Leaf and Simulated Whole‐Canopy Photosynthesis in Two Co‐Occurring Tree Species

Hollinger, David Y.

doi:10.2307/1938716

Cited by 66 publications

(49 citation statements)

References 26 publications

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“…The highest N mass values were in deciduous trees and the lowest values were among grasses, forbs, and evergreen chaparral species. This pattern is consistent with other studies (29)(30)(31), and is likely linked to species differences and to environmental variation. Deciduous trees at Jasper Ridge tend to grow in mesic or wet environments, whereas evergreen shrub species tend to be found in more xeric conditions, where light is abundant but water is limiting.…”

supporting

confidence: 93%

“…Low W L values were found, again, among grasses, followed by in evergreen woody plants including Quercus agrifolia and Adenostoma fasciculatum. Although we expected W L in June to be a reflection of early drought stress and access to perennial water sources, there was a rare heavy rain event on June 4, 2011 (immediately preceding data collection), so patterns in leaf water content are likely more similar to what would be expected earlier in the year (30).…”

mentioning

confidence: 93%

“…Deciduous trees at Jasper Ridge tend to grow in mesic or wet environments, whereas evergreen shrub species tend to be found in more xeric conditions, where light is abundant but water is limiting. Evergreen plants are able to assimilate carbon for more of the year, however, and so they may accrue similar amounts of carbon annually, meaning that lower rates of photosynthesis and lower N mass do not necessarily indicate a competitive disadvantage (30). The low N mass values in grasses and forbs (from 0.52% to 0.74%) are likely a result of grass senescence, given that the sampling and flight took place in early June; a previous study of N mass in Jasper Ridge grasslands in April found higher concentrations and no difference between serpentine and sandstone substrates (32).…”

mentioning

confidence: 99%

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Environmental and community controls on plant canopy chemistry in a Mediterranean-type ecosystem

Dahlin

Asner

Field

2013

Proc. Natl. Acad. Sci. U.S.A.

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Understanding how and why plant communities vary across space has long been a goal of ecology, yet parsing the relative importance of different influences has remained a challenge. Species-specific models are not generalizable, whereas broad plant functional type models lack important detail. Here we consider plant trait patterns at the local scale and ask whether plant chemical traits are more closely linked to environmental gradients or to changes in species composition. We used the visible-to-shortwave infrared (VSWIR) spectrometer of the Carnegie Airborne Observatory to develop maps of four plant chemical traits—leaf nitrogen per mass, leaf carbon per mass, leaf water concentration, and canopy water content—across a diverse Mediterranean-type ecosystem (Jasper Ridge Biological Preserve, CA). For all four traits, plant community alone was the strongest predictor of trait variation (explaining 46–61% of the heterogeneity), whereas environmental gradients accounted for just one fourth of the variation in the traits. This result emphasizes the critical role that species composition plays in mediating nutrient and carbon cycling within and among different communities. Environmental filtering and limits to similarity can act strongly, simultaneously, in a spatially heterogeneous environment, but the local-scale environmental gradients alone cannot account for the variation across this landscape.

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confidence: 93%

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confidence: 93%

mentioning

confidence: 99%

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Environmental and community controls on plant canopy chemistry in a Mediterranean-type ecosystem

Dahlin

Asner

Field

2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Hollinger (1992) used just such a framework, combining data on leaf photosynthesis, transpiration, and nitrogen use by oaks in Californian savannas with calculations of water and nutrient availability in the rooting zone to predict that deciduous Quercus lobata should dominate areas with high resource densities, while evergreen Q. agrifolia should dominate drier, less fertile areas. But even this approach, based on maximizing canopy photosynthesis, falls a bit short -it is not clear what limits the soil area exploited by individual trees in a savanna, and the belowground costs of roots used to obtain water and nutrients are ignored.…”

