Stand and tree-level variability on stem form and tree volume in Pinus pinea L.: A multilevel random components approach

Calama, Rafael; Montero, Gregorio

doi:10.5424/srf/2006151-00951

Cited by 26 publications

(22 citation statements)

References 44 publications

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“…The tree variables d and h had a significant effect on the allometric relationships for biomass and volume, in agreement with other authors (António et al, 2007;Calama and Montero, 2006). Some studies had tested other variables with success, namely with tree age for eucalypts in Congo (Saint-Andre et al, 2005), stand age for Pinus pinaster in Aquitaine (Porté et al, 2002), sapwood area to stem diameter for several boreal species (Bond-Lamberty et al, 2002).…”

Section: Biomass Equationssupporting

confidence: 79%

Biomass allometry and carbon factors for a Mediterranean pine (Pinus pinea L.) in Portugal

Correia¹,

Tomé²,

Pacheco³

et al. 2010

For. syst.

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Forests play an important role in the global carbon balance because they offset a large portion of the carbon dioxide emitted through human activities. Accurate estimates are necessary for national reporting of greenhouse gas inventories, carbon credit trading and forest carbon management but in Portugal reliable and accessible forest carbon measurement methodologies are still lacking for some species. The objective of this study was to provide forest managers with a comprehensive database of carbon factors and equations that allows estimating stand-level carbon stocks in Pinus pinea L. (P. pinea), regardless of the tree inventory information available. We produced aboveground biomass and stem volume equations, biomass expansion factors (BEF) by component as well as wood basic density (WBD) and component carbon fraction in biomass. A root-to-shoot ratio is also presented using data from trees in which the root system was completely excavated. We harvested 53 trees in centre and south Portugal covering different sizes (6.5 to 56.3 cm), ages (10 to 45 years) and stand densities (20 to 580 trees ha -1 ). The results indicate that aboveground allometry in P. pinea is not comparable with other pines and varies considerably with stand characteristics, highlighting the need to develop stand-dependent factors and equations for local or regional carbon calculations. BEF aboveground decreases from open (1.33 ± 0.03 Mg m -3 ) to closed stands (1.07 ± 0.01 Mg m -3 ) due to a change in biomass allocation pattern from stem to branches. Average WBD was 0.50 ± 0.01 Mg m -3 but varies with tree dimensions and the root-to-shoot ratio found was 0.30 ± 0.03. The carbon fraction was statistically different from the commonly used 0.5 factor for some biomass components. The equations and factors produced allow evaluating carbon stocks in P. pinea stands in Portugal, contributing to a more accurate estimation of carbon sequestered by this forest type.Key words: Pinus pinea; carbon balance; climate change; biomass inventory. Resumen Alometría de la biomasa y factores de carbono para un pino Mediterráneo (Pinus pinea L.) en PortugalLos bosques juegan un papel importante en el balance global del carbono porque desplazan una gran porción del dióxido de carbono emitidos por actividades humanas. Se necesitan estimaciones precisas para los informes nacionales de los inventarios de los gases de efecto invernadero, mercados de créditos de carbono, y manejo de carbono en los bosques. Pero en Portugal todavía faltan, para algunas especies, metodologías de mediciones fiables y accesibles de carbono en los bosques. El objetivo de este estudio es proporcionar a los gestores forestales una base de datos completa de los factores y ecuaciones del carbono que permitan estimar los stocks de carbono a nivel de rodal, en Pinus pinea, independientemente de la información disponible de los inventarios de árbol. Producimos ecuaciones de biomasa del matorral, y del volumen del troco, factores de expansión de biomasas (BEF) por componente así como densi...

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Section: Biomass Equationssupporting

confidence: 79%

Biomass allometry and carbon factors for a Mediterranean pine (Pinus pinea L.) in Portugal

Correia¹,

Tomé²,

Pacheco³

et al. 2010

For. syst.

