Carbon-use strategies in stem radial growth of two oak species, one Temperate deciduous and one Mediterranean evergreen: what can be inferred from seasonal variations in the δ13C of the current year ring?

2019 ◽  
Vol 39 (8) ◽  
pp. 1329-1341
Author(s):  
Cécile Vincent-Barbaroux ◽  
Daniel Berveiller ◽  
Caroline Lelarge-Trouverie ◽  
Rodrigo Maia ◽  
Cristina Máguas ◽  
...  

Abstract Tree ring synthesis is a key process in wood production; however, little is known of the origin and fate of the carbon involved. We used natural 13C abundance to investigate the carbon-use process for the ring development in a temperate deciduous (Quercus petraea (Matt.) Liebl.) and a Mediterranean evergreen (Quercus ilex L.) oak. The sapwood carbon reserves, phloem sucrose contents, stem respired CO2 efflux and their respective carbon isotope compositions (δ13C) were recorded over 1 year, in the native area of each species. The seasonal δ13C variation of the current year ring was determined in the total ring throughout the seasons, as well as in slices from the fully mature ring after the growth season (intra-ring pattern). Although the budburst dates of the two oaks were similar, the growth of Quercus ilex began 50 days later. Both species exhibited growth cessation during the hot and dry summer but only Q. ilex resumed in the autumn. In the deciduous oak, xylem starch storage showed clear variations during the radial growth. The intra-ring δ13C variations of the two species exhibited similar ranges, but contrasting patterns, with an early increase for Q. petraea. Comparison between δ13C of starch and total ring suggested that Q. petraea (but not Q. ilex) builds its rings using reserves during the first month of growth. Shifts in ring and soluble sugars δ13C suggested an interspecific difference in either the phloem unloading or the use of fresh assimilate inside the ring. A decrease in ring δ13C for both oaks between the end of the radial growth and the winter is attributed to a lignification of ring cell walls after stem increment. This study highlighted the differences in carbon-use during ring growth for evergreen and deciduous oaks, as well as the benefits of exploring the process using natural 13C abundance.

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2985
Author(s):  
Martin Kubov ◽  
Peter Fleischer ◽  
Jozef Rozkošný ◽  
Daniel Kurjak ◽  
Alena Konôpková ◽  
...  

European oak species have long been considered relatively resistant to different disturbances, including drought. However, several recent studies have reported their decline initiated by complex changes. Therefore, we compared mature sessile oak trees (Quercus petraea (Matt.), Liebl.) infested versus non-infested by hemiparasitic yellow mistletoe (Loranthus europaeus Jacq.) during the relatively dry vegetation season of 2019. We used broad arrays of ecophysiological (maximal assimilation rate Asat, chlorophyll a fluorescence, stomatal conductance gS, leaf morphological traits, mineral nutrition), growth (tree diameter, height, stem increment), and water status indicators (leaf water potential Ψ, leaf transpiration T, water-use efficiency WUE) to identify processes underlying vast oak decline. The presence of mistletoe significantly reduced the Ψ by 1 MPa, and the WUE by 14%. The T and gS of infested oaks were lower by 34% and 38%, respectively, compared to the non-infested oaks, whereas the Asat dropped to 55%. Less pronounced but significant changes were also observed at the level of photosystem II (PSII) photochemistry. Moreover, we identified the differences in C content, which probably reduced stem increment and leaf size of the infested trees. Generally, we can conclude that mistletoe could be a serious threat that jeopardizes the water status and growth of oak stands.


2020 ◽  
Vol 66 (No. 2) ◽  
pp. 49-62
Author(s):  
Anna Prokůpková

The paper deals with the effect of environmental factors and management on various mixed lowland forests in the Medník National Natural Monument, Czech Republic, over a 20-year period. The objectives were to evaluate the structure, production, dynamics and radial growth in relation to climatic conditions in the mixed hornbeam-oak, herb-rich beech and spruce forest stands. The tree density decreased by 8.5% (to 120–1,364 trees·ha<sup>–1</sup>), while stand volume increased by 28.0% (to 244–767 m<sup>3</sup>·ha<sup>–1</sup>) from 1998 to 2018. Large-leaved lime (Tilia platyphyllos Scop.) and Norway spruce (Picea abies /L./ Karst.) showed high variability and sensitivity to climatic factors in radial growth compared to stability and resistance in sessile oak (Quercus petraea /Matt./ Liebl.) and European beech (Fagus sylvatica L.). April, June and July were determined as the most significant months in relation to diameter increment. The synergism of precipitation deficit and high air temperature was a limiting factor of growth in the studied lowland area. The frequency of negative pointer years with extremely low radial growth has been increasing recently. Generally, hornbeam-oak stands are characterized by rich structure, high density and lower productivity, herb-rich beech stands represent rich structured productive forests and spruce forests are very productive stands but with low ecological stability.


Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 250
Author(s):  
Kristine Vander Mijnsbrugge ◽  
Arion Turcsán ◽  
Éva Erdélyi ◽  
Hans Beeckman

Background and Objectives: Studying responses in woody plants upon water limitation is gaining importance due to the predicted increase in frequency and intensity of droughts in Europe. We studied the variation in radial growth and in wood anatomical traits caused by water limited growth conditions in offspring from Quercus petraea (Matt.) Liebl., Q. robur L. and their morphological intermediates grown in the same environment. Materials and Methods: Cross sections were prepared from the stems of 210 three-year-old potted seedlings, comprising control plants and seedlings that experienced from late spring until early autumn of the first growing season two sequential periods of water with-holding each followed by plentiful re-watering. Pith radius, ring width of the three growing seasons and latewood vessel diameter in second and third growing season were measured. Presence of intra-annual density fluctuations, dendritic patterns of latewood vessels and the level of ring closure of earlywood vessels were observed. The traits were modelled to examine the explanatory power of the taxon of the mother tree and the drought treatment. Results: Most of the traits displayed significant differences between offspring from Q. petraea and Q. robur and offspring from the morphological intermediates behaved inconsistent among the traits. Most of the traits were significantly affected by the drought stress in the first growing season. Apart from radial growth, also latewood vessel size was reduced in the two growing seasons following the year in which drought was imposed on the seedlings, suggesting an adaptation to improve the tolerance to drought stress. We also found an indication for a compensation growth mechanism, counteracting the lost growing time during the drought stress, as the level of ring closure of the earlywood vessels in the year following the drought treatment was further advanced in the treated seedlings, an effect that disappeared in the subsequent year. Conclusion: Oaks exposed to drought adapt their growth and xylem structure to improve drought resistance. While youth growth of Q. robur is more competition-oriented, with a faster juvenile growth, Q. petraea seems to invest more in a precautious growth, being more prepared for stressful conditions. It is therefore possible that Q. robur seedlings may suffer more from intensified droughts than Q. petraea seedlings.


2009 ◽  
Vol 34 (-1) ◽  
pp. 49-56 ◽  
Author(s):  
Daniel Patón ◽  
Ricardo García-Herrera ◽  
Javier Cuenca ◽  
Mamen Galavis ◽  
Fidel Roig

Influence of Climate on Radial Growth of Holm Oaks (Quercus Ilex Subsp. Ballota Desf) from SW SpainA total of 47 trunk sections from Holm Oak (Quercus ilex subsp. ballota Desf) trees growing at two different sites at the Extremadura region (SW Spain) were considered in the computation of a regional tree-ring chronology useful to interpret the tree-ring/Mediterranean climate relationships. This is the first dendroclimatological research of Holm Oaks conducted to reveal its potential use as a climatic proxy. The obtained tree-ring chronologies were compared with climatic parameters based on monthly, seasonal and annual rainfall, and monthly maximum, minimum and average temperature. The best correlations were obtained with maximum temperatures during the period between previous winter and early spring. Influence of rainfall was less relevant. Growth of this species indicates a typical bimodal (spring and autumn) strategy that avoids low winter temperatures and summer drought. Despite some technical difficulties recognizing tree rings in Holm Oaks, its good sensitivity to climate variability and its wide distribution and longevity (~800 years), allow us to consider this species as a good candidate for temperature reconstructions in the Mediterranean Basin.


2020 ◽  
Vol 40 (5) ◽  
pp. 621-636
Author(s):  
Sara Palacio ◽  
Eric Paterson ◽  
Alison J Hester ◽  
Salvador Nogués ◽  
Gladys Lino ◽  
...  

Abstract Herbivory is one of the most globally distributed disturbances affecting carbon (C)-cycling in trees, yet our understanding of how it alters tree C-allocation to different functions such as storage, growth or rhizodeposition is still limited. Prioritized C-allocation to storage replenishment vs growth could explain the fast recovery of C-storage pools frequently observed in growth-reduced defoliated trees. We performed continuous 13C-labeling coupled to clipping to quantify the effects of simulated browsing on the growth, leaf morphology and relative allocation of stored vs recently assimilated C to the growth (bulk biomass) and non-structural carbohydrate (NSC) stores (soluble sugars and starch) of the different organs of two tree species: diffuse-porous (Betula pubescens Ehrh.) and ring-porous (Quercus petraea [Matt.] Liebl.). Carbon-transfers from plants to bulk and rhizosphere soil were also evaluated. Clipped birch and oak trees shifted their C-allocation patterns above-ground as a means to recover from defoliation. However, such increased allocation to current-year stems and leaves did not entail reductions in the allocation to the rhizosphere, which remained unchanged between clipped and control trees of both species. Betula pubescens and Q. petraea showed differences in their vulnerability and recovery strategies to clipping, the ring-porous species being less affected in terms of growth and architecture by clipping than the diffuse-porous. These contrasting patterns could be partly explained by differences in their C cycling after clipping. Defoliated oaks showed a faster recovery of their canopy biomass, which was supported by increased allocation of new C, but associated with large decreases in their fine root biomass. Following clipping, both species recovered NSC pools to a larger extent than growth, but the allocation of 13C-labeled photo-assimilates into storage compounds was not increased as compared with controls. Despite their different response to clipping, our results indicate no preventative allocation into storage occurred during the first year after clipping in either of the species.


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