Individual variation in acorn production by five species of southern Appalachian oaks

Greenberg, Cathryn H.

doi:10.1016/s0378-1127(99)00226-1

Cited by 117 publications

(141 citation statements)

References 14 publications

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“…Estimation of acorn production and acorn mass Acorns were harvested by a trapping method using containers (Greenberg 2000). Four containers (0.45 m diameter at the top) were placed on the soil under selected trees at the north, south, east, and west positions, at three-quarters of the distance from the stem to the edge of the crown.…”

Section: Experimental Locationsmentioning

confidence: 99%

Do ecological and silvicultural factors influence acorn mass in Holm Oak (southwestern Spain)?

et al. 2011

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The effect of orientation, location, year, and pruning treatment on mean acorn mass in two open woodland experimental locations (Huelva, South-Western Spain) of Holm Oak (Quercus ilex L. subsp. ballota [Desf.] Samp.) was analyzed during [2001][2002][2003][2004][2005][2006]. Data were analyzed by using a mixed linear model, where the covariates were tree size parameters (circumference at 80 cm height, crown size), topographic position (wet index and flow length), intraspecific competition, total acorn crops per tree (weight and number), and climatic parameters. Average estimated acorn mass was 3.17 g acorn -1 in the Calañas location and 4.12 g acorn -1 in the San Bartolomé location, with significant differences between locations, among individual trees and across years. Acorns from the south sides of trees were significantly heavier than those at other positions. The effect of pruning treatment and the interactions location 9 treatment and treatment 9 year were not significant. Our study provides no evidence that pruning affects acorn mass. None of the analyzed covariates related to tree size, topographic position and intraspecific competition explained the difference among trees, suggesting that heritable factors play an important role. Specific climatic parameters during September, the most important month for acorn growth, may explain the effects of year and location 9 year on acorn mass. In addition, there appeared to be a ''trade-off'' between acorn mass and number of acorns.

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Section: Experimental Locationsmentioning

confidence: 99%

Do ecological and silvicultural factors influence acorn mass in Holm Oak (southwestern Spain)?

et al. 2011

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“…Acorns were harvested by using a trapping method (containers) (see [6,12,13]). Four containers 0.45 m in diameter at the top were placed under the selected trees following the north, south, east and west directions at three-quarters of the crown radius distance from the base of the trees.…”

Section: Estimation Of Acorn Productionmentioning

confidence: 99%

“…In other Quercus forests, acorn production is also very important towards regeneration [13,14] since the amount and quality of the acorns obtained are crucial factors in the development of new holm oak stands [9,25]. However, the absence of regeneration in dehesas cannot be ascribed to a lack of acorns.…”

Section: Introductionmentioning

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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“…Commonly, in some oak species including the holm oak, there are trees that produce almost exclusively female flowers whereas other trees produce male flowers Greenberg, 2000). Within the genus Quercus two general patterns of acorn development have been described: annual and biennial.…”

Section: Flowering and Fruitingmentioning

confidence: 99%

“…Consequently, these studies leave out acorn size and weight, which are important in calculating acorn yields. There is high variation in seed size both within and across oak species (Sork, 1993;Greenberg, 2000). Some authors have suggested the hypothesis that woody species with longer intermast interval are likely to produce larger seeds, likely as an adaptation to increase seedling survival (Aizen and Woodcock, 1992;García et al, 2000;Sork, 1993).…”

Section: Acorn Size and Morphologymentioning

confidence: 99%

Acorn production in Spanish holm oak woodlands

2006

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We present a review on the state-of-the-art of fruit prodution in Western Iberia woodlands («dehesas»), and particularly in Q. ilex (holm oak) «dehesas». This threatened ecosystem is of very high ecological and economical importance. Quercus sp. fruits (acorns) are essential for wildlife, and for pig fattening in «dehesas». In the first part of this review we briefly describe the phenology of the holm oak and the factors affecting acorn morphology and chemical composition.In the second half we analyze the main known factors reported in the literature that determine acorn production: pruning, stand characteristics, and site (weather and soil). We make several suggestions to improve future research and detect the existing gaps in the undertanding of acorn production.Fruit production is highly variable, both between and within years and individuals. The mean production in «dehesas» (mean density circa 50 trees/ha) is around 250-600 kg/ha (≈100 g/canopy-m 2 , CV > 100%). Acorn morphology is also very variable, with mean sound acorn size around 3.5 × 1.6 cm, CV ≈ 10% (3.5 g/acorn, CV > 50%). Silviculture plays an essential role in acorn production. Acorn production per tree seems to be negatively related to density. The effect of pruning is less clear: production seems to be reduced in the first and second years after pruning. After the third year it is not possible to discern from the literature whether there is any response to pruning or not. Weather and soil (site) also impact production and their effects should be explored in future management. The influence of genetics is unknown and should also be addressed. Longer data series are necessary. The dasometric features of the stands need to be characterized, in order to better understand production and compare results from different locations. Much research is still required to understand the functioning of fruiting in these woodlands.Key words: Quercus ilex, holm oak, acorn, fruit production, dehesa, agrosilvopastoral systems. Resumen Producción de bellota en las dehesas españolas de encinaEl alto interés ecológico y económico de la producción de fruto en las dehesas ibéricas, concretamente las de encina (Quercus ilex), nos ha movido a realizar una revisión del estado actual de conocimientos. Los frutos (bellotas) de Quercus sp. resultan esenciales para la fauna salvaje y el engorde de ganado porcino en las dehesas. En la primera parte de este trabajo se describen brevemente las características fenológicas de la especie, así como los factores que influyen en la variabilidad morfológica y la composición bromatológica del fruto. En la segunda parte se analizan los factores fundamentales estudiados en la bibliografía que determinan la producción: la poda, las características dasométricas (densidad y distribución diamétrica) y la influencia del sitio (suelo y clima). Se realizan sugerencias para mejorar futuras líneas de trabajo, así como se subrayan áreas de conocimiento deficitarias.La producción es muy variable tanto intra-como interanualmente. La producció...

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Individual variation in acorn production by five species of southern Appalachian oaks

Cited by 117 publications

References 14 publications

Do ecological and silvicultural factors influence acorn mass in Holm Oak (southwestern Spain)?

Do ecological and silvicultural factors influence acorn mass in Holm Oak (southwestern Spain)?

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

Acorn production in Spanish holm oak woodlands

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