Effect of black walnut (Juglans nigra) on the understorey vegetation - a case study of South Moravian forests (Czech Republic)

Abstract

The article analyses the influence of black walnut on forest phytocoenosis in South Moravian forests and assesses how its representation may affect the understorey vegetation of the forest ecosystems. In July 2014, 31 relevés were processed in the South Moravian forests. These were stands of pure black walnut (Juglans nigra) as well as black walnut with small-leaved lime (Tilia cordata), along with neighbouring autochthonous stands (pure ash - European and narrow-leaved), oak (summer oak), or their mixtures. Ellenberg's indicator values reveal differences in the plant communities under black walnut comparing those under native tree species for the variables nitrogen, soil reaction and temperature. In addition, total cover is significantly higher under walnut. Other differences are visible from the detrended correspondence analysis ordination. The study also confirmed that in the stands of black walnut the preference of some species is suppressed, for example Brachypodium sylvaticum and Poa nemoralis in alluvial forests and Melica uniflora in hilly forests.

Keywords

• ellenberg's indicator values
• herb layer
• indigenous species
• ordination
• relevés