Comparative Analysis of Alien Red Oak (Quearcus rubra L.) and Native Common Oak (Quercus robur L.) Vegetation in Lithuania

Abstract

Some alien tree species used in forestry can cause major problems as invaders of natural and seminatural ecosystems. The aim of this study was to determinate the differences in alien Quercus rubra and native common oak Quercus robur vegetation structure and species composition. Investigations were done in South-West of Lithuania. Plant species composition of Quercus rubra forests was investigated in 2005-2006. 30 geobotanical descriptions were done. All species in the stand were recorded. Projection cover was estimated according Braun-Blanquet scale. Geobatanical descriptions made in natural Quercus robur forests were selected and compared with Quercus rubra vegetation structure and composition. The difference of Quercus rubra and Quercus robur forests species composition was evaluated using Canonical Correspondence Analysis. It was determined that vegetation structure of alien Qurcus rubra stand and natural Quercus robur forest differed. Cover of second tree layer and herb layer was lower in Quercus rubra stands. Cover of shrub layer was slightly higher in Quercus rubra stands. Species number was significantly lower in Quercus rubra stands. Majority of character nemoral euthrophic species was lacking in Quercus rubra stands