Floristical Changes in Central European Forest Ecosystems during the Past Decades as an Expression of Changing Site Conditions : Causes and Consequences of Accelerating Tree Growth in Europe. Proceedings of the International Seminar

1999

6 Abb., 39 Lit

Unselbständiges Werk

13756

200059022

Changing floristical composition of vegetation stands can be used as an indication of changing site conditions. Phytosociological relevés (e.g. permanent plot or quasipermanent plot analysis) allow to draw conclusions concerning changes of floristical and site conditions in the course of time. Three case studies from both central and southern Germany are used to discuss the potentials and limitations of the interpretation of such results. Based upon that the results of such studies from all over Central Europe are reviewed briefly. The most essential results are: (1) Increasing nitrogen availability is the driving factor of floristical change in the forests of Central Europe. (2) In most cases the floristical composition does not reflect the current soil acidification process; increasing representativity of acid indicator species is a rare event, restricted to areas which are/were intensively influenced by (acid) immissions. (3) A general trend of the representativity of light indicator species during the last decades cannot be seen; changing representativity of the light indicator species especially depends either on changing forest (land use) management practices (high forest management instead of coppincing, "Hochwald" versus "Niederwald", "Mittelwald"; expiring forest grazing management) or on reduced crown density e.g. as a consequence of the so-called "new type forest disease", (4) Species number per relevé is depending on many different reasons, most of them of very local extension; therefore changes in species number in the course of time can neither be used as an indication of the direction nor the extent nor the reason of the current successional processes. (5) Successional change as an effect of "global change" cannot be evidenced in the forests of Central Europe with phytosociological methods up to now.