The study sites

Since 1999, the Department of Plant Ecology and Ecosystem Research investigates mixed deciduous forests on the south-eastern edge of the Hainich in the vicinity of the village Weberstedt (51°05’28’’N, 10°31’24’’O). All 12 stands are situated in protection zones 1 and 2 of the National Park in an elevation of 350m a.s.l. on inclinations lower than 5%. The studied stands grow on superficially acid (stagnic) Luvisol derived from loess (average depth of around 76cm) with clay contents less than 40% in the upper 30cm of the soil. In the study period from 2005 to 2007, the length of the vegetation period varied from 217 to 250 days. Low precipitation results frequently in long periods of drought (see diagram for 2006).

The closed tree layer of the studied stands contains the character species beech, linden, ash, mountain maple, and hornbeam and is subject to natural self-thinning leading to large amounts of deadwood. The stands are in the stage of maturity with single trees reaching up to 40m in height. Neighbouring stands show varying levels of tree-species diversity (Shannon-index based on crown projection area from 0.2 to 1.5), which are result of different ownerships and historical forest management and not of edaphic differences. Historical maps indicate a forest cover at least since the middle of the 18th century. During this period silvicultural management systems such as selective cutting (Plenterwald) or coppicing with standards (Mittelwald) were widely spread. In the Central European context, the chosen stands are close to natural forests and only single stems have been taken out of the stands in the last 40 years.