Leaf phenology correlates with fruit production in European beech (Fagus sylvatica) and in temperate oaks (Quercus robur and Quercus petraea)

Author(s):  
Valentin Journé ◽  
Thomas Caignard ◽  
Andrew Hacket-Pain ◽  
Michał Bogdziewicz
2004 ◽  
Vol 34 (11) ◽  
pp. 2340-2350 ◽  
Author(s):  
Gary Kerr

The effects of mixing ash (Fraxinus excelsior L.) with cherry (Prunus avium L.), oak (Quercus petraea (Matt.) Lieb., and Quercus robur L.), and beech (Fagus sylvatica L.) were investigated using a balanced two-component competition experiment. In general, two patterns of growth were observed. Firstly, in the ash–cherry experiment, two rapidly growing species altered their stem form and showed a plastic response to interspecific competition, and both species maintained a position in the upper canopy. Secondly, in the ash–oak and ash–beech experiments, a two-tier canopy formed with ash in the upper canopy, and interspecific competition resulted in an early nursing effect on the ash. In both patterns of growth, competition affected stem diameter and the shape of the tree with few, and only short-lived, effects on height. The maximum relative yield totals were 1.78 for ash–cherry, 1.77 for ash–oak, and 1.44 for ash–beech, indicating that the mixtures studied may be more productive in their early phase of growth than equivalent areas of pure species.


2016 ◽  
Author(s):  
Ylva Persson ◽  
Guy Schurgers ◽  
Riikka Rinnan ◽  
Thomas Holst

Abstract. English oak (Quercus robur) and European beech (Fagus sylvatica) are amongst the most common tree species growing in Europe, influencing the annual Biogenic Volatile Organic Compound (BVOC) budget in this region. Studies have shown great variability in the emissions from these tree species, originating from both genetic variability and differences in climatic conditions between study sites. In this study, we examine the emission patterns for English oak and European beech in genetically identical individuals and the potential variation within and between sites. Leaf scale BVOC emissions, net assimilation rates and stomatal conductance were measured at the International Phenological Garden sites of Ljubljana (Slovenia), Grafrath (Germany) and Taastrup (Denmark). Sampling was conducted during three campaigns between May and July 2014. Our results show that English oak mainly emitted isoprene whilst European beech released monoterpenes. The relative contribution of the most emitted compounds from the two species remained stable across latitudes. The contribution of isoprene for English oak from Grafrath and Taastrup ranged between 92–97 % of the total BVOC emissions, whilst sabinene and limonene for European beech ranged between 30.5–40.5 % and 9–15 % respectively for all three sites. The relative contribution of isoprene for English oak at Ljubljana was lower (78 %) in comparison to the other sites, most likely caused by frost damage in early spring. The variability in total leaf-level emission rates from the same site was small, whereas there were greater differences between sites. These differences were probably caused by short-term weather events and plant stress. A difference in age did not seem to affect the emission patterns for the selected trees. This study highlights the significance of within-genotypic variation of BVOC emission capacities for English oak and European beech, the influence of climatic variables such as temperature and light on emission intensities and the potential stability in relative compound contribution across a latitudinal gradient.


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