scholarly journals Summer-drought constrains the phenology and growth of two coexisting Mediterranean oaks with contrasting leaf habit: implications for their persistence and reproduction

Trees ◽  
2009 ◽  
Vol 23 (4) ◽  
pp. 787-799 ◽  
Author(s):  
Gabriel Montserrat-Martí ◽  
Jesús Julio Camarero ◽  
Sara Palacio ◽  
Carmen Pérez-Rontomé ◽  
Rubén Milla ◽  
...  
Keyword(s):  
Summer Drought ◽  
Leaf Habit ◽  
Mediterranean Oaks

Contrasting functional strategies following severe drought in two Mediterranean oaks with different leaf habit: Quercus faginea and Quercus ilex subsp. rotundifolia

2020 ◽  
Author(s):  
David Alonso-Forn ◽  
José Javier Peguero-Pina ◽  
Juan Pedro Ferrio ◽  
Maurizio Mencuccini ◽  
Óscar Mendoza-Herrer ◽  
...  
Keyword(s):  
Life Span ◽  
Quercus Ilex ◽  
Soil Water Potential ◽  
Leaf Life Span ◽  
Severe Drought ◽  
Summer Drought ◽  
Drought Period ◽  
Quercus Faginea ◽  
Leaf Habit ◽  
Mediterranean Oaks

Abstract Nowadays, evergreen sclerophyllous and winter-deciduous malacophyllous oaks with different paleogeographical origins coexist under Mediterranean-type climates, such as the mixed forests of the evergreen Quercus ilex subsp. rotundifolia Lam. and the winter-deciduous Quercus faginea Lam. Both Mediterranean oaks constitute two examples of contrasting leaf habit, so it could be expected that they would have different functional strategies to cope with summer drought. In this study, we analysed photosynthetic, photochemical and hydraulic traits of different organs for Q. faginea and Q. ilex subsp. rotundifolia under well-watered conditions and subjected to very severe drought. The coordinated response between photosynthetic and hydraulic traits explained the higher photosynthetic capacity of Q. faginea under well-watered conditions, which compensated its shorter leaf life span at the expense of higher water consumption. The progressive imposition of water stress evidenced that both types of Mediterranean oaks displayed different functional strategies to cope with water limitations. Specifically, the decrease in mesophyll conductance associated with edaphic drought seems to be the main factor explaining the differences found in the dynamics of net CO2 assimilation throughout the drought period. The sharp decline in photosynthetic traits of Q. faginea was coupled with a strong decrease in shoot hydraulic conductance in response to drought. This fact probably avoided extensive xylem embolism in the stems (i.e., ‘vulnerability segmentation’), which enabled new leaf development after drought period in Q. faginea. By contrast, leaves of Q. ilex subsp. rotundifolia showed effective photoprotective mechanisms and high resistance to drought-induced cavitation, which would be related with the longer leaf life span of the evergreen Mediterranean oaks. The co-occurrence of both types of Mediterranean oaks could be related to edaphic conditions that ensure the maintenance of soil water potential above critical values for Q. faginea, which can be severely affected by soil degradation and climate change.

scholarly journals Effects of a nursery CO2enriched atmosphere on the germination and seedling morphology of two Mediterranean oaks with contrasting leaf habit

New Forests ◽  
2004 ◽  
Vol 28 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Pilar Cortes ◽  
Josep Maria Espelta ◽  
Robert Savé ◽  
Carme Biel
Keyword(s):  
Seedling Morphology ◽  
Leaf Habit ◽  
Mediterranean Oaks

scholarly journals Response to natural and simulated browsing of two Mediterranean oaks with contrasting leaf habit after a wildfire

2006 ◽  
Vol 63 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Josep Maria Espelta ◽  
Abdessamad Habrouk ◽  
Javier Retana
Keyword(s):  
Leaf Habit ◽  
Mediterranean Oaks ◽  
Simulated Browsing

Co-occurrence of trees with different leaf habit: A functional approach on Mediterranean oaks

1998 ◽  
Vol 19 (3) ◽  
pp. 195-204 ◽  
Author(s):  
Claire Damesin ◽  
Serge Rambal ◽  
Richard Joffre
Keyword(s):  
Functional Approach ◽  
Leaf Habit ◽  
Mediterranean Oaks

White clover sensitivity to UV-B radiation - biochemical relationships and interaction with drought

2003 ◽  
pp. 273-277
Author(s):  
R.W. Hofmann ◽  
B.D. Campbell ◽  
E.E. Swinny ◽  
S.J. Bloor ◽  
K.R. Markham ◽  
...  
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Ultraviolet B ◽  
Summer Drought ◽  
Stress Protection ◽  
Trade Offs ◽  
Population Comparisons ◽  
Potential Benefits ◽  
Quercetin Glycosides ◽  
Balance Trade

