Displaying publications 1 - 20 of 343 in total

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  1. Bryan JE, Shearman PL, Asner GP, Knapp DE, Aoro G, Lokes B
    PLoS ONE, 2013;8(7):e69679.
    PMID: 23874983 DOI: 10.1371/journal.pone.0069679
    The Malaysian states of Sabah and Sarawak are global hotspots of forest loss and degradation due to timber and oil palm industries; however, the rates and patterns of change have remained poorly measured by conventional field or satellite approaches. Using 30 m resolution optical imagery acquired since 1990, forest cover and logging roads were mapped throughout Malaysian Borneo and Brunei using the Carnegie Landsat Analysis System. We uncovered ∼364,000 km of roads constructed through the forests of this region. We estimated that in 2009 there were at most 45,400 km(2) of intact forest ecosystems in Malaysian Borneo and Brunei. Critically, we found that nearly 80% of the land surface of Sabah and Sarawak was impacted by previously undocumented, high-impact logging or clearing operations from 1990 to 2009. This contrasted strongly with neighbouring Brunei, where 54% of the land area remained covered by unlogged forest. Overall, only 8% and 3% of land area in Sabah and Sarawak, respectively, was covered by intact forests under designated protected areas. Our assessment shows that very few forest ecosystems remain intact in Sabah or Sarawak, but that Brunei, by largely excluding industrial logging from its borders, has been comparatively successful in protecting its forests.
    Matched MeSH terms: Trees*
  2. Haron NW, Chew MY
    ScientificWorldJournal, 2012;2012:234820.
    PMID: 22619629 DOI: 10.1100/2012/234820
    The carnivorous Utricularia (Lentibulariaceae) is a small herb of multifarious wet habitats worldwide. Eleven of the 14 Peninsular Malaysian species range into the mountains. Distribution, disturbance adaptability and collection frequency were used to formulate their commonness category. Common (U. aurea, U. bifida, and U. minutissima) and fairly common (U. gibba and U. uliginosa) species are mostly lowland plants that ascend to open montane microhabitats, while the fairly common (U. striatula), narrow-range (U. caerulea pink form and U. involvens), rare (U. furcellata and U. scandens), and endemic (U. vitellina) species are restricted to mountainous sites. Common species that colonise dystrophic to oligotrophic man-made sites in late succession could serve as predictors for general health and recovery of wet habitats. Rarer species are often locally abundant, their niches situated around pristine forest edges. When in decline, they indicate the beginning of problems affecting the forest. Utricularia is reportedly nutritious, mildly astringent, and diuretic. Preadapted to nutrient-poor, waterlogged soils, U. bifida is suitable as an alternative for small-scale herb cultivation on low pH, wet poor soils usually deemed not suitable for any crops.
    Matched MeSH terms: Trees*
  3. Chu C, Lutz JA, Král K, Vrška T, Yin X, Myers JA, et al.
    Ecol. Lett., 2019 Feb;22(2):245-255.
    PMID: 30548766 DOI: 10.1111/ele.13175
    Climate is widely recognised as an important determinant of the latitudinal diversity gradient. However, most existing studies make no distinction between direct and indirect effects of climate, which substantially hinders our understanding of how climate constrains biodiversity globally. Using data from 35 large forest plots, we test hypothesised relationships amongst climate, topography, forest structural attributes (stem abundance, tree size variation and stand basal area) and tree species richness to better understand drivers of latitudinal tree diversity patterns. Climate influences tree richness both directly, with more species in warm, moist, aseasonal climates and indirectly, with more species at higher stem abundance. These results imply direct limitation of species diversity by climatic stress and more rapid (co-)evolution and narrower niche partitioning in warm climates. They also support the idea that increased numbers of individuals associated with high primary productivity are partitioned to support a greater number of species.
    Matched MeSH terms: Trees*
  4. Ledo A, Cornulier T, Illian JB, Iida Y, Kassim AR, Burslem DF
    Ecol Appl, 2016 Dec;26(8):2374-2380.
