Central Europe maintains a considerable diversity of dry-mesic oak forests as the main representatives of zonal forest vegetation types in Hungary, covering the major part of foothills of the middle-range mountain, Inner Western Carpathians. The 669 m high, Triassic limestone hill called ‘Vár-hegy’ belongs to the Bükk Mountains. The annual mean temperature is about 8◦C and the annual precipitation is about 650 mm. The core area of the reserve (94 ha) is covered mainly by close-to-nature. long untouched oak dominated forests stands: Pannonic woods with Quercus petraea and Carpinus betulus; Pannonian-Balkanic Turkey oak-sessile oak forests; Pannonian woods with Quercus pubescens. It has been set aside for preservation in 1991, though several previous conservation acts had already secured almost spontaneous natural development of the stands. Most of the area was cut around 1880, however, several over-mature trees were retained. The intensive use in the previous centuries and during the world wars left a sessile oak dominated, 120-130-year-old, mostly coppice forest. The abandonment and the precedent severe oak decline contributed to generate a more diverse forest composition and structure developing towards a mixed forest with pronounced ‘old-growth’ characteristics.

Rich fen and grassland communites formerly used for haymaking in the transition between the middle boreal and northern boreal vegetation zone, and in the transition between oceanic and continental vegetation sections in Central Norway

The Sani Environmental Observatory (S.E.O.) is located within a mature, near-coastal Aleppo pine (Pinus halepensis L.) ecosystem at the peninsula of Kassandra, in Chalkidiki, Greece. It is part of the Stavronikita forest, which comprises approximately 300 ha of land covered mainly by forests and to a lesser extend by shrubs and pastures. The Observatory aims primarily at the assessment of the carbon and water balance of this typical low-elevation forest ecosystem to the ongoing climatic shift. Such ecosystems may be prone to the intensified heat and drought events, as well as to the associated insects’ and pathogens’ outbreaks, which are increasingly occurring at the Mediterranean region and particularly at its eastern part. Although Aleppo pines, as well as other Mediterranean pines, are generally adapted to the region’s xerothermic conditions, the in-depth understanding of their ecophysiological and growth responses will allow us to predict the potential of such ecosystems to adapt to climate change. SEO also serves to assess the carbon stocks and fluxes and the contribution of these natural, old-growth ecosystems to carbon sequestration and, thus, to climate change mitigation. S.E.O. is developed by the Forest Research Institute (Lab of Forest Ecophysiology) of the Hellenic Agricultural Organization Dimitra with the support of Sani Resort SA, the owner of the studied forest ecosystem, presenting a nice example of collaboration between the research community and the private sector. Given that SEO is located at a region of high touristic and aesthetic value, close to a wetland and the sea, the Observatory also plans actions to familiarize people with environmental monitoring and the multiple functions and services of the studied Mediterranean ecosystem.

The site Klausen-Leopoldsdorf is part of the European Level II Forest Monitoring System in the frame of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). The site was established in 1995 and is, since 2006, part of the LTER Austria network. It is situated in a homogenous 80 years-old managed beech stand about 20km west of Vienna. The LTER-CWN research area in Klausenleopoldsdorf is divided into 3 subplots: a measuring weir, a dendrometer/sapflow measuring facility and GHG-chambers for measuring the fluxes of CO2 and other relevant GHG´s. All 3 subplots were installed in 2019 to collect high-resolution data. The measuring weir is located at about 475m a.s.l and the other subplots (denrometer/sapflow, GHG measuring chambers) are located at about 510m a.s.l. The observed catchment of the measuring weir has an area of 46 hectares. The dominating soil types in the catchment are Planosoils and Stagnosols. The subplots are situated in the near vicinity of the ICP-forest plot.

Berchtesgaden National Park was established in 1978 and is the only German national park located at the Alps. It comprises three major valleys and covers an elevantional range from 600 to 2700 m. Ecosystems include montane mixed forest and subalpine coniferous forest, alpine grasslands, pastures and rocky habitats. The Department for Research and Monitoring is linked to the Techincal University of Munich. It conducts monitoring on climate, hydrology, ecosystem dynamics and biodiversity. Main research topics include drivers of natural ecosystem dynamics, human impacts on ecosystems and climate change effects on ecosystems.