During summertime in New Zealand, white clover experiences high levels of ultraviolet-B (UV-B) radiation. This frequently coincides with periods of summer drought. We investigated responses to UV-B and to the combination of UV-B and drought in various white clover populations, including New Zealand cultivars and ecotypes as well as overseas germplasm. The results were obtained under controlled environmental conditions in three independent trials. Overall, white clover growth was reduced by UV-B. The population comparisons indicated that low growth rate and adaptation to other forms of stress may be related to UV-B tolerance under well-watered conditions, but not during extended periods of drought. Flavonoid pigments that are involved in stress protection were strongly increased under UV-B and were further enhanced in the combination of UV-B and drought. The responses among these flavonoids were highly specific, with more pronounced UV-B-induced increases in quercetin glycosides, compared to their closely related kaempferol counterparts. UV-B toler ance of the less productive white clover populations was linked to the accumulation of quercetin compounds. In conclusion, these studies suggest (i) that slow-growing white clover ecotypes adapted to other stresses have higher capacity for biochemical acclimation to UV-B under well-watered conditions and (ii) that these biochemical attributes may also contribute to decreased UV-B sensitivity across white clover populations under drought. The findings alert plant breeders to potential benefits of selecting productive germplasm for high levels of specific flavonoids to balance trade-offs between plant productivity and stress tolerance. Keywords: Drought, flavonoids, genetic variation, HPLC, kaempferol, quercetin, str ess, Trifolium repens L., ultraviolet-B, white clover

scholarly journals The Role of Recent (1985–2014) Patterns of Land Abandonment and Environmental Factors in the Establishment and Growth of Secondary Forests in the Iberian Peninsula

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 817
Author(s):  
Marina Palmero-Iniesta ◽  
Josep Maria Espelta ◽  
Mario Padial-Iglesias ◽  
Òscar Gonzàlez-Guerrero ◽  
Lluís Pesquer ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Iberian Peninsula ◽  
Forest Cover ◽  
Secondary Forest ◽  
Forest Growth ◽  
Deciduous Forests ◽  
Secondary Forests ◽  
Study Region ◽  
Leaf Habit ◽  
Forest Establishment

Farmland abandonment has been a widespread land-use change in the Iberian Peninsula since the second half of the 20th century, leading to the establishment of secondary forests across the region. In this study, we aimed to address changes in the recent (1985–2014) emergence patterns of these forests and examine how environmental factors affected their growth by considering differences in leaf-habit types. We used a combination of Landsat-derived land-cover maps and aboveground biomass (AGB) maps from the European Space Agency to assess the secondary forest establishment and growth, respectively, in the study region. We also obtained a set of topographic, climatic and landscape variables from diverse GIS layers and used them for determining changes over time in the environmental drivers of forest establishment and AGB using general linear models. The results highlight that secondary forest cover was still increasing in the Iberian Peninsula at a rate above the European average. Yet, they also indicate a directional change in the emergence of secondary forests towards lower and less steep regions with higher water availability (mean rainfall and SPEI) and less forest cover but are subjected to greater drought events. In addition, these environmental factors differentially affect the growth of forests with different leaf-habit types: i.e., needleleaf secondary forests being less favoured by high temperature and precipitation, and broadleaf deciduous forests being most negatively affected by drought. Finally, these spatial patterns of forest emergence and the contrasting responses of forest leaf-habits to environmental factors explained the major development of broadleaf evergreen compared to broadleaf deciduous forests and, especially, needleleaf secondary forests. These results will improve the knowledge of forest dynamics that have occurred in the Iberian Peninsula in recent decades and provide an essential tool for understanding the potential effects of climate warming on secondary forest growth.

scholarly journals Regeneration dynamics in fragmented landscapes at the leading edge of distribution: Quercus suber woodlands as a study case

2021 ◽  
Author(s):  
Jorge Luis Montero-Muñoz ◽  
Carmen Ureña ◽  
Diego Navarro ◽  
Valentín Herrera ◽  
Pilar Alonso-Rojo ◽  
...  
Keyword(s):  
Tree Growth ◽  
Quercus Suber ◽  
Forest Recovery ◽  
Tree Cover ◽  
Distribution Area ◽  
Soil Parameters ◽  
Old Fields ◽  
Summer Drought ◽  
Regeneration Dynamics ◽  
Positive Effect

Abstract Aims We studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by Quercus suber in its lower limits of rainfall and temperature. Two hypotheses were established: (1) regeneration of Quercus species is strongly favored by the presence of tree cover; and (2) growth of Q. suber is driven by the climatic variables that represent the lower ecological limit of its leading distribution edge. Methods We selected woodlands and old fields with and without tree remnants (n = 3 per type), and analyzed stand structure, soil parameters and tree growth. Results Succession was arrested in old fields without tree remnants. By contrast, remnant trees were accelerators of forest recovery in old fields. Tree cover played a fundamental role in Quercus recruitment throughout seed dispersal and facilitation that mitigate the effects of summer drought on seedlings. Also, tree cover improved soil parameters (e.g., organic matter) that are important factors for understanding differences in regeneration. Winter/spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September. Conclusions Regeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of Q. suber where Q. ilex is increasing in abundance. Although temperature has a positive effect on the tree growth of Q. suber, when demographic processes are considered, decreases in water availability likely play a critical role in Q. ilex recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.

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