Annual budget and seasonal variation of aboveground and belowground net primary productivity in a lowland dipterocarp forest in Borneo

Kho, Lip Khoon; Malhi, Yadvinder; Tan, Sylvester

doi:10.1002/jgrg.20109

Cited by 40 publications

(62 citation statements)

References 107 publications

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“…In tropical forests, strong spatiotemporal variation in these losses makes quantifying and tracking them highly challenging. Illustrating this variation are the contrasting losses from two 1 ha plots in a Borneo forest in each of three intervals (LAMBIR site; Kho et al, 2013; Table 11). Tropicalforest disturbance regimes predominantly involve frequent small-scale canopy gaps (< 150 m 2 ) caused by branchfalls or treefalls; larger forest openings from storms, blowdowns, or extreme drought are increasingly rare in time and space as these disturbances increase in size (Chambers et al, 2013;Gloor et al, 2009;Magnabosco Marra et al, 2014;Marvin et al, 2014;di Vittorio et al, 2014).…”

Section: Tree Mortalitymentioning

confidence: 99%

“…A study in the central Amazon combining remote sensing and ground observations (di Vittorio et al, 2014) found mortality losses to follow a power-law distribution with disturbed area, up to and including the region's extremely large blowdowns; these researchers concluded that the biomass losses observed solely in existing plots would be an inaccurate indicator (biased low) of landscape-scale dynamics. A separate compli- Kho et al (2013). cation is the disproportionate influence on biomass stocks from the deaths of scattered very large trees. In French Guianan old-growth forest (Rutishauser et al, 2010), such tree deaths were found to largely drive the heterogeneity in biomass dynamics among plots and through time.…”

Section: Tree Mortalitymentioning

confidence: 99%

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Reviews and syntheses: Field data to benchmark the carbon cycle models for tropical forests

et al. 2017

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Abstract. For more accurate projections of both the global carbon (C) cycle and the changing climate, a critical current need is to improve the representation of tropical forests in Earth system models. Tropical forests exchange more C, energy, and water with the atmosphere than any other class of land ecosystems. Further, tropical-forest C cycling is likely responding to the rapid global warming, intensifying water stress, and increasing atmospheric CO 2 levels. Projections of the future C balance of the tropics vary widely among global models. A current effort of the modeling community, the IL-AMB (International Land Model Benchmarking) project, is to compile robust observations that can be used to improve the accuracy and realism of the land models for all major biomes. Our goal with this paper is to identify field observations of tropical-forest ecosystem C stocks and fluxes, and of their long-term trends and climatic and CO 2 sensitivities, that can serve this effort. We propose criteria for reference-level field data from this biome and present a set of documented examples from old-growth lowland tropical forests. We offer these as a starting point towards the goal of a regularly updated consensus set of benchmark field observations of C cycling in tropical forests.

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Section: Tree Mortalitymentioning

confidence: 99%

Section: Tree Mortalitymentioning

confidence: 99%

Reviews and syntheses: Field data to benchmark the carbon cycle models for tropical forests

et al. 2017

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“…Tropical rainforests in nearby south-east Asia often show little or no clear seasonal dynamics in canopy cover and productivity (Kho et al, 2013) but are well known for synchronous mast fruiting with a return frequency of around 2-10 years (Visser et al, 2011). The general flowering in these forests that is associated with these mast fruiting events has been shown to be triggered by irregular droughts (Sakai et al, 2006).…”

Section: Tropical Rainforestmentioning

confidence: 99%

Reviews and syntheses: Australian vegetation phenology: new insights from satellite remote sensing and digital repeat photography

