# Betula nigra

Betulaceae. 15 equations apply. Each output lists them most specific first: fitted on this species, on a variety of it, pooled fits that included it, then its genus and family. Within each step, equations the authors advised against go last, then those read from compilations; more trees come first. The order shows how specific the evidence is, not which equation predicts best.

Wood density 0.53 g/cm³, estimated from 2 samples in 2 studies by the [Global Wood Density Database v.2](https://doi.org/10.5281/zenodo.16919509) (Fischer et al. 2026, https://doi.org/10.1111/nph.70860; CC BY 4.0).

## Aboveground biomass

1. Repola & Ahnlund Ulvcrona 2014 (same genus): Fitted on the genus Betula; 86 trees across all species; DBH 1–11 cm; Read from the original paper.
   - [Birch aboveground biomass, young dense stands, N Sweden (Table 5)](https://treeallometry.org/equations/repola-2014-agb-birch/), Repola & Ahnlund Ulvcrona 2014: Betula, Sweden; inputs DBH + Height; DBH 1–11 cm; 86 trees.

2. Repola 2008 (same genus): Fitted on the genus Betula; 127 trees across all species; DBH 2.5–38 cm; Read from the original paper.
   - [Birch total above-ground biomass excluding foliage, Model 1a (Eq. 11)](https://treeallometry.org/equations/repola-2008-betula-total/), Repola 2008: Betula, Finland; inputs DBH + Height; DBH 2.5–38 cm; 127 trees.

3. Westfall et al. 2024 (same genus): Fitted on the genus Betula; 38 trees across all species; DBH 2.54–46.99 cm; Read from the original paper.
   - [NSVB birch spp., species-level (all ecodivisions): total aboveground biomass (without foliage), Schumacher-Hall model (Eq. 1)](https://treeallometry.org/equations/westfall-2024-betula-spp-agb/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 2.54–46.99 cm; 38 trees.

## Stem biomass

1. Repola & Ahnlund Ulvcrona 2014 (same genus): Fitted on the genus Betula; 86 trees across all species; DBH 1–11 cm; Read from the original paper.
   - [Birch stem biomass, young dense stands, N Sweden (Table 5)](https://treeallometry.org/equations/repola-2014-stem-birch/), Repola & Ahnlund Ulvcrona 2014: Betula, Sweden; inputs DBH + Height; DBH 1–11 cm; 86 trees.

## Branch biomass

1. Repola & Ahnlund Ulvcrona 2014 (same genus): Fitted on the genus Betula; 86 trees across all species; DBH 1–11 cm; Read from the original paper.
   - [Birch living branch biomass, young dense stands, N Sweden (Table 5)](https://treeallometry.org/equations/repola-2014-branch-birch/), Repola & Ahnlund Ulvcrona 2014: Betula, Sweden; inputs DBH + Height; DBH 1–11 cm; 86 trees.

2. Westfall et al. 2024 (same genus): Fitted on the genus Betula; 38 trees across all species; DBH 2.54–46.99 cm; Read from the original paper.
   - [NSVB birch spp., species-level (all ecodivisions): branch biomass (wood and bark), Schumacher-Hall model (Eq. 1)](https://treeallometry.org/equations/westfall-2024-betula-spp-branch/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 2.54–46.99 cm; 38 trees.

## Foliage biomass

1. Westfall et al. 2024 (same genus): Fitted on the genus Betula; 38 trees across all species; DBH 2.54–46.99 cm; Read from the original paper.
   - [NSVB birch spp., species-level (all ecodivisions): foliage biomass, Schumacher-Hall model (Eq. 1)](https://treeallometry.org/equations/westfall-2024-betula-spp-foliage/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 2.54–46.99 cm; 38 trees.

2. Repola & Ahnlund Ulvcrona 2014 (same genus): Fitted on the genus Betula; Number of trees not stated; Read from the original paper.
   - [Birch foliage biomass, young dense stands, N Sweden (Table 5)](https://treeallometry.org/equations/repola-2014-foliage-birch/), Repola & Ahnlund Ulvcrona 2014: Betula, Sweden; inputs DBH.

## Stem volume

1. Westfall et al. 2024 (this species): Fitted on this species; 11 trees; DBH 2.54–44.2 cm; Read from the original paper.
   - [NSVB river birch, species-level (all ecodivisions): total stem wood volume (inside bark), Schumacher-Hall model (Eq. 1)](https://treeallometry.org/equations/westfall-2024-betula-nigra-volume/), Westfall et al. 2024: Betula nigra, United States; inputs DBH + Height; DBH 2.54–44.2 cm; 11 trees.

2. Westfall et al. 2024 (same genus): Fitted on the genus Betula; 144–394 trees across all species; DBH 2.54–88.39 cm; Read from the original paper.
   - [NSVB birch spp., species-level (all ecodivisions): total stem wood volume (inside bark), segmented model (Eq. 2), D ≥ 11 in (27.94 cm)](https://treeallometry.org/equations/westfall-2024-betula-spp-volume-large/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 27.94–88.39 cm; 394 trees.
   - [NSVB birch spp., species-level (all ecodivisions): total stem wood volume (inside bark), segmented model (Eq. 2), D < 11 in (27.94 cm)](https://treeallometry.org/equations/westfall-2024-betula-spp-volume-small/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 2.54–27.94 cm; 394 trees.
   - [NSVB birch spp., Hot Continental Regime Mountains (M220): total stem wood volume (inside bark), segmented model (Eq. 2), D ≥ 11 in (27.94 cm)](https://treeallometry.org/equations/westfall-2024-betula-spp-m220-volume-large/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 27.94–88.39 cm; 236 trees.
   - [NSVB birch spp., Hot Continental Regime Mountains (M220): total stem wood volume (inside bark), segmented model (Eq. 2), D < 11 in (27.94 cm)](https://treeallometry.org/equations/westfall-2024-betula-spp-m220-volume-small/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 2.54–27.94 cm; 236 trees.
   - [NSVB birch spp., Subtropical Division (230): total stem wood volume (inside bark), segmented model (Eq. 2), D ≥ 11 in (27.94 cm)](https://treeallometry.org/equations/westfall-2024-betula-spp-230-volume-large/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 27.94–71.37 cm; 144 trees.
   - [NSVB birch spp., Subtropical Division (230): total stem wood volume (inside bark), segmented model (Eq. 2), D < 11 in (27.94 cm)](https://treeallometry.org/equations/westfall-2024-betula-spp-230-volume-small/), Westfall et al. 2024: Betula, United States; inputs DBH + Height; DBH 2.54–27.94 cm; 144 trees.