This research is designed to collect data on diversity in subtropical forest ecosystems and relate it to ecosystem services such as primary productivity, carbon storage, prevention of soil erosion, and invasion resistance to exotic plants. This data describes the Comparative Study Sites (CSPs), used to compare the planted diversity experiment with naturally grown forests. The plots have a size of 30x30m and are situated in the Gutianshan Nature reserve, Zhejiang Province, China. Data were collected in 2008. They comprise geographical locations, elevation, inclination, exposition of the plots, an estimated age of the plot, height and cover of two tree layers, the shrub layer and the herb layer, and cover of bare soil. This data set includes environmental measures on the CSPs that are of interest for all researchers.

The utilization of the forest until the 1990ies allowed us to employ a stratified sampling for establishing observational plots (in the following called Comparative Study Plots, CSPs) according to successional stages. Although most of the forest are belongs to intermediate or late successional stages, young stands are located in the peripheral buffer zone of the Gutianshan NNR, where logging has been performed until the present. Plots were assigned to five strata according to the average age of tree layer individuals (1: < 20 yrs, 2: < 40 yrs, 3: < 60 yrs, 4: < 80 yrs, 5:  80 yrs). CSP locations within strata were selected randomly; however, due to inaccessibility and excessive slopes (> 50°) of many locations, parts to the NNR had to be excluded from sampling, thus, resulting in an uneven distribution of some of the plots (Fig. 1). In total, 27 CSPs were established between May and July 2008. Species recording was performed between May and October 2008 with several visits per plot. Each CSP has a size of 30 m by 30 m, which approximates to the plot size (1 mu plot) in the BEF-Experiment at Xingangshan (Jiangxi, Fig. 1). The corners of every CSP were permanently marked with magnets and subareas of each CSP were set apart for measuring various ecosystem functioning variables, among them basic soil properties. Soil moisture was assessed on soil samples taken from five different layers of the mineral soil in 10 cm-intervals on three dates (summer and autumn 2008, spring 2009). We used mean values by averaging the soil water contents over all layers and all dates. Topsoil samples (0-5 cm) were taken in summer 2009 from four locations in each plot, pooled in a bulk sample per CSP, air-dried and then used to determine pH, both measured in H2O and 1 M KCl. A complete inventory of woody species and bamboo (Pleioblastus amarus) (> 1 m height) was carried out on the whole plot. All herbaceous species and tree recruits (i.e. seedlings and saplings ≤ 1 m height) were recorded in a central subplot of 10 m x 10 m. All individuals were identified to the species level, making use of herbarium samples and comparisons with correctly identified individuals, and counted per species. The proportion of unidentifiable individuals in a CSP ranged between 0 % and 2.3 %. These individuals were not included in the subsequent data analysis.

The Gutianshan National Nature Reserve (NNR) is located in the western part of Zhejiang Province (29º8'18" – 29º17'29" N, 118º2'14" – 118º11'12" E, Fig. 1). The Gutianshan NNR has an area of approximately 81 km2 and was initially established as a National Forest Reserve in 1975 and became a National Nature Reserve in 2001. The NNR comprises a large portion of broad-leaved forests of advanced successional stages (Hu & Yu 2008), which have not been managed since the beginning of the 1990ies, as well as young successional stages and conifer plantations, mainly of Cunninghamia lanceolata and Pinus massoniana. --- The vegetation is composed of different types of subtropical evergreen and mixed broad-leaved forests (Yu et al. 2001). Most of the stands are secondary forests, evidenced by maximum tree ages of 180 years, by agricultural terraces in almost all plots and by the presence of charcoal in almost all soil profiles. Around the Gutianshan NRR extensive deforestation has occurred during the Great Leap Forward in the 1950s, as in most parts of Southeast China. However, due to prevailing steep slopes, the Gutianshan area was only marginally usable for agricultural activities, and thus an exceptionally intact forest cover has been preserved. --- The climate at Gutianshan NNR is warm and temperate with a short dry season in November and December and with warm summers (Fig. 2). The climatic conditions are characteristic for the subtropics with an annual average temperature of 15.1°C, January minimum temperatures of -6.8°C, July maximum temperatures of 38.1°C and an accumulated temperature sum (≥ 5°C) of 5221.5 degree days.

Most of the data were collected in 2008, while some additional data were also collected in 2009.

The forest is representative for Chinese mixed broad-leaved forests (Wu 1980, Hu & Yu 2008, Legendre et al. 2009), with evergreen species dominating the forest in number of individuals (Yu et al. 2001) but with approximately similar proportions of deciduous species in terms of species number (Lou and Jin 2000). A total of 1426 seed plant species of 648 genera and of 149 families has been recorded as occurring naturally in the NNR. About 258 of the species are woody (Lou and Jin 2000).

Data can be used as covariates in other data sets. Successional age (Age of the 5th largest tree) and diersity of tree species are the main explanatory variables (species number)