A Dráva durvaszemcsés folyóvízi üledékéből előkerült szubfosszilis uszadékfák dendrokronológiai és faanatómiai vizsgálata

This paper presents preliminary results of dendro-chronological analyses of the first occurrence of subfossil tree trunks from drava alluvial sediments. Driftwood logs were found at an outer bend of the Drava river near the village of Babócsa. The site is covered by >6 m fluvial sand and gravel. Trunks are arranged horizontally, roughly in the same bed, between massive gravel and sand layers.. Fourteen samples had been collected within a hundred metre long outcrop, ar-ranged in three distinct sets.. half of the samples are oak (Quercus roburl., n=7), fewer samples belonged to beech (Fagus sylvatica, n=2), wych elm (Ulmus scabra, n=1), eu-ropean white elm (Ulmus laevis, n=2) and finally a there are one sample each of poplar (Populus spp.) and larch (Larix decidua). the samples were processed following the stan-dard dendrochronological protocol. ring width was measured to the nearest 0.01mm. despite the most likely origin of the samples is the riverbank; the oak trunks had narrow tree-ring sequences. an oak trunk of a diameter not more 20 cm con-tains more than 240 rings and two other oak samples have about 200 rings. These three long series could be crossdat-ed, forming a 249 year long chronology. The chronology built from the three synchronized records (sample codes bab002, bab003, bab007) was tested with surrounding oak master chronologies, without success. The first subfossil wood re-mains from the drava river and their loating chronology will be of help to understand changes in river dynamics and the former composition of the tree species on the floodplain.

Pastureland Copses As Habitats For A Primeval Forest Relict: A Unique Location Of The Rosalia Longicorn Rosalia Alpina (L.) (Coleoptera: Cerambycidae) In The Polish Carpathians

The Rosalia longicorn Rosalia alpina is regarded as a primeval forest relict and occurs mainly in old beech woodland in mountain areas. This paper describes a locality of the species in a copse surrounded by pastures, lying in open farmland situated at some distance from woodlands. The larval host plant was Wych Elm Ulmus glabra. The trees at this locality were dying from Dutch elm disease, which is caused by the fungus Ophiostoma sp. It is demonstrated that under favourable circumstances R. alpina can also colonise copses in pastureland, a hitherto unknown habitat for this species. At the same time this newly discovered locality may signify a change in the species’ habitat preferences. R. alpina is under threat, however, from the possible felling of the dead trees by the landowner; conservation measures should therefore include a mechanism for financial compensation in return for not cutting the trees down. This work has shown that copses may be used by endangered saproxylic species. The discovery of a R. alpina locality in a pastureland copse gives an indication of the importance of pockets of unmanaged habitat in the farming landscape, which could be contributing to the preservation of populations of rare species.

Dendrometric, phytopathological and entomological characteristics of a wych elm tree on mt. Goc

Valuable broadleaves, including also wych elms, belong to the category of rare tree species in the growing stock of Serbia. The conservation of Serbian forest diversity and the genetic potential of these tree species require a multidisciplinary study. In this respect, we undertook a dendrometric and health analysis of a wych elm tree on Goc, as it is a rarity by its dimensions, not only from the local, but also from the regional aspects. The tree is 266 years old, its diameter at breast height is 2.09 m, height 42.1 m, and volume (d>3 cm) 56.35 m3. Current height increment culminated early, at the age of 20-30 years, attaining 0.5 m, and current diameter increment at the age of 40-50 years when its value was 14.4 mm. The above data point to a high productivity of this elm tree and to favourable site and stand conditions of its development. On the other hand, its current diameter increment and height over the last period (1.7 mm, and 0.03 m respectively) indicate that the tree was in the phase of physiological dying. 10 species of fungi were identified on the tree (facultative parasites or saprophytes), the most significant being Armillaria mellea and Aurantioporus fissilis, which caused central heartwood decay. Other fungi developed saprophytically in the dead part of the stem or in dead branches. Eight insect species (secondary and tertiary pests) were identified, including the two most dangerous elm beetles (Scolytus scolytus and S. multistriatus). Together with the species Saperda punctata and Cerambyx scopolii, they accelerated the dying process of twigs and branches, as well as of the whole tree. Ambrosia beetle Xyleborus monographus infested the stem and the large dead branches and caused minor technical damage in wood. The species Dorcus paralelopipedus, Oryctes nasicornis and Valgus hemipterus supported the faster progress of wood-rotting fungi and thus contributed to physiological weakening and shortened the life cycle of the study elm tree.