Buch Bioform.Indb
Total Page：16
File Type：pdf, Size：1020Kb
Floren and Schmidl (eds.) 2008: Canopy arthropod research in Europe 61 Tree species composition and historic chang- es of the Central European oak/beech region Carsten Rüther 1 and Helge Walentowski 2 1 Lorettoplatz 8, 72072 Tübingen, Germany 2 Bavarian Forest Institute (LWF), Am Hochanger 11, 85354 Freising, Germany Corresponding author: Carsten Rüther, email: [email protected] Citation: Rüther, C. and Walentowski, H., 2008. Tree species composition and historic changes of the Central European oak/beech region. In: Floren, A. and Schmidl, J. (eds): Canopy arthropod research in Europe, pp. 61-88, bioform entomology, Nuremberg. Abstract After the ending of the nal glaciations, tree species re-immigrated to Central Europe from their southern refuges. Fagus sylvatica (beech) was the last principal tree species to arrive at the northernmost areas of the Central European region, viz. north-western Germany, Denmark and southern Sweden. Due to their high competitive ability, F. sylvatica plays a predominant role in Central European Fagion-forest communities, whose native ranges are lowlands and low mountain ranges. Depending on local soil and climatic conditions, other tree genera are included such as Quercus (oak), Picea (spruce) and Abies ( r) (both Pinaceae). Indeed, only under exceptional environmental conditions is the competitive ability of F. sylvatica limited in such a man- ner that other tree species may predominate. Even rare occurrences of one associated tree species within beech forests may assure a long habitat tradition for specialised biocoenoses. Since the Neolithic period, human activities interfered with the forest-covered regions of Central Europe. The forests were changed sig- ni cantly by multiple historical uses and management techniques. Anthropogenic transformation of the forests was driven by wood pasture, pollarding techniques, litter utilisation, coppicing, coppicing with standards and high-forest systems (selective and clear-cutting). These had crucial effects on tree species composition as well as the stand climate of the forests. They changed the spatial and temporal structures of the stands as well as the cycling of soil matter. Another effect of human activities was drastic reduction of forest cover. The unwitting transition of tree species composition nished in the Middle Ages. Since then, human interference has concentrated on targeted timber selection. These alterations make clear that structural components and site conditions of commercial forests deviate considerably from those of the original natural forests. Modern management methods have to consider biodiversity and the degree of naturalness with regard to the tradition of old-growth trees, natural tree species combination and natural ground layer vegetation. Important stan- dards for a sustainable forestry combined with conservation of biodiversity are heterogeneity, complexity and scale. Zusammenfassung Nach der letzten Eiszeit wanderten die Baumarten aus ihren südlichen Refugien wieder nach Mitteleuropa ein. Als letzte der Hauptbaumarten erreichte die Buche (Fagus sylvatica) die nördlichen Gebiete Mitteleu- ropas: Nordwestdeutschland, Dänemark, Südschweden. Aufgrund ihrer ausgeprägten Konkurrenzkraft spielt sie in den mitteleuropäischen Fagion-Gesellschaften eine vorherrschende Rolle; derartige buchen- reiche Wälder würden natürlicherweise weite Teile der niederen Lagen und der unteren und mittleren Mit- telgebirgsstufe bedecken. Andere Baumarten wie Eiche, Fichte und Tanne sind in Abhängigkeit von den lokalen Boden- und Klimabedingungen am Aufbau der Baumschicht mehr oder weniger stark beteiligt. Nur 62 Rüther and Walentowski: Tree species composition and historic changes… auf Sonderstandorten ist die Konkurrenzkraft der Buche derart eingeschränkt, dass andere Baumarten zur Vorherrschaft gelangen können: daher kann gerade das seltene Vorkommen einer Begleitbaumart innerhalb von Buchenwäldern als Beweis für eine lange Habitattradition des Bestandes herangezogen werden. Seit dem Neolithikum be ein usst der Mensch die Waldlandschaft Mitteleuropas. Die Wälder wurden aufgrund der vielfältigen histo rischen Nutzungen und Bewirtschaftungstechniken erheblich verändert. Für die Veränderun- gen waren in erster Linie die Waldweide, die Schneitelwirtschaft, die Streunutzung, die Nieder- und Mittel- waldwirtschaft sowie die Hochwaldwirtschaft (Kahlschlag, Plenterwaldwirtschaft) verantwortlich. Diese hatten entscheidenden Ein uss auf die Baumartenzusammensetzung und das Bestandsklima der Wälder. Darüber hinaus veränderten sich die räumliche Struktur und die zeitliche Entwicklung der Bestände sowie die Stoff- kreisläufe im Boden. Parallel dazu führten die anthropogenen Eingriffe zu einer drastischen Verringerung