers develop infrequently, slowly, and predictably, potential losses from comandra blister rust can be reduced by timely and appropriate removal of damaged trees.

scholarly journals Selection of mixed-effects parameters in a variable–exponent taper equation for birch trees in northwestern Spain

2013 ◽  
Vol 70 (7) ◽  
pp. 707-715 ◽  
Author(s):  
Esteban Gómez-García ◽  
Felipe Crecente-Campo ◽  
Ulises Diéguez-Aranda
Keyword(s):  
Variable Exponent ◽  
Mixed Effects ◽  
Birch Trees ◽  
Northwestern Spain ◽  
Taper Equation ◽  
Selection Of

Bark Thickness and Bark Volume in Southwestern Oregon Douglas-Fir

1990 ◽  
Vol 5 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Douglas A. Maguire ◽  
David W. Hann
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Bark Thickness ◽  
Breast Height ◽  
Taper Equation ◽  
Taper Equations ◽  
Height Predictions

Abstract A segmented polynomial taper equation for southwestern Oregon Douglas-fir (Pseudotsuga menziesii) predicts double bark thickness (dbt) at any point above breast height. Below breast height predictions assume conformity to a neiloid frustrum. The equations facilitate estimation of inside bark diameter (dib) given outside bark (dob) measurements. Bark volume and bark biomass can also be estimated when supplemented with existing dib taper equations developed for southwestern Oregon. West J. Appl. For. 5(1):5-8.

scholarly journals Height Growth Pattern of Lodgepole Pine in Relation to Natural Subregions in Alberta

2004 ◽  
Vol 19 (3) ◽  
pp. 154-159 ◽  
Author(s):  
G. Geoff Wang ◽  
Shongming Huang ◽  
David J. Morgan
Keyword(s):  
Growth Pattern ◽  
Lodgepole Pine ◽  
Quantitative Measure ◽  
Site Index ◽  
Height Growth ◽  
Growth Patterns ◽  
Volume Estimation ◽  
The Other ◽  
Breast Height ◽  
Variable Site

Abstract Based on the provincial stem analysis and permanent sample plot (PSP) data of 1,580 felled dominant and codominant trees, height growth patterns of lodgepole pine were compared among the three major natural subregions [Sub-Alpine (SAL), Upper Foothills (UFH), and Lower Foothills (LFH)] in Alberta. The comparison used the ratio of heights at 70 and 30 years of breast height age (Z ratio) as a quantitative measure of height growth pattern (i.e., the response variable), site index (height at breast height age of 50 years) as the covariate, and natural subregion as the factor. Results indicated that: (1) the height growth pattern in the SAL natural subregion was significantly different from other natural subregions; and (2) no significant differences in height growth pattern were found between other natural subregions. Two polymorphic height and site index curves were developed: one for the SAL natural subregion and the other for the UFH and LFH natural subregions. Comparisons between the two curves and the previously developed provincial curve indicated that, for the same site index, trees in the SAL subregion grow consistently slower after 50 years. When the provincial height and site index curve was applied to the SAL natural subregion, large differences (≤14%) in gross volume estimation were found. However, volume estimation differences were very small (<2%) when the provincial curve was applied to the other two natural subregions. It is recommended that the natural subregion-based curves should be used for predicting lodgepole pine site index or height at any age in the SAL natural subregion. West. J. Appl. For. 19(3):154–159.

scholarly journals Silvicultural performance of forest species introduced in integrated livestock forest system in Lavras, MG, Brazil

2017 ◽  
Vol 47 (12) ◽  
Author(s):  
Erick Martins Nieri ◽  
Renato Luiz Grisi Macedo ◽  
Nelson Venturin ◽  
Regis Pereira Venturin ◽  
José Alvim Pinto Júnior ◽  
...  
Keyword(s):  
Survival Rate ◽  
Block Design ◽  
Minas Gerais ◽  
The Other ◽  
Forest Species ◽  
Diameter At Breast Height ◽  
African Mahogany ◽  
Breast Height ◽  
Red Cedar ◽  
Randomized Complete Block Design

ABSTRACT: The objective of this study was to evaluate the silvicultural performance of four forest species introduced in a setting for integrated livestock forest (ILF) in a pasture in Lavras, Minas Gerais, Brazil. The species included were the Australian red cedar (seminal and clonal), African mahogany, teak, and guanandi. A split plot scheme with a randomized complete block design comprising four replicates and 48 plants per plot, was used in the following arrangement: (3(3x2) +7x2) m. The evaluation times (12, 18, 31, 36, and 43 months after planting) corresponded to the subplots. Performances of all four species were evaluated on the basis of their survival rate, height (H) and diameter at breast height (DBH). Based on the performance of the species with regard to these parameters, the clonal Australian red cedar showed a greater growth in DBH and height in the ILF setting as compared to the other species, which indicates it to be a suitable species for the region of Lavras, MG as long as its survival control occurs in the implantation phase.

Circumferential variation in the relative density of lodgepole pine

1989 ◽  
Vol 19 (2) ◽  
pp. 276-279
Author(s):  
Josefina S. Gonzalez
Keyword(s):  
Relative Density ◽  
Present Method ◽  
Lodgepole Pine ◽  
Breast Height ◽  
Two Samples ◽  
The Mean

The circumferential variation in the wood relative density of lodgepole pine (Pinuscontorta var. latifolia Engelm.) was examined in eight discs taken at breast height. The purpose was to determine if the present method of analyzing two opposite radial strips from pith to bark was sufficient for estimating the mean density of the disc. Results showed that two samples taken opposite each other would give comparable or better approximation of the mean density of the disc than would three or four samples taken at random.

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