The datasets consist of growth and mortality observations recorded in a mixed beech-hornbeam naturally regenerated stand in Hesse forest (NE of France). The study was conducted in the 64 plots (squares of 5.25 m size) comprising the experimental site over a twelve years period since 2001 until 2012. We took advantage of an instrumented experiment belonging to the European flux-monitoring network (CarboEurope IP) and set up in 2001 in Hesse forest to install these experimental plots with annual tree monitoring. Moreover, we controlled environmental factors, such as climate and soil characteristics that may be involved in individual tree mortality and in the course of stand size-density trajectories. Measurements included tree species and status (dead or alive), girth at breast height for all trees and total height for a sample of living trees (beech, hornbeam and oak).

The size-density trajectories of the 64 plots describing the course of the number of living trees in relation with the mean stand girth, in logarithmic scales, were modeled with a piecewise polynomial function fitted with a mixed-effects model. On the other hand, an individual tree mortality model was fitted with a logit function including several independent variables defined at tree, plot and stand levels. Four data tables with corresponding headings tables are provided: 1- one for stand data at plot level, 2- one at tree level for mortality data, 3- another one for height measurements made on a tree sample of beech, hornbeam and oak trees and 4- a last one making the correspondence between sample tree numbers and tree inventory numbers. There are some missing data due essentially to the installation of ecophysiological instrumentation in the experimental design (see the manuscript for more details).

These datasets are the support for a preprint paper : N.Le Goff, J.-M. Ottorini, F.Ningre. (bioRxiv, 2025). Dynamics of a mixed beech (Fagus silvatica L.) and hornbeam (Carpinus betulus L.) natural regeneration in North-East France: evolution of stand density and species composition with an insight into tree mortality factors.