    PMID: 27907254 DOI: 10.1002/eap.1450
    Accurate estimation of tree biomass is necessary to provide realistic values of the carbon stored in the terrestrial biosphere. A recognized source of errors in tree aboveground biomass (AGB) estimation is introduced when individual tree height values (H) are not directly measured but estimated from diameter at breast height (DBH) using allometric equations. In this paper, we evaluate the performance of 12 alternative DBH : H equations and compare their effects on AGB estimation for three tropical forests that occur in contrasting climatic and altitudinal zones. We found that fitting a three-parameter Weibull function using data collected locally generated the lowest errors and bias in H estimation, and that equations fitted to these data were more accurate than equations with parameters derived from the literature. For computing AGB, the introduced error values differed notably among DBH : H allometric equations, and in most cases showed a clear bias that resulted in either over- or under-estimation of AGB. Fitting the three-parameter Weibull function minimized errors in AGB estimates in our study and we recommend its widespread adoption for carbon stock estimation. We conclude that many previous studies are likely to present biased estimates of AGB due to the method of H estimation.
    Matched MeSH terms: Trees*
  5. Numata S, Yasuda M, Suzuki RO, Hosaka T, Noor NS, Fletcher CD, et al.
    PLoS ONE, 2013;8(11):e79095.
    PMID: 24260159 DOI: 10.1371/journal.pone.0079095
    In South-East Asian dipterocarp forests, many trees synchronize their reproduction at the community level, but irregularly, in a phenomenon known as general flowering (GF). Several proximate cues have been proposed as triggers for the synchronization of Southeast Asian GF, but the debate continues, as many studies have not considered geographical variation in climate and flora. We hypothesized that the spatial pattern of GF forests is explained by previously proposed climatic cues if there are common cues for GF among regions. During the study, GF episodes occurred every year, but the spatial occurrence varied considerably from just a few forests to the whole of Peninsular Malaysia. In 2001, 2002 and 2005, minor and major GF occurred widely throughout Peninsular Malaysia (GF2001, GF2002, and GF2005), and the geographical patterns of GF varied between the episodes. In the three regional-scale GF episodes, most major events occurred in regions where prolonged drought (PD) had been recorded prior, and significant associations between GF scores and PD were found in GF2001 and GF2002. However, the frequency of PD was higher than that of GF throughout the peninsula. In contrast, low temperature (LT) was observed during the study period only before GF2002 and GF2005, but there was no clear spatial relationship between GF and LT in the regional-scale episodes. There was also no evidence that last GF condition influenced the magnitude of GF. Thus, our results suggest that PD would be essential to trigger regional-scale GF in the peninsula, but also that PD does not fully explain the spatial and temporal patterns of GF. The coarse relationships between GF and the proposed climatic cues may be due to the geographical variation in proximate cues for GF, and the climatic and floristic geographical variations should be considered to understand the proximate factors of GF.
    Matched MeSH terms: Trees/physiology*
  6. Liu X, Burslem DFRP, Taylor JD, Taylor AFS, Khoo E, Majalap-Lee N, et al.
    Ecol. Lett., 2018 05;21(5):713-723.
    PMID: 29536604 DOI: 10.1111/ele.12939
    Partitioning of soil phosphorus (P) pools has been proposed as a key mechanism maintaining plant diversity, but experimental support is lacking. Here, we provided different chemical forms of P to 15 tree species with contrasting root symbiotic relationships to investigate plant P acquisition in both tropical and subtropical forests. Both ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) trees responded positively to addition of inorganic P, but strikingly, ECM trees acquired more P from a complex organic form (phytic acid). Most ECM tree species and all AM tree species also showed some capacity to take up simple organic P (monophosphate). Mycorrhizal colonisation was negatively correlated with soil extractable P concentration, suggesting that mycorrhizal fungi may regulate organic P acquisition among tree species. Our results support the hypothesis that ECM and AM plants partition soil P sources, which may play an ecologically important role in promoting species coexistence in tropical and subtropical forests.
    Matched MeSH terms: Trees*
  7. Phua MH, Tsuyuki S, Furuya N, Lee JS
    J. Environ. Manage., 2008 Sep;88(4):784-95.
    PMID: 17629393
    Tropical deforestation is occurring at an alarming rate, threatening the ecological integrity of protected areas. This makes it vital to regularly assess protected areas to confirm the efficacy of measures that protect that area from clearing. Satellite remote sensing offers a systematic and objective means for detecting and monitoring deforestation. This paper examines a spectral change approach to detect deforestation using pattern decomposition (PD) coefficients from multitemporal Landsat data. Our results show that the PD coefficients for soil and vegetation can be used to detect deforestation using change vector analysis (CVA). CVA analysis demonstrates that deforestation in the Kinabalu area, Sabah, Malaysia has significantly slowed from 1.2% in period 1 (1973 and 1991) to 0.1% in period 2 (1991 and 1996). A comparison of deforestation both inside and outside Kinabalu Park has highlighted the effectiveness of the park in protecting the tropical forest against clearing. However, the park is still facing pressure from the area immediately surrounding the park (the 1 km buffer zone) where the deforestation rate has remained unchanged.
