Secondary succession in clear-cut areas of a beech forest. Permanent plot research 1971-2013

In winter 1970/71 a broad clear-cut aisle was felled through the Gottingen Forest for a new road building project. Here in summer 1971 two permanent plots (F1, F2, 8 x 8 m(2) each) were established. Since abandonment of the project the plots with their natural succession have been investigated continuously by phytosociological methods. Every year the vegetation was recorded twice in spring and summer, mainly by estimate of the cover of the layers and species. For the evaluation the releves of 43 years have been concentrated by combining several years respectively in Tables 1,2 in the supplement. For every plant species absolute constancy values and the median of coverage degree are given in comparison with an actual releve of the nearby beech forest. The potential natural vegetation of the plot areas belongs to Galio odorati-Fagetum typicum (F1) or Hordelymo-Fagetum circaeetosum (F2). The following succession stages and phases have been distinguished: 1. Herbaceous pioneer stage (5 respectively 4 years): Species-rich vegetation of patchy structure, mainly composed by long-lived herbs and grasses, also by some short-lived plants. Most of the species of the following stages, e.g. almost all young woody plants were already present. Average species number (MAZ): 62-63. The vegetation can be classified as Epilobio-Atropetum bellae-donnae. 2. Shrub stage (5-8 years): Dense small wood until 5 m height with increasing amount of shade for the undergrowth. 2a: Rubus scrub phase (3-4 years): Almost impenetrable scrub of Rubus species and other young ligneous plants of 2-3 m height, still with many plants of the first stage (MAZ 61-68). The vegetation belongs to the Sambuco racemosae-Rubetum rudis. 2b: Preforest phase (2-4 years): Dominance of young trees growing up to 5 m height. Under its shade decrease of the Rubus species and many light-demanding herbaceous plants. Beginning of a moss layer. MAZ 50-58. 3: Young forest stage (already since 33 respectively 31 years): Gradual development of a pole stand with natural thinning, a partly decreasing shrub layer and an increasingly forest-like herb layer. 3a: Pioneer forest phase (15-20 years): Still-growing dense stands of pioneer trees (F1: Betula pendula, F2: Fraxinus excelsior and Prunus avium) and loose to dense shrub layer. Herb layer still relatively species-rich (MAZ 61-54). 3b: Intermediate forest phase (since 18 respectively 11 years): opened young forest with thicker stems (pole stand to young timber), different shrub layer and more species-poor herb layer, almost of forest plants. In F1 dense after-growth of Fagus sylvatica, in F2 still missing. Moss layer disappearing. MAZ 38-45 only.