Section: Top-down Modelsmentioning

confidence: 99%

Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox

2002

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Patterns in the dominance of evergreen vs. deciduous plants have long interested ecologists, biogeographers, and global modellers. But previous models to account for these patterns have signifi cant weaknesses. Bottom-up, mechanistic models -based on physiology, competition, and natural selection -have often been non-quantitative or restricted to a small range of habitats, and almost all have ignored belowground costs and whole-plant integration. Top-down, ecosystem-based models have succeeded in quantitatively reproducing several patterns, but rely partly on empirically derived constants and thresholds that lack a mechanistic explanation. It is generally recognized that seasonal drought can favor deciduous leaves, and that infertile soils can favor long-lived evergreen leaves. But no model has yet explained three great paradoxes, involving dominance by 1) evergreens in highly seasonal, boreal forests, 2) deciduous larch in many nutrient-poor peatlands, and 3) evergreen leaf-exchangers in nutrient-poor subtropical forests, even though they shed their leaves just as frequently as deciduous species. This paper outlines a generalized optimality model to account for these and other patterns in leaf longevity and phenology, based on maximizing whole-plant carbon gain or height growth, and building on recent advances in our understanding of the quantitative relationships of leaf photosynthesis, nitrogen content, and mass per unit area to leaf life-span. Only a whole-plant approach can explain evergreen dominance under realistic ecological conditions, or account for the boreal paradox, the larch paradox, the leaf-exchanger paradox, and expected shifts in shade tolerance associated with leaf phenology. Poor soils favor evergreens not merely by increasing the costs of nutrient acquisition, but also by depressing the maximum rate of photosynthesis and thus the seasonal contrast in photosynthetic return between leaves adapted to favorable vs. unfavorable conditions. The dominance of evergreens in western North America beyond the coastal zone of mild winters and winter rainfall appears related to the unusually long photosynthetic season for evergreen vs. deciduous plants there. Future models for optimal leaf phenology must incorporate differences between evergreen and deciduous plants in allocation to photosynthetic vs. non-photosynthetic tissue, rooting depth, stem allometry, xylem anatomy, and exposure to herbivores and leaching, and analyze how these differences interact with the photosynthetic rate, transpiration, and nutrient demands of leaves with different life-spans to affect rates of height growth in specifi c microsites.

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“…A área foliar e a variável derivada "índice de área foliar"(IAF) são determinantes da produtividade ) e do consumo de água da vegetação (Macfarlane et al, 2000), de vez que participam na interceptação da radiação solar e nas trocas energéticas e gasosas, afetando a transpiração (Angelocci & Valancogne, 1993;Coelho Filho et al, 2004;, a evaporação da água no solo (Allen et al, 1998) e a fotossíntese (Hollinger, 1992).…”

Section: Introductionunclassified

Método para estimativa do IAF de árvores isoladas ou de plantações com dossel fechado

Filho

Nova²,

Angelocci³

et al. 2012

Rev. bras. eng. agríc. ambient.

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R ESU M OObjetivou-se, com o presente trabalho, descrever e testar um método simplificado de baixo custo (IAF-LUX) para estimativa do índice de área foliar (IAF) em comparação com um equipamento comercial (LAI-2000, Li-Cor ® ). Ambos foram avaliados em um seringal e em árvores de lima ácida "Tahiti"; posteriormente, os dois métodos foram comparados com medidas destrutivas de área foliar realizadas em uma árvore adulta de lima ácida 'Tahiti'; notou-se, então, que os desvios dos resultados pelo IAF-LUX em relação aos do LAI-2000 foram no máximo de 7,4% na seringueira e de 3,6% em lima ácida "Tahiti". A estimativa da área foliar total utilizando-se o LAI 2000, mostrou boa concordância com as medidas diretas; resultados semelhantes foram obtidos com o IAF-LUX (5% de erro). Para as condições em que foi desenvolvido o trabalho os métodos com base em medida de radiação apresentaram boa precisão na estimativa da área foliar total das árvores de lima ácida, ficando patente que este método pode substituir vantajosamente as outras técnicas usadas, em comparação pelo baixo custo do equipamento, pela facilidade de operação no campo e análise dos dados. Palavras-chave: LAI-2000, luxímetro, citros, Hevea sppMethod to estimate the LAI for isolated trees and continuous canopy crops A B ST R A C T This paper aimed to describe and evaluate a low-cost simplified method (IAF-LUX method) for leaf area index (LAI) estimation, in comparison with well-tested commercial equipment (LAI-2000, Li-Cor®), being both applied for a rubber tree plantation and for a 'Tahiti' acid lime orchard. Later, the results of the both methods were also compared with destructive measurements of leaf area carried out in other 'Tahiti' acid lime adult tree. Considering LAI-2000 as reference, the proposed IAF-LUX method showed deviations of 7.4% for rubber tree and 3.6% for acid lime 'Tahiti'. Comparing the IAF-LUX with destructive measurements, a deviation of 5.0% was observed in acid lime, while LAI-2000 showed deviation of 7.0%. Based on these results, it is concluded that the IAF-LUX method may be used for determining leaf area in the two species, replacing advantageously the other destructive or non-destructive techniques because it is of low cost, easily operated and non-destructive procedure.

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Leaf and Simulated Whole‐Canopy Photosynthesis in Two Co‐Occurring Tree Species

Cited by 66 publications

References 26 publications

Environmental and community controls on plant canopy chemistry in a Mediterranean-type ecosystem

Environmental and community controls on plant canopy chemistry in a Mediterranean-type ecosystem

Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox

Método para estimativa do IAF de árvores isoladas ou de plantações com dossel fechado

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