    Matched MeSH terms: Trees*
  8. Feeley KJ, Joseph Wright S, Nur Supardi MN, Kassim AR, Davies SJ
    Ecol. Lett., 2007 Jun;10(6):461-9.
    PMID: 17498145
    The impacts of global change on tropical forests remain poorly understood. We examined changes in tree growth rates over the past two decades for all species occurring in large (50-ha) forest dynamics plots in Panama and Malaysia. Stem growth rates declined significantly at both forests regardless of initial size or organizational level (species, community or stand). Decreasing growth rates were widespread, occurring in 24-71% of species at Barro Colorado Island, Panama (BCI) and in 58-95% of species at Pasoh, Malaysia (depending on the sizes of stems included). Changes in growth were not consistently associated with initial growth rate, adult stature, or wood density. Changes in growth were significantly associated with regional climate changes: at both sites growth was negatively correlated with annual mean daily minimum temperatures, and at BCI growth was positively correlated with annual precipitation and number of rainfree days (a measure of relative insolation). While the underlying cause(s) of decelerating growth is still unresolved, these patterns strongly contradict the hypothesized pantropical increase in tree growth rates caused by carbon fertilization. Decelerating tree growth will have important economic and environmental implications.
    Matched MeSH terms: Trees/growth & development*
  9. Yamada T, Yamada Y, Okuda T, Fletcher C
    Oecologia, 2013 Jul;172(3):713-24.
    PMID: 23183820 DOI: 10.1007/s00442-012-2529-z
    Differences in the density of conspecific tree individuals in response to environmental gradients are well documented for many tree species, but how such density differences are generated and maintained is poorly understood. We examined the segregation of six dipterocarp species among three soil types in the Pasoh tropical forest, Malaysia. We examined how individual performance and population dynamics changed across the soil types using 10-year demographic data to compare tree performance across soil types, and constructed population matrix models to analyze the population dynamics. Species showed only minor changes in mortality and juvenile growth across soil types, although recruitment differed greatly. Clear, interspecific demographic trade-offs between growth and mortality were found in all soil types. The relative trade-offs by a species did not differ substantially among the soil types. Population sizes were projected to remain stable in all soil types for all species with one exception. Our life-table response experiment demonstrated that the population dynamics of a species differed only subtly among soil types. Therefore, species with strong density differences across soil types do not necessarily differ greatly in their population dynamics across the soil types. In contrast, interspecific differences in population dynamics were large. The trade-off between mortality and growth led to a negative correlation between the contributions of mortality and growth to variations in the population growth rate (λ) and thus reduced their net contributions. Recruitment had little impact on the variation in λ. The combination of these factors resulted in little variation in λ among species.
    Matched MeSH terms: Trees/growth & development; Trees/physiology*
  10. Iida Y, Poorter L, Sterck F, Kassim AR, Potts MD, Kubo T, et al.
    Ecology, 2014 Feb;95(2):353-63.
    PMID: 24669729
    Tree architecture, growth, and mortality change with increasing tree size and associated light conditions. To date, few studies have quantified how size-dependent changes in growth and mortality rates co-vary with architectural traits, and how such size-dependent changes differ across species and possible light capture strategies. We applied a hierarchical Bayesian model to quantify size-dependent changes in demographic rates and correlated demographic rates and architectural traits for 145 co-occurring Malaysian rain-forest tree species covering a wide range of tree sizes. Demographic rates were estimated using relative growth rate in stem diameter (RGR) and mortality rate as a function of stem diameter. Architectural traits examined were adult stature measured as the 95-percentile of the maximum stem diameter (upper diameter), wood density, and three tree architectural variables: tree height, foliage height, and crown width. Correlations between demographic rates and architectural traits were examined for stem diameters ranging from 1 to 47 cm. As a result, RGR and mortality varied significantly with increasing stem diameter across species. At smaller stem diameters, RGR was higher for tall trees with wide crowns, large upper diameter, and low wood density. Increased mortality was associated with low wood density at small diameters, and associated with small upper diameter and wide crowns over a wide range of stem diameters. Positive correlations between RGR and mortality were found over the whole range of stem diameters, but they were significant only at small stem diameters. Associations between architectural traits and demographic rates were strongest at small stem diameters. In the dark understory of tropical rain forests, the limiting amount of light is likely to make the interspecific difference in the effects of functional traits on demography more clear. Demographic performance is therefore tightly linked with architectural traits such as adult stature, wood density, and capacity for horizontal crown expansion. The enhancement of a demographic trade-off due to interspecific variation in functional traits in the understory helps to explain species coexistence in diverse rain forests.
