Modelling number, vertical distribution, and size of live branches on coniferous tree species in British Columbia

Linnell, NemecAmanda F.; ParishRoberta,; GoudieJames, W

doi:10.1139/x2012-060

Cited by 15 publications

(10 citation statements)

References 41 publications

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“…While the vertical distribution of forest biomass has been researched intensively (e.g. Tahvanainen and Forss 2008;Ruiz-González and Álvarez-González 2011;Nemec et al 2012;Jiménez et al 2013), studies that address the horizontal forest or tree biomass distribution are sparse. Kershaw and Maguire (1996) and Xu and Harrington (1998) modelled the horizontal distribution of leaf biomass -but not AGB.…”

Section: Introductionmentioning

confidence: 99%

Improving precision of field inventory estimation of aboveground biomass through an alternative view on plot biomass

et al. 2020

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We contrast a new continuous approach (CA) for estimating plot-level above-ground biomass (AGB) in forest inventories with the current approach of estimating AGB exclusively from the tree-level AGB predicted for each tree in a plot, henceforth called DA (discrete approach). With the CA, the AGB in a forest is modelled as a continuous surface and the AGB estimate for a fixed-area plot is computed as the integral of the AGB surface taken over the plot area. Hence with the CA, the portion of the biomass of in-plot trees that extends across the plot perimeter is ignored while the biomass from trees outside of the plot reaching inside the plot is added. We use a sampling simulation with data from a fully mapped two hectare area to illustrate that important differences in plot-level AGB estimates can emerge. Ideally CA-based estimates of mean AGB should be less variable than those derived from the DA. If realized, this difference translates to a higher precision from field sampling, or a lower required sample size. In our case study with a target precision of 5% (i.e. relative standard error of the estimated mean AGB), the CA required a 27.1% lower sample size for small plots of 100 m2 and a 10.4% lower sample size for larger plots of 1700 m2. We examined sampling induced errors only and did not yet consider model errors. We discuss practical issues in implementing the CA in field inventories and the potential in applications that model biomass with remote sensing data. The CA is a variation on a plot design for above-ground forest biomass; as such it can be applied in combination with any forest inventory sampling design.

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Section: Introductionmentioning

confidence: 99%

Improving precision of field inventory estimation of aboveground biomass through an alternative view on plot biomass

et al. 2020

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“…The crown morphology plasticity of a sapling influences both light capture and the use of growth resources and may reflect important implications related to the ability of a sapling to conduct efficient photosynthesis in the understory of a light-limiting environment and to compete with neighbours (Williams, Messier & Kneeshaw, 1999;Nikinmaa et al, 2003;Navarro-Cerrillo et al, 2018). For conifer saplings, crown morphology plasticity has been described by a series of characteristics in terms of the number of branches per whorl, the ratio of leader height to lateral branch growth, and the crown depth or crown ratio (Williams, Messier & Kneeshaw, 1999;Sattler & Lemay, 2001;Nemec, Parish & Goudie, 2002;Saud et al, 2016). The crown morphology of conifer saplings varies from a conical crown form to a more flat-topped form in the forest understory under different light conditions (Pearcy & Yang, 1998).…”

Section: Introductionmentioning

confidence: 99%

Effect of strip shelterwood-cuts on the crown morphology plasticity of natural regeneratedPinus tabuliformissaplings in northeastern China

Gao

Feng

Yin

et al. 2020

PeerJ

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The study analysed the effect of shelterwood-cut strips on the outermost crown profiles and crown characteristics of naturally regenerated Pinus tabuliformis saplings in northeastern China. A total of 49 regenerated saplings from shelterwood-cut strips and 30 from uncut strips were collected. Nonlinear quantile regression was used to develop the outermost crown profile model for the saplings from the shelterwood-cut and uncut strips. The quantile value suitable for describing the outermost crown profiles of the two types of strips was selected using nonparametric boundary regression. The difference in crown morphologies between the shelterwood-cut strips and uncut strips was compared. The results showed that with the same diameter at breast height, the crown radii of the uncut strip saplings were larger than those of the shelterwood-cut strip saplings within the range of 0.2–1.0 for the relative depth into the crown. The largest crown radius of the saplings from the uncut strips was larger than that of the saplings from the shelterwood-cut strips. The inflection points of the shelterwood-cut strip sapling crowns were larger than those of the uncut strip sapling crowns. The crown volume of the small uncut strip saplings was larger than that of the shelterwood-cut strip saplings, and the difference in crown volume decreased with increasing sapling size. The saplings in the early stage of the uncut strips showed a greater growth rate than those of the shelterwood-cut strips, but their growth rate slowed over the long term according to branch-length annual growth. The present study provides a reference for forest management strategy decision making in promoting natural regeneration.

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“…While the vertical distribution of forest biomass has been researched intensively (e.g. Nemec et al 2012, Jiménez et al 2013, Ruiz-González and Álvarez-González 2011, Tahvanainen and Forss 2008, studies that address the horizontal forest or tree biomass distribution are sparse. Kershaw and Maguire (1996) and Xu and Harrington (1998), modelled the horizontal distribution of leaf biomassbut not AGB.…”

Section: Introductionmentioning

confidence: 99%

Improving precision of field inventory estimation of above ground biomass through an alternative view on plot biomass

Kleinn

Magnussen

Noelke

et al. 2020

Preprint

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We contrast a new continuous approach (CA) to estimation of plot level above-ground biomass (AGB) in forest inventories with the current approach of deriving the AGB estimate exclusively from the tree-level AGB predicted for each tree in a plot; henceforth called DA (discrete approach). In CA the AGB in a forest is modelled as a continuous surface and the AGB estimate for a fixed area plot is computed as the integral of the AGB surface taken over the plot. Hence with CA, the portions of biomass in plot-trees that extend across a plot perimeter is ignored while the biomass from trees outside the plot reaching inside the plot is added. We use a sampling simulation with data from a fully mapped 2 ha area to illustrate, that important differences in plot-level AGB estimates can emerge, and that one should expect CA-based estimates of AGB to be less variable than with the DA, which translates to a higher precision of estimates from field plots: in our case study, for a target precision of estimation of 5%, the required sample size was 27% lower for small plots of 100m 2 when using the CA and 10% lower for larger plots of 1700m 2 . We discuss practical issues to implementing CA in field inventories and discuss the expected potential for applications that model biomass from remote sensing data.

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Modelling number, vertical distribution, and size of live branches on coniferous tree species in British Columbia

Cited by 15 publications

References 41 publications

Improving precision of field inventory estimation of aboveground biomass through an alternative view on plot biomass

Improving precision of field inventory estimation of aboveground biomass through an alternative view on plot biomass

Effect of strip shelterwood-cuts on the crown morphology plasticity of natural regeneratedPinus tabuliformissaplings in northeastern China

Improving precision of field inventory estimation of above ground biomass through an alternative view on plot biomass

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