The Gesäuse Nationalpark and the Johnsbach valley belong to the Ennstal Alps, a part of the Northern Limestone Alps. They are situated in the province of Styria in the center of Austria. Together, they form the joint test site named Gesäuse-Johnsbachtal. This region is characterized by a mountainous landscape which is cut by the river “Enns”. In the north, it borders Eisenwurzen Nature Park and is only 6 km away from the Kalkalpen, a National Park in Upper Austria. In the south, the borders are the Eisenerzer Alps. The total area of the site is about 155 km². The terrain shows a great elevation range from 600-700 m in the Johnsbach valley to over 2300 m in the summit region of the Gesäuse, with Hochtor (2369 m) being the highest mountain. Due to the great range of altitude differences within small areas the Gesäuse-Johnsbachtal shows extremely diverse habitats and, consequently, species of animals and plants. In general, the landscape is dominated by mountain forests along with high Alpine rock formations and meadows. These complex topographic, hydrological, geological, geomorphological and meteorological conditions pose a scientific challenge for all kinds of environmental monitoring and modeling.

The Nature reserve Bos t’Ename is situated on the Belgian loess belt about 25 km south of Ghent. It has an area of 160 ha. 60 ha mixed deciduous ‘ancient forest’ forest, 40 ha restoration of woodpasture on former agricultural land, 35 ha regeneration of forest in a silt quary, 25 ha semi open cultural landscape (meadows, hedges,…). "Bos t'Ename" belongs to one of the classified lanscapes of Flanders The woodland where previously managed as coppice with standards. The history is exceptionally well studied. It is managed as multifunctional forest containing strict forest reserves an coppice with standards.

The site consists of high elevation vegetation in central Mediterranean basin, along the Apennines mountain range: xerophitic primary grassland (Pediculari elegantis-Seslerietum tenuifoliae) and mesophitic primary grassland (Luzulo italiacae-Festucetum macratherae), with important resident and migratory bird communities. Six plots, each one 100 m2 large, grouped in two cluster-plots including each one three plots, representative of a larger area of 0,5 km2 ca., ranging from 2100 to 2300 m a.s.l. (alpic and Mediterranean high-mountain belts.

The total NPHK is currently (since 2020) about 12,000 ha, but the eLTER site corresponds to the former perimeter of the NPHK and represents an urbanised protected area of about 60km2 (or 6,000ha) located in the Province of Limburg in the East of Belgium. The NPHK (inaugurated in 2006 and extended from 6000ha to its current 12000ha in 2020), located in a former coal mining area is surrounded by 10 municipalities with more than 200,000 inhabitants, equivalent to a population density of 450/km2 . The park covers a rich variety of habitats, including heathlands, deciduous forest, coniferous forest and fens and evidently the corresponding diversity of fauna and flora. Several research groups from universities and institutes are monitoring and measuring abiotic and biotic parameters throughout the different ecosystems. Research on ecosystem services are also playing a major role, including tourism and mobility.

This site is located on the territory of National Park “Rila”, Bulgaria. Parangalitsa has been a reserve since 1933. It is situated on part of the southwestern slopes of Rila mountain, covering 1,509 hectares. It contains some of the oldest pine tree forests in Europe with an average age of over 200 years. The site is a part of the network of bioecological stations of Forest Research Institute – BAS and research is focused on highly productive coniferous forests with unique biomass. In the main experimental plots, long-term complex studies were conducted during the period 1979 - 1998, a large-scale database was created and a number of significant scientific results were obtained. In the period 2000 - 2018, separate targeted studies were carried out - focused on some ecosystem processes, which allows the analysis and evaluation of the functioning of ecosystems to be don

The Aelmoeseneie Forest is a 28.5 ha mixed deciduous forest in the community of Gontrode, just southeast of Ghent. The largest part of the forest is ‘ancient forest’, i.e. it is permanently forested since before 1775, while the forest is surrounded by agricultural land (mostly pastures). The soil consists of a silt loam to loam soil (Planosol), overlaying a mosaic of tertiary clayey and sandy deposits with high base saturation starting at 50 cm depth. Forest management is designed to obtain a more natural tree species composition and to conserve biodiversity. More info can be found at www.aelmoeseneiebos.ugent.be.

The site comprises 4 km stretch of a complete alluvial floodplane managed as a private nature reserve some 10 kilometer upstream of the city of Leuven. Since 1990, human interference in the river channel has stopped resulting in a spontaneous meander evolution and roughening of the river channel. This has induced frequent (e.g. yearly) inundations, thus avoiding flood damage in the city of Leuven downstream and this without creating the usual storm basins.

This LTER-site corresponds with a 0.25 ha intensive forest monitoring plot (ICP Forests Level II) including a 0.25 ha buffer zone. The site is located in a homogeneous stand of Corsican pine (Pinus nigra ssp. laricio var. Corsicana Loud.) planted in 1930 on former heathland and is part of Gewestbos Ravels, a landscape (about 1000 ha) with deciduous and coniferous forests, heathland, bogs and pastures in the northern part of the Campine ecoregion of Flanders. The terrain is gently sloping (1-2 %) and the soil is a well-drained sandy soil (Endogleyic Folic Brunic Albic Arenosol (Dystric)). Ground vegetation is dominated by ferns (Dryopteris dilatata and D. carthusiana) and Vaccinium myrtillus. After a storm in February 2007 felled several trees an understorey of Betula pubescens started to develop. Intensive monitoring was started in 1987 with the main objective to study the effects of air pollution on biogeochemical cycling and forest performance (growth, vitality). This yielded a number of long-term data series including on atmospheric deposition, air quality, soil and soil solution chemistry, tree mineral nutrition, ground vegetation and growth. Monitoring will be continued in the future as a statutory task of INBO.

The aim of the Brigalow Catchment Study is to determine the effects of land clearing and land use change on hydrology, water quality, soil fertility and crop and animal productivity in the Brigalow Belt bioregion of central Queensland, Australia

The LTER-site of Wijnendale Forest is a 90 ha scientific zone located in a larger mixed atlantic beech-oak-woodland (300 ha), in the North-West of Belgium, 20 km south of Bruges. The site is located on moderately wet to dry sandy soils. The site is an ancient woodland that used to be managed as coppice with standards. Over the last 100 years it was gradually transformed to a mixed high forest, mainly of oak and beech. The site contains - an ICP Forests Level II plot (0.25 ha), in which effects of air pollution on the forest ecosystem are monitored, according to standard protocols. - a strict forest reserve of 65 ha: here, natural dynamics of forest structure and ground vegetation are monitored, and its effects on biological diversity. - a 25 ha buffer zone, containing both forest and open grassland (extensively managed for nature conservation), where 'open field' measurements are performed. The sampling network in the strict reserve includes >100 sampling plots (0.1 ha) combined with a 1 ha core area. In these plots, full dendrometric surveys (tree position, species, DBH, height, ...) and ground vegetation relevees are performed every 10 years. Additionally, standardised sampling of saproxylic beetles, mosses and fungi were performed and high-resolution air-borne LIDAR and hyperspectral data were recorded in 2012-2014. Main aims for the future are the continuation of the observational networks to provide longer robust time-series that allow more thorough analysis and investigation.