Taper curve models for Scots pine and their applications

Kilkki, Pekka; Varmola, Martti

doi:10.14214/aff.7621

Cited by 4 publications

(4 citation statements)

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“…The endogenous variables included in the equation group were bark thickness at the preceding and following relative heights, and the respective exogenous variables were diameter over bark at breast height, tree height, and tree age. The equation group model used in this study requires far less calculations than the model proposed by Kilkki and Varmola (1981), which includes bark thickness at all other relative heights as endogenous variables. The resulting equation group includes equations for estimating bark thickness at each fixed relative height.…”

Section: Modelling Of Bark Thicknessmentioning

confidence: 99%

Modelling bark thickness of Picea abies with taper curves

Laasasenaho

Melkas

Aldén

2005

Forest Ecology and Management

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Section: Modelling Of Bark Thicknessmentioning

confidence: 99%

Modelling bark thickness of Picea abies with taper curves

Laasasenaho

Melkas

Aldén

2005

Forest Ecology and Management

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“…The most straightforward way might be to estimate tree trunk tapering and then divide the trunk into sections corresponding to the size requirements of any assortment. Estimation of trunk tapering is relatively straightforward since there is a large body of literature discussing taper curves (Kilkki and Varmola 1981, Ojansuu and Maltamo 1995, Gaffrey et al 1998, Strub et al 2005, Saarinen et al 2019. Such a procedure, however, would neglect quality requirements, apart from the required dimensions.…”

Section: Introductionmentioning

confidence: 99%

Empirical observations of the yield of logs from trees of the boreal region

Kärenlampi¹

2022

BALT FOR

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The yield of sawlogs and plywood logs from boreal trees is discussed. First, taper curves are used to compute geometric (maximal) sawlog and plywood log contents. Then, a quality reduction is implemented, according to previously published models. Finally, the outcome is verified using empirical observations. Regarding spruce trees, the different estimates of sawlog content agree. In the case of birch and pine trees, the estimates differ. The sawlog and plywood log yield from large trees is greater than prognosticated one, probably due to missing over-aged trees in the empirical data. The yield of sawlogs and plywood logs from small trees is smaller than prognosticated one, most of the empirical data originating from thinnings with a focus on the quality of the remaining trees. The sawlog content of individual trees from clearcutting displays a skew distribution around the expected value. The distribution in thinning trunks shows a binary component, with a large proportion of trees with zero sawlog content. Keywords: sawlog; plywoodlog; Picea abies; Betula species; Pinus sylvestris

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“…The existing taper curve equations for Finnish conditions by [29], include the diameter at 20% relative height as a reference diameter to which the ratios with other diameters at various relative heights is calculated. Stem volume can be obtained by integrating the taper curve function or using diameters at multiple heights to calculate volume of stem sections with geometrical shapes (e.g., cylinder or cone) and aggregating them [29,34,35]. Taper equations commonly rely on allometric relationships and include traditionally easily measurable attributes as predictors (e.g., DBH and tree height) [29,[36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Effects of Sample Size on Parametrizing a Taper Curve Equation and the Resultant Stem-Volume Estimates

Saarinen

Kankare

Pyörälä

et al. 2019

Forests

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Large and comprehensive datasets, traditionally based on destructive stem analysis or other labor-intensive approaches, are commonly considered as a necessity in developing stem-volume equations. The aim here was to investigate how a decreasing number of sample trees affects parametrizing an existing taper curve equation and resultant stem-volume estimates. Furthermore, the potential of terrestrial laser scanning (TLS) in producing taper curves was examined. A TLS-based taper curve was derived for 246 Scots pines (Pinus sylvestris L.) from southern Finland to parametrize an existing taper curve equation. To assess sensitivity of the parametrization regarding sample size, the number of Scots pines included in the parametrization varied between full census and 1 Scots pine at a time. Root mean square error of stem-volume estimates remained ≤20.9% and the mean absolute difference was relatively constant (≤9.0%) between stem-volume estimates when the sample size included ≥46 Scots pines. Thus, it can be concluded that, with a rather small sample size, a taper curve equation can be re-parametrized for local conditions using point clouds from TLS to produce consistent stem-volume estimates.

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Taper curve models for Scots pine and their applications

Cited by 4 publications

References 0 publications

Modelling bark thickness of Picea abies with taper curves

Modelling bark thickness of Picea abies with taper curves

Empirical observations of the yield of logs from trees of the boreal region

Assessing the Effects of Sample Size on Parametrizing a Taper Curve Equation and the Resultant Stem-Volume Estimates

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