et al. 2016

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Abstract. Phenology is the study of periodic biological occurrences and can provide important insights into the influence of climatic variability and change on ecosystems. Understanding Australia's vegetation phenology is a challenge due to its diverse range of ecosystems, from savannas and tropical rainforests to temperate eucalypt woodlands, semiarid scrublands, and alpine grasslands. These ecosystems exhibit marked differences in seasonal patterns of canopy development and plant life-cycle events, much of which deviates from the predictable seasonal phenological pulse of temperate deciduous and boreal biomes. Many Australian ecosystems are subject to irregular events (i.e. drought, flooding, cyclones, and fire) that can alter ecosystem composition, structure, and functioning just as much as seasonal change. We show how satellite remote sensing and ground-based digital repeat photography (i.e. phenocams) can be used to improve understanding of phenology in Australian ecosystems. First, we examine temporal variation in phenology on the continental scale using the enhanced vegetation index (EVI), calculated from MODerate resolution Imaging Spectroradiometer (MODIS) data. Spatial gradients are revealed, ranging from regions with pronounced seasonality in canopy development (i.e. tropical savannas) to regions where seasonal variation is minimal (i.e. tropical rainforests) or high but irregular (i.e. arid ecosystems). Next, we use time series colour information extracted from phenocam imagery to illustrate a range of phenological signals in four contrasting Australian ecosystems. These include greening and senescing events in tropical savannas and temperate eucalypt understorey, as well as strong seasonal dynamics of individual trees in a seemingly static evergreen rainforest. We also demonstrate how phenology links with ecosystem gross primary productivity (from eddy covariance) and discuss why these processes are linked in some ecosystems but not others. We conclude that phenocams have the potential to greatly improve the current understanding of Australian ecosystems. To facilitate the sharing of this information, we have formed the Australian Phenocam Network (http://phenocam.org.au/).

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“…Although much of the belowground allocation returns to the atmosphere relatively rapidly (80 % was lost as CO 2 within one year in a plantation in Hawaii; Giardina et al 2004), the belowground C flux can make a considerable contribution to the soil organic matter in some ecosystems (e.g., Clemmensen et al 2013). Root growth occurs mainly in the wet season in seasonal tropical forests, particularly during the transitions between seasons (Cavelier et al 1999;Kho et al 2013;Yavitt and Wright 2001), while fine root mortality occurs mainly during the dry season (Kummerow et al 1990). A study on Barro Colorado Island reported that dead fine roots disappear quickly (Yavitt and Wright 2001), so it is possible that death and decomposition of very fine roots and associated mycorrhizal fungi might contribute to the dry season decline in soil organic matter.…”

Section: Seasonal Dynamics Of Soil Organic Mattermentioning

confidence: 99%

Seasonal changes in soil organic matter after a decade of nutrient addition in a lowland tropical forest

Turner¹,

Yavitt

Harms

et al. 2015

Biogeochemistry

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Soil organic matter is an important pool of carbon and nutrients in tropical forests. The majority of this pool is assumed to be relatively stable and to turn over slowly over decades to centuries, although changes in nutrient status can influence soil organic matter on shorter timescales. We measured carbon, nitrogen, and phosphorus concentrations in soil organic matter and leaf litter over an annual cycle in a long-term nutrient addition experiment in lowland tropical rain forest in the Republic of Panama. Total soil carbon was not affected by a decade of factorial combinations of nitrogen, phosphorus, or potassium. Nitrogen addition increased leaf litter nitrogen concentration by 7 % but did not affect total soil nitrogen. Phosphorus addition doubled the leaf litter phosphorus concentration and increased soil organic phosphorus by 50 %. Surprisingly, concentrations of carbon, nitrogen, and phosphorus in soil organic matter declined markedly during the four-month dry season, and then recovered rapidly during the following wet season. Between the end of the wet season and the late dry season, total soil carbon declined by 16 %, total nitrogen by 9 %, and organic phosphorus by between 19 % in control plots and 25 % in phosphorus addition plots. The decline in carbon and nitrogen was too great to be explained by changes in litter fall, bulk density, or the soil microbial biomass. However, a major proportion of the dry-season decline in soil organic phosphorus was explained by a corresponding decline in the soil microbial biomass. These results have important implications for our understanding of the stability and turnover of organic matter in tropical forest soils, because they demonstrate that a considerable fraction of the soil organic matter is seasonally transient, despite the overall pool being relatively insensitive to long-term changes in nutrient status.

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Annual budget and seasonal variation of aboveground and belowground net primary productivity in a lowland dipterocarp forest in Borneo

Cited by 40 publications

References 107 publications

Reviews and syntheses: Field data to benchmark the carbon cycle models for tropical forests

Reviews and syntheses: Field data to benchmark the carbon cycle models for tropical forests

Reviews and syntheses: Australian vegetation phenology: new insights from satellite remote sensing and digital repeat photography

Seasonal changes in soil organic matter after a decade of nutrient addition in a lowland tropical forest

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