Water relations of oak species growing in the natural CO<sub>2</sub> spring of Rapolano (central Italy)

Tognetti, Roberto; Giovannelli, Alessio; Longobucco, A; Miglietta, Franco; Raschi, A.

doi:10.1051/forest:19960229

Cited by 42 publications

(29 citation statements)

References 13 publications

(15 reference statements)

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“…Osmotic [3] might allow them to maintain higher relative water content and turgor pressure [ 15], thus being able to sustain growth and metabolism during drought [20]. Contrasting results are, however, reported in the literature [21].…”

Section: Introductioncontrasting

confidence: 50%

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Responses of two Populus clones to elevated atmospheric CO₂ concentration in the field

Tognetti¹,

Longobucco

Raschi³

et al. 1999

Ann. For. Sci.

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Section: Introductioncontrasting

confidence: 50%

“…As a result of the increase in assimilation rate and decrease in leaf transpiration, ITE [21] for American sycamore and sweetgum, and some effects for sugar maple seedlings. In contrast, Morse et al [15] and Tognetti et al [20] reported a lowering of …”

Section: Introductionmentioning

confidence: 82%

Responses of two Populus clones to elevated atmospheric CO₂ concentration in the field

Tognetti¹,

Longobucco

Raschi³

et al. 1999

Ann. For. Sci.

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“…In mid-summer, clearly after anthesis, little fruits will fatten if their water status (cell turgor) is suitable. When the water potential falls below -3.2 to -3.5 MPa, which is close to the turgor loss point for holm oak [32], the lack of cell turgor and the accumulation of abscisic acid and ethylene can stop the development of fruits and cause them to fall [4].…”

Section: Discussionmentioning

confidence: 99%

Influence of pruning and the climatic conditions on acorn production in holm oak (Quercus ilex L.) dehesas in SW Spain

et al. 2008

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-Acorn production by Quercus ilex L. ssp. ballota (Desf.) Samp. in SW Spain was assessed, and variations between years and the influence of pruning on it were examined. To this end, an experimental study was conducted at two different sites (Calañas and San Bartolomé, in the province of Huelva) where trees were subjected to traditional (light, moderate or heavy) pruning and also to a new (crown-regeneration) pruning method. Acorn yield was quantified over a period of 5 years in the Calañas plot and 4 in the San Bartolomé plot, and found to average at 95.61 ± 0.76 g DM/m 2 , which is equivalent to 6.5 ± 0.05 kg DM/tree; however, yield figures varied markedly between years depending on the particular climatic conditions. The average acorn production was correlated with the water potential in mid summer (end of July); the annual, spring and autumn rainfall; and the actual evapotranspiration for the period from September (previous year) to August. No significant differences in acorn production between traditional pruning intensities were detected; in fact, there were only hints that heavy pruning might result in decreased acorn yields. The new pruning method used, crown-regeneration, seems promising with a view to increasing acorn yield; however, it should be tested on larger sample sizes before any final conclusions can be drawn in this respect. Based on the results, the present health status of holm oaks in southwestern Spain (a result of sustained decline) and the low value of firewood -which used to be a very important source of income from pruning a few decades ago -, the authors recommend reducing the frequency and intensity of pruning in the dehesas of the study area.holm oak / acorn production / pruning / masting Résumé -Influence de la taille et des conditions climatiques sur la production de glands par le chêne vert (Quercus ilex L.) en dehesas dans le sud ouest de l'Espagne. La production de glands par Quercus ilex L. ssp. ballota (Desf.) Samp. dans le sud ouest de l'Espagne a été mesurée, et l'influence de la taille sur les variations interannuelles a été examinée. Dans ce but, une étude expérimentales a été conduite dans deux sites (Calañas et San Bartolomé dans la province de Huelva) où des arbres ont été soumis à une taille traditionnelle (légère, modérée ou forte) et aussi à une nouvelle méthode de taille (régénération de couronne). La production de glands a été quantifiée sur une période de 5 ans sur le site de Calañas et de 4 ans sur celui de San Bartolomé et était en moyenne de 95,61 ± 0,76 g de matière sèche/m 2 , ce qui équivaut à 6,5 ± 0,05 kg de matière sèche/arbre. Cependant la production a varié de façon marquée entre années en relation avec les particularités climatiques. La moyenne de production de glands était corrélée avec le potentiel hydrique au milieu de l'été (fin juillet) ; avec les précipitations annuelles, du printemps et de l'automne, et avec l'évapotranspiration pour les périodes allant de septembre (année précédente) à août. Aucune différence significative de productio...

