Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m2·g‐1) is used to convert dry leaf litter biomass (g·m‐2) into leaf area per ground unit area (m2·m‐2). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m2) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm2·g‐1. Nevertheless, no relationship was found between SLA and stand canopy closure or PAI. On the contrary, a significant relationship between SLA and soil properties was observed. Both SLA and leaf area had the lowest values in the most hydromorphic soil with the highest nitrogen content. On the other hand, the highest values of SLA and leaf area were observed on the plots with the lowest nitrogen content. This spatial variability of SLA was taken into account to estimate LAI from litter collected at eight plots. For our study site, we conclude that neglecting SLA spatial variability is at the source of 8‐24% error in the calculation of LAI.

[1]  K. Pregitzer,et al.  Leaf area and foliar biomass relationships in northern hardwood forests located along an 800 km acid deposition gradient , 1991 .

[2]  I. White,et al.  Using Ellenberg indicator values to assess soil quality in British forests from ground vegetation : a pilot study , 1997 .

[3]  C. Braak,et al.  Ecological amplitudes of plant species and the internal consistency of Ellenberg’s indicator values for moisture , 1987 .

[4]  F. Bussotti,et al.  Leaf morphology and macronutrients in broadleaved trees in central Italy , 2000, Trees.

[5]  John D. Aber,et al.  A Method for Estimating Foliage-Height Profiles in Broad-Leaved Forests , 1979 .

[6]  F. Goulet,et al.  Leaf morphology plasticity in response to light environment in deciduous tree species and its implication on forest succession , 1986 .

[7]  J. Pontailler,et al.  Validity of leaf areas and angles estimated in a beech forest from analysis of gap frequencies, using hemispherical photographs and a plant canopy analyzer , 1999 .

[8]  J. Vanseveren,et al.  Index foliaire, paramètres foliaires et caractéristiques édaphiques stationnelles dans quelques peuplements forestiers de Lorraine belge , 1977 .

[9]  E. Dufrene,et al.  Estimation of deciduous forest leaf area index using direct and indirect methods , 1995, Oecologia.

[10]  G. Minotta,et al.  Effects of light and soil fertility on growth, leaf chlorophyll content and nutrient use efficiency of beech (Fagus sylvatica L.) seedlings , 1996 .

[11]  A. Granier,et al.  Water balance, transpiration and canopy conductance in two beech stands , 2000 .

[12]  P. Reich,et al.  Response of Ulmus americana seedlings to varying nitrogen and water status. 1 Photosynthesis and growth. , 1989, Tree physiology.

[13]  J. Heath,et al.  Effects of elevated CO2 on leaf gas exchange in beech and oak at two levels of nutrient supply: Consequences for sensitivity to drought in beech , 1997 .

[14]  T. W. Jurik,et al.  Temporal and spatial patterns of specific leaf weight in successional northern hardwood tree species , 1986 .

[15]  Jan Èermák.  Leaf distribution in large trees and stands of the floodplain forest in southern Moravia , 1998 .

[16]  J. Kuuluvainen,et al.  Timber supply and life cycle harvest of nonindustrial private forest owners: an empirical analysis of the Finnish case , 1991 .

[17]  C. Braak,et al.  Ecological amplitudes of plant species and the internal consistency of Ellenberg's indicator values for moisture , 2004, Vegetatio.

[18]  C. Field,et al.  Scaling Physiological Processes: Leaf to Globe , 1995 .

[19]  M. Abrams,et al.  Photosynthesis, water relations, and leaf morphology of xeric versus mesic Quercusrubra ecotypes in central Pennsylvania in relation to moisture stress , 1992 .

[20]  M. Diekmann,et al.  Beech forest communities in the Nordic countries – a multivariate analysis , 1999, Plant Ecology.

[21]  H. Bartelink.  Allometric relationships for biomass and leaf area of beech (Fagus sylvatica L.). , 1997 .

[22]  G. Aussenac,et al.  Etude bioclimatique d'une futaie feuillue (Fagus silvatica L. et Quercus sessiliflora Salisb.) de l'Est de la France. I - Analyse des profils microclimatiques et des caractéristiques anatomiques et morphologiques de l'appareil foliaire , 1977 .

[23]  M. Abrams,et al.  Gas exchange, leaf structure and nitrogen in contrasting successional tree species growing in open and understory sites during a drought. , 1995, Tree physiology.

[24]  M. Huston,et al.  A comparison of direct and indirect methods for estimating forest canopy leaf area , 1991 .

[25]  A. P. Schaffers,et al.  Reliability of Ellenberg indicator values for moisture, nitrogen and soil reaction: a comparison with field measurements , 2000 .

[26]  R. Shaw,et al.  Leaf area measurements based on hemispheric photographs and leaf-litter collection in a deciduous forest during autumn leaf-fall , 1989 .

[27]  S. Hobbie.  Interactions between Litter Lignin and Nitrogenitter Lignin and Soil Nitrogen Availability during Leaf Litter Decomposition in a Hawaiian Montane Forest , 2000, Ecosystems.

[28]  Kalevi Kull,et al.  Leaf weight per area and leaf size of 85 Estonian woody species in relation to shade tolerance and light availability , 1994 .

[29]  A comparison of four methods for determining leaf area index in successional hardwood forests , 1985 .

[30]  K. Cleve,et al.  Fertilizer induced morphological and chemical responses of a quaking aspen stand in interior Alaska , 1977 .

[31]  Eric Ceschia,et al.  The carbon balance of a young Beech forest , 2000 .

[32]  A. Thimonier.  Changements de la végétation et des sols en forêt tempérée européenne au cours de la période 1970-1990: rôle possible des apports atmosphériques , 1994 .

[33]  A. Lang,et al.  Validity of surface area indices of Pinus radiata estimated from transmittance of the sun's beam , 1991 .

[34]  D. Watson.  Comparative Physiological Studies on the Growth of Field Crops: I. Variation in Net Assimilation Rate and Leaf Area between Species and Varieties, and within and between Years , 1947 .

[35]  S. T. Gower,et al.  A comparison of optical and direct methods for estimating foliage surface area index in forests , 1994 .

[36]  G. Carter,et al.  Variability in leaf optical properties among 26 species from a broad range of habitats. , 1998, American journal of botany.

[37]  A. Thimonier,et al.  Floristic changes in the herb-layer vegetation of a deciduous forest in the Lorraine Plain under the influence of atmospheric deposition , 1992 .

[38]  J. Cermak.  Leaf distribution in large trees and stands of the floodplain forest in southern Moravia. , 1998, Tree physiology.

[39]  M. Diekmann,et al.  A new species index for forest vascular plants: development of functional indices based on mineralization rates of various forms of soil nitrogen , 1998 .

[40]  Ruprecht Düll,et al.  Zeigerwerte von Pflanzen in Mitteleuropa , 1992 .

[41]  P. Castro-Díez,et al.  Leaf morphology and leaf chemical composition in three Quercus (Fagaceae) species along a rainfall gradient in NE Spain , 1997, Trees.

[42]  S. Jose,et al.  Leaf Area-Productivity Relationships Among Mixed-Species Hardwood Forest Communities of the Central Hardwood Region , 1997 .

[43]  Keith Kirby,et al.  Changes in the ground flora in Wytham Woods, southern England from 1974 to 1991 - implications for nature conservation. , 2000 .