A comparative analysis of foliar chemical composition and leaf construction costs of beech (Fagus sylvatica L.), sycamore maple (Acer pseudoplatanus L.) and ash (Fraxinus excelsior L.) saplings along a light gradient Any Mary Petritan, Burghard von Lüpke, Ion Catalin Petritan To cite this version: Any Mary Petritan, Burghard von Lüpke, Ion Catalin Petritan. A comparative analysis of foliar chemical composition and leaf construction costs of beech (Fagus sylvatica L.), sycamore maple (Acer pseudoplatanus L.) and ash (Fraxinus excelsior L.) saplings along a light gradient. Annals of Forest Sci- ence, Springer Nature (since 2011)/EDP Science (until 2010), 2010, 67 (6), 10.1051/forest/2010023. hal-00883638 HAL Id: hal-00883638 https://hal.archives-ouvertes.fr/hal-00883638 Submitted on 1 Jan 2010 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Ann. For. Sci. 67 (2010) 610 Available online at: c INRA, EDP Sciences, 2010 www.afs-journal.org DOI: 10.1051/forest/2010023 Original article A comparative analysis of foliar chemical composition and leaf construction costs of beech (Fagus sylvatica L.), sycamore maple (Acer pseudoplatanus L.) and ash (Fraxinus excelsior L.) saplings along a light gradient AnyMaryPetritan1,2*, Burghard von Lupke¨ 1, Ion Catalin Petritan1 1 Department of Silviculture and Forest Ecology of the Temperate Zones, Georg-August University Göttingen, Büsgenweg 1, 37077 Göttingen, Germany 2 Department of Silviculture and Forest Ecology, Institute of Forest Research and Management, Closca 13, 500040 Brasov, Romania (Received 19 August 2009; accepted 1 December 2009) Keywords: Abstract leaf construction cost / • Construction cost (g glucose g−1), chemical composition and morphology of leaves of beech (Fagus foliar chemical composition / sylvatica L.) and two co-occurring valuable broadleaved species (sycamore maple – Acer pseudopla- shade tolerance / tanus L. – and ash – Fraxinus excelsior L.) were investigated along a horizontal light gradient (3–60% mixed species broad leaf stand / of above canopy radiation) and from top to bottom within the crowns in a fairly even-aged mixed- irradiance species thicket established by natural regeneration beneath a patchy shelterwood canopy. • Construction cost and carbon concentration increased with irradiance in ash and sycamore maple and were independent of irradiance in beech. Leaf traits expressed on an area basis, like construction cost, nitrogen content and leaf mass (LMA) increased significantly with irradiance in all three species and decreased from top to bottom within crowns. • The shade tolerant beech invested more glucose to produce a unit foliar biomass, but less to build a unit foliar area due to lower LMA. Thereby beech was able to display a greater total leaf area, what at least in parts counterbalanced the lower values of Na as compared to ash and sycamore maple. 1. INTRODUCTION gNm−2) and lower photosynthetic capacity per unit leaf area (Frak et al., 2001; Le Roux et al., 2001). Na generally is pos- Among the various growth factors, light plays an outstandig itively related to irradiance and by this also to crown posi- role in forests, at least on mesic sites in temperate regions tion. It increases within the crown from bottom to top (Kull (Kimmins, 1997), and it can easily be manipulated by silvi- and Niinemets, 1993; Niinemets, 1995). Ellsworth and Reich cultural means (Röhrig et al., 2006). One of the most respon- (1993) observed an increase of Na and photosynthetic capac- sive traits to light change is leaf morphology. Particularly the ity within the canopy from bottom to top in an 18-m tall Acer measure “leaf mass per unit leaf area” (LMA, g m−2)orits saccharum stand and explained this pattern as a direct conse- inverse “specific leaf area” (SLA, m2 g−1) is know as an ap- quence of the vertical variation of LMA since leaf N concen- propiate acclimation to enhance the carbon assimilation poten- tration per unit mass was independent of canopy position. The tial of plants: higher LMA enables increased carbon acquisi- authors consider the observed LMA distribution pattern within tion in high light, while lower LMA improves light harvesting the canopy as responsible for an up to 45% higher photosyn- in low light (Niinemets and Tenhunen, 1997). LMA increases thetic yield as compared with a homogeneous distribution. with increasing irradiance, a reaction which most plants – if Irradiance may also influence the proportion of carbon in- not all – show in such a pronounced manner that LMA even vested in structural components in leaves. Niinemets and Kull has been proposed as a suitable species-specific estimator of (1998) found that lignin concentrations increased at the ex- long term light climate (Niinemets, 1997). The modification