Specific leaf area formula
Eight published studies conducted in different biomes and climate types were selected Table 1 , for a total of plant species belonging to families. Negative relationships between LT and photosynthetic Enriquez et al. LT was also measured with different pieces of equipment Table 1. In Roderick et al. However, since its measurement is not straightforward, a number of estimates have been proposed.
Leaf thickness has therefore often been estimated, and a number of surrogates have been proposed and used see White and Montes-R, One such estimate is the ratio of leaf fresh mass to surface area e. For the three study sites, all material was collected from robust, well-grown plants. Depending on the size of the individual leaves, LT was measured on five to ten points per leaf blade , avoiding the mid-vein.
In particular, Vendramini et al. Aquatics were removed from the original data set because their particular leaf anatomy confounds predictions of density. As such, it has been widely used for screening purposes in crop science and community ecology.
The species belong to more than 29 families some species not yet identified in SA-Med and span a very wide range of growth forms see Tables 1 and 5. In the laboratory, they were rehydrated according to the standardized protocol described by Garnier et al. The aim of this paper is to demonstrate that LT can be safely deduced from these two traits, which are much easier to measure.
Atkin et al. The amount of light absorbed by a leaf, and the diffusion pathway of CO 2 through its tissues depend, at least partially, on its thickness Givnish, ; Agusti et al. Midgley, unpubl. The determination of leaf thickness is not straightforward, however. Leaf thickness LT plays an important role in leaf and plant functioning and is related to species' strategies of resource acquisition and use.
Changes in specific leaf area of dominant plants in temperate grasslands along a 2500-km transect in northern China
Lloret and M. Vilà, unpubl. Building on Witkowski and Lamont and Roderick et al. At each site, species were selected from the most abundant ones FR-Med, Garnier et al. For herbaceous and small woody species, samples were taken from plants in full light; while for tall woody species, these were taken from the part of the plant lit by direct sunlight at the time of sampling.
The species were classified according to their growth form see Table 1. Only two of the eight datasets displayed a significant difference in the intercepts, and the only significant difference among the most represented growth forms was for trees. For Tables 2 — 5 and Fig. The number of succulent species used in Fig. These 16 taxa were not identified to the species level, and in the absence of unequivocal information, these were not assigned to a specific growth form.
After cutting from the plants, the samples stem or twig segments bearing leaves were wrapped in moist paper and conserved in a cool box until further processing. Statistical analyses were conducted in two ways, using a total of data points Table 1. Species were classified according to their growth form see Table 1 ; forbs include all herbaceous dicotyledonous species including Fabaceae.
The methods differed among studies see Table 1. The three original experiments were conducted in sites with a Mediterranean climate. Twenty-two of them were selected from Garnier et al. After rehydration, the youngest fully expanded leaves free from herbivore or pathogen damage were chosen from each stem.
Due to theoretical considerations see the Introduction , only species with laminar leaves were selected from these studies, i.
To determine the saturated fresh mass of leaves, they were immediately weighed. The wide variation in leaf morphology e. In FR-Med, a total of 44 species were studied data from the same species measured in different locations were considered as independent data points. Only studies in which traits were measured after some re-hydration prior to measurement were selected Garnier et al.