A comparison of three taper equation formulations and an analysis of the slenderness coefficient for Taiwan incense cedar (Calocedrus formosana)

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.

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Taper Equations for Five Major Commercial Tree Species in Manitoba, Canada

Western Journal of Applied Forestry ◽

10.1093/wjaf/22.3.163 ◽

2007 ◽

Vol 22 (3) ◽

pp. 163-170 ◽

Cited By ~ 20

Author(s):

Ryan J. Klos ◽

G. Geoff Wang ◽

Qing-Lai Dang ◽

Ed W. East

Keyword(s):

Populus Tremuloides ◽

Picea Glauca ◽

Pinus Banksiana ◽

White Spruce ◽

Jack Pine ◽

Volume Estimation ◽

Trembling Aspen ◽

Stem Form ◽

Taper Equation ◽

Taper Equations

Abstract Kozak's variable exponent taper equation was fitted for balsam poplar (Populus balsamifera L.), trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca [Moench] Voss), black spruce (Picea mariana [Mill.] B.S.P.), and jack pine (Pinus banksiana Lamb.) in Manitoba. Stem taper variability between two ecozones (i.e., Boreal Shield and Boreal Plains) were tested using the F-test. Regional differences were observed for trembling aspen, white spruce, and jack pine, and for those species, separate ecozone-specific taper equations were developed. However, the gross total volume estimates using the ecozone-specific equations were different from those of the provincial equations by only 2 percent. Although the regional difference in stem form was marginal within a province, a difference of approximately 7 percent of gross total volume estimation was found when our provincial taper equations were compared with those developed in Alberta and Saskatchewan. These results suggest that stem form variation increases with spatial scale and that a single taper equation for each species may be sufficient for each province.

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Taper, Volume, and Weight Equations for Red Pine in West Virginia

Northern Journal of Applied Forestry ◽

10.1093/njaf/25.3.151 ◽

2008 ◽

Vol 25 (3) ◽

pp. 151-153 ◽

Cited By ~ 5

Author(s):

Lichun Jiang ◽

John R. Brooks

Keyword(s):

West Virginia ◽

Ease Of Use ◽

Red Pine ◽

Seemingly Unrelated Regression ◽

Stem Volume ◽

West Virginia University ◽

Individual Tree ◽

Unrelated Regression ◽

Taper Equation ◽

Volume Equations

Abstract Compatible taper, volume, and weight equations were developed for planted red pine in West Virginia. The data were based on stem analysis of 26 trees from West Virginia University Research Forest, located in northern West Virginia. A commonly used segmented polynomial taper equation was chosen because of its balance between prediction accuracy and ease of use. Seemingly unrelated regression was used to simultaneously fit the system of equations for inside and outside bark data. When compared with existing total stem volume equations developed by Fowler (Fowler, G.W., 1997, Individual tree volume equations for red pine in Michigan, North. J. Appl. For. 14:53–58) and by Gilmore et al. (Gilmore, D.W., et al., 2005, Thinning red pine plantations and the Langsaeter hypothesis: A northern Minnesota case study. North, J. Appl. For. 22:19–25), a positive bias was evident that increased directly with stem diameter for trees from this region.

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

Canadian Journal of Forest Research ◽

10.1139/cjfr-2020-0163 ◽

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.

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A model for predicting the value of forest stands in various market conditions in British Columbia

The Forestry Chronicle ◽

10.5558/tfc85387-3 ◽

2009 ◽

Vol 85 (3) ◽

pp. 387-391

Author(s):

Mihai Pavel ◽

Björn O Andersson

Keyword(s):

British Columbia ◽

Dynamic Programming ◽

Dynamic Programming Algorithm ◽

Inventory Systems ◽

Programming Algorithm ◽

Forest Stands ◽

Market Conditions ◽

Second Growth ◽

Taper Equation ◽

Individual Trees

A model for predicting the value of forest stands was developed at FPInnovations – Feric Division. The model uses standard cruise data collected in British Columbia (BC) and company sort descriptions to predict the distribution of wood volume by species and grade sort for each proposed harvest site. The model is capable of quickly analyzing different scenarios (i.e., different sort sets) to reflect changing market conditions. Within the model, a taper equation is applied to each tree to calculate the diameters inside the bark, and quality and pathological descriptors from cruise data are used. A Dynamic Programming algorithm is used to predict the combination of logs that maximizes the value of each stem, and results are summarized and extended from individual trees to cruise plots, then to harvest blocks and/or stands. The model was successfully tested for second-growth stands with relatively few defects on Coastal BC. Improvements are being implemented to enhance its applicability to more complex stands. Key words: value of forest stands, economic operability, optimal bucking of trees, Dynamic Programming, computer model, inventory systems

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