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Kivonat:

For characterizing the cenological circumstances of tree of heaven in Hungary in 16 stands altogether 52 recordings have been made, the great part of which outside Budapest. Records are classified by the soil forming rock into 4 groups (on sand, loess, limestone and dolomite), these are evaluated by the soil forming rock, and aggregated too. During recording special attention have been paid to species, which were found at the edges of stands and their closest vicinity. The purpose of this was to obtain approximate data from the vegetation, which existed at the given area before the establishment of tree of heaven. From the records group participation of life forms (Raunkiaer), social behaviour types and ecological indicator values (Borhidi) have been counted, by the results the vegetation impoverishing effect of tree of heaven is obvious.

Group participation of cenological groups shows prominently high percentage of indifferent species outside and inside stands as well. In case of elements within the group of deciduous forests a rise can be seen in comparison with that of outside stands. Proportion of plants of anthropo-zoogenous semishrubs, turfs and meadows decreases, among them the strongest (to its one fifth) decrease can be experienced within the group of Festucetalia valesiacae elements. Within the cenological group of disturbed habitats, partly increase, partly decrease can be seen. Hemerobic grades of habitats at the edge of stands belong to beta-euhemerobic–mesohemerobic, and the stands themselves to beta-euhemerobic–polyhemerobic group.

In the crown layer of investigated stands of tree of heaven Robinia pseudoacacia and Morus alba are present as accidental elements independently of soil type. In the shrub layer of stands Crataegus monogyna is a common accessorical element, Robinia pseudoacacia, Rosa canina and Sambucus nigra are subaccessorical with a relatively low abundance. From accidental elements of the shrub layer Acer negundo is prominent with its high abundance. The herb layer is dominated by the subconstant Galium aparine, accessorical elements are Ballota nigra, Bromus sterilis and Bilderdykia convolvulus. Among subaccessorical elements Anthriscus cerefolium is worthy of mention, which occurred in all soil types, and Muscari comosum and Ribes aureum, which accompanied almost only stands of sandy soils.

The herbaceous layer was the richest (25 species) of the oldest stand (at least 37 years old at Kunadacs). To my mind this is connected with the age of the stand, because from the members of the surrounding flora – after an adequate period passes – inside stands appear and remain species, which can permanently live together with tree of heaven.