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Available from: Tanaka Kenzo, Mar 07, 2014
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    • "Although the basal areas of large trees (DBH C 10 cm) did not differ between the sites, the AGB of large trees in Balai Ringin was approximately 20 % higher than the large tree AGB value in Sabal; this difference may be explained by the higher densities of big trees (e.g., DBH class [ 80 cm) in Balai Ringin. This high density of big trees may be a result of higher growth rate of remaining trees after logging compared with those of Sabal, because trees on fertile soils usually show a higher growth rate than trees on infertile soils, such as in heath forests (Brunig 1996; Kendawang et al. 2007). In contrast, small tree biomasses and basal areas (1 B DBH \ 10 cm) in Sabal were double those in Balai Ringin. "
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    ABSTRACT: Although an estimation of forest biomass is essential for the development of a carbon storage baseline in the ‘‘Reducing Emissions from Deforestation and Degradation in Developing Countries’’ scheme, few have been conducted in logged-over rain forests of Southeast Asia. We measured the aboveground and belowground biomass in logged-over mixed dipterocarp forests growing on an infertile soil with bleached white sand (Sabal) and on a clay and nutrient-rich soil (Balai Ringin) in Sarawak, Malaysia. We established four 0.5-ha plots on each site and calculated the biomass. Basal area and stand density of large trees (diameter at breast height, DBH C 10 cm) were relatively similar in Sabal (27.0 m2, 720 tree ha-1) and Balai Ringin (28.9 m2, 586 tree ha-1). However, the corresponding measurements for small trees (1 B DBH\ 10 cm) were twice as large in Sabal than in Balai Ringin. Aboveground biomass (AGB) in the forests was less than half of the value recorded for undisturbed forests in Borneo, even 20 years after logging. Although total AGB was 20 % smaller in Sabal (205 Mg ha-1) than in Balai Ringin (242 Mg ha-1), the total belowground biomass (TBGB) was 20 % greater in Sabal (59.6 Mg ha-1) than in Balai Ringin (44.6 Mg ha-1). The larger TBGB in Sabal was due to the larger amounts of small roots (diameter \5 mm) in Sabal (26.8 Mg ha-1) compared to Balai Ringin (5.8 Mg ha-1). This accumulation of small roots at Sabal may have contributed to rapid nutrient absorption from infertile soil.
    Journal of Forest Research 09/2014; 20(1). DOI:10.1007/s10310-014-0465-y · 0.78 Impact Factor
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    • "These two factors strongly depend on landscape topography and secondary forest structure (biomass and stand density) (Sanchez 1976; Davies et al. 1998; Ohta et al. 2000; Davies 2001; Slik 2005; Tanaka et al. 2007). Hence, the long-term monitoring of environmental conditions and planted seedling performance in diverse topographies and forest structures is important for the development of rehabilitation techniques, particularly in tropical secondary forest, which have relatively large variability in the dynamics and/or growth of secondary tree species compared to temperate forests (Whitmore 1984, 1998; Kendawang et al. 2007). However, despite these compelling arguments, there have been few integrated evaluations of the external effects on planted seedling performance, and long-term monitoring has rarely been performed in tropical secondary forests. "
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    ABSTRACT: Enrichment planting with climax trees such as dipterocarps is required to rehabilitate degraded tropical forests in Southeast Asia, because these forests have been damaged by various anthropogenic activities. Severely degraded tropical secondary forests are the most important targets for enrichment planting in the region, because secondary forest trees potentially provide moderate conditions for planted seedlings by preventing strong sunlight and high temperatures. In an enrichment planting site located in Sarawak, Malaysia, we explored how variation in secondary forest structure (biomass and stand density) and soil (nutrient and water) conditions influenced the mortality and growth rates of planted dipterocarp seedlings (Parashorea macrophylla, Wyatt-Sm. ex P.S. Ashton) over the period from 2000–2007. Experimental plots were set up on different topographical features (slopes and valleys). Using the data collected, we demonstrated the ways in which environmental factors, such as soil nitrogen content, relate to climax tree seedling growth and mortality in degraded tropical secondary forests dominated by the genera Macaranga, Ficus, and Glochidion. Stand density and total aboveground biomass of secondary forest trees were significantly lower in the valley plots than on the slopes, whereas soil total nitrogen and water contents were significantly higher in valley plots. Over seven years, the total biomass of trees increased, whereas the density of secondary forest trees decreased in all plots. Nutrient stocks (nitrogen, phosphorus, potassium, calcium, and magnesium) in the soil (0–5 cm) also decreased over seven years in all plots. Height, diameter, and mortality of planted seedlings were higher in the valley plots than on slopes. Multiple stepwise regression demonstrated significant positive effects of total soil nitrogen and water content on the relative growth rate of seedlings over seven years. There were no significant relationships between seedling mortality and any of the environmental factors measured, including soil conditions. We conclude that (1) seedling growth was enhanced by soil total nitrogen rather than by available phosphorus or potassium, and (2) planted seedlings grew faster and died more often in the valley plots than on the slopes.
    Soil Science and Plant Nutrition 04/2013; 59(2):218-228. DOI:10.1080/00380768.2012.762895 · 0.73 Impact Factor
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    • "Quantifying the initial few decades of biomass changes in secondary forests after degradation will decrease these uncertainties since biomass accumulation during the initial stage is usually very large and shows complex changes (Brown and Lugo, 1990). For example, many tropical secondary forests show rapid rates of aboveground production during the initial stage of succession (Ewel, 1971; Ewel et al., 1983; Uhl and Jordan, 1984; Lugo, 1992; Jepsen, 2006; Kendawang et al., 2007), but the rate sometimes declines significantly following "
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    ABSTRACT: Uncertainties in the rate of biomass variation with forest ageing in tropical secondary forests, particularly in belowground components, limit the accuracy of carbon pool estimates in tropical regions. We monitored changes in above- and belowground biomass, leaf area index (LAI), and biomass allocation to the leaf component to determine the variation in carbon accumulation rate with forest age after shifting cultivation in Sarawak, Malaysia. Nine plots in a 4-year-old forest and fourteen plots in a 10-year-old forest were monitored for 5 and 7 years, respectively. Forest and plant part biomass were calculated from an allometric equation obtained from the same forest stands. Both above- and belowground biomass increased rapidly during the initial decade after abandonment. In contrast, a much slower rate of biomass accumulation was observed after the initial decade. LAI also increased by approximately double from the 4-year-old to 10-year-old forest, and then gently increased to the 17-year-old forest. We also found that allocation variation in leaf biomass and nitrogen was closely related to the rate of biomass accumulation as a forest aged. During the first decade after abandonment, a high biomass and nitrogen allocation to the leaf component may have allowed for a high rate of biomass accumulation. However, reduction in those allocations to leaf component after the initial decade may have helped to suppress the biomass accumulation rate in older secondary forests. Roots accounted for 14.0–16.1% of total biomass in the 4–17-year-old abandoned secondary forests. We also verified the model predicted values for belowground biomass by Cairns et al. (1997) and Mokany et al. (2006), although both models overestimated the values throughout our data sets by 45–50% in the 10-year-old forest. The low root:shoot ratio in the secondary forests may have caused this overestimation. Therefore, our results suggest that we should modify the models to estimate belowground biomass considering the low root:shoot ratio in tropical secondary forests.
    Forest Ecology and Management 07/2010; 260(5):875-882. DOI:10.1016/j.foreco.2010.06.006 · 2.66 Impact Factor
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