Oecologia

, Volume 155, Issue 2, pp 287–299

Soil nutrients affect spatial patterns of aboveground biomass and emergent tree density in southwestern Borneo

Ecosystem Ecology - Original Paper

Abstract

Studies on the relationship between soil fertility and aboveground biomass in lowland tropical forests have yielded conflicting results, reporting positive, negative and no effect of soil nutrients on aboveground biomass. Here, we quantify the impact of soil variation on the stand structure of mature Bornean forest throughout a lowland watershed (8–196 m a.s.l.) with uniform climate and heterogeneous soils. Categorical and bivariate methods were used to quantify the effects of (1) parent material differing in nutrient content (alluvium > sedimentary > granite) and (2) 27 soil parameters on tree density, size distribution, basal area and aboveground biomass. Trees ≥10 cm (diameter at breast height, dbh) were enumerated in 30 (0.16 ha) plots (sample area = 4.8 ha). Six soil samples (0–20 cm) per plot were analyzed for physiochemical properties. Aboveground biomass was estimated using allometric equations. Across all plots, stem density averaged 521 ± 13 stems ha−1, basal area 39.6 ± 1.4 m2 ha−1 and aboveground biomass 518 ± 28 Mg ha−1 (mean ± SE). Adjusted forest-wide aboveground biomass to account for apparent overestimation of large tree density (based on 69 0.3-ha transects; sample area = 20.7 ha) was 430 ± 25 Mg ha−1. Stand structure did not vary significantly among substrates, but it did show a clear trend toward larger stature on nutrient-rich alluvium, with a higher density and larger maximum size of emergent trees. Across all plots, surface soil phosphorus (P), potassium, magnesium and percentage sand content were significantly related to stem density and/or aboveground biomass (RPearson = 0.368–0.416). In multiple linear regression, extractable P and percentage sand combined explained 31% of the aboveground biomass variance. Regression analyses on size classes showed that the abundance of emergent trees >120 cm dbh was positively related to soil P and exchangeable bases, whereas trees 60–90 cm dbh were negatively related to these factors. Soil fertility thus had a significant effect on both total aboveground biomass and its distribution among size classes.

Keywords

Carbon sequestration Dipterocarpaceae Land use change Nutrient limitation Phosphorus 

Supplementary material

442_2007_906_MOESM1_ESM.xls (309 kb)
ESM 1 (XLS 309 kb)
442_2007_906_MOESM2_ESM.doc (150 kb)
ESM 2 (DOC 149 kb)

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Gary D. Paoli
    • 1
    • 2
  • Lisa M. Curran
    • 3
  • J. W. F. Slik
    • 4
  1. 1.Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborUSA
  2. 2.Indonesian Resource InstituteBogorIndonesia
  3. 3.Yale School of Forestry and Environmental StudiesNew HavenUSA
  4. 4.Nationaal Herbarium Nederland Leiden University BranchLeidenThe Netherlands

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