Canadian national biomass equations: new parameter estimates that include British Columbia data

Ung, Chhun-Huor; Bernier, Pierre BernierP.; Guo, Xiaojing

doi:10.1139/x07-224

Cited by 137 publications

(129 citation statements)

References 3 publications

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“…We could have compared estimates generated using reconstructed DBH only with estimates generated using DBH and HT, as alternative models that could have been applied do exist [36,37]. However, this analysis would have been a model inter-comparison exercise that compares the relative difference between estimates of biomass increment using DBH and HT relative to the use of DBH only, not an accuracy assessment directly.…”

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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“…Between 1% to 5% of the samples were affected by some form of management and these observations were excluded from the samples. The biomass of bark, branches, foliage, and stemwood was calculated from dimension analysis based on diameter and height [41,42]. Total aboveground biomass was then calculated from Interior Douglas-fir was differentiated from the coastal variety by only including trees east of the Cascade/Coastal Mountain range.…”

Section: Forest Inventory Datamentioning

confidence: 99%

“…Whereas many comparable models predict the annual increments of diameter and height before deriving the growth rate of stemwood volume or biomass, Sawtooth assumes aboveground biomass growth as the dependent variable [30]. For this study, estimates of aboveground biomass growth were derived from dimension analysis of the tree diameter and height using Canada's national biomass equations [42] and a dry weight-to-carbon ratio of 0.5 [43]. The Default 1 equation predicted the natural logarithm of the aboveground biomass growth of the k th tree as:…”

Section: Modellingmentioning

confidence: 99%

“…Other stand-replacing disturbances were not considered, setting P m,SimSR,H , P m,SimSR,I , and P m,SimSR,P to 0.0. Upon completing the time-intervals of each stand, the aboveground biomass of each tree was partitioned into foliage, bark, branches, and stemwood based on species-specific allometric equations [42]. The belowground biomass for each tree was derived from aboveground biomass based on allometric equations for coniferous trees [55].…”

Section: Modellingmentioning

confidence: 99%

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Low Tree-Growth Elasticity of Forest Biomass Indicated by an Individual-Based Model

Hember

Kurz

2018

Forests

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Environmental conditions and silviculture fundamentally alter the metabolism of individual trees and, therefore, need to be studied at that scale. However, changes in forest biomass density (Mg C ha −1 ) may be decoupled from changes in growth (kg C year −1 ) when the latter also accelerates the life cycle of trees and strains access to light, nutrients, and water. In this study, we refer to an individual-based model of forest biomass dynamics to constrain the magnitude of system feedbacks associated with ontogeny and competition and estimate the scaling relationship between changes in tree growth and forest biomass density. The model was driven by fitted equations of annual aboveground biomass growth (G ag ), probability of recruitment (P r ), and probability of mortality (P m ) parameterized against field observations of black spruce (Picea mariana (Mill.) BSP), interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), and western hemlock (Tsuga heterophylla (Raf.) Sarg.). A hypothetical positive step-change in mean tree growth was imposed half way through the simulations and landscape-scale responses were then evaluated by comparing pre-and post-stimulus periods. Imposing a 100% increase in tree growth above calibrated predictions (i.e., contemporary rates) only translated into 36% to 41% increases in forest biomass density. This corresponded with a tree-growth elasticity of forest biomass (ε G,SB ) ranging from 0.33 to 0.55. The inelastic nature of stand biomass density was attributed to the dependence of mortality on intensity of competition and tree size, which decreased stand density by 353 to 495 trees ha −1 , and decreased biomass residence time by 10 to 23 years. Values of ε G,SB depended on the magnitude of the stimulus. For example, a retrospective scenario in which tree growth increased from 50% below contemporary rates up to contemporary rates indicated values of ε G,SB ranging from 0.66 to 0.75. We conclude that: (1) effects of warming and increasing atmospheric concentrations of carbon dioxide and reactive nitrogen on biomass production are greatly diminished, but not entirely precluded, scaling up from individual trees to forest landscapes; (2) the magnitude of decoupling is greater for a contemporary baseline than it is for a pre-industrial baseline; and (3) differences in the magnitude of decoupling among species were relatively small. To advance beyond these estimates, studies must test the unverified assumptions that effects of tree size and stand competition on rates of recruitment, mortality, and growth are independent of climate change and atmospheric concentrations of carbon dioxide and nitrogen.

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“…Considering that many more stem taper data have become available since then, a research project has been undertaken to compile stem taper data across Canada and produce taper models for the whole country and for most tree species. As in the Canadian national biomass equations (Lambert et al 2005, Ung et al 2008, the application context of these taper models is the national forest inventory, meaning that they rely on DBH with or without tree height for a given species. The objective is to present the resulting models after describing the available data and the adopted method.…”

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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Canadian national biomass equations: new parameter estimates that include British Columbia data

Cited by 137 publications

References 3 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

Low Tree-Growth Elasticity of Forest Biomass Indicated by an Individual-Based Model

Canadian national taper models

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