Root distribution and seasonal water status in weathered granitic bedrock under chaparral

Sternberg, Paul D.; Anderson, Michael A.; Graham, Robert C.; Beyers, Jan L.; Tice, Kathy R.

doi:10.1016/0016-7061(96)00019-5

Cited by 84 publications

(73 citation statements)

References 14 publications

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“…Based on this water budget, we conclude that 66 mm of water, or 57% of the total, came from other sources. We surmise that a significant fraction of moisture probably came from below the fractured shale layer, supporting the measurements of Lewis and Burgy (1964) and Sternberg et al (1996). But we cannot discount a loss of water from the boles of the trees because we measured significant shrinkage with weekly dendrometer band measurements.…”

Section: Evaporation and Soil Moisturesupporting

confidence: 73%

“…To survive across the hot dry summer in Mediterranean climates, many grass species adopt an annual life cycle and transmit their genetic information in the form of seed. Trees, growing adjacent to (or over) grasses, tap deeper sources of soil water (Lewis and Burgy, 1964;Griffin, 1973;Ehleringer and Dawson, 1992;Sternberg et al, 1996) or they can remedy soil moisture deficits through hydraulic lift (Ishikawa and Bledsoe, 2000). They also have the physiological capacity to withstand severe soil water deficits (Griffin, 1988).…”

Section: Introductionmentioning

confidence: 99%

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How plant functional-type, weather, seasonal drought, and soil physical properties alter water and energy fluxes of an oak–grass savanna and an annual grassland

Baldocchi

Kiang

2004

Agricultural and Forest Meteorology

534

415

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Savannas and open grasslands often co-exist in semi-arid regions. Questions that remain unanswered and are of interest to biometeorologists include: how do these contrasting landscapes affect the exchanges of energy on seasonal and annual time scales; and, do biophysical constraints imposed by water supply and water demand affect whether the land is occupied by open grasslands or savanna? To address these questions, and others, we examine how a number of abiotic, biotic and edaphic factors modulate water and energy flux densities over an oak-grass savanna and an annual grassland that coexist in the same climate but on soils with different hydraulic properties.The net radiation balance was greater over the oak woodland than the grassland, despite the fact that both canopies received similar sums of incoming short and long wave radiation. The lower albedo and lower radiative surface temperature of the transpiring woodland caused it to intercept and retain more long and shortwave energy over the course of the year, and particularly during the summer dry period.The partitioning of available energy into sensible and latent heat exchanged over the two canopies differed markedly. The annual sum of sensible heat exchange over the woodland was 40% greater than that over the grassland (2.05 GJ m −2 per year versus 1.46 GJ m −2 per year). With regards to evaporation, the oak woodland evaporated about 380 mm of water per year and the grassland evaporated about 300 mm per year. Differences in available energy, canopy roughness, the timing of physiological functioning, water holding capacity of the soil and rooting depth of the vegetation explained the observed differences in sensible and latent heat exchange of the contrasting vegetation surfaces.The response of canopy evaporation to diminishing soil moisture was quantified by comparing normalized evaporation rates (in terms of equilibrium evaporation) with soil water potential and volumetric water content measurements. When soil moisture was ample normalized values of latent heat flux density were greater for the grassland (1.1-1.2) than for the oak savanna (0.7-0.8) and independent of moisture content. Normalized rates of evaporation over the grassland declined as volumetric water content dropped below 0.15 m 3 m −3 , which corresponded with a soil water potential of −1.5 MPa. The grassland senesced and quit transpiring when the volumetric water content of the soil dropped below −2.0 MPa. The oak trees, on the other hand, were able to transpire, albeit at low rates, under very dry soil conditions (soil water potentials below −4.0 MPa). The trees were able to endure such low water potentials and maintain basal levels of metabolism because * Corresponding author. Baldocchi et al. / Agricultural and Forest Meteorology 123 (2004) ecological forcings kept the tree density and leaf area index of the woodland low, physiological factors forced the stomata to close progressively and the trees were able to tap deeper water sources (below 0.6 m) than the grasses.