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“…Thus consistent changes in the rainfall or temperature regime, rather than in CO # , might be necessary before differences in tree-ring growth become evident, because of the reduced soil-water depletion at the CO # -enriched site. Furthermore, studies of Q. ilex and Q. pubescens at another CO # spring (called ' Bossoleto ') have indicated that the decrease in stomatal conductance caused by elevated CO # may be less evident during severe summer drought stress at high vapour pressure deficits (Tognetti et al, 1996(Tognetti et al, , 1998b(Tognetti et al, , 1999 than during periods of relatively low drought stress (Chaves et al, 1995). Quercus ilex and Q. pubescens also showed a lower foliage area at the corresponding sapwood area under elevated CO # (Tognetti et al, 1998b(Tognetti et al, , 1999.…”

Section: mentioning

confidence: 99%

Comparative stem‐growth rates of Mediterranean trees under background and naturally enhanced ambient CO₂ concentrations

Tognetti¹,

Cherubini²,

Innes³

2000

New Phytologist

145

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 Ring widths of five Mediterranean forest tree species (Arbutus unedo, Fraxinus ornus, Quercus cerris, Quercus ilexand Quercus pubescens) growing close to a natural source of CO # in Tuscany, Italy and at a nearby control site were compared. At the CO # -enriched site, trees have been growing for decades under elevated CO # concentrations. They originated from parent trees that also grew under elevated CO # in natural conditions, and they have been continuously exposed to elevated CO # throughout their growth. Tree-ring series from each of the species were prepared. Assigning calendar dates to rings was difficult but possible, and ring-width series were built for all species. The ring-width data were analysed using a two-sided t-test to assess if there was a difference between the radial growth at the CO # -enriched site and the control site. The cumulative basal area at the same cambial age at both sites was also compared using a Wilcoxon test. Radial growth of trees at the CO # -enriched site was not significantly different from growth at the control site. For each species, year by year, radial growth at the CO # -enriched site was tested against the control site and significant differences were found in only a few years ; these differences were not synchronous with extreme climatic events. The expected increase in above-ground productivity, as one of the ecosystem responses to increasing CO # during drought stress, was not observed in this Mediterranean woody plant community, despite being water-limited. Other resource limitations, such as low nutrient availability (common in the Mediterranean region), may have counteracted the positive effect of elevated CO # under drought stress, or trees may have acclimated to the high CO # .

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Water relations of oak species growing in the natural CO₂ spring of Rapolano (central Italy)

Abstract: Summary — The effect of elevated atmospheric carbon dioxide on water relations was examined on downy oak (Quercus pubescens) and holm oak (Q ilex)

Cited by 42 publications

References 13 publications

Responses of two Populus clones to elevated atmospheric CO₂ concentration in the field

Responses of two Populus clones to elevated atmospheric CO₂ concentration in the field

Influence of pruning and the climatic conditions on acorn production in holm oak (Quercus ilex L.) dehesas in SW Spain

Comparative stem‐growth rates of Mediterranean trees under background and naturally enhanced ambient CO₂ concentrations

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Water relations of oak species growing in the natural CO2 spring of Rapolano (central Italy)

Abstract: Summary — The effect of elevated atmospheric carbon dioxide on water relations was examined on downy oak (Quercus pubescens) and holm oak (Q ilex)

Cited by 42 publications

References 13 publications

Responses of two Populus clones to elevated atmospheric CO2 concentration in the field

Responses of two Populus clones to elevated atmospheric CO2 concentration in the field

Influence of pruning and the climatic conditions on acorn production in holm oak (Quercus ilex L.) dehesas in SW Spain

Comparative stem‐growth rates of Mediterranean trees under background and naturally enhanced ambient CO2 concentrations

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Water relations of oak species growing in the natural CO₂ spring of Rapolano (central Italy)

Responses of two Populus clones to elevated atmospheric CO₂ concentration in the field

Responses of two Populus clones to elevated atmospheric CO₂ concentration in the field

Comparative stem‐growth rates of Mediterranean trees under background and naturally enhanced ambient CO₂ concentrations