A revised hydrological model for the Central Amazon: The importance of emergent canopy trees in the forest water budget

Kunert, Norbert; Aparecido, L. M. T.; Wolff, Stefan; Higuchi, Níro; Santos, Joaquim dos; Araújo, Alessandro; Trumbore, Susan E.

doi:10.1016/j.agrformet.2017.03.002

Cited by 61 publications

(70 citation statements)

References 60 publications

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“…Overall, our E t estimate for mature rubber plantations in Sumatra (1.3 mm day −1 ) falls into the lower range of values provided from previous studies for tropical rainforests (1.3-2.6 mm day −1 ;Becker, 1996;Calder, Wright, & Murdiyarso, 1986;Kunert et al, 2017;McJannet, Fitch, Disher, & Wallace, 2007) and is much lower than estimates for Acacia plantations in Borneo (2.3 mm day −1Cienciala et al, 2000). Overall, our E t estimate for mature rubber plantations in Sumatra (1.3 mm day −1 ) falls into the lower range of values provided from previous studies for tropical rainforests (1.3-2.6 mm day −1 ;Becker, 1996;Calder, Wright, & Murdiyarso, 1986;Kunert et al, 2017;McJannet, Fitch, Disher, & Wallace, 2007) and is much lower than estimates for Acacia plantations in Borneo (2.3 mm day −1Cienciala et al, 2000).…”

supporting

confidence: 59%

Rubber tree transpiration in the lowlands of Sumatra

et al. 2017

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The expansion of rubber cultivation in Southeast Asia raises concerns about the integrity of the hydrological cycle. From mainland Asia, high evapotranspiration from rubber plantations was reported. Our study was conducted in the Sumatran lowlands (Indonesia), where rubber is grown by small holders under maritime climate. We assessed patterns of water use with sap flux methods, focusing on influences of tree age and size. We first tested a field measurement scheme in methodological experiments and subsequently applied it to 10 plots in monocultural rubber plantations. Among fully leaved, mature stands, maximum sap flux densities decreased with increasing tree diameter in 14-and 16-year-old plantations, but not in 7-and 8-year-old ones.Consequently, tree water use increased more steeply with increasing diameter in the younger than in the older plantations. In contrast to this, among the same five mature plantations, stand-scale transpiration decreased with increasing mean tree diameter and height. This was due to a negative linear relationship between diameter and stand density. Among seven fully leaved plantations, stand age explained 95% of the site-to-site variability in transpiration. Temporally, rubber transpiration showed pronounced seasonality due to leaf shedding. Transpiration in our study was substantially lower than in rubber plantations in mainland Asia; reasons include differences in methods, management, and climate. In Sumatra, rubber may be ecohydrologically less concerning than, for example, oil palm plantations, due to low transpiration and periodical leaf shedding. Our study endorses the importance of considering age, management, climate, and species in ecohydrological assessments of tropical plantation landscapes.

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confidence: 59%

Rubber tree transpiration in the lowlands of Sumatra

et al. 2017

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“…There are at least four likely ecological explanations for this finding. Also, recent studies have shown that a few large trees can account for a large proportion of ecosystem-level ET (Kunert et al, 2017), because of their large canopies, large stem storage capacity, and ability to take up deep soil water throughout much of the year (Nepstad et al, 1994). Our LiDAR measurements showed annual height growth reaching 2 m, a process probably requiring large amounts of water.…”

Section: Ecosystem Functionsmentioning

confidence: 52%

Prolonged tropical forest degradation due to compounding disturbances: Implications for CO₂ and H₂O fluxes