    Matched MeSH terms: Trees/anatomy & histology*; Trees/growth & development*
  11. Farrukh Mukhamedov
    MyJurnal
    In the present paper we provide a construction of Quantum Markov chain on a Cayley tree. Moreover, we give a concrete example of such chains, which is shift invariant and has the clustering property
    Matched MeSH terms: Trees
  12. Marryanna Lion, Siti-Aisah Shamsuddin, Wan Mohd Shukri Wan Ahmad
    Sains Malaysiana, 2017;46:359-363.
    Sap flow pattern of Tectona grandis planted at lowland forest assessed. This study aimed to determine the sap movement
    of two different diameter sizes T. grandis. Two sizes selected were 16 and 38 cm in diameter at breast height (dbh). Sap
    flow meter (SFM) used to assess the sap velocity rates at the interval of 30 min within 24 h for 15 days. Diurnal sap flow
    of T. grandis shows that mean velocity is high during day time compared night time. Small diameter has high sap flow
    compared to that of bigger diameter. A flow rates was high at the inner layer and less at outer layer for smaller tree. The
    variation was vice versa when the tree was getting bigger. Variations in sap flow of T. grandis characterized by several
    environmental factors. It was found that size contribute in the differed sap flow of T. grandis.
    Matched MeSH terms: Trees
  13. Qie L, Lewis SL, Sullivan MJP, Lopez-Gonzalez G, Pickavance GC, Sunderland T, et al.
    Nat Commun, 2018 01 19;9(1):342.
    PMID: 29352254 DOI: 10.1038/s41467-018-02920-x
    The original version of this Article contained an error in the third sentence of the abstract and incorrectly read "Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha-1 year-1 (95% CI 0.14-0.72, mean period 1988-2010) above-ground live biomass", rather than the correct "Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha-1 year-1 (95% CI 0.14-0.72, mean period 1988-2010) in above-ground live biomass carbon". This has now been corrected in both the PDF and HTML versions of the Article.
    Matched MeSH terms: Trees
  14. Tan Lee CY, Ngatirin NR, Zainol Z
    MyJurnal
    Personality represents the mixture of features and qualities that built an individual’s distinctive characters including thinking, feeling and behaving. Traditionally, self-assessment method via questionnaire is the most common means to identify personality. Since recommender systems and advertisement
    campaigns have evolved rapidly, personality computing has become a popular research field to provide personalisation to users. Currently, researchers have utilised social media data for automatically predicting personality. However, it is complex to mine the social media data as they are noisy, free-format, and
    of varying length and multimedia. This paper proposes a decision tree C4.5 algorithm to automatically predict personality based on Big Five model. The Big Five Inventory and ZeroR algorithm were included to be served as the baseline for performance evaluation. Experimental evaluation demonstrated that C4.5
    performs better than ZeroR in terms of accuracy.
    Keywords: Big Five, decision tree, personality, social media
    Matched MeSH terms: Decision Trees
  15. Suresh A, Karthikraja V, Lulu S, Kangueane U, Kangueane P
    Bioinformation, 2009 Nov 17;4(5):197-205.
    PMID: 20461159
    The formation of protein homodimer complexes for molecular catalysis and regulation is fascinating. The homodimer formation through 2S (2 state), 3SMI (3 state with monomer intermediate) and 3SDI (3 state with dimer intermediate) folding mechanism is known for 47 homodimer structures. Our dataset of forty-seven homodimers consists of twenty-eight 2S, twelve 3SMI and seven 3SDI. The dataset is characterized using monomer length, interface area and interface/total (I/T) residue ratio. It is found that 2S are often small in size with large I/T ratio and 3SDI are frequently large in size with small I/T ratio. Nonetheless, 3SMI have a mixture of these features. Hence, we used these parameters to develop a decision tree model. The decision tree model produced positive predictive values (PPV) of 72% for 2S, 58% for 3SMI and 57% for 3SDI in cross validation. Thus, the method finds application in assigning homodimers with folding mechanism.
    Matched MeSH terms: Decision Trees
  16. SANDOSHAM AA, BENNETT GF, FONG YL, OMAR EI
    Singapore Med J, 1965 Mar;6(1):47-8.
