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Manna ash (Fraxinus ornus L.) is a typical deciduous tree of South European distributioin reaching the northern border of its range in the Carpathian Basin. The correlation between age and basal diameter of this tree was analysed in three ecologically contrasting habitats, as follows. (1) Succesional habitat. Abandonedframland with scattered occurrence of manna ash as a colonisong tree of this area. (2) Austrian pine plantation, where manna ash often forms a spontaneous subordinate tree or shrub layer. (3) Cotino-Quercetum pubescentis, the naturla vegetation on south facing calcareous hillslopes in Hungary, where Quercus pubescenes Willd. and Fraxinus ornus codominate in the low canopy. At each sampling site 21 individuals were selected with an even distribution within circumference categories ranging  from 6cm to 60cm. Circumference measurements were made at the base of the trunk, or cores were taken by a driller. Linear regression analysis was applied to test the correlation between age and diameter.

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The paper advocates a more extensive use of additive trees in community ecology. When the distance/dissimilarity coefficient is selected carefully, these trees can illuminate structural aspects that are not obvious otherwise. In particular, starting from squared distances based on presence/absence data, the resulting trees approximate relationships in species richness, a feature not available through other graphical techniques. The construction of additive trees is illustrated by three actual examples, representing different circumstances in the analysis of grassland community data.

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Litter mass represents a key factor in the process of carbon sequestration. Pine plantations are known to accumulate high amounts of litter, which may act as real carbon sink only if it persists for long time. Thus, predicting litter mass by means of robust and straightforward models which convey information from several ecological predictors become crucial in this framework. The aim of this paper was to test for relationships between environmental predictors and pine litter mass (total branch, needle and cone) by Generalized Linear Models, exploring the contribution of different environmental variables in describing patterns of pine litter mass. Different predictors accounting for seasonality, spatial and geomorphological variability, pine stand properties, remotely sensed derived biomass were taken into account. Considering total litter mass, observed vs. predicted values showed a statistically highly significant relation (p < 0.001) by retaining four variables: elevation, latitude, stand age and season. Similar results were achieved for the needle litter mass, which represented anyway the largest fraction of the litter. Regarding branch litter mass, only stand age appeared to be a significant variable. For cone litter mass, no variables were statistically significant in explaining its variance. Potential ecological background processes responsible for the correlations between variables are discussed.

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Community Ecology
Authors:
F. Jordán
,
T. Kalapos
, and
P. Csontos

R.W. Sterner and J.J. Elser. 2002. Ecological Stoichiometry - the biology of elements from molecules to biosphere. Princeton University Press, Princeton, New Jersey, 439 pp. (with 117 figures and tables). ISBN: 0-691-07491-9, paperback, price: USD 29.95, GBP 19.95. M. Black and H.W. Pritchard (eds.) 2002. Dessication and survival in plants. Drying without dying. CABI Publishing, Wallingford, x+412 pp. ISBN: 0-85199-534-9, hardback, price: GBP 75.00. B.D. Booth, S.D. Murphy, C.J. Swanton. 2003. Weed ecology in natural and agricultural systems. CABI Publishing, Wallingford, viii+303 pp. ISBN 0-85199-528-4, paperback, price: GBP 35.00, USD 60.00.

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Community Ecology
Authors:
I. Scheuring
,
J. Podani
, and
P. Csontos

Cushing, J. M., R. F. Costantino, B. Dennis, R. A. Desharnais and S. H. Henson 2003. Chaos in Ecology. Experimental Nonlinear Dynamics (Theoretical Ecology Series). Academic Press, San Diego, xiv+225 pp. ISBN: 0-12-198876-7, hard cover, price: EUR 70.95, GBP 46.95, USD 68.95; E. van der Maarel (ed.) 2005. Vegetation Ecology. Blackwell, Oxford, x+395 pp. ISBN: 0-632-05761-0, paperback, price: USD 79.95, GBP 34.99; S. Mazzoleni, G. di Pasquale, M. Mulligan, P. di Martino and F. Rego (eds.) 2004. Recent Dynamics of the Mediterranean Vegetation and Landscape. Wiley, Chichester, xiv+306 pp. ISBN: 0-470-09369-2, hard cover, price: EUR 165; Forget, P. M., J. E. Lambert, P. E. Hulme and S. B. Vander Wall (eds) 2005. Seed Fate: Predation, Dispersal and Seedling Establishment. CABI Publishing, Wallingford, xv+410 pp. ISBN: 0-85199-806-2, hard cover, price: GBP 75.00, USD 140.00;

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Abstract  

Pentaerythritol may react with tetraethoxy-silane and ammonium-polyphosphate in flame retarded polyolefins and an interfacial layer can be formed around the ammonium-polyphosphate particles. It is advantageous to study such systems using methods of thermal and surface analysis together.

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