Figure 1.
Linear relationship between stand age (years) and species successional status mean (years; left), standard error (SE; middle) and annual change (years; right).
Stand values are calculated using all tree stems within each secondary forest stand.
Figure 2.
Ultrametric tree of species used for leaf trait phylogenetic signal analyses.
Foliar %C is provided after the species name as it was the only trait identified as having significant phylogenetic signal. The scale bar (lower left corner) represents 10 million years.
Figure 3.
Percentage total living trees in understory and overstory crown exposure (CE) positions; 1–3, and 4–5, respectively.
Stand development phases (top) correspond to those described by Waring and Running (2007) [24] and Oliver and Larson (1990) [25].
Figure 4.
Stand structural and species characteristics for successional forest study sites.
Species diversity is calculated using the Shannon-Weiner metric and species similarity is calculated using a Chao-Jaccard index versus primary forest composition. Michaelis-Menten relationship is shown between biomass and stand age, while quadratic are shown between tree height and diameter at breast height (DBH) and stand age.
Table 1.
Stand characteristics of all successional and primary (Pr) forest study sites (mean±std. dev.).
Table 2.
Eigenvectors of stand and soil Principal Components Analysis (PCA) axes.
Figure 5.
Selected soil properties for successional forest study sites.
Significant linear regressions are shown in grey (N = 13). Linear regressions for soil δ15N were significant using separate depth points (N = 39) and for soil δ13C following exclusion of the 7 year old stand outlier (N = 12).
Table 3.
Soil properties for all successional and primary (Pr) forest study sites.
Figure 6.
Soil δ15N values versus stand age by soil depth.
A significant relationship exists between stand age and δ15N for all samples (R2 = 0.26, P = 0.0881, N = 12) and a trend at 5 cm depth (R2 = 0.26, P = 0.0881, N = 12).
Figure 7.
Foliar δ15N and δ13C values versus stand age and species successional status.
Significant linear regressions are shown in grey.
Figure 8.
Foliar-minus-soil δ15N and δ13C values versus stand age and species successional status.
Significant linear regressions are shown in grey.
Table 4.
Characteristics of tree species selected for analysis of foliar properties.
Table 5.
Pearson correlations among leaf trait variables.
Table 6.
Pearson correlations among the predictor variables stand age (years), species successional status (status), and the PCA derived axes of stand biomass and structure and soil texture and fertility.
Table 7.
Best subsets models of leaf traits versus stand age, species successional status, and Principal Component Analysis (PCA) derived gradients in stand biomass and structure, and soil texture and fertility.
Table 8.
Regressions of foliar variables versus stand age (years)/species successional status (years).