Brando

Silvério

Maracahipes‐Santos

et al. 2019

Global Change Biology

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Drought, fire, and windstorms can interact to degrade tropical forests and the ecosystem services they provide, but how these forests recover after catastrophic disturbance events remains relatively unknown. Here, we analyze multi‐year measurements of vegetation dynamics and function (fluxes of CO2 and H2O) in forests recovering from 7 years of controlled burns, followed by wind disturbance. Located in southeast Amazonia, the experimental forest consists of three 50‐ha plots burned annually, triennially, or not at all from 2004 to 2010. During the subsequent 6‐year recovery period, postfire tree survivorship and biomass sharply declined, with aboveground C stocks decreasing by 70%–94% along forest edges (0–200 m into the forest) and 36%–40% in the forest interior. Vegetation regrowth in the forest understory triggered partial canopy closure (70%–80%) from 2010 to 2015. The composition and spatial distribution of grasses invading degraded forest evolved rapidly, likely because of the delayed mortality. Four years after the experimental fires ended (2014), the burned plots assimilated 36% less carbon than the Control, but net CO2 exchange and evapotranspiration (ET) had fully recovered 7 years after the experimental fires ended (2017). Carbon uptake recovery occurred largely in response to increased light‐use efficiency and reduced postfire respiration, whereas increased water use associated with postfire growth of new recruits and remaining trees explained the recovery in ET. Although the effects of interacting disturbances (e.g., fires, forest fragmentation, and blowdown events) on mortality and biomass persist over many years, the rapid recovery of carbon and water fluxes can help stabilize local climate.

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“…Others have scaled transpiration to the stand using similar methods as ours (Bucci et al, ; Granier, Huc, & Barigah, ; Horna et al, ), for example, by using a range of tree diameters (Horna et al, ) or a range of crown dominance (Aparecido et al, ; Kunert et al, ). More commonly, though, measurements extend only to individual trees (Kunert et al, ; Meinzer, James, & Goldstein, ; O'Brien et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Although it is well known that climate gradients in montane environments amplify the spatial variability in species composition along ecotonal boundaries, the effect of species-specific differences on transpiration is less clearly understood. The few studies that address this in Neotropical forests have suggested that variation in transpiration is controlled less by species-specific differences than by physical tree attributes, including tree height and hydraulic architecture (Andrade et al, 1998;Kunert et al, 2017;Meinzer, Goldstein, & Andrade, 2001). Given many upscaling studies in temperate forests apportion transpiration within stands using species-specific sap flux estimates (Ewers et al, 2002;Granier & Lostau, 1994;Moore, Bond, Jones, Phillips, & Meinzer, 2004;Oren, Philips, Ewers, Pataki, & Megonigal, 1999), such approaches may be inappropriate in diverse tropical forests.…”

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confidence: 99%

Upscaling transpiration in diverse forests: Insights from a tropical premontane site

et al. 2017

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Upscaling water use of individual trees to stands using sap flux techniques is a common method for partitioning site water balance, but few such studies have occurred in the tropics. Increasing interests in the role of tropical forests in global cycles have spurred upscaling studies in natural tropical forests, which present challenges from greater tree species and functional diversity, and potential factors that would reduce transpiration, such as frequent cloud cover and wet canopy conditions. In a premontane wet tropical forest in central Costa Rica, sap flow was measured in 15 trees stratified into 5 size classes based on tree diameters. None of the trees belonged to the same species, genus, or even family. We also accounted for potential radial variation in sap flux density. Data were scaled to estimate transpiration within a small 2.2‐ha watershed using stand surveys of sapwood area. Stand transpiration averaged only 1.4 ± 0.7 mm day−1 within this forested watershed due to persistent low radiation, evaporative demand, and frequent wet canopy conditions. Our systematic approach used tree size attributes to scale water use to the stand, given difficulties to quantify species differences in such a diverse ecosystem. Contrary to previous evidence on temperate trees, the large trees sampled did not exhibit flow reductions in deeper sapwood, which warrants further study. These results highlight some unique aspects of measuring transpiration in wet tropical forests that are important to consider for future studies in diverse stands.

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A revised hydrological model for the Central Amazon: The importance of emergent canopy trees in the forest water budget

Cited by 61 publications

References 60 publications

Rubber tree transpiration in the lowlands of Sumatra

Rubber tree transpiration in the lowlands of Sumatra

Prolonged tropical forest degradation due to compounding disturbances: Implications for CO₂ and H₂O fluxes

Upscaling transpiration in diverse forests: Insights from a tropical premontane site

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A revised hydrological model for the Central Amazon: The importance of emergent canopy trees in the forest water budget

Cited by 61 publications

References 60 publications

Rubber tree transpiration in the lowlands of Sumatra

Rubber tree transpiration in the lowlands of Sumatra

Prolonged tropical forest degradation due to compounding disturbances: Implications for CO2 and H2O fluxes

Upscaling transpiration in diverse forests: Insights from a tropical premontane site

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Prolonged tropical forest degradation due to compounding disturbances: Implications for CO₂ and H₂O fluxes