pense of cellulose and hemicellulose with increasing irradi- in leaf morphology is further accompanied by changes in fo- ance. Inasmuch as lignin contains more carbon than cell wall liar chemistry (Niinemets, 1999). A lower LMA in low light polysaccharides, and as carbon concentration and the ener- −1 is coupled with lower nitrogen content per unit leaf area (Na, getic costs of foliage construction (CC, g glucose g ,Vertregt and Penning de Vries, 1987) are directly linked, Niinemets * Corresponding author: [email protected] (1999) assumed that leaf construction requires more energy Article published by EDP Sciences Ann. For. Sci. 67 (2010) 610 A.M. Petritan et al. with increasing irradiance. But reports on the response of CC tion costs and leaf chemical modifications. For this test we to varying irradiance are not consistent. Whereas some authors phrased the following hypotheses: found CC to be lower at high light (Sims and Pearcy, 1994), others show higher values at high light (Barthod and Epron, (1) along a natural horizontal light gradient we espect that 2005; Niinemets, 1999;Poorteretal.,2006). leaves of saplings growing under high light have higher construction costs (CC), higher carbon content and higher All these morphological and physiological leaf acclimation nitrogen content per unit area (Na) than leaves of saplings to varying irradiance are thought to contribute to shade toler- growing in shade; ance of tree species. In an exhaustive review Valladares and (2) the variation of foliar nitrogen content and leaf construc- Niinemets (2008) stated that shade tolerance is a “complex, tion cost within a crown from base to top is comparable ff multifaceted property of plants that is achieved by di erent with that of the horizontal light gradient; ff suites of traits in di erent species”. They analysed key points (3) under common light conditions, beech as our most shade and supporting evidence of the two major hypotheses regard- tolerant species has higher leaf construction cost (CC), ing the suites of traits responsible for species’ shade toler- higher leaf carbon content and lower leaf nitrogen content ance: (i) efficiency of carbon gain in low light (Givnish, 1988) (Na) than the less shade tolerant sycamore maple and ash. and (ii) stress tolerance in understorey conditions (Kitajima, 1994). An extension of the first hyphothesis on carbon gain ff is a assumed trade-o between a high survival rate under low 2. MATERIALS AND METHODS light and high growth in high-light (Kobe et al., 1995). In a previous study (Petri¸tan et al., 2007) carried out on saplings in 2.1. Study site mixed-stands of sycamore maple (Acer pseudoplatanus), ash (Fraxinus excelsior) and beech (Fagus sylvatica) we took this The study was carried out in a mixed deciduous stand with an hypothesis as a basis and found that beech showed the highest overstory of 120 year old beech (Fagus sylvatica), hornbeam (Carpi- survivorship in shade and the lowest growth rate in high-light nus betulus), ash (Fraxinus excelsior), sycamore maple (Acer pseudo- and hence could be ranked as shade-tolerant. For sycamore platanus), Norway maple (Acer platanoides),andsessileoak(Quer- maple and ash the same criteria led to a ranking as mid-tolerant cus petraea), located in the community forest Wibbecke, near Göt- species. Another companion study, covering a more extended tingen (Lower Saxony, Germany, 10◦ 02 11 E, 51◦ 34 46 N). The light gradient (3–60% of above canopy radiation), confirmed site is characterized by shallow limestone plateau with rendzina soil these shade-tolerance ranks (Petri¸tan et al., 2009). Beech had a or partly haplic luvisol, rich in nutrient supply, but rather poor in wa- greater specific leaf area (SLA), greater total leaf area per unit ter supply during dry periods in summer. Altitude above sea level tree height, and showed the greatest plasticity in traits that im- ranges from 151 to 200 m, mean annual rainfall is 780 mm (370 mm prove leaf display in shade, like plagiotropy or a sturdier leaf in the growing season), and average annual temperature is 7, 8 ◦C. support system. Ash and sycamore maple showed a marked 20–30 y ago natural regeneration started. Within the last 10 y no har- and constant increase in growth rates with increasing irradi- vesting or silvicultural interventions have been carried out. Thus, we ance and an inability to strongly reduce their growth rates in can assume fairly stable canopy conditions in the overstory during deep shade. They displayed most of their leaf area at the top this period. The canopy closure is patchy, ranging from fully closed of the crown, while beech displayed its leaves along the entire parts to large gaps. Thus, it provides a broad gradient of light condi- tree height.