RTG 2300 - Study design, location, topography and climatic conditions of research plots in 2020

This dataset provides information about the study design, topography, geographic location and climatic conditions of the research plots of the interdisciplinary research training group 'RTG2300: Enrichment of European beech forests with conifers'. In each of forty forest stands, plots of 0.25 ha in size (called regular measurement plots, RMPs) were established in fall 2017 across the federal state of Lower Saxony, northwest Germany. The plots are grouped in eight so-called 'quintets'. Each quintet comprises five plots representing different forest stand types: three pure plots (European beech (Fagus sylvatica), Douglas-fir (Pseudotsuga menziesii), Norway spruce (Picea abies)) and two beech-conifer mixtures (beech-Douglas-fir and beech-Norway spruce). Four of the eight quintets are located in the southern part of the study area in the Solling and Harz mountain ranges. The other four quintets are located in the northern part of the study area in the North German plain. The southern plots are located in higher altitudes with lower mean annual temperatures and a higher annual precipitation. Growing conditions on the northern plots are less favorable than on the southern sites, in particular with respect to precipitation. On a subset of twenty out of the forty plots, intensive surveys such as root growth measurements, nitrogen retention analyses, or experiments on regeneration dynamics are carried out, besides the regular measurements on all plots. These intensive measurement plots (IMPs) comprise two southern and two northern quintets. Permanent, highly intensive measurements are conducted on special measurement plots (SMPs) that are a subset of 10 out of the 20 IMPs