    PMID: 14306412
    An immature Glossy Tree-Starling (Aplonis panayensis strigatus), also known as ‘burong perling’ in Malay, was captured in the vicinity of the Institute for Medical Research, Kuala Lumpur. It was found to harbour a small malaria parasite which showed the characteristics of the sub-genus Novyella (Corradetti et al, 1963) viz:
    1. Trophozoites small with little cytoplasm, relatively large nuclear elements, the parasite usually applied to the host-cell nucleus.
    2. Schizonts with usually less than eight merozoites. 3. Pigment small and difficult to see except in the schizonts and in the gametocytes where the pigment granules are large and usually clustered at one end.
    4. The parasite rarely distorts the host erythrocyte. Unfortunately the bird died a few days later before detailed work on duration of the schizogonic cycle and experimental transmission could be done. The parasite has the following morphological features and most of the larger forms, asexual and sexual, assume the characteristic position proximal to the nucleus of the avian erythrocyte. Trophozoites: The earliest forms are ‘rings’ with a fairly marked vacuole. As the organism grows older, it produces a grain or two of pigment. The parasite at this stage tends to occupy a polar position in the host erythrocyte. Schizonts: The segmenting forms are usually attached to the pole end of the host-cell nucleus. The number of chromatin segments varies from 3 to 8, with a prevalent range of 4 to 6. The cytoplasm is scanty and pale with a prominent little mass of blackish-brown pigment or a close collection of granules. A rare mature schizont with 8 merozoites was seen in which the nucleus of the parasitised erythrocyte was displaced somewhat similar to figure 20 of Plate I portrayed in the original paper by Manwell (1935). Gametocytes: The sexual forms are often narrow and elongate, and are closely applied to the nucleus of the host erythrocyte. The outline of the parasite is frequently irregular. The cytoplasm is pale and vacuolated with coarse conspicuous granules of blackish-brown pigment usually collected at one end; sometimes either one or both ends curved around the host-cell nucleus. Although this parasite has some affinites to both P. nucleophiltim and P. hexamerium the lack of adequate study of the avian malarias of South-East Asia precludes even provisional identification of this parasite. On two occasions numerous gametocytes were seen in the peripheral blood of the bird and four species of laboratory-reared culicines (three indigenous to Malaya) were allowed to feed on it. Ten Andes togoi, 19 Culex sitiens and seven Culex fatigans were completely refractory to development of the parasite. Two of 17 Aedes aegypti had a single small oocyst each; both oocysts appeared to be degenerating. A Giemsa-stained thin blood film together with drawings made from the microscope showing the different forms of the parasite were demonstrated. REFERENCES
    Corradetti, A., Garnham, P. C. & Laird, M. (i963). Parassitologia, 5, 1-4.
    Manwell, R. D. (l935). Amer. J. Trop. Med 15, 265-283.
    ...(1938). Ibid., 18, 565-575
    Matched MeSH terms: Trees*
  17. Shima K, Yamada T, Okuda T, Fletcher C, Kassim AR
    Sci Rep, 2018 01 18;8(1):1024.
    PMID: 29348596 DOI: 10.1038/s41598-018-19250-z
    Selective logging that is commonly conducted in tropical forests may change tree species diversity. In rarely disturbed tropical forests, locally rare species exhibit higher survival rates. If this non-random process occurs in a logged forest, the forest will rapidly recover its tree species diversity. Here we determined whether a forest in the Pasoh Forest Reserve, Malaysia, which was selectively logged 40 years ago, recovered its original species diversity (species richness and composition). To explore this, we compared the dynamics of secies diversity between unlogged forest plot (18.6 ha) and logged forest plot (5.4 ha). We found that 40 years are not sufficient to recover species diversity after logging. Unlike unlogged forests, tree deaths and recruitments did not contribute to increased diversity in the selectively logged forests. Our results predict that selectively logged forests require a longer time at least than our observing period (40 years) to regain their diversity.
    Matched MeSH terms: Trees*
  18. Koh LP, Miettinen J, Liew SC, Ghazoul J
    Proc. Natl. Acad. Sci. U.S.A., 2011 Mar 22;108(12):5127-32.
