Table 1.
Medians, ranges, and sample sizes (n) of size metrics.
Table 2.
Medians, ranges, and sample sizes (n) of biomass components (dry mass).
Table 3.
Means, ranges, and sample sizes (n) of biomass components as proportions of their sum (aboveground biomass, not including fruits).
Fig 1.
Size distributions of eight tree species.
(a) Aboveground biomass, (b) belowground biomass, (c) basal diameter, and (d) height are shown for each species. Each symbol represents one individual tree. Color and symbol indicate the fertilization treatment, as indicated in the legend. Data were jittered horizontally for visual clarity. Vertical dotted lines separate the points to clarify which points correspond to which species.
Fig 2.
Allocation to aboveground biomass across tree size.
(a) Robinia pseudoacacia and (b) Betula nigra. Each symbol represents an individual tree. Colors and symbols indicate treatments, as in Fig 1. Linear regression equations and p values are shown.
Fig 3.
Allocation to foliage across tree size.
The fractions of aboveground biomass comprised of foliage are shown for (a) Robinia pseudoacacia, (b) Betula nigra, (c) Gliricidia sepium, (d) Casuarina equisetifolia, (e) Psidium cattleianum, (f) Acacia koa, (g) Morella faya, and (h) Dodonaea viscosa. Each symbol represents one individual tree. Colors and symbols indicate treatments, as in Fig 1. Linear regression equations and p values are shown.
Fig 4.
Models for aboveground biomass (AGB) of Robinia pseudoacacia.
(a) The best fit model according to AIC, which models aboveground biomass as a function of the square of basal diameter (D, in cm) multiplied by height (H, in m), with different parameters for each treatment. Colors and symbols of the points indicate treatments, as in Fig 1. Colors of curves are analogous: blue is the control; orange is the +10 g N m−2 y−1 treatment; red is the +15 g N m−2 y−1 treatment; and purple is the +15 g N m−2 y−1 +15 g P m−2 y−1 treatment. (b) Aboveground biomass as a function of basal diameter (D) only. Colors and symbols of the points indicate treatments, as in Fig 1. The fit is shown in black because it does not depend on treatment. The fits shown on the panels are the same as in Tables 3 and 6.
Table 4.
Best fit models.
Table 5.
Best fit models without a treatment effect.
Table 6.
Best fit models without canopy area.
Table 7.
Model fits with diameter only.
Fig 5.
Diameter-driven allometric relationships of species and functional types (Nitrogen-fixing vs. non-fixing tree species).
(a) Aboveground biomass is plotted as a function of diameter (D, in cm) (b) Foliar biomass is plotted as a function of diameter.
Fig 6.
Comparison of our allometric equations to other published equations.
We used the input variables (basal diameter, tree height, canopy dimensions) from our trees to estimate biomass components from our equations and from equations from (a) Böhm et al. (2011) for Robinia pseudoacacia, (b) Harrington & Fownes (1993) for Gliricidia sepium, and (c) Xue et al. (2016) for Casuarina equisetifolia. Each symbol represents one (a) Robinia pseudoacacia, (b) Gliricidia sepium, or (c) Casuarina equisetifolia tree from our dataset. The 1:1 line is plotted in each panel (dotted) along with a linear regression (solid; equations and adjusted R2 listed on the figure). See methods for the details of these comparisons.