The Cairngorms National Park is one of 15 National Parks in the UK (one of two in Scotland) and is Britain's largest National Park (4,528 km2). It is the location for some of the most spectacular landscapes in Britain and is home to an incredible diversity of wildlife and plants. http://cairngorms.co.uk/the-park/facts-figures/ The aims of the National Park are: • To conserve and enhance the natural and cultural heritage of the area; • To promote sustainable use of the natural resources of the area; • To promote understanding and enjoyment (including enjoyment in the form of recreation) of the special qualities of the area by the public; • To promote sustainable economic and social development of the area’s communities. Cairngorms National Park, seven broad habitats can be identified: • Enclosed farmlands • Woodlands • Open waters (rivers, lochs, wetlands and floodplains) • Mountains • Moorland • Semi-natural grasslands • Urban • Population of c17,500 • 25.8% of population over 60 (higher than Scottish average) • Average health index in top 25% of Scotland (based on deprivation indices) • Extensive core paths network • 55 Munros including 5 summits over 4000 feet • 3 ski centres • National Cycle Network Route 7 • 1 Long Distance Route (Speyside Way) • Relatively low atmospheric pollution • Annual precipitation over 2250mm on summits and under 900mm in straths • Average annual snow cover 200 days on summits and 50 days on low-ground • Prevailing winds from south-west

Monitoring stations in Aukštaitija NP started functioning in 1993. Aukstaitija station (LT01) was founded in strict reserve zone of Aukstaitija national park in Ažvinčių old forest, Versminis river closed basin. The area of the basin is 101.5 ha. The lowest place is at 159.5 m, the highest - 188.6 m above sea level. Geographical co-ordinates of the basin are: longitude - 26*03*20* - 26*04*50*, latitude - 55*26*00* - 55*26*53*. The climate is characterised as average cold with high humidity and abundant precipitation. The average air temperature is 5.8 C, average precipitation - 682 mm. Length of vegetation period - 189 days. Side glavioacvalic accumulation forms with sand, gravel and stones are typical for river basin and in the western part of the basin, with the decrease of surface altitude transfers into fliuvioglacial terrace delta plain with fine sand, and at the source- into marsh accumulation forms with organic sediments. At the eastern side of the basin, which has higher altitudes, the typical for this basin glavioacvalic accumulation forms transfer into gravel sand. Carbonates start foaming at 45 cm depth (Gulbinas et al., 1996). The saturation of the river water with the oxygen is very weak. The average yearly oxygen concentration equals to 2.9 mg/l (minimal allowable concentration – 6 mg/l). The pH value of the water fluctuates from 7.10-7.75 mg/l, which indicates the alkalisation of the water. Concentration of hydro-carbonate ions varies in the intervals of 148-224 mg/l. Concentrations of sulphates and chlorides are very small. Calcium and magnesium ions are dominating in the media of cations. Concentration of natrium ions is insignificant – 2 mg/l 9DLK=120 mg/l), concentration of kalium ions reaches only tenths of mg/l (DLK=50 mg/l). According to the size of mineralisation the river water could be described as having average mineralisation levels. Concentrations of nitrogen materials (ammonium nitrogen, nitrates) are small, compared to maximum allowable concentrations (DLK) set for surface waters. Concentrations of phosphates are small. Silicium concentrations fluctuate from 2 mg/l to 9 mg/l (Čeponienė, 1997). Main ecosystems Coniferous multi-layered forest stands are prevailing in the basin, which are mainly pine trees with a mixture of spruce. Those stands usually have a second and third tree layer with abundant under layer vegetation. Spruce stands are also of complicated structure. The second and third spruce layer with abundant under layer vegetation are common. Remarkable amounts of territory are occupied by mixed conifer-deciduous or mixed conifer forests. Pure birch stands in more wet habitats in the vicinity of Versminis river source can also be found. According to the forest stand age they are old pure overmature or with accompanying forest stands of several age classes. It is mainly multi-aged and multi-layered over mature pine and spruce stands. In addition The study was based on monitoring data on crown defoliation of more than 3000 Scots pine (Pinus sylvestris L.) trees from 20 permanent observation stands (POS) annually obtained between 1994 and 2009 in Aukstaitija national park (ANP), located in the eastern part of Lithuania (Fig. 1). Over 16yr period mean values of crown defoliation of every sample pine stand were computed annually. Therefore the total number of treatments made N=320. These stands were classified according to stand maturity: 4 sapling stands (45 to 50 years – Table 1, section “Stand maturity”, group 1), 5 middle aged stands (61 – 80 years – group 2), 4 premature stands (81-100 years – group 3), 3 mature stands (101-120 years – group 4) and 4 over mature stands (> 121 years – group 5). Main characteristics of the considered stands are compiled in table 1. All stands represent the prevailing in Lithuania Pinetum vaccinio-myrtilosum forest type.

Beech forest in the Central italian Apennines