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Section: Evaporation and Soil Moisturesupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

How plant functional-type, weather, seasonal drought, and soil physical properties alter water and energy fluxes of an oak–grass savanna and an annual grassland

Baldocchi

Kiang

2004

Agricultural and Forest Meteorology

534

415

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show abstract

“…However, the specific depths to which tree roots penetrate vary with precipitation, potential evapotranspiration, and tree species (Gale and Grigal, 1987;Schenk and Jackson, 2002a, b). The depth of root penetration also varies with the thickness and properties of soil, and the characteristics of bedrock (Kochenderfer, 1973;Stone and Kalisz, 1991;Anderson et al, 1995;Sternberg et al, 1996;Hubbert et al, 2001a, b;Witty et al, 2003;Bornyasz et al, 2005;Nicoll et al, 2006;Graham et al, 2010).…”

Section: Form Function and Distribution Of Tree Rootsmentioning

confidence: 99%

Reviews and syntheses: on the roles trees play in building and plumbing the critical zone

et al. 2017

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Abstract. Trees, the most successful biological power plants on earth, build and plumb the critical zone (CZ) in ways that we do not yet understand. To encourage exploration of the character and implications of interactions between trees and soil in the CZ, we propose nine hypotheses that can be tested at diverse settings. The hypotheses are roughly divided into those about the architecture (building) and those about the water (plumbing) in the CZ, but the two functions are intertwined. Depending upon one's disciplinary background, many of the nine hypotheses listed below may appear obviously true or obviously false. (1) Tree roots can only physically penetrate and biogeochemically comminute the immobile substrate underlying mobile soil where that underlying substrate is fractured or pre-weathered. (2) In settings where the thickness of weathered material, H , is large, trees primarily shape the CZ through biogeochemical reactions within the rooting zone. (3) In forested uplands, the thickness of mobile soil, h, can evolve toward a steady state because of feedbacks related to root disruption and tree throw. (4) In settings where h H and the rates of uplift and erosion are low, the uptake of phosphorus into trees is buffered by the fine-grained fraction of the soil, and the ultimate source of this phosphorus is dust. (5) In settings of limited water availability, trees maintain the highest length density of functional roots at depths where water can be extracted over most of the growing season with the least amount of energy expenditure. (6) Trees grow the majority of their roots in the zone where the most growth-limiting resource is abundant, but they also grow roots at other depths to forage for other resources and to hydraulically redistribute those resources to depths where they can be taken up more efficiently. (7) Trees rely on matrix water in the unsaturated zone that at times may have anPublished by Copernicus Publications on behalf of the European Geosciences Union. 5116 S. L. Brantley et al.: Reviews and syntheses: on the roles trees play in building and plumbing the critical zone isotopic composition distinct from the gravity-drained water that transits from the hillslope to groundwater and streamflow. (8) Mycorrhizal fungi can use matrix water directly, but trees can only use this water by accessing it indirectly through the fungi. (9) Even trees growing well above the valley floor of a catchment can directly affect stream chemistry where changes in permeability near the rooting zone promote intermittent zones of water saturation and downslope flow of water to the stream. By testing these nine hypotheses, we will generate important new cross-disciplinary insights that advance CZ science.

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“…Em caso de solos pouco desenvolvidos, como os Neossolos em questão, a camada saprolítica assume importante papel ambiental, pois altera o crescimento e desenvolvimento da vegetação e os fluxos hídricos no perfil (Schafer et al, 1979;Lietzke & Weber, 1981;Stolt & Baker, 1994;Sternberg et al, 1996;Pedron et al, 2009;Stürmer et al, 2009). Entretanto, a falta de informações sobre aspectos morfológicos, químicos, físicos e mineralógicos desses materiais saprolíticos, no Brasil, tem contribuído para o uso inadequado dos Neossolos, especialmente os mais rasos, e sua consequente degradação.…”

Section: Introductionunclassified

Hydraulic conductivity and water retention in leptosols-regosols and saprolite derived from sandstone, Brazil

Pedron

Fink²,

Rodrigues³

et al. 2011

Rev. Bras. Ciênc. Solo

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Root distribution and seasonal water status in weathered granitic bedrock under chaparral

Cited by 84 publications

References 14 publications

How plant functional-type, weather, seasonal drought, and soil physical properties alter water and energy fluxes of an oak–grass savanna and an annual grassland

How plant functional-type, weather, seasonal drought, and soil physical properties alter water and energy fluxes of an oak–grass savanna and an annual grassland

Reviews and syntheses: on the roles trees play in building and plumbing the critical zone

Hydraulic conductivity and water retention in leptosols-regosols and saprolite derived from sandstone, Brazil

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