Table 1.
Field sites of montane rainforest selected in Central Sulawesi (Indonesia) with reference to the species studied, geographical information and climatea.
Table 2.
Summary of the elemental concentrations (mean value ± SD) of various plant tissues from three Symplocos species and dominant neighbouring plant species collected at tropical montane forest sites in Central Sulawesi.
Fig 1.
Aluminium (Al) concentrations in various plant tissues for three Symplocos species from Central Sulawesi (mg·kg-1 dry mass).
For each species, five individual trees were measured, with ca. five large samples per tree for leaf and bark material, and one root and wood sample per tree. Leaves were classified according to three developmental stages (young, mature, and old). Different letters indicate significant differences between mean values (Wilcoxon Rank Sum Test, P < 0.05). Boxes show the median, 25th and 75th percentiles, error bars show 10th and 90th percentiles, and individual points show outliers.
Fig 2.
Boxplots showing aluminium (Al) concentrations (mg·kg-1 dry mass) in leaves for three species of Symplocos, showing the median, 25th and 75th percentiles, 10th and 90th percentiles as error bars, and outliers as individual points.
Leaves were grouped into three different developmental stages (young, mature, and old). Different letters indicate significant differences between mean values (Wilcoxon Rank-Sum Test, P < 0.05).
Fig 3.
pHH2O values of soil samples (n = 135) from the surface soil layer of Symplocos trees in Central Sulawesi.
Five individual trees per species were sampled for three species at three field sites (D = Dali, N = Nokilalaki, R = Rorekautimbu). The pH values are shown in relation to 1) the distance from the tree trunk, 2) the soil depth, and 3) the sampling site. Distances from the tree trunk depended on the tree crown width (near = at 0.15 to 0.45 m from the trunk; middle = at 0.50 to 0.25 m from the trunk, i.e. half the radius of the tree crown; far = 1.85–5.00 m, i.e. outside the tree crown). Depth classes 1, 2, and 3 were at 5 to 7 cm, 30 to 32 cm, and 40 to 42 cm, respectively. The box plots show the median, 25th and 75th percentiles, error bars show 10th and 90th percentiles, and individual points show outliers. Different letters indicate significant differences between mean values (Wilcoxon Rank-Sum Test, P < 0.05).
Table 3.
Elemental concentration of water extracted soluble ionsa in soil samples from three montane rainforest field sites in central Sulawesi.
The values represent mean values (± SD) for three depth classes near five Symplocos trees sampled per site. For each tree, nine soil samples were taken.
Fig 4.
Correlation between aluminium (Al) and calcium (Ca) concentrations in three Symplocos species from Central Sulawesi.
Five trees were sampled for each species. Different symbols represent different plant tissues and organs. The solid line represents the regression line. S. odoratissima: P = 0.02, n = 124; S. ophirensis: P < 0.01, n = 134; S. ambangensis: P < 0.01, n = 135.