Figure 1.
Map of Sabah and forest quality map of Malua Forest Reserve.
(A) Allocated production forest is shown across Sabah (light green, also including Malua Forest Reserve). The study sites (marked in red) are located in the Malua Forest Reserve and the Danum Valley Conservation Area (dark green). (B) Forest quality map of the Malua Forest Reserve (visual interpretation of aerial photographs, 1∶17,500). The boundary of the Sabah Biodiversity Experiment (500 ha) is outlined (red). Forest classification is based on number of trees ≥60 cm DBH derived from crown size. Cloud forest: >16 trees ha−1, Moderate: 9–16 trees ha−1, Poor: 5–8 trees ha−1, Very Poor: 1–4 trees ha−1, Shrubs/Bare Land/Grassland: none, Plantation: Oil palm monoculture.
Table 1.
Site characteristics of a pre-logging survey completed in 1983.
Table 2.
Comparison of basal area, volume and selected stocks and fluxes related to C turnover processes.
Figure 2.
Pre-enrichment planting C balance for the Sabah Biodiversity Experiment.
The area is located in selectively logged forest of the Malua Forest Reserve. All components are given as mean ± SEM Mg C ha−1, except for C fluxes (*), which are reported as Mg C ha−1 yr−1. Values in parenthesis indicate the percentage of single C stocks to total organic C (167.9 Mg C ha−1).
Figure 3.
Total aboveground C stocks (TAGC) and basal area in selectively logged an unlogged forest.
All species (square), dipterocarps (circle) and pioneer species only (triangle) (mean ± SEM; n = 4). Decreases in dipterocarp basal area but not in carbon stocks were compensated by the pioneers.
Figure 4.
Across study comparison of basal area, aboveground biomass and C.
Mean (plus or minus one SEM) are shown for basal area (m2 ha−1), total aboveground biomass (TAGB Mg ha−1), and total aboveground carbon (TAGC Mg C ha−1) assessed at Danum Valley Conservation Area and nearby selectively logged areas including the Sabah Biodiversity Experiment. Berry 2010 (circle): selectively logged measurements were taken 18 years after harvest; Pinard 1996 (triangle) and Tangki 2008 (diamond): 20 years after harvest; this study (quadrat): 22 years after harvest. All unlogged measurements are from Danum Valley Convervation Area except Pinard 1996 which were taken on unlogged Ulu Segama forest. Note that Berry 2010 (logged and unlogged) and Pinard 1996 (logged) did not specify basal area.
Figure 5.
Measured soil organic C (SOC) and bulk density with depth for the Sabah Biodiversity Experiment (Saner 2009). Overlayed points are soil organic C typical of the Kretam soil association (SFD 2008), which is found at Malua Forest Reserve. The line is a smoothed loess curve of mean SOC (±95% CI).
Figure 6.
Monthly estimates of litterfall.
Time series of total fine litterfall (solid line; mean±95% CI) and precipitation (dashed line; mean). Days indicate litter collections (n = 25) in 2006/07. Mean litterfall and rainfall were calculated over the fourteen days prior to collection.