    PMID: 21383161 DOI: 10.1073/pnas.1018776108
    Rising global demands for food and biofuels are driving forest clearance in the tropics. Oil-palm expansion contributes to biodiversity declines and carbon emissions in Southeast Asia. However, the magnitudes of these impacts remain largely unquantified until now. We produce a 250-m spatial resolution map of closed canopy oil-palm plantations in the lowlands of Peninsular Malaysia (2 million ha), Borneo (2.4 million ha), and Sumatra (3.9 million ha). We demonstrate that 6% (or ≈880,000 ha) of tropical peatlands in the region had been converted to oil-palm plantations by the early 2000s. Conversion of peatswamp forests to oil palm led to biodiversity declines of 1% in Borneo (equivalent to four species of forest-dwelling birds), 3.4% in Sumatra (16 species), and 12.1% in Peninsular Malaysia (46 species). This land-use change also contributed to the loss of ≈140 million Mg of aboveground biomass carbon, and annual emissions of ≈4.6 million Mg of belowground carbon from peat oxidation. Additionally, the loss of peatswamp forests implies the loss of carbon sequestration service through peat accumulation, which amounts to ≈660,000 Mg of carbon annually. By 2010, 2.3 million ha of peatswamp forests were clear-felled, and currently occur as degraded lands. Reforestation of these clearings could enhance biodiversity by up to ≈20%, whereas oil-palm establishment would exacerbate species losses by up to ≈12%. To safeguard the region's biodiversity and carbon stocks, conservation and reforestation efforts should target Central Kalimantan, Riau, and West Kalimantan, which retain three-quarters (3.9 million ha) of the remaining peatswamp forests in Southeast Asia.
    Matched MeSH terms: Trees/growth & development*
  19. Hwang WH, Shen TJ
    Biometrics, 2010 Dec;66(4):1052-60.
    PMID: 20002401 DOI: 10.1111/j.1541-0420.2009.01371.x
    Many well-known methods are available for estimating the number of species in a forest community. However, most existing methods result in considerable negative bias in applications, where field surveys typically represent only a small fraction of sampled communities. This article develops a new method based on sampling with replacement to estimate species richness via the generalized jackknife procedure. The proposed estimator yields small bias and reasonably accurate interval estimation even with small samples. The performance of the proposed estimator is compared with several typical estimators via simulation study using two complete census datasets from Panama and Malaysia.
    Matched MeSH terms: Trees*
  20. Newbery DM, Kennedy DN, Petol GH, Madani L, Ridsdale CE
    Philos. Trans. R. Soc. Lond., B, Biol. Sci., 1999 Nov 29;354(1391):1763-82.
    PMID: 11605620
    Changes in species composition in two 4-ha plots of lowland dipterocarp rainforest at Danum, Sabah, were measured over ten years (1986-1996) for trees > or = 10 cm girth at breast height (gbh). Each included a lower-slope to ridge gradient. The period lay between two drought events of moderate intensity but the forest showed no large lasting responses, suggesting that its species were well adapted to this regime. Mortality and recruitment rates were not unusual in global or regional comparisons. The forest continued to aggrade from its relatively (for Sabah) low basal area in 1986 and, together with the very open upper canopy structure and an abundance of lianas, this suggests a forest in a late stage of recovery from a major disturbance, yet one continually affected by smaller recent setbacks. Mortality and recruitment rates were not related to population size in 1986, but across subplots recruitment was positively correlated with the density and basal area of small trees (10-< 50cm gbh) forming the dense understorey. Neither rate was related to topography. While species with larger mean gbh had greater relative growth rates (rgr) than smaller ones, subplot mean recruitment rates were correlated with rgr among small trees. Separating understorey species (typically the Euphorbiaceae) from the overstorey (Dipterocarpaceae) showed marked differences in change in mortality with increasing gbh: in the former it increased, in the latter it decreased. Forest processes are centred on this understorey quasi-stratum. The two replicate plots showed a high correspondence in the mortality, recruitment, population changes and growth rates of small trees for the 49 most abundant species in common to both. Overstorey species had higher rgrs than understorey ones, but both showed considerable ranges in mortality and recruitment rates. The supposed trade-off in traits, viz slower rgr, shade tolerance and lower population turnover in the understorey group versus faster potential growth rate, high light responsiveness and high turnover in the overstorey group, was only partly met, as some understorey species were also very dynamic. The forest at Danum, under such a disturbance-recovery regime, can be viewed as having a dynamic equilibrium in functional and structural terms. A second trade-off in shade-tolerance versus drought-tolerance is suggested for among the understorey species. A two-storey (or vertical component) model is proposed where the understorcy-overstorey species' ratio of small stems (currently 2:1) is maintained by a major feedback process. The understorey appears to be an important part of this forest, giving resilience against drought and protecting the overstorey saplings in the long term. This view could be valuable for understanding forest responses to climate change where drought frequency in Borneo is predicted to intensify in the coming decades.
    Matched MeSH terms: Trees*
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