der Wald äche. Bis ins Mittelalter erfolgten die Veränderungen eher unbewusst; seit dem Spätmittelalter hat der Mensch durch die Auswahl bestimmter Baumarten bewusst in die Baumartenzusammensetzung eingegriffen. Die Veränderungen machen deutlich, dass die strukturellen Eigenschaften und die Standortbedingungen der bewirtschafteten Wälder deutlich von denen natürlicher Wälder abweichen. Um den weiteren Verlust an Bio- diversität aufzuhalten, muss die moderne nachhaltige Forstwirtschaft klar de[ nierten Mindestanforderungen an Biodiversität und Naturnähe gerecht werden, d.h. in Bezug auf Strukturparameter (v.a. Alt- und Totholz), standortscharakteristische Arten (Baumartenzusammensetzung, Bodenvegetation) und Funktionalität (räum- liche und zeitliche Heterogenität und Komplexität). Introduction Eemian periods (128000-115000 B.P.), large herbi vores were still present. These periods Naturally, the temperate forest zone of showed a very similar development of for- Central Europe would be a mostly uniform est reestablishment after glaciation in com- forest area (forest cover 95%), dominated parison with the early Holocene (10300 B.P.). by deciduous trees. Only dunes, marshes, Therefore, the stated signi cant impact of the bogs, rocky outcrops and few alpine regions large herbivores, which became extinct at the above the upper timberline were once un- start of the Holocene on the vegetation has to wooded (Ellenberg 1996). The vast progress be rejected (LWF 2000). made in palaeobotany and the amount of Conversely, Central Europe is also a zone data available prove conclusively that Europe of most intensive anthropogenic use. Since was natu rally forested, either with or without at least the second half of the sixth mille- mega-herbivores (Litt 2000). Pollen diagrams nium before Christ (B.C.), forests of natural from many localities across Central Europe origin were transformed progressively by show a clear pattern of post-glaciation refor- human in uence (Lang 1994, Küster 1996, estation, its tree species combinations and 1998a). In north-western Germany as well also the degree of openness of European as in some loess regions of central and forests, both during Eemian inter-glacial pe- southern Germany, the rst farm cultiva- riod and the beginning of the Holocene prior tions were established. The regions’ inhab- to human intervention. Pollen samples show itants farmed elds and bred cattle, pigs, exactly the same result: measured by the sheep and goats. Cattle pastured freely in ratio of non-tree pollen to tree-pollen, the the surrounding forests, a method still prac- European landscape was nearly covered by tised locally in extensively-managed areas woodland which formed forests in the true in the Balkan Peninsula and Carpathians. sense and without resembling a park land- In addition to the production of timber, re- scape. This is true for the entirety of Cen- wood, lumber and leaf litter, the early farm- tral Europe, since none of the known pollen ers also took fruit for their diet, to extract pro les deviate from this picture by showing oil or as a winter supply for their domestic signi cant amounts of non-tree pollen. In both animals. Further forest uses followed, such the Holstein (347000-362000 B.P.) and the as the production of charcoal or ash burning Floren and Schmidl (eds.) 2008: Canopy arthropod research in Europe 63 and subsidiary uses such as bee keeping or Anthropogenic impact on Central Euro- tan-bark peeling. pean forests has differed both regionally and These forest uses effected a complex temporally. Thus, the original conditions of change of structural and ecological conditions these forests can only be estimated. Never- in the forests, alterations of species abun- theless, some quantitative changes can be dance and species combination as well as detected and qualitative effects assessed. a clear reduction of the forest area. Decisive These include: factors for the degree of anthropogenic trans- (1) diminishment of welfare and protective formation were duration, intensity and nature functions; of the impacts and the resultant ecological (2) alteration of tree species composition site conditions. In extensively-grazed areas, (including direct and indirect in uence non-natural open pastures with individual on the role of indigenous species for groups of bushes as well as park-like stages the vegetation and introduction of for- and groves, alternating with closed forest eign species); stands, were formed (Pott 1983, Ellenberg (3) modi cation of forest structure; 1996). Instead of natural forests, numerous (4) impact on forest dynamics/cyclic phas- substitute communities emerged, so that a di- es; verse mosaic of secondary forests, pastures, (4) modi cation of micro-climate; meadows, heaths and elds is found today. (5) change