Gas exchange and water relations of evergreen and deciduous tropical savanna trees

Goldstein, G.; Rada, Fermín; Rundel, Philip W.; Azócar, Aura; Orozco, A.

doi:10.1051/forest:198905art0100

Cited by 40 publications

(41 citation statements)

References 3 publications

(2 reference statements)

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“…Similar results for γ have been observed in previous field (e.g., [40,41]), and modeling studies (e.g., [16]). This parametric optimization allows the ASRL model to adjust estimates of canopy geometry, energy absorption/transmission, and hydrological absorption capacity for each study site.…”

Section: Predicted Tree Heights At the Site Scalesupporting

confidence: 78%

Allometric Scaling and Resource Limitations Model of Tree Heights: Part 3. Model Optimization and Testing over Continental China

Park

Choi

et al. 2014

Remote Sensing

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Abstract:The ultimate goal of our multi-article series is to demonstrate the Allometric Scaling and Resource Limitation (ASRL) approach for mapping tree heights and biomass. This third article tests the feasibility of the optimized ASRL model over China at both site (14 meteorological stations) and continental scales. Tree heights from the Geoscience Laser Altimeter System (GLAS) waveform data are used for the model optimizations. Three selected ASRL parameters (area of single leaf, α; exponent for canopy radius, η; and OPEN ACCESS Remote Sens. 2014, 6 3534 root absorption efficiency, γ) are iteratively adjusted to minimize differences between the references and predicted tree heights. Key climatic variables (e.g., temperature, precipitation, and solar radiation) are needed for the model simulations. We also exploit the independent GLAS and in situ tree heights to examine the model performance. The predicted tree heights at the site scale are evaluated against the GLAS tree heights using a two-fold cross validation (RMSE = 1.72 m; R 2 = 0.97) and bootstrapping (RMSE = 4.39 m; R 2 = 0.81). The modeled tree heights at the continental scale (1 km spatial resolution) are compared to both GLAS (RMSE = 6.63 m; R 2 = 0.63) and in situ (RMSE = 6.70 m; R 2 = 0.52) measurements. Further, inter-comparisons against the existing satellite-based forest height maps have resulted in a moderate degree of agreements. Our results show that the optimized ASRL model is capable of satisfactorily retrieving tree heights over continental China at both scales. Subsequent studies will focus on the estimation of woody biomass after alleviating the discussed limitations.

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Section: Predicted Tree Heights At the Site Scalesupporting

confidence: 78%

Allometric Scaling and Resource Limitations Model of Tree Heights: Part 3. Model Optimization and Testing over Continental China

Park

Choi

et al. 2014

Remote Sensing

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“…While Gartner et al (1990) and Sobrado (1993Sobrado ( , 1997 reported that deciduous species were capable of higher rates of water transport, others have shown evergreen species to be more hydraulically efficient (Goldstein et al 1987(Goldstein et al , 1989. In more recent work, Brodribb et al (2002 demonstrated a substantial overlap of hydraulic traits between evergreen and deciduous species from a Costa Rican dry forest.…”

Section: Introductionmentioning

confidence: 93%

Hydraulic architecture of deciduous and evergreen dry rainforest tree species from north-eastern Australia

Choat

Ball

Luly

et al. 2004

Trees

198

166

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Hydraulic conductivity and xylem anatomy were examined in stems of two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret., and two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., from a seasonally dry rainforest in north Queensland, Australia. The deciduous species possessed hydraulic architecture typical of drought-sensitive plants, i.e. low wood density, wider xylem vessels, higher maximal rates of sapwood specific hydraulic conductivity (K s ) and high vulnerability to drought-induced embolism. In contrast, the evergreen species had lower rates of K h and leaf specific conductivity (K L ) but were less susceptible to embolism. The evergreen species experienced leaf water potentials <−4.0 MPa during the dry season, while the deciduous species shed their leaves before leaf water potentials declined below −2.0 MPa. Thus, the hydraulic architecture of the evergreens allows them to withstand the greater xylem pressure gradients required to maintain water transport to the canopy during the dry season. Our results are consistent with observations made in neotropical dry forests and demonstrate that drought-deciduous species with low wood density and high water storage capacity are

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“…Water availability is spatially heterogeneous for an individual species within a location [72]. For example, evergreen and deciduous plants in dry regions have different root systems and water use efficiencies (evergreen > deciduous as in [73,74]). Kempes et al [14] have demonstrated an improvement of the ASRL model based on optimization of γ that generated a lower variance in the model error.…”

Section: Optimized Asrl Model Predictionsmentioning

confidence: 99%

Allometric Scaling and Resource Limitations Model of Tree Heights: Part 1. Model Optimization and Testing over Continental USA

Shi

Choi

et al. 2013

Remote Sensing

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A methodology to generate spatially continuous fields of tree heights with an optimized Allometric Scaling and Resource Limitations (ASRL) model is reported in this first of a multi-part series of articles. Model optimization is performed with the Geoscience Laser Altimeter System (GLAS) waveform data. This methodology is demonstrated by mapping tree heights over forested lands in the continental USA (CONUS) at 1 km spatial resolution. The study area is divided into 841 eco-climatic zones based on three forest types, annual total precipitation classes (30 mm intervals) and annual average temperature classes (2 °C intervals). Three model parameters (area of single leaf, α, exponent for canopy radius, η, and root absorption efficiency, γ) were selected for optimization, that is, to minimize the difference between actual and potential tree heights in each of the eco-climatic zones over the CONUS. Tree heights predicted by the optimized model were evaluated against GLAS heights using a two-fold cross validation approach (R 2 = 0.59; RMSE = 3.31 m). Comparison at the pixel level between GLAS heights (mean = 30.6 m; standard deviation = 10.7) and model predictions (mean = 30.8 m; std. = 8.4) were also performed. Further, the model predictions were compared to existing satellite-based forest height maps. The optimized ASRL model satisfactorily reproduced the pattern of tree heights over the CONUS. Subsequent articles in this series will document further improvements with the ultimate goal of mapping tree heights and forest biomass globally.

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Gas exchange and water relations of evergreen and deciduous tropical savanna trees

Cited by 40 publications

References 3 publications

Allometric Scaling and Resource Limitations Model of Tree Heights: Part 3. Model Optimization and Testing over Continental China

Allometric Scaling and Resource Limitations Model of Tree Heights: Part 3. Model Optimization and Testing over Continental China

Hydraulic architecture of deciduous and evergreen dry rainforest tree species from north-eastern Australia

Allometric Scaling and Resource Limitations Model of Tree Heights: Part 1. Model Optimization and Testing over Continental USA

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