Variable-exponent taper equations for jack pine, black spruce, and balsam fir in eastern Canada

Sharma, Mahadev; Zhang, S.Y

doi:10.1016/j.foreco.2004.03.035

Cited by 107 publications

(127 citation statements)

References 13 publications

(17 reference statements)

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“…An alternative, such as was used in our example application where tree level errors were propagated to the stand level, is to sample all live and dead trees in fixed area plots to reconstruct the growth of the whole stand [2,3], a method that has shown promise if the aim is to successfully detect climate and global change-related trends from tree-ring data [42], but remains challenged by the inability to sample trees that have died in the past and subsequently decayed [33]. In addition, replacing the relatively basic equations used in this study with more sophisticated methods that are sensitive to the effect of stand conditions on height-diameter relationships [43], tree volume [44,45], or biomass [46] should also improve the estimates of annual growth increment that could be obtained at both the tree and forest levels, for species where such models are available.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Whole Tree Growth Increment Derived from Tree-Ring Series for Use in Assessments of Changes in Forest Productivity across Various Spatial Scales

Metsaranta

Bhatti

2016

Forests

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Abstract:The inherent predictability of inter-annual variation in forest productivity remains unknown. Available field-based data sources for understanding this variability differ in their spatial resolution, temporal resolution, and typical units of measure. Nearly all other tree and forest characteristics are in practice derived from measurements of diameter at breast height (DBH). Therefore, diameter increment reconstructed annually from tree-ring data can be used to estimate annual growth increments of wood volume, but the accuracy and precision of these estimates requires assessment. Annual growth estimates for n = 170 trees sampled for whole stem analysis from five tree species (jack pine, lodgepole pine, black spruce, white spruce, and trembling aspen) in Western Canada were compared against increments derived from breast height measurements only. Inter-annual variability of breast height and whole tree growth increments was highly correlated for most trees. Relative errors varied by species, diameter class, and the equation used to estimate volume (regional vs. national). A simple example of the possible effect of this error when propagated to the stand level is provided.

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Section: Discussionmentioning

confidence: 99%

Evaluation of Whole Tree Growth Increment Derived from Tree-Ring Series for Use in Assessments of Changes in Forest Productivity across Various Spatial Scales

Metsaranta

Bhatti

2016

Forests

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“…This approach is based on the assumption that the stem form varies continuously along the length of a tree and eliminates the need to develop segmented taper functions for different portions of the stem. In comparison with single and segmented taper models, this approach usually provides the lowest degree of local bias and the greatest precision in taper predictions (e.g., Bi, 2000;Kozak, 1988;Sharma and Zhang, 2004), although they have the disadvantage that cannot be analytically integrated to calculate total stem or log volumes. Kozak (2004) developed two new models based on his original 1988 model in order to reduce the associated multicollinearity.…”

Section: Stem Taper Selected Functionsmentioning

confidence: 99%

Un modèle pour l’estimation du volume commercialisable du pin sylvestre dans les principales régions de montagne d’Espagne

2009

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Abstract• Accurate estimation of stem volume makes it possible to estimate the monetary value of one of the many commodities and services that forests provide to society, i.e. timber.• In the present study a compatible volume system for Scots pine in the major mountain ranges of Spain (the Pyrenees, Southern Iberian Range, Northern Iberian Range, Soria and Burgos Mountains, Central Range and Galician Mountains) was developed with data from 2 682 destructively sampled trees. Several well-known taper functions were evaluated. A second-order continuous-time autoregressive error structure was used to correct the inherent autocorrelation in the hierarchical data, allowing the model to be applied to irregularly spaced and unbalanced data.• The compatible segmented model of Fang et al. (2000) best described the experimental data. It is therefore recommended for estimating diameter at a specific height, height to a specific diameter, merchantable volume, and total volume for the six mountain ranges analyzed.• The non-linear extra sum of squares method indicated differences in mountain range-specific taper functions. A different taper function should therefore be used for each mountain range in Spain.Mots-clés : équation de forme / modèle segmenté / équation compatible / pin sylvestre Résumé -Un modèle pour l'estimation du volume commercialisable du pin sylvestre dans les principales régions de montagne d'Espagne.• L'estimation précise du volume des tiges permet d'estimer la valeur du bois qui est un des nombreux produits et services que la forêt apporte à la société.• Dans cette étude, nous avons développé un modèle compatible de volume du pin sylvestre avec les mesures obtenues pour 2 682 arbres abattus dans les principales zones de montagne en Espagne, les Pyrénées, le sud et le nord de l'Ibérie, les montagnes de Soria et Burgos, le centre et les montagnes de Galice. Nous avons évalué plusieurs équations de profil de tiges bien connues. Pour corriger les autocorrélations inhérentes aux données hiérarchiques, nous avons utilisé un modèle d'erreur autoregressif à l'ordre 2 en temps continu, ce qui permet au modèle d'être appliqué à des données irrégulièrement espacées dans le temps et non équilibrées.• Le modèle segmenté compatible de Fang et al. (2000) décrit le mieux les données expérimentales. Il est donc recommandé pour estimer le diamètre à une hauteur donnée, la hauteur à un diamètre donné, le volume commercial et le volume total pour les six zones montagneuses étudiées.• La méthode des moindres carrés généralisés non linéaires indique des différences entre équations de profils de tiges des différentes zones montagneuses. Il faut donc utiliser une équation de profil de tige par zone de montagne en Espagne.

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“…In eastern Canada, these models are available for a few species only. Sharma and Zhang (2004) Newnham (1988) fitted a stem taper model for red pine (Pinus resinosa Sol.). In western Canada, different studies provide these models for a larger array of species: Newnham (1992) for jack pine, lodgepole pine (Pinus contorta var.…”

Section: Résumémentioning

confidence: 99%

Canadian national taper models

Ung

Guo

Fortin

2013

The Forestry Chronicle

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Work was done to gather stem taper data for most forest tree species across Canada. They were used for producing taper models to be applied for the purposes of the national forest inventory and for regional purposes when regional taper models are not available. The models are based on squared DBH and on measured or predicted tree height. A taper equation based on the dimensional analysis approach was adopted to fit Canadian national taper models using the collected data. The model parameters were estimated using a mixed model for taking into account variance heterogeneity and withintree autocorrelation. In spite of the different protocols for data collection, the accuracy of the proposed stem taper models is similar to that found in previous studies. Consequently, the models seem suitable for pre-harvest estimation of sawlog volume nationally or regionally.

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Variable-exponent taper equations for jack pine, black spruce, and balsam fir in eastern Canada

Cited by 107 publications

References 13 publications

Evaluation of Whole Tree Growth Increment Derived from Tree-Ring Series for Use in Assessments of Changes in Forest Productivity across Various Spatial Scales

Evaluation of Whole Tree Growth Increment Derived from Tree-Ring Series for Use in Assessments of Changes in Forest Productivity across Various Spatial Scales

Un modèle pour l’estimation du volume commercialisable du pin sylvestre dans les principales régions de montagne d’Espagne

Canadian national taper models

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