Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 96. (Budapest 2004)

Molnár, J., Erdei, B. ; Hably, L.: The transport of leaves and fruits - a taphonomical study of leaf litter

surface may get transported by the wind more easily than leaves with smaller lamina. At the same time, however, it must be taken into consideration as well that larger leaves are heavier than smaller ones (if density is more or less constant) and in addition larger leaves may get stuck more easily in the surrounding trees and shrubs or even in the herbaceous layer. Since the surface and weight of leaves correlate well, presumably both factors have an influence on the 'transport potential' of a leaf. According to FERGUSON (1985) the size of the leaf does not affect the distance it is transported to if 'weight/unit of surface' is constant and there are no obstacles in the transport route. FERGUSON (1985) investigated the relation of 'leaf size' and 'leaf weight/unit of surface' by several species. The increase of size is generally coupled with the increase of leaf density if the sample is taken from a certain part of the leafy crown. The correlation of leaf size and density eliminates if sample is taken from all over the leafy crown since factors like exposure, etc. are varying locally in the crown (density of sun leaves is higher than that of shade leaves). Presumably this is the reason why we have not found significant differences of leaf density in the closer and distant quadrats. As regards leaf size studies different results obtained from field observations appear, as well. Based on a study of leaf litter by Alnus glutinosa (LINNAEUS) G AERTNER 1791 (SPICER 1975, 1980, 1981) there was no significant difference of leaf size in various distances from the tree trunk, although, this species does not have definitely sun or shade leaves. The leaves of a Tilia tree were also studied and moving away from the trunk leaf size increased (FERGUSON 1985). However, most studies prove the opposite (SPICER 1975, 1980, 1981) and so do results of this study. It is evident that wind velocity is important during leaf fall. In stormy weather sun leaves at the top of the leafy crown may be transported quite far from the parent tree. Since the size of these leaves is always smaller than that of shade leaves presumably the lower average leaf size in distant quadrats is attributable in part to sun leaves. From the point of view of palaeoclimatology the size of leaves in a fossil flora has great importance: the analysis of the leaf size pattern of a fossil leaf flora may contribute with useful pieces of information to the reconstruction of the terrestrial palaeoclimate of a certain area. Numerous studies dealt with this question after BAILEY & SINNOTT'S classical works (1915, 1916), e.g. DILCHER (1973) attempted to characterize recent vegetation types with their leaf size patterns (e.g. cool-temperate, humid montane, etc.), or WOLFE'S (1993) Climate Leaf Analysis Multivariate Program (CLAMP) using leaf morphological traits. Thus, the result of palaeoclimatic reconstructions considerably depends on the fact how far from the source area and which direction fossil leaves were trans-