View full text Add to dashboard Cite

show abstract

“…8 (RMSE around 1.55). The stem form of stone pine has only been characterized in Spain by Calama and Montero (2006), who obtained a 60% lower RMSE (1.71 compared to 2.72 obtained in this study) because they analyzed the diameter inside the bark. There are few taper models for black pine, (Meridieu, 1998), and the results are similar to those observed in Central Spain (RMSE = 0.84).…”

Section: Discussionmentioning

confidence: 99%

“…The autocorrelation may be explained by the effect of stand conditions (e.g., stand density, thinning effects, etc.) on stem form (Calama & Montero, 2006), because stand conditions have a great impact on crown length and stem diameter (Burkhart & Tomé, 2012). Figure 2 shows an example of the autocorrelation plots of the residuals obtained for Scots pine (sp=21).…”

Section: Model Fittingmentioning

confidence: 99%

“…Most taper functions can be included in the following groups: single and segmented taper models, trigonometric equations, and variable-form taper models. Stem taper functions are usually based on the diameter at breast height (dbh), and predict diameter over bark (Rojo et al, 2005;Crecente-Campo et al, 2009); though they can also predict diameter inside bark (Garber & Maguire, 2003;Calama & Montero, 2006) and bark thickness (Laasasenaho et al, 2005).…”

Section: Study Area and Data Collectionmentioning

confidence: 99%

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Comparison of stem taper equations for eight major tree species in the Spanish Plateau

Rodríguez¹,

Lizarralde²,

Bravo

2015

For. syst.

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Aim of study: A stem taper function and a compatible merchantable volume system are compared to evaluate which provides a better description of the stem profile for the main species in central Spain.Area of study: This research was carried out in the region of Castile-Leon, located in Central Spain.Material and Methods: A total of 6,357 trees were selected for destructive sampling. All models were fitted using a first-order continuous autoregressive error structure to address the problem of autocorrelation.Main results: In terms of accuracy, the root mean square error (RMSE) in both models ranged from 0.75 to 2.72 depending on the species analyzed, presenting values similar to those reported in other studies. Small differences in the goodness-of-fit for both procedures were also found, and the Stud model provided better accuracy for 6 of the 8 species studied, with RMSE reductions of 0.5% to 8.6%. The RMSE obtained in the cross-validation phase was on average 1.22 times higher than what was obtained in the fitting phase.Research highlights: The non-linear extra sum of squares method indicated that the stem taper differs among the five softwood species and three hardwood species. In hardwoods, the first inflection point is lower than in softwoods (at around 5%) and the second inflection point is higher (at around 85%) than those of softwoods.Keywords: taper function; volume system; Central Spain; softwoods; hardwoods.

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“…Construction of taper and volume-ratio equations entails the compilation of longitudinal data on each tree, resulting in a lack of independence between observations and biased estimates of parameters if ordinary least squared techniques are used in constructing the models (Calama & Montero 2006). Observations from the same unit of analysis, the trees, are correlated (Gregoire & Schabenberger 1996b, Garber & Maguire 2003, Leites & Robinson 2004.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear mixed model approaches to estimating merchantable bole volume for Pinus occidentalis

Bueno-López¹,

Bevilacqua²

2012

iForest

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The ability to predict cumulative bole volume to any predefined upper stem diameter on a standing tree is essential for estimating current inventory levels and making informed decisions regarding the management of forest resources. Several types of mathematical models have been developed to predict cumulative bole volume, requiring only the collection of low cost data but high accuracy tree measurements. This paper reports on the comparison of a variable-exponent taper model and a volume-ratio model for estimating inside-bark cumulative bole volume to three predefined upper stem diameters using stem analysis data Pinus occidentalis trees in La Sierra, Dominican Republic. Each sampled tree was measured at multiple points on the bole, making observations spatially correlated within the tree. Inference problems due to autocorrelation were addressed by using a nonlinear mixed-effects model fitted by restricted maximum likelihood (REML) and including two random parameter coefficients at tree level in each of the two models tested. Using an independent validation data set, the variable-exponent taper model with two random parameters demonstrated better predictive ability as compared to the volume-ratio model when estimating cumulative bole volume to the three predefined upper stem diameters. The taper model allows flexible volume estimation for the population average as well for specific trees

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Stand and tree-level variability on stem form and tree volume in Pinus pinea L.: A multilevel random components approach

Cited by 26 publications

References 44 publications

Biomass allometry and carbon factors for a Mediterranean pine (Pinus pinea L.) in Portugal

Biomass allometry and carbon factors for a Mediterranean pine (Pinus pinea L.) in Portugal

Comparison of stem taper equations for eight major tree species in the Spanish Plateau

Nonlinear mixed model approaches to estimating merchantable bole volume